Sample records for flared processing losses

  1. Reduction of Hydrocarbon Losses to Flare Systems

    E-Print Network [OSTI]

    Page, J.

    1979-01-01T23:59:59.000Z

    merit consideration because the losses and associated economic penalties are assumed to be small. Flare gas flow is not easily measured and as a result, most plants are unaware of how much product they are actually losing during normal operation...

  2. Flare System Optimization

    E-Print Network [OSTI]

    Aegerter, R.

    Flare losses are typically the largest source of variable losses in a refinery or chemical plant. Since most plant flare systems are complex, there can be many opportunities to reduce costs. Losses to the flare can include process gases, fuel gas...

  3. Automatic Solar Flare Tracking Using Image Processing Qu Ming and Shih Frank (shih@njit.edu)

    E-Print Network [OSTI]

    Automatic Solar Flare Tracking Using Image Processing Techniques Qu Ming and Shih Frank (shih Center for Solar-Terrestrial Research, New Jersey Institute of Technology Newark, NJ 07102 Big Bear Solar Abstract. Measurement of the evolution properties of solar flares through their complete cyclic development

  4. UNDERSTANDING THE IMPACT OF RETURN-CURRENT LOSSES ON THE X-RAY EMISSION FROM SOLAR FLARES

    SciTech Connect (OSTI)

    Holman, Gordon D., E-mail: Gordon.D.Holman@nasa.gov [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

    2012-01-20T23:59:59.000Z

    I obtain and examine the implications of one-dimensional analytic solutions for return-current losses on an initially power-law distribution of energetic electrons with a sharp low-energy cutoff in flare plasma with classical (collisional) resistivity. These solutions show, for example, that return-current losses are not sensitive to plasma density, but are sensitive to plasma temperature and the low-energy cutoff of the injected nonthermal electron distribution. A characteristic distance from the electron injection site, x{sub rc}, is derived. At distances less than x{sub rc} the electron flux density is not reduced by return-current losses, but plasma heating can be substantial in this region, in the upper, coronal part of the flare loop. Before the electrons reach the collisional thick-target region of the flare loop, an injected power-law electron distribution with a low-energy cutoff maintains that structure, but with a flat energy distribution below the cutoff energy, which is now determined by the total potential drop experienced by the electrons. Modifications due to the presence of collisional losses are discussed. I compare these results with earlier analytical results and with more recent numerical simulations. Emslie's conjecture that there is a maximum integrated X-ray source brightness on the order of 10{sup -15} photons cm{sup -2} s{sup -1} cm{sup -2} is examined. I find that this is not actually the maximum brightness and its value is parameter dependent, but it is nevertheless a valuable benchmark for identifying return-current losses in hard X-ray spectra. I discuss an observational approach to identifying return-current losses in flare data, including identification of a return-current 'bump' in X-ray light curves at low photon energies.

  5. Reducing Safety Flaring through Advanced Control 

    E-Print Network [OSTI]

    Hokanson, D.; Lehman, K.; Matsumoto, S.; Takai, N.; Takase, F.

    2010-01-01T23:59:59.000Z

    An advanced process control application, using DMCplus® (Aspen Technology, Inc.), was developed to substantially reduce fuel gas losses to the flare at a large integrated refining / petrochemical complex. Fluctuations in internal fuel gas system...

  6. Reducing Safety Flaring through Advanced Control

    E-Print Network [OSTI]

    Hokanson, D.; Lehman, K.; Matsumoto, S.; Takai, N.; Takase, F.

    2010-01-01T23:59:59.000Z

    An advanced process control application, using DMCplus® (Aspen Technology, Inc.), was developed to substantially reduce fuel gas losses to the flare at a large integrated refining / petrochemical complex. Fluctuations in internal fuel gas system...

  7. Numerical Study of Magnetic Reconnection Processes in Solar Flares

    E-Print Network [OSTI]

    Chen, P. F.

    for not writing in my native language--Chinese, which I love so deeply. I would feel the greatest happiness solar physics group. Special thanks go to Prof. Y. Q. Hu at University of Science and Technology;Extended Abstract The solar flare represents a sudden release of energy (1029­1033 erg within 100­1000 s

  8. Diagnostics of the Heating Processes in Solar Flares Using Chromospheric Spectral Lines

    E-Print Network [OSTI]

    J. X. Cheng; M. D. Ding; J. P. Li

    2006-09-25T23:59:59.000Z

    We have calculated the H$\\alpha$ and Ca {\\sc ii} 8542 {\\AA} line profiles based on four different atmospheric models, including the effects of nonthermal electron beams with various energy fluxes. These two lines have different responses to thermal and nonthermal effects, and can be used to diagnose the thermal and nonthermal heating processes. We apply our method to an X-class flare that occurred on 2001 October 19. We are able to identify quantitatively the heating effects during the flare eruption. We find that the nonthermal effects at the outer edge of the flare ribbon are more notable than that at the inner edge, while the temperature at the inner edge seems higher. On the other hand, the results show that nonthermal effects increase rapidly in the rise phase and decrease quickly in the decay phase, but the atmospheric temperature can still keep relatively high for some time after getting to its maximum. For the two kernels that we analyze, the maximum energy fluxes of the electron beams are $\\sim$ 10$^{10}$ and 10$^{11}$ ergs cm$^{-2}$ s$^{-1}$, respectively. However, the atmospheric temperatures are not so high, i.e., lower than or slightly higher than that of the weak flare model F1 at the two kernels. We discuss the implications of the results for two-ribbon flare models.

  9. A common stochastic process rules gamma-ray burst prompt emission and X-ray flares

    E-Print Network [OSTI]

    Guidorzi, C; Frontera, F; Margutti, R; Baldeschi, A; Amati, L

    2015-01-01T23:59:59.000Z

    Prompt gamma-ray and early X-ray afterglow emission in gamma-ray bursts (GRBs) are characterized by a bursty behavior and are often interspersed with long quiescent times. There is compelling evidence that X-ray flares are linked to prompt gamma-rays. However, the physical mechanism that leads to the complex temporal distribution of gamma-ray pulses and X-ray flares is not understood. Here we show that the waiting time distribution (WTD) of pulses and flares exhibits a power-law tail extending over 4 decades with index ~2 and can be the manifestation of a common time-dependent Poisson process. This result is robust and is obtained on different catalogs. Surprisingly, GRBs with many (>=8) gamma-ray pulses are very unlikely to be accompanied by X-ray flares after the end of the prompt emission (3.1 sigma Gaussian confidence). These results are consistent with a simple interpretation: an hyperaccreting disk breaks up into one or a few groups of fragments, each of which is independently accreted with the same pro...

  10. Partonic Energy Loss and the Drell-Yan Process

    E-Print Network [OSTI]

    G. T. Garvey; J. C. Peng

    2003-01-31T23:59:59.000Z

    We examine the current status of the extraction of the rate of partonic energy loss in nuclei from A dependent data. The advantages and difficulties of using the Drell-Yan process to measure the energy loss of a parton traversing a cold nuclear medium are discussed. The prospects of using relatively low energy proton beams for a definitive measurement of partonic energy loss are presented.

  11. Evolution of the Loop-Top Source of Solar Flares--Heating and Cooling Processes

    E-Print Network [OSTI]

    Yan Wei Jiang; Siming Liu; Wei Liu; Vahe Petrosian

    2005-08-24T23:59:59.000Z

    We present a study of the spatial and spectral evolution of the loop-top (LT) sources in a sample of 6 flares near the solar limb observed by {\\it RHESSI}. A distinct coronal source, which we identify as the LT source, was seen in each of these flares from the early ``pre-heating'' phase through the late decay phase. Spectral analyses reveal an evident steep power-law component in the pre-heating and impulsive phases, suggesting that the particle acceleration starts upon the onset of the flares. In the late decay phase the LT source has a thermal spectrum and appears to be confined within a small region near the top of the flare loop, and does not spread throughout the loop, as is observed at lower energies. The total energy of this source decreases usually faster than expected from the radiative cooling but much slower than that due to the classical Spitzer conductive cooling along the flare loop. These results indicate the presence of a distinct LT region, where the thermal conductivity is suppressed significantly and/or there is a continuous energy input. We suggest that plasma wave turbulence could play important roles in both heating the plasma and suppressing the conduction during the decay phase of solar flares. With a simple quasi-steady loop model we show that the energy input in the gradual phase can be comparable to that in the impulsive phase and demonstrate how the observed cooling and confinement of the LT source can be used to constrain the wave-particle interaction.

  12. Is FLARE for Solar flare?

    E-Print Network [OSTI]

    D. Fargion

    2005-12-07T23:59:59.000Z

    The Fermi Lab Liquid ARgon experiment, FLARE, a huge neutrino argon-liquid project detector of 50 kt mass, might in a near future enlarge the neutrino telescope accuracy revealing in detail solar, supernova, atmospheric as well as largest solar flares neutrino. Indeed the solar energetic (E_p > 100 MeVs) flare particles (protons, alpha) while scattering among themselves or hitting the solar atmosphere must produce on sun prompt charged pions, whose decay (as well as their sequent muon decays) into secondaries is source of a copious solar neutrino "flare" (at tens or hundreds MeV energy). These brief (minutes) neutrino "burst" at largest flare peak may overcome by three to five order of magnitude the steady atmospheric neutrino noise on the Earth, possibly leading to their emergence and detection above the thresholds. The largest prompt "burst" solar neutrino flare may be detected in future FLARE neutrino detectors both in electron and positron and possibly in its muon pair neutrino component. Our estimate for the recent and exceptional October - November 2003 solar flares and last January 20th 2005 exceptional flare might lead to a few events for future FLARE or near unity for present Super-KamiokandeII. The neutrino spectra may reflect the neutrino flavor oscillations and mixing in flight. In neutrino detectors a surprising (correlated) muon appearance may occur while a rarer tau appearance may even marginally take place. A comparison of the solar neutrino flare signal with other neutrino foreground is estimated: it offer the first opportunity for an independent road map to disentangle the neutrino flavor puzzles, as well a prompt alarm system for dangerous solar flare eruptions.

  13. Energy Loss in Nuclear Drell-Yan Process

    E-Print Network [OSTI]

    Jian-Jun Yang; Guang-Lie Li

    1998-05-21T23:59:59.000Z

    By means of the nuclear parton distributions which can be used to provide a good explanation for the EMC effect in the whole x range, we investigate the energy loss effect in nuclear Drell-Yan process. When the cross section of lepton pair production is considered varying with the center-of-mass energy of the nucleon-nucleon collision, we find that the nuclear Drell-Yan(DY) ratio is suppressed due to the energy loss, which balances the overestimate of the DY ratio only in consideration of the effect of nuclear parton distributions.

  14. Method for reducing iron losses in an iron smelting process

    DOE Patents [OSTI]

    Sarma, Balu (Airmont, NY); Downing, Kenneth B. (Greenville, SC)

    1999-01-01T23:59:59.000Z

    A process of smelting iron that comprises the steps of: a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; b) maintaining conditions in said reactor to cause (i) at least some of the iron oxide to be chemically reduced, (ii) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (iii) carbon monoxide gas to rise through the slag; c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: e) keep the temperature of the molten iron at or below about 1550.degree. C. and f) keep the slag weight at or above about 0.8 tonne per square meter.

  15. Method for reducing iron losses in an iron smelting process

    DOE Patents [OSTI]

    Sarma, B.; Downing, K.B.

    1999-03-23T23:59:59.000Z

    A process of smelting iron that comprises the steps of: (a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; (b) maintaining conditions in said reactor to cause (1) at least some of the iron oxide to be chemically reduced, (2) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (3) carbon monoxide gas to rise through the slag; (c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and (d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: (1) keep the temperature of the molten iron at or below about 1550 C and (2) keep the slag weight at or above about 0.8 ton per square meter. 13 figs.

  16. Cryogenic loss monitors with FPGA TDC signal processing

    SciTech Connect (OSTI)

    Warner, A.; Wu, J.; /Fermilab

    2011-09-01T23:59:59.000Z

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highlight the processing techniques used.

  17. Hyperaccretion after the Blandford-Znajek Process: a New Model for GRBs with X-Ray Flares Observed in Early Afterglows

    E-Print Network [OSTI]

    Wei-Hua Lei; Ding-Xiong Wang; Yuan-Chuan Zou; Lei Zhang

    2008-02-04T23:59:59.000Z

    We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is powered by a rotating black hole (BH) invoking the BZ process. The second stage is a quiet stage, in which the BZ process is shut off, and the accretion onto the BH is depressed by the torque exerted by the magnetic coupling (MC) process. Part of the rotational energy transported by the MC process from the BH is stored in the disk as magnetic energy. In the third stage, the MC process is shut off when the magnetic energy in the disk accumulates and triggers the magnetic instability. At this moment, the hyperaccretion process may onset, and the jet launched in this restarted central engine generates the observed X-ray flares. This model can account for energies and timescales of GRBs with X-ray flares observed in early afterglows.

  18. Particle-acceleration timescales in TeV blazar flares

    E-Print Network [OSTI]

    Joni Tammi; Peter Duffy

    2008-12-01T23:59:59.000Z

    Observations of minute-scale flares in TeV Blazars place constraints on particle acceleration mechanisms in those objects. The implications for a variety of radiation mechanisms have been addressed in the literature; in this paper we compare four different acceleration mechanisms: diffusive shock acceleration, second-order Fermi, shear acceleration and the converter mechanism. When the acceleration timescales and radiative losses are taken into account, we can exclude shear acceleration and the neutron-based converted mechanism as possible acceleration processes in these systems. The first-order Fermi process and the converter mechanism working via SSC photons are still practically instantaneous, however, provided sufficient turbulence is generated on the timescale of seconds. We propose stochastic acceleration as a promising candidate for the energy-dependent time delays in recent gamma-ray flares of Markarian 501.

  19. Estimating Water Quality Pollution Impacts Based on Economic Loss Models in Urbanization Process

    E-Print Network [OSTI]

    Yu, Qian

    . Research has targeted the assessment toward economic loss evaluation Grossman and Alan 1995; Ofiara 2001Estimating Water Quality Pollution Impacts Based on Economic Loss Models in Urbanization Process and spatial characteristics of different water quality parameters, and simulating economic loss of water

  20. OVERVIEW OF SOLAR FLARES The Yohkoh Perspective

    E-Print Network [OSTI]

    Hudson, Hugh

    that solar flares begin with high-energy processes. The key elements are accelerated particlesChapter 8 OVERVIEW OF SOLAR FLARES The Yohkoh Perspective Hugh Hudson Space Sciences Laboratory, UC of Glasgow, Glasgow G12 8QQ, Scotland, U.K. lyndsay@astro.gla.ac.uk Josef I. Khan Dept. of Physics

  1. OVERVIEW OF SOLAR FLARES The Yohkoh Perspective

    E-Print Network [OSTI]

    California at Berkeley, University of

    observations from space from the 1960s, revealed that solar flares begin with high-energy processes. The keyChapter 8 OVERVIEW OF SOLAR FLARES The Yohkoh Perspective Hugh Hudson Space Sciences Laboratory, UC of Glasgow, Glasgow G12 8QQ, Scotland, U.K. lyndsay@astro.gla.ac.uk Josef I. Khan Dept. of Physics

  2. Particle Acceleration by Fast Modes in Solar Flares

    E-Print Network [OSTI]

    Huirong Yan; A. Lazarian; V. Petrosian

    2008-05-08T23:59:59.000Z

    We address the problem of particle acceleration in solar flares by fast modes which may be excited during the reconnection and undergo cascade and are subjected to damping. We extend the calculations beyond quasilinear approximation and compare the acceleration and scattering by transit time damping and gyroresonance interactions. We find that the acceleration is dominated by the so called transit time damping mechanism. We estimate the total energy transferred into particles, and show that our approach provides sufficiently accurate results We compare this rate with energy loss rate. Scattering by fast modes appears to be sufficient to prevent the protons from escaping the system during the acceleration. Confinement of electrons, on the other hand, requires the existence of plasma waves. Electrons can be accelerated to GeV energies through the process described here for solar flare conditions.

  3. Gel and process for preventing loss of circulation, and combination process for enhanced recovery

    SciTech Connect (OSTI)

    Sandiford, B.B.; Zillmer, R.C.

    1987-02-17T23:59:59.000Z

    A process is described for reducing the loss of circulation fluids into flow passages of a subterranean formation during well drilling, completion, or workover operations, the circulation fluids being selected from the group consisting of drilling fluids, completion fluids and workover fluids. The process comprises: (a) stopping the injection of a circulation fluid selected from the group consisting of drilling fluids, completion fluids and workover fluids into a wellbore; (b) introducing into the flow passages, an effective amount of a gel-forming composition comprising i. an aqueous solution comprising a first substance selected from the group consisting of polyvinyl alcohols, polyvinyl alcohol copolymers, and mixtures thereof, ii. an amount of an aldehyde, and iii. an amount of a crosslinking catalyzing substance, which in combination with the aqueous solution and the aldehyde is operable for effecting gelation, at the temperature of the subterranean formation, of the gel-forming composition in a period of time no greater than about 12 minutes after being introduced into the subterranean formation; and (c) allowing the gel-forming composition to enter into the flow passages and to form a gel therein within the period of time mentioned in step (b), thereby reducing the loss of the circulation fluid upon resuming well drilling, completion or workover operation.

  4. Process and design techniques for low loss integrated silicon photonics

    E-Print Network [OSTI]

    Sparacin, Daniel Knight

    2006-01-01T23:59:59.000Z

    Microprocessors have truly revolutionized the efficiency of the world due to the high-volume and low-cost of complimentary metal oxide semiconductor (CMOS) process technology. However, the traditional scaling methods by ...

  5. Cryogenic loss monitors with FPGA TDC signal processing

    E-Print Network [OSTI]

    Warner, A

    2012-01-01T23:59:59.000Z

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highligh...

  6. Sauget Plant Flare Gas Reduction Project

    E-Print Network [OSTI]

    Ratkowski, D. P.

    2007-01-01T23:59:59.000Z

    Empirical analysis of stack gas heating value allowed the Afton Chemical Corporation Sauget Plant to reduce natural gas flow to its process flares by about 50% while maintaining the EPA-required minimum heating value of the gas streams....

  7. Achieve smokeless flaring -- Air or steam assist?

    SciTech Connect (OSTI)

    Chaudhuri, M.; Diefenderfer, J.J.

    1995-06-01T23:59:59.000Z

    Because of the technological advances made during the past several years, flare system design has become more important with respect to the economics of plant operation. There are many options available to the engineer during the initial design phase of a flare system for a chemical process industries (CPI) plant. An earlier CEP article covered the basics of flare design and how to choose and size the right equipment, such as stack height and diameter, tip design, pilots and pilots flame detectors, seals, and so on. One of the most important factors is how to achieve smokeless operation, which is accomplished by either steam-assisted or air-assisted elevated flare stack assemblies. This article compares the two approaches and outlines the advantages and disadvantages of each with respect to economics, practicality, and operability. Table 1 summarizes the data for a typical plant in the U.S. Gulf Coast area that will be used as the basis for comparing costs.

  8. Energy Loss Effect in High Energy Nuclear Drell-Yan Process

    E-Print Network [OSTI]

    Chun-Gui Duan; Li-Hua Song; Li-Juan Huo; Guang-Lie Li

    2004-05-13T23:59:59.000Z

    The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effect on the parton distribution as in deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of the nuclear parton distribution studied only with lepton deep inelastic scattering experimental data, measured Drell-Yan production cross sections for 800GeV proton incident on a variety of nuclear targets are analyzed within Glauber framework which takes into account energy loss of the beam proton. It is shown that the theoretical results with considering the energy loss effect are in good agreement with the FNAL E866.

  9. Model-Based Control of Nonlinear Systems Subject to Sensor Data Losses: A Chemical Process Case Study

    E-Print Network [OSTI]

    Sontag, Eduardo

    Model-Based Control of Nonlinear Systems Subject to Sensor Data Losses: A Chemical Process Case, Los Angeles, CA 90095-1592, USA, davidmps@ucla.edu, pdc@seas.ucla.edu. Controller Process x Data feedback control of nonlinear uncertain systems subject to sensor data losses. We compare three different

  10. Flare Ribbon Energetics in the Early Phase of an SDO Flare

    E-Print Network [OSTI]

    Fletcher, L; Hudson, H S; Innes, D E

    2014-01-01T23:59:59.000Z

    The sites of chromospheric excitation during solar flares are marked by extended extreme ultraviolet ribbons and hard X-ray footpoints. The standard interpretation is that these are the result of heating and bremsstrahlung emission from non-thermal electrons precipitating from the corona. We examine this picture using multi-wavelength observations of the early phase of an M-class flare SOL2010-08-07T18:24. We aim to determine the properties of the heated plasma in the flare ribbons, and to understand the partition of the power input into radiative and conductive losses. Using GOES, SDO/EVE, SDO/AIA and RHESSI we measure the temperature, emission measure and differential emission measure of the flare ribbons, and deduce approximate density values. The non-thermal emission measure, and the collisional thick target energy input to the ribbons are obtained from RHESSI using standard methods. We deduce the existence of a substantial amount of plasma at 10 MK in the flare ribbons, during the pre-impulsive and early...

  11. Parameterization of solar flare dose 

    E-Print Network [OSTI]

    Lamarche, Anne Helene

    1995-01-01T23:59:59.000Z

    A critical aspect of missions to the Moon or Mars is the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare ...

  12. Solar Flares and particle acceleration

    E-Print Network [OSTI]

    of Glasgow, UK STFC Summer School, Armagh, 2012 #12;Solar flares: basics X-raysradiowavesParticles1AU Figure energy ~2 1032 ergs #12;"Standard" model of a solar flare/CME Solar corona T ~ 106 K => 0.1 keV per MeV Proton energies >100 MeV Large solar flare releases about 1032 ergs (about half energy

  13. XMM-Newton Data Processing for Faint Diffuse Emission: Proton Flares, Exposure Maps and Report on EPIC MOS1 Bright CCDs Contamination

    E-Print Network [OSTI]

    J. Pradas; J. Kerp

    2005-08-04T23:59:59.000Z

    We present a study of the in-flight performance of the XMM-Newton EPIC MOS and pn detectors, with focus on the influence of proton flares and vignetting on the data. The very wide range in the conditions of our sample of observations, in terms of exposure length and background intensities, allows the detection of a wide range in the spectra of the proton flares, in contrast to the hard-spectrum flares proposed by Lumb et al.(2002) or Read et al.(2003) We also find an up to now unreported contamination in the low energy regime (Econtamination yields in "bright CCDs" in the observations. Its effect must be taken into account for the study of sources detected in the affected CCDs. With respect to vignetting, we present in-flight exposure maps and we propose a method to repeat this calculation for user-definable energy bands. All the results presented here, have the goal to enable the study of very faint extended sources with XMM-Newton, like nearby galactic X-ray halos or the soft X-ray background.

  14. Gamma-ray burst flares: X-ray flaring. II

    SciTech Connect (OSTI)

    Swenson, C. A.; Roming, P. W. A., E-mail: cswenson@astro.psu.edu [Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2014-06-10T23:59:59.000Z

    We present a catalog of 498 flaring periods found in gamma-ray burst (GRB) light curves taken from the online Swift X-Ray Telescope GRB Catalogue. We analyzed 680 individual light curves using a flare detection method developed and used on our UV/optical GRB Flare Catalog. This method makes use of the Bayesian Information Criterion to analyze the residuals of fitted GRB light curves and statistically determines the optimal fit to the light curve residuals in an attempt to identify any additional features. These features, which we classify as flares, are identified by iteratively adding additional 'breaks' to the light curve. We find evidence of flaring in 326 of the analyzed light curves. For those light curves with flares, we find an average number of ?1.5 flares per GRB. As with the UV/optical, flaring in our sample is generally confined to the first 1000 s of the afterglow, but can be detected to beyond 10{sup 5} s. Only ?50% of the detected flares follow the 'classical' definition of ?t/t ? 0.5, with many of the largest flares exceeding this value.

  15. Readout process and noise elimination firmware for the Fermilab beam loss system

    SciTech Connect (OSTI)

    Wu, Jinyuan; Baumbaugh, Alan; Drennan, Craig; Thurman-Keup, Randy; Lewis, Jonathan; Shi, Zonghan; /Fermilab

    2007-05-01T23:59:59.000Z

    In the Fermilab Beam Loss Monitor System, inputs from ion chambers are integrated for a short period of time, digitized and processed to create the accelerator abort request signals. The accelerator power supplies employing 3-phase 60Hz AC cause noise at various harmonics on our inputs which must be eliminated for monitoring purposes. During accelerator ramping, both the sampling frequency and the amplitudes of the noise components change. As such, traditional digital filtering can partially reduce certain noise components but not all. A nontraditional algorithm was developed in our work to eliminate remaining ripples. The sequencing in the FPGA firmware is conducted by a micro-sequencer core we developed: the Enclosed Loop Micro-Sequencer (ELMS). The unique feature of the ELMS is that it supports the ''FOR'' loops with pre-defined iterations at the machine code level, which provides programming convenience and avoids many micro-complexities from the beginning.

  16. Soft X-ray Pulsations in Solar Flares

    E-Print Network [OSTI]

    Simões, Paulo J A; Fletcher, Lyndsay

    2014-01-01T23:59:59.000Z

    The soft X-ray emissions of solar flares come mainly from the bright coronal loops at the highest temperatures normally achieved in the flare process. Their ubiquity has led to their use as a standard measure of flare occurrence and energy, although the bulk of the total flare energy goes elsewhere. Recently Dolla et al. (2012) noted quasi-periodic pulsations (QPP) in the soft X-ray signature of the X-class flare SOL2011-02-15, as observed by the standard photometric data from the GOES (Geostationary Operational Environmental Satellite) spacecraft. We analyze the suitability of the GOES data for this kind of analysis and find them to be generally valuable after Sept. 2010 (GOES-15). We then extend Dolla et al. results to a list of X-class flares from Cycle 24, and show that most of them display QPP in the impulsive phase. During the impulsive phase the footpoints of the newly-forming flare loops may also contribute to the observed soft X-ray variations. The QPP show up cleanly in both channels of the GOES dat...

  17. Thermal and non-thermal energies in solar flares

    E-Print Network [OSTI]

    Pascal Saint-Hilaire; Arnold O. Benz

    2005-03-03T23:59:59.000Z

    The energy of the thermal flare plasma and the kinetic energy of the non-thermal electrons in 14 hard X-ray peaks from 9 medium-sized solar flares have been determined from RHESSI observations. The emissions have been carefully separated in the spectrum. The turnover or cutoff in the low-energy distribution of electrons has been studied by simulation and fitting, yielding a reliable lower limit to the non-thermal energy. It remains the largest contribution to the error budget. Other effects, such as albedo, non-uniform target ionization, hot target, and cross-sections on the spectrum have been studied. The errors of the thermal energy are about equally as large. They are due to the estimate of the flare volume, the assumption of the filling factor, and energy losses. Within a flare, the non-thermal/thermal ratio increases with accumulation time, as expected from loss of thermal energy due to radiative cooling or heat conduction. Our analysis suggests that the thermal and non-thermal energies are of the same magnitude. This surprising result may be interpreted by an efficient conversion of non-thermal energy to hot flare plasma.

  18. Smokeless Control of Flare Steam Flow Rate

    E-Print Network [OSTI]

    Agar, J.; Balls, B. W.

    1979-01-01T23:59:59.000Z

    the First Industrial Energy Technology Conference Houston, TX, April 22-25, 1979 FLARE GAS FLOW RATE MEASUREMENT "Accurate measurement of the very low flow rates which are normally present is very difficult" 0, p 15-8). "It is generally considered too...-04-91 Proceedings from the First Industrial Energy Technology Conference Houston, TX, April 22-25, 1979 to calibration conditions. Turndown is 40:1 and pressure loss is negligible. APPLICATION FLOW RATE The mass flow meter described has been applied to a wide...

  19. Interferometric at-wavelength flare characterization of EUV optical systems

    DOE Patents [OSTI]

    Naulleau, Patrick P. (Oakland, CA); Goldberg, Kenneth Alan (Berkeley, CA)

    2001-01-01T23:59:59.000Z

    The extreme ultraviolet (EUV) phase-shifting point diffraction interferometer (PS/PDI) provides the high-accuracy wavefront characterization critical to the development of EUV lithography systems. Enhancing the implementation of the PS/PDI can significantly extend its spatial-frequency measurement bandwidth. The enhanced PS/PDI is capable of simultaneously characterizing both wavefront and flare. The enhanced technique employs a hybrid spatial/temporal-domain point diffraction interferometer (referred to as the dual-domain PS/PDI) that is capable of suppressing the scattered-reference-light noise that hinders the conventional PS/PDI. Using the dual-domain technique in combination with a flare-measurement-optimized mask and an iterative calculation process for removing flare contribution caused by higher order grating diffraction terms, the enhanced PS/PDI can be used to simultaneously measure both figure and flare in optical systems.

  20. Flare Gas Recovery in Shell Canada Refineries

    E-Print Network [OSTI]

    Allen, G. D.; Wey, R. E.; Chan, H. H.

    1983-01-01T23:59:59.000Z

    the flow properties for compressor selection? What controls should be incorporated? How much operator and maintenance effort will be required for safe, efficient operation? What kind of process and hardware problems should be watched for? When...? This paper will touch on all these issues. SYSTEM CONFIGURATION A schematic of a typical refinery flare gas recovery facility is shown in Figure I. The facilities include the following pieces of equipment: - compressor suction drum - compressor set...

  1. Transition Region Emission and Energy Input to Thermal Plasma During the Impulsive Phase of Solar Flares

    E-Print Network [OSTI]

    J. C. Raymond; G. Holman; A. Ciaravella; A. Panasyuk; Y. -K. Ko; J. Kohl

    2007-01-12T23:59:59.000Z

    The energy released in a solar flare is partitioned between thermal and non-thermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the energy radiated at transition region temperatures during the impulsive phases of flares. We use UVCS measurements of O VI photons produced by 5 flares and subsequently scattered by O VI ions in the corona to determine the 5.0 thermal energy and the conductive losses deduced from RHESSI and GOES X-ray data using areas from RHESSI images to estimate the loop volumes, cross-sectional areas and scale lengths. The transition region luminosities during the impulsive phase exceed the X-ray luminosities for the first few minutes, but they are smaller than the rates of increase of thermal energy unless the filling factor of the X-ray emitting gas is ~ 0.01. The estimated conductive losses from the hot gas are too large to be balanced by radiative losses or heating of evaporated plasma, and we conclude that the area of the flare magnetic flux tubes is much smaller than the effective area measured by RHESSI during this phase of the flares. For the 2002 July 23 flare, the energy deposited by non-thermal particles exceeds the X-ray and UV energy losses and the rate of increase of the thermal energy.

  2. Integration of analysis and experiment for Stirling cycle processes: Part 1, Gas spring hysteresis loss

    SciTech Connect (OSTI)

    Kornhauser, A.A.; Smith, J.L. Jr.

    1988-01-01T23:59:59.000Z

    Heat transfer-related hysteresis loss can be an important factor in the performance of Stirling and other reciprocating machines. Analytical predictions of hysteresis loss have been available to designers, but until now they were not experimentally verified. Hysteresis loss was measured in a piston-cylinder gas spring over a range of speeds, pressures, gases, bore/stroke ratios, volume ratios, and internal extended surface geometries. An analysis of a simplified one-dimensional energy equation produced non-dimensional parameters that were used to correlate the experimental data. The loss expression from the analysis was adjusted to fit the correlated data. 7 refs., 8 figs.

  3. Parameterization of solar flare dose

    E-Print Network [OSTI]

    Lamarche, Anne Helene

    1995-01-01T23:59:59.000Z

    A critical aspect of missions to the Moon or Mars is the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very...

  4. Return currents and energy transport in the solar flaring atmosphere

    E-Print Network [OSTI]

    Codispoti, Anna; Piana, Michele; Pinamonti, Nicola

    2013-01-01T23:59:59.000Z

    According to a standard ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated to these local currents has an ohmic nature and significantly shortens the acceleration electron path. In the present paper we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. Specifically, we show that this new formula for the energy l...

  5. Historical Processes and Genetic Implications of Limb Reduction and Loss in an Island Skink Lineage

    E-Print Network [OSTI]

    Siler, Cameron David

    2011-12-31T23:59:59.000Z

    Evolutionary simplification, or loss of complex characters, is a major theme in studies of body form evolution. The apparently infrequent evolutionary reacquisition of complex characters has led to the assertion (Dollo's ...

  6. The impact of personal gains and losses on social identification processes

    E-Print Network [OSTI]

    Iuzzini, Jonathan Lawrence

    1998-01-01T23:59:59.000Z

    This thesis integrates a number of social ge Micrographics. psychological principles to study individual-level benefit (gain) and discrimination (loss) in a group setting. Using a variation of the minimal group paradigm, participants were assigned...

  7. "Memory loss" during mineral processing: application to base metals traceability Julie Machault (1, 2, *), Luc Barbanson (1), Thierry Aug (2), Laurent Bailly (2) et Alexandre

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    processing, target minerals, Neves Corvo. 1 Introduction The demand in mineral resources is increasing" is proposed and the relations between memory loss and global kinetic rate of flotation are established. The "global memory loss", namely as the "the experimental memory loss". For the Neves Corvo plant

  8. THE THERMAL PROPERTIES OF SOLAR FLARES OVER THREE SOLAR CYCLES USING GOES X-RAY OBSERVATIONS

    SciTech Connect (OSTI)

    Ryan, Daniel F.; Gallagher, Peter T. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Milligan, Ryan O.; Dennis, Brian R.; Kim Tolbert, A.; Schwartz, Richard A.; Alex Young, C. [Solar Physics Laboratory (Code 671), Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-10-15T23:59:59.000Z

    Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) on board the Geostationary Operational Environmental Satellite (GOES) have been used to derive these properties, but have been limited by a number of factors, including the lack of a consistent background subtraction method capable of being automatically applied to large numbers of flares. In this paper, we describe an automated Temperature and Emission measure-Based Background Subtraction method (TEBBS), that builds on the methods of Bornmann. Our algorithm ensures that the derived temperature is always greater than the instrumental limit and the pre-flare background temperature, and that the temperature and emission measure are increasing during the flare rise phase. Additionally, TEBBS utilizes the improved estimates of GOES temperatures and emission measures from White et al. TEBBS was successfully applied to over 50,000 solar flares occurring over nearly three solar cycles (1980-2007), and used to create an extensive catalog of the solar flare thermal properties. We confirm that the peak emission measure and total radiative losses scale with background subtracted GOES X-ray flux as power laws, while the peak temperature scales logarithmically. As expected, the peak emission measure shows an increasing trend with peak temperature, although the total radiative losses do not. While these results are comparable to previous studies, we find that flares of a given GOES class have lower peak temperatures and higher peak emission measures than previously reported. The TEBBS database of flare thermal plasma properties is publicly available at http://www.SolarMonitor.org/TEBBS/.

  9. Linearly polarized X-ray flares following short gamma-ray bursts

    E-Print Network [OSTI]

    Y. Z. Fan; Bing Zhang; Daniel Proga

    2005-11-16T23:59:59.000Z

    Soft X-ray flares were detected to follow the short-duration gamma-ray burst GRB 050724. The temporal properties of the flares suggest that they are likely due to the late time activity of the central engine. We argue that if short GRBs are generated through compact star mergers, as is supported by the recent observations, the jet powering the late X-ray flares must be launched via magnetic processes rather than via neutrino-antineutrino annihilations. As a result, the X-ray flares following short GRBs are expected to be linearly polarized. The argument may also apply to the X-ray flares following long GRBs. Future observations with the upcoming X-ray polarimeters will test this prediction.

  10. Konus-Wind and Helicon-Coronas-F Observations of Solar Flares

    E-Print Network [OSTI]

    Pal'shin, V D; Aptekar, R L; Golenetskii, S V; Kokomov, A A; Svinkin, D S; Sokolova, Z Ya; Ulanov, M V; Frederiks, D D; Tsvetkova, A E

    2014-01-01T23:59:59.000Z

    Results of solar flare observations obtained in the Konus-Wind experiment from November, 1994 to December, 2013 and in the Helicon Coronas-F experiment during its operation from 2001 to 2005, are presented. For the periods indicated Konus-Wind detected in the trigger mode 834 solar flares, and Helicon-Coronas-F detected more than 300 solar flares. A description of the instruments and data processing techniques are given. As an example, the analysis of the spectral evolution of the flares SOL2012-11-08T02:19 (M 1.7) and SOL2002-03-10T01:34 (C5.1) is made with the Konus-Wind data and the flare SOL2003-10-26T06:11 (X1.2) is analyzed in the 2.223 MeV deuterium line with the Helicon-Coronas-F data.

  11. From coronal observations to MHD simulations, the building blocks for 3D models of solar flares

    E-Print Network [OSTI]

    Janvier, Miho; Demoulin, Pascal

    2015-01-01T23:59:59.000Z

    Solar flares are energetic events taking place in the Sun's atmosphere, and their effects can greatly impact the environment of the surrounding planets. In particular, eruptive flares, as opposed to confined flares, launch coronal mass ejections into the interplanetary medium, and as such, are one of the main drivers of space weather. After briefly reviewing the main characteristics of solar flares, we summarize the processes that can account for the build up and release of energy during their evolution. In particular, we focus on the development of recent 3D numerical simulations that explain many of the observed flare features. These simulations can also provide predictions of the dynamical evolution of coronal and photospheric magnetic field. Here we present a few observational examples that, together with numerical modelling, point to the underlying physical mechanisms of the eruptions.

  12. Particle acceleration in solar flares: observations versus numerical simulations

    E-Print Network [OSTI]

    Particle acceleration in solar flares: observations versus numerical simulations A O Benz, P C processes such as isotropization and magnetic trapping are made. Keywords: Particle acceleration, hard X. As the electric field of reconnection with possible parallel component capable of particle acceleration is limited

  13. Recovering Flare Gas Energy - A Different Approach

    E-Print Network [OSTI]

    Brenner, W.

    depend on a compressor to pull suction on the pressurized flare line and pump the gas into a plant-wide fuer gas system. Because SunOlin shares its flare system with an adjacent oil refinery, any change to the flare system operation could have far... design and operating scheme incorporating the results of the HAZOP study. The major features of our flare gas recovery system, then, are as follows: A 30" main flare gas header originating in the adjacent oil refinery is routed through the Sun...

  14. Multi-wavelength analysis of high energy electrons in solar flares: a case study of August 20, 2002 flare

    E-Print Network [OSTI]

    J. Kasparova; M. Karlicky; E. P. Kontar; R. A. Schwartz; B. R. Dennis

    2005-08-30T23:59:59.000Z

    A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and MDI observations with advanced methods and techniques never previously applied in the solar flare context. A new method to account for X-ray Compton backscattering in the photosphere (photospheric albedo) has been used to deduce the primary X-ray flare spectra. The mean electron flux distribution has been analysed using both forward fitting and model independent inversion methods of spectral analysis. We show that the contribution of the photospheric albedo to the photon spectrum modifies the calculated mean electron flux distribution, mainly at energies below 100 keV. The positions of the Halpha emission and hard X-ray sources with respect to the current-free extrapolation of the MDI photospheric magnetic field and the characteristics of the radio emission provide evidence of the closed geometry of the magnetic field structure and the flare process in low altitude magnetic loops. In agreement with the predictions of some solar flare models, the hard X-ray sources are located on the external edges of the Halpha emission and show chromospheric plasma heated by the non-thermal electrons. The fast changes of Halpha intensities are located not only inside the hard X-ray sources, as expected if they are the signatures of the chromospheric response to the electron bombardment, but also away from them.

  15. Reorganization of visual processing in macular degeneration: Replication and clues about the role of foveal loss q

    E-Print Network [OSTI]

    Kanwisher, Nancy

    study reported reorganization fol- lowing loss of visual input as a result of optic radiation damage

  16. Magnetic reconnection configurations and particle acceleration in solar flares

    E-Print Network [OSTI]

    Chen, P. F.

    types of solar flares. Upper panel: two-ribbon flares; Lower panel: compact flares. The color shows space under different magnetic configurations. Key words: solar flares, magnetic reconnection, particleMagnetic reconnection configurations and particle acceleration in solar flares P. F. Chen, W. J

  17. RETURN CURRENTS AND ENERGY TRANSPORT IN THE SOLAR FLARING ATMOSPHERE

    SciTech Connect (OSTI)

    Codispoti, Anna; Torre, Gabriele; Piana, Michele; Pinamonti, Nicola [Dipartimento di Matematica, Universita di Genova, via Dodecaneso 35, I-16146 Genova (Italy)

    2013-08-20T23:59:59.000Z

    According to the standard Ohmic perspective, the injection of accelerated electrons into the flaring region violates local charge equilibrium and therefore, in response, return currents are driven by an electric field to equilibrate such charge violation. In this framework, the energy loss rate associated with these local currents has an Ohmic nature and significantly shortens the accelerated electron path. In the present paper, we adopt a different viewpoint and, specifically, we study the impact of the background drift velocity on the energy loss rate of accelerated electrons in solar flares. We first utilize the Rutherford cross-section to derive the formula of the energy loss rate when the collisional target has a finite temperature and the background instantaneously and coherently moves up to equilibrate the electron injection. We then use the continuity equation for electrons and imaging spectroscopy data provided by RHESSI to validate this model. We show that this new formula for the energy loss rate provides a better fit of the experimental data with respect to the model based on the effects of standard Ohmic return currents.

  18. UNIVERSAL BEHAVIOR OF X-RAY FLARES FROM BLACK HOLE SYSTEMS

    SciTech Connect (OSTI)

    Wang, F. Y.; Dai, Z. G.; Yi, S. X. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Xi, S. Q., E-mail: fayinwang@nju.edu.cn, E-mail: dzg@nju.edu.cn [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China)

    2015-01-01T23:59:59.000Z

    X-ray flares have been discovered in black hole systems such as gamma-ray bursts, the tidal disruption event Swift J1644+57, the supermassive black hole Sagittarius A* at the center of our Galaxy, and some active galactic nuclei. Occurrences of X-ray flares are always accompanied by relativistic jets. However, it is still unknown whether or not there is a physical analogy among such X-ray flares produced in black hole systems spanning nine orders of magnitude in mass. Here, we report observed data of X-ray flares and show that they have three statistical properties similar to solar flares, including power-law distributions of their energies, durations, and waiting times, which can be explained by a fractal-diffusive, self-organized criticality model. These statistical similarities, together with the fact that solar flares are triggered by a magnetic reconnection process, suggest that all of the X-ray flares are consistent with magnetic reconnection events, implying that their concomitant relativistic jets may be magnetically dominated.

  19. Modeling Gamma-Ray Burst X-Ray Flares within the Internal Shock Model

    E-Print Network [OSTI]

    Maxham, Amanda

    2009-01-01T23:59:59.000Z

    X-ray afterglow light curves have been collected for over 400 Swift gamma-ray bursts with nearly half of them having X-ray flares superimposed on the regular afterglow decay. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge and spread, producing prompt emission and X-ray flares. We pay special attention to the time history of central engine activity, internal shocks, and observed flares, but do not calculate the shock dynamics and radiation processes in detail. Using the empirical E_p - E_iso (Amati) relation with an assumed Band function spectrum for each collision and an empirical flare temporal pr...

  20. Monitoring of FR Cnc Flaring Activity

    E-Print Network [OSTI]

    A. Golovin; M. Andreev; E. Pavlenko; Yu. Kuznyetsova; V. Krushevska; A. Sergeev

    2007-12-10T23:59:59.000Z

    Being excited by the detection of the first ever-observed optical flare in FR Cnc, we decided to continue photometrical monitoring of this object. The observations were carried out at Crimean Astrophysical Observatory (Crimea, Ukraine; CrAO - hereafter) and at the Terskol Observatory (Russia, Northern Caucasus). The obtained lightcurves are presented and discussed. No distinguishable flares were detected that could imply that flares on FR Cnc are very rare event.

  1. Reorganization of visual processing in macular degeneration: Replication and clues about the role of foveal loss q

    E-Print Network [OSTI]

    Baker, Chris I.

    - lowing loss of visual input as a result of optic radiation damage (Dilks, Serences, Rosenau, Yantis, & Mc

  2. Reducing Emissions in Plant Flaring Operations

    E-Print Network [OSTI]

    Duck, B.

    2011-01-01T23:59:59.000Z

    -05-10 Proceedings of the 2011 Industrial Energy Technology Conference New Orleans, Louisiana, May 17-19, 2011 over 12 inches per hour. The pilot system incorporates a windshield, strainer and a true premix burner capable of firing in 0% oxygen environments... of the knockout drum since all the flare gases are available at this single point. Compressors take suction from the flare gas header and compress and cool it for reuse in the refinery fuel gas system. As flare gas flows through the flare header...

  3. alberta flare research: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    O. Terry 5 FLARE: Fast Layout for Augmented Reality Applications Microsoft Research Energy Storage, Conversion and Utilization Websites Summary: FLARE: Fast Layout for Augmented...

  4. Earth Planets Space, , , Flares and the Chromosphere

    E-Print Network [OSTI]

    Hudson, Hugh

    The radiative energy of a solar flare appears mainly in the optical and UV continuum, which form in the lowerSSL, UC Berkeley, CA USA 94720-7450 2University of Glasgow, UK (Received xxxx xx, 2003; Revised xxxx produces in the photospheric magnetic field. Key words: Solar flares, Solar chromosphere, Solar corona

  5. Forward Modelling of Standing Slow Modes in Flaring Coronal Loops

    E-Print Network [OSTI]

    Yuan, D; Banerjee, D; Antolin, P

    2015-01-01T23:59:59.000Z

    Standing slow mode waves in hot flaring loops are exclusively observed in spectrometers and are used to diagnose the magnetic field strength and temperature of the loop structure. Due to the lack of spatial information, the longitudinal mode cannot be effectively identified. In this study, we simulate standing slow mode waves in flaring loops and compare the synthesized line emission properties with SUMER spectrographic and SDO/AIA imaging observations. We find that the emission intensity and line width oscillations are a quarter period out of phase with Doppler shift velocity both in time and spatial domain, which can be used to identify a standing slow mode wave from spectroscopic observations. However, the longitudinal overtones could be only measured with the assistance of imagers. We find emission intensity asymmetry in the positive and negative modulations, this is because the contribution function pertaining to the atomic emission process responds differently to positive and negative temperature variat...

  6. A MODEL FOR THE ESCAPE OF SOLAR-FLARE-ACCELERATED PARTICLES

    SciTech Connect (OSTI)

    Masson, S.; Antiochos, S. K. [Space Weather Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); DeVore, C. R., E-mail: sophie.masson@nasa.gov [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)

    2013-07-10T23:59:59.000Z

    We address the problem of how particles are accelerated by solar flares can escape into the heliosphere on timescales of an hour or less. Impulsive solar energetic particle (SEP) bursts are generally observed in association with so-called eruptive flares consisting of a coronal mass ejection (CME) and a flare. These fast SEPs are believed to be accelerated directly by the flare, rather than by the CME shock. However, the precise mechanism by which the particles are accelerated remains controversial. Regardless of the origin of the acceleration, the particles should remain trapped in the closed magnetic fields of the coronal flare loops and the ejected flux rope, given the magnetic geometry of the standard eruptive-flare model. In this case, the particles would reach the Earth only after a delay of many hours to a few days (coincident with the bulk ejecta arriving at Earth). We propose that the external magnetic reconnection intrinsic to the breakout model for CME initiation can naturally account for the prompt escape of flare-accelerated energetic particles onto open interplanetary magnetic flux tubes. We present detailed 2.5-dimensional magnetohydrodynamic simulations of a breakout CME/flare event with a background isothermal solar wind. Our calculations demonstrate that if the event occurs sufficiently near a coronal-hole boundary, interchange reconnection between open and closed fields can occur. This process allows particles from deep inside the ejected flux rope to access solar wind field lines soon after eruption. We compare these results to standard observations of impulsive SEPs and discuss the implications of the model on further observations and calculations.

  7. Universal Behavior of X-ray Flares from Black Hole Systems

    E-Print Network [OSTI]

    Wang, F Y; Yi, S X; Xi, S Q

    2014-01-01T23:59:59.000Z

    X-ray flares have been discovered in black hole systems, such as gamma-ray bursts, the tidal disruption event Swift J1644+57, the supermassive black hole Sagittarius A$^*$ at the center of our Galaxy, and some active galactic nuclei. Their occurrences are always companied by relativistic jets. However, it is still unknown whether there is a physical analogy among such X-ray flares produced in black hole systems spanning nine orders of magnitude in mass. Here we report the observed data of X-ray flares, and show that they have three statistical properties similar to solar flares, including power-law distributions of energies, durations, and waiting times, which both can be explained by a fractal-diffusive self-organized criticality model. These statistical similarities, together with the fact that solar flares are triggered by a magnetic reconnection process, suggest that all of the X-ray flares are consistent with magnetic reconnection events, implying that their concomitant relativistic jets may be magnetica...

  8. Extremely Large EUV Late Phase of Solar Flares

    E-Print Network [OSTI]

    Liu, Kai; Zhang, Jie; Cheng, Xin; Liu, Rui; Shen, Chenglong

    2015-01-01T23:59:59.000Z

    The second peak in the Fe XVI 33.5 nm line irradiance observed during solar flares by Extreme ultraviolet Variability Experiment (EVE) is known as Extreme UltraViolet (EUV) late phase. Our previous paper (Liu et al. 2013) found that the main emissions in the late phase are originated from large-scale loop arcades that are closely connected to but different from the post flare loops (PFLs), and we also proposed that a long cooling process without additional heating could explain the late phase. In this paper, we define the extremely large late phase because it not only has a bigger peak in the warm 33.5 irradiance profile, but also releases more EUV radiative energy than the main phase. Through detailedly inspecting the EUV images from three point-of-view, it is found that, besides the later phase loop arcades, the more contribution of the extremely large late phase is from a hot structure that fails to erupt. This hot structure is identified as a flux rope, which is quickly energized by the flare reconnection...

  9. Sub-GeV flashes in $?-$ray burst afterglows as probes of underlying bright UV flares

    E-Print Network [OSTI]

    Yizhong Fan; Tsvi Piran

    2006-04-17T23:59:59.000Z

    Bright optical and X-ray flares have been observed in many Gamma-ray Burst (GRB) afterglows. These flares have been attributed to late activity of the central engine. In most cases the peak energy is not known and it is possible and even likely that there is a significant far-ultraviolet component. These far-ultraviolet photons escape our detection because they are absorbed by the neutral hydrogen before reaching Earth. However, these photons cross the blast wave produced by the ejecta that have powered the initial GRB. They can be inverse Compton upscattered by hot electrons within this blast wave. This process will produce a strong sub-GeV flare that follows the high energy (soft X-ray) tail of the far-UV flare but lasts much longer and can be detected by the upcoming {\\em Gamma-Ray Large Area Telescope} (GLAST) satellite. This signature can be used to probe the spectrum of the underlying far-ultraviolet flare. The extra cooling produced by this inverse Compton process can lower the X-ray emissivity of the forward shock and explain the unexpected low early X-ray flux seen in many GRBs.

  10. ON THE FLARE-INDUCED SEISMICITY IN THE ACTIVE REGION NOAA 10930 AND RELATED ENHANCEMENT OF GLOBAL WAVES IN THE SUN

    SciTech Connect (OSTI)

    Kumar, Brajesh; Venkatakrishnan, P. [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Badi Road, Udaipur 313 004 (India); Mathur, Savita [High Altitude Observatory, 3080 Center Green Drive, Boulder, CO 80302 (United States); Tiwari, Sanjiv Kumar [Max-Planck-Institut fuer Sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau (Germany); Garcia, R. A., E-mail: brajesh@prl.res.in, E-mail: pvk@prl.res.in, E-mail: savita@ucar.edu, E-mail: tiwari@mps.mpg.de, E-mail: rafael.garcia@cea.fr [Laboratoire AIM, CEA/DSM-CNRS, Universite Paris 7 Diderot, IRFU/SAp, Centre de Saclay, 91191, Gif-sur-Yvette (France)

    2011-12-10T23:59:59.000Z

    A major flare (of class X3.4) occurred on 2006 December 13 in the active region NOAA 10930. This flare event has remained interesting to solar researchers for studies related to particle acceleration during the flare process and the reconfiguration of magnetic fields as well as fine-scale features in the active region. The energy released during flares is also known to induce acoustic oscillations in the Sun. Here, we analyze the line-of-sight velocity patterns in this active region during the X3.4 flare using the Dopplergrams obtained by the Global Oscillation Network Group (GONG) instrument. We have also analyzed the disk-integrated velocity observations of the Sun obtained by the Global Oscillation at Low Frequency (GOLF) instrument on board the Solar and Heliospheric Observatory spacecraft as well as full-disk collapsed velocity signals from GONG observations during this flare to study any possible connection between the flare-related changes seen in the local and global velocity oscillations in the Sun. We apply wavelet transform to the time series of the localized velocity oscillations as well as the global velocity oscillations in the Sun spanning the flare event. The line-of-sight velocity shows significant enhancement in some localized regions of the penumbra of this active region during the flare. The affected region is seen to be away from the locations of the flare ribbons and the hard X-ray footpoints. The sudden enhancement of this velocity seems to be caused by the Lorentz force driven by the 'magnetic jerk' in the localized penumbral region. Application of wavelet analysis to these flare-induced localized seismic signals shows significant enhancement in the high-frequency domain (5 <{nu} < 8 mHz) and a feeble enhancement in the p-mode oscillations (2 <{nu} < 5 mHz) during the flare. On the other hand, the wavelet analysis of GOLF velocity data and the full-disk collapsed GONG velocity data spanning the flare event indicates significant post-flare enhancements in the high-frequency global velocity oscillations in the Sun, as evident from the wavelet power spectrum and the corresponding scale-average variance. The present observations of the flare-induced seismic signals in the active region in context of the driving force are different as compared to previous reports on such cases. We also find indications of a connection between flare-induced localized seismic signals and the excitation of global high-frequency oscillations in the Sun.

  11. Statistical analysis of the dynamics of secondary electrons in the flare of a high-voltage beam-type discharge

    SciTech Connect (OSTI)

    Demkin, V. P.; Mel'nichuk, S. V. [National Research Tomsk State University, 36, Lenin Ave., 634050 Tomsk (Russian Federation)

    2014-09-15T23:59:59.000Z

    In the present work, results of investigations into the dynamics of secondary electrons with helium atoms in the presence of the reverse electric field arising in the flare of a high-voltage pulsed beam-type discharge and leading to degradation of the primary electron beam are presented. The electric field in the discharge of this type at moderate pressures can reach several hundred V/cm and leads to considerable changes in the kinetics of secondary electrons created in the process of propagation of the electron beam generated in the accelerating gap with a grid anode. Moving in the accelerating electric field toward the anode, secondary electrons create the so-called compensating current to the anode. The character of electron motion and the compensating current itself are determined by the ratio of the field strength to the concentration of atoms (E/n). The energy and angular spectra of secondary electrons are calculated by the Monte Carlo method for different ratios E/n of the electric field strength to the helium atom concentration. The motion of secondary electrons with threshold energy is studied for inelastic collisions of helium atoms and differential analysis is carried out of the collisional processes causing energy losses of electrons in helium for different E/n values. The mechanism of creation and accumulation of slow electrons as a result of inelastic collisions of secondary electrons with helium atoms and selective population of metastable states of helium atoms is considered. It is demonstrated that in a wide range of E/n values the motion of secondary electrons in the beam-type discharge flare has the character of drift. At E/n values characteristic for the discharge of the given type, the drift velocity of these electrons is calculated and compared with the available experimental data.

  12. acute gout flare: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ones (X9) are selected as representative of the flaring Sun. The emission measure distribution vs. temperature, EM(T), of the flaring regions is derived from YohkohSXT...

  13. anterior chamber flare: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ones (X9) are selected as representative of the flaring Sun. The emission measure distribution vs. temperature, EM(T), of the flaring regions is derived from YohkohSXT...

  14. Earth Planets Space, 00, 000--000, 2000 Solar Flare Mechanism Based on Magnetic Arcade

    E-Print Network [OSTI]

    Earth Planets Space, 00, 000--000, 2000 Solar Flare Mechanism Based on Magnetic Arcade Reconnection, Princeton, NJ 08543­0451 (Received ; Revised ; Accepted ) We propose a model describing physical processes is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary

  15. Investigation of plasma velocity field solar flare footpoints

    E-Print Network [OSTI]

    Mrozek, Tomasz

    of Wroclaw NCN Grant 2011/01/M/ST9/06096 #12;The Solar Flare - observations #12;chromosphere corona photosphere The Solar Flare - cartoon - conversion of magnetic energy into other forms - transport of energyInvestigation of plasma velocity field in solar flare footpoints from RHESSI observations T. Mrozek

  16. STATISTICS OF FLARES SWEEPING ACROSS SUNSPOTS

    SciTech Connect (OSTI)

    Li Leping; Zhang Jun, E-mail: lepingli@ourstar.bao.ac.c, E-mail: zjun@ourstar.bao.ac.c [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2009-11-20T23:59:59.000Z

    Flare ribbons are always dynamic and sometimes sweep across sunspots. After examining 588 (513 M-class and 75 X-class) flare events observed by the TRACE satellite and the Hinode/Solar Optical Telescope from 1998 May to 2009 May, we choose the event displaying one of the flare ribbons that completely sweeps across the umbra of a main sunspot of the corresponding active region, and finally obtain 20 (7 X-class and 13 M-class) events as our sample. In each event, we define the main sunspot completely swept across by the flare ribbon as the A-sunspot and its nearby opposite polarity sunspot as the B-sunspot. Observations show that the A-sunspot is a following polarity sunspot in 18 events and displays flux emergence in 13 cases. All of the B-sunspots are relatively simple, exhibiting either one main sunspot or one main sunspot and several small neighboring sunspots (pores). In two days prior to the flare occurrence, the A-sunspot rotates in all the cases, while the B-sunspot rotates in 19 events. The total rotating angle of the A-sunspot and B-sunspot rotates is 193{sup 0} on average, and the rotating directions are the same in 12 events. In all cases; the A-sunspot and B-sunspot manifest shear motions with an average shearing angle of 28.{sup 0}5, and in 14 cases, the shearing direction is opposite to the rotating direction of the A-sunspot. We suggest that the emergence, the rotation, and the shear motions of the A-sunspot and B-sunspot result in the phenomenon that flare ribbons sweep across sunspots completely.

  17. Blazar Flaring Rates Measured with GLAST

    E-Print Network [OSTI]

    C. D. Dermer; B. L. Dingus

    2003-12-22T23:59:59.000Z

    We derive the minimum observing time scales to detect a blazar at a given flux level with the LAT on GLAST in the scanning and pointing modes. Based upon Phase 1 observations with EGRET, we predict the GLAST detection rate of blazar flares at different flux levels. With some uncertainty given the poor statistics of bright blazars, we predict that a blazar flare with integral flux >~ 200e-8 ph(> 100 MeV) cm^{-2} s^{-1}, which are the best candidates for Target of Opportunity pointings and extensive temporal and spectral studies, should occur every few days.

  18. Blazar Flaring Rates Measured with GLAST

    E-Print Network [OSTI]

    Dermer, C D

    2004-01-01T23:59:59.000Z

    We derive the minimum observing time scales to detect a blazar at a given flux level with the LAT on GLAST in the scanning and pointing modes. Based upon Phase 1 observations with EGRET, we predict the GLAST detection rate of blazar flares at different flux levels. With some uncertainty given the poor statistics of bright blazars, we predict that a blazar flare with integral flux >~ 200e-8 ph(> 100 MeV) cm^{-2} s^{-1}, which are the best candidates for Target of Opportunity pointings and extensive temporal and spectral studies, should occur every few days.

  19. On the detection of neutrinos from solar flares using pion-decay photons to provide a time window template

    E-Print Network [OSTI]

    de Wasseige, G; van Eijndhoven, N; Evenson, P; Klein, K -L

    2015-01-01T23:59:59.000Z

    Since the end of the eighties and in response to a reported increase in the total neutrino flux in the Homestake experiment in coincidence with solar flares, solar neutrino detectors have searched for solar flare signals. Even though these detectors have used different solar flare samples and analyses, none of them has been able to confirm the possible signal seen by Homestake. Neutrinos from the decay of mesons, which are themselves produced in collisions of accelerated ions with the solar atmosphere would provide a novel window on the underlying physics of the hadronic acceleration and interaction processes during solar flares. Solar flare neutrino flux measurements would indeed help to constrain current parameters such as the composition of the accelerated flux, the proton/ion spectral index and the high energy cutoff or the magnetic configuration in the interaction region. We describe here a new way to search for these neutrinos by considering a specific solar flare sample and a data driven time window te...

  20. The Relation between Solar Eruption Topologies and Observed Flare Features I: Flare Ribbons

    E-Print Network [OSTI]

    Savcheva, A; McKillop, S; McCauley, P; Hanson, E; Su, Y; Werner, E; DeLuca, E E

    2015-01-01T23:59:59.000Z

    In this paper we present a topological magnetic field investigation of seven two-ribbon flares in sigmoidal active regions observed with Hinode, STEREO, and SDO. We first derive the 3D coronal magnetic field structure of all regions using marginally unstable 3D coronal magnetic field models created with the flux rope insertion method. The unstable models have been shown to be a good model of the flaring magnetic field configurations. Regions are selected based on their pre-flare configurations along with the appearance and observational coverage of flare ribbons, and the model is constrained using pre-flare features observed in extreme ultraviolet and X-ray passbands. We perform a topology analysis of the models by computing the squashing factor, Q, in order to determine the locations of prominent quasi-separatrix layers (QSLs). QSLs from these maps are compared to flare ribbons at their full extents. We show that in all cases the straight segments of the two J-shaped ribbons are matched very well by the flux...

  1. GRB Flares: A New Detection Algorithm, Previously Undetected Flares, and Implications on GRB Physics

    E-Print Network [OSTI]

    Swenson, C A

    2013-01-01T23:59:59.000Z

    Flares in GRB light curves have been observed since shortly after the discovery of the first GRB afterglow. However, it was not until the launch of the Swift satellite that it was realized how common flares are, appearing in nearly 50% of all X-ray afterglows as observed by the XRT instrument. The majority of these observed X-ray flares are easily distinguishable by eye and have been measured to have up to as much fluence as the original prompt emission. Through studying large numbers of these X-ray flares it has been determined that they likely result from a distinct emission source different than that powering the GRB afterglow. These findings could be confirmed if similar results were found using flares in other energy ranges. However, until now, the UVOT instrument on Swift seemed to have observed far fewer flares in the UV/optical than were seen in the X-ray. This was primarily due to poor sampling and data being spread across multiple filters, but a new optimal co-addition and normalization of the UVOT ...

  2. RADIO EMISSION OF SOLAR FLARE PARTICLE ACCELERATION

    E-Print Network [OSTI]

    RADIO EMISSION OF SOLAR FLARE PARTICLE ACCELERATION A. O. Benz Abstract The solar corona is a very be considered as a particle accelerator. The free mobility of charged particles in a dilute plasma to accelerate particles in resonance. From a plasma physics point of view, acceleration is not surprising

  3. WASTE INCINERATION wr090203 Activity 090203 SNAP CODE: 090203 SOURCE ACTIVITY TITLE: WASTE INCINERATION Flaring in Oil Refinery NOSE CODE: 109.03.11 NFR CODE:

    E-Print Network [OSTI]

    So Nox; Nmvoc Ch; Co Co; No Nh

    Flares are commonly used during petroleum refining for the safe disposal of waste gases during process upsets (e.g., start-up, shut-down, system blow-down) and emergencies to combust the organic content of waste emission streams without recovering/using the associated energy. 2 CONTRIBUTION TO TOTAL EMISSIONS Although flaring emission estimates are approximate, total hydrocarbon emissions from flaring at Canadian petroleum refineries during 1988 represented about 0.1 % of the refinery sector process and fugitive emissions that also included petroleum marketing emissions (CPPE, 1990). Thus the flaring operation at refineries is estimated to contribute a very small fraction of the total HC emissions in Canada. Emissions from flaring activities may also include: particulate, SOx, NOx, CO and other NMVOC. The CO2 contribution of both miscellaneous vent and flare emission sources represented approximately 9 % of the total petroleum refinery SO2 emission in Canada during 1988. Emissions estimates from flaring in petroleum refineries as reported in the CORINAIR90 inventory are summarised in Table 1. Table 1: Contribution to total emissions of the CORINAIR90 inventory (28 countries) Source-activity SNAP-code Contribution to total emissions [%

  4. The shock reprocessing model of electron acceleration in impulsive solar flares

    E-Print Network [OSTI]

    Robert Selkowitz; Eric G. Blackman

    2005-09-14T23:59:59.000Z

    We propose a new two-stage model for acceleration of electrons in solar flares. In the first stage, electrons are accelerated stochastically in a post-reconnection turbulent downflow. The second stage is the reprocessing of a subset of these electrons as they pass through a weakly compressive fast shock above the apex of the closed flare loop on their way to the chromosphere. We call this the "shock reprocessing" model. The model reproduces the energy dependent arrival time delays observed for both the pulsed and smooth components of impulsive solar flare x-rays with physically reasonable parameters for the downflow region. The model also predicts an emission site above the loop-top, as seen in the Masuda flare. The loop-top source distinguishes the shock reprocessing model from previous models. The model makes testable predictions for the energy dependence of footpoint pulse strengths and the location and spectrum of the loop-top emission, and can account for the observed soft-hard-soft trend in the spectral evolution of footpoint emission. Our model highlights the concept that reconnection is an acceleration environment rather than a single process. Which combination of processes operate may depend on the initial conditions that determine, for example, whether the reconnection downflow is turbulent. The shock reprocessing model comprises one such combination.

  5. Magnetic changes observed in a solar flare

    SciTech Connect (OSTI)

    Moore, R.L.; Hurford, G.J.; Jones, H.P.; Kane, S.R.

    1984-01-01T23:59:59.000Z

    We present observations of a fairly large impulsive flare (1B/M4, starting 17:22 UT, 1980 April 10). Observations of the microwave/hard X-ray burst show the time development of the impulsive energy release. Chromospheric (H..cap alpha..) and photospheric (Fe I lambda5324) filtergrams and photospheric (Fe I lambda8688) magnetograms, intensitygrams, and velocitygrams show magnetic strucutre, flare emission, mass motion, and magnetic changes. From these observations, we conclude: 1. The flare was triggered by a small emerging magnetic bipole. 2. The peak impulsive energy release occurred in the explosive eruption of a filament from over the magnetic inversion line. Hence: a) The filament eruption was the magnetic transient in the heart of the primary energy release in the chromosphere and corona. b) The primary energy release did not occur in approximately stationary magnetic loops, but on field lines undergoing violet motion and drastic changes in direction. 3. In the photospheric magnetograph lines. Fe I lambda5324 and Fe I lambda8688, the impulsive peak of the flare produced emission in a unipolar area of a sunspot. In synchrony with the emission, the polarity of this area transiently reversed in the lambda8688 magnetigrams; apparently, this was an artifact of the line emission. 4. Within a few minutes after the explosive filament eruption. a) A permanent decrease in magnetic flux accompanied the truncation of an umbra. b) A permanent increase in magnetic flux accompanied the severance of the penumbral bridge to a satellite sunspot. Apparently, thee genuine photospheric magnetic changes were consequences of strong flare-wrought magnetic changes in the chromospher and corona.

  6. Approved Module Information for CE3001, 2014/5 Module Title/Name: Process Economics and Loss

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Brammer) * Capital cost estimation * Variable cost estimation * Inflation, escalation and location effects in maintaining the viability of the chemical and process industries. * The methodologies to estimate costs the effects of hazards. Knowledge and understanding * A range of cost estimation techniques * The factors

  7. Continuous and H-alpha emission of a flare of July 4, 1974

    SciTech Connect (OSTI)

    Babin, A.N.; Diatel, N.P.; Livshits, M.A.

    1985-12-01T23:59:59.000Z

    The position of a white flare is compared with those of bright nodes in the H-alpha line, as well as with the position of the neutral line of the longitudinal magnetic field. Under the assumption that the brightest knot of the white flare, adjacent to the umbra of a sunspot, does not alter its position with time, it is found that the knot coincides with the position of one of the knots of the H-alpha flare immediately before the explosive phase; subsequently, the distance between the emission maxima increases to several arc seconds. An equidensitometric analysis permitted an estimate of the energy of the event: the flux in the optical continuum exceeds the H-alpha emission by almost two orders of magnitude, while the power near the flare maximum is about 10 to the 27th erg/sec for both types of emission. The entire event is connected with the process in loops rising to heights of less than 7000 km. 18 references.

  8. TIDAL DISRUPTION FLARES: THE ACCRETION DISK PHASE

    SciTech Connect (OSTI)

    Montesinos Armijo, Matias; De Freitas Pacheco, Jose A. [Observatoire de la Cote d'Azur, Laboratoire Cassiopee, Universite de Nice Sophia-Antipolis Bd de l'Observatoire, BP 4229, 06304 Nice Cedex 4 (France)

    2011-08-01T23:59:59.000Z

    The evolution of an accretion disk, formed as a consequence of the disruption of a star by a black hole, is followed by solving numerically hydrodynamic equations. The present investigation aims to study the dependence of resulting light curves on dynamical and physical properties of such a transient disk during its existence. One of the main results derived from our simulations is that blackbody fits of X-ray data tend to overestimate the true mean disk temperature. In fact, the temperature derived from blackbody fits should be identified with the color X-ray temperature rather than the average value derived from the true temperature distribution along the disk. The time interval between the beginning of the circularization of the bound debris and the beginning of the accretion process by the black hole is determined by the viscous (or accretion) timescale, which also fixes the rising part of the resulting light curve. The luminosity peak coincides with the beginning of matter accretion by the black hole and the late evolution of the light curve depends on the evolution of the debris fallback rate. Peak bolometric luminosities are in the range 10{sup 45}-10{sup 46} erg s{sup -1}, whereas peak luminosities in soft X-rays (0.2-2.0 keV) are typically one order of magnitude lower. The typical timescale derived from our preferred models for the flare luminosity to decay by two orders of magnitude is about 3-4 yr. Predicted soft X-ray light curves reproduce quite well data on galaxies in which a variable X-ray emission possibly related to a tidal event was detected. In the cases of NGC 3599 and IC 3599, data are reproduced well by models defined by a black hole with mass {approx}10{sup 7} M{sub sun} and a disrupted star of about 1 solar mass. The X-ray variation observed in XMMSL1 is consistent with a model defined by a black hole with mass {approx}3 x 10{sup 6} M{sub sun} and a disrupted star of 1 solar mass, while that observed in the galaxy situated in the cluster A1689 is consistent with a model including a black hole of {approx}10{sup 7} M{sub sun} and a disrupted star of {approx}0.5 M{sub sun}.

  9. Flares in GRB afterglows from delayed magnetic dissipation

    E-Print Network [OSTI]

    Dimitrios Giannios

    2006-06-19T23:59:59.000Z

    One of the most intriguing discoveries made by the Swift satellite is the flaring activity in about half of the afterglow lightcurves. Flares have been observed on both long and short duration GRBs and on time scales that range from minutes to ~1 day after the prompt emission. The rapid evolution of some flares led to the suggestion that they are caused by late central engine activity. Here, I propose an alternative explanation that does not need reviving of the central engine. Flares can be powered by delayed magnetic dissipation in strongly magnetized (i.e. with initial Poynting to kinetic flux ratio $\\simmore 1$) ejecta during its deceleration due to interaction with the external medium. A closer look at the length scales of the dissipation regions shows that magnetic dissipation can give rise to fast evolving and energetic flares. Multiple flares are also expected in the context of the model.

  10. TOWARD RELIABLE BENCHMARKING OF SOLAR FLARE FORECASTING METHODS

    SciTech Connect (OSTI)

    Bloomfield, D. Shaun; Higgins, Paul A.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, College Green, Dublin 2 (Ireland); McAteer, R. T. James, E-mail: shaun.bloomfield@tcd.ie [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003-8001 (United States)

    2012-03-10T23:59:59.000Z

    Solar flares occur in complex sunspot groups, but it remains unclear how the probability of producing a flare of a given magnitude relates to the characteristics of the sunspot group. Here, we use Geostationary Operational Environmental Satellite X-ray flares and McIntosh group classifications from solar cycles 21 and 22 to calculate average flare rates for each McIntosh class and use these to determine Poisson probabilities for different flare magnitudes. Forecast verification measures are studied to find optimum thresholds to convert Poisson flare probabilities into yes/no predictions of cycle 23 flares. A case is presented to adopt the true skill statistic (TSS) as a standard for forecast comparison over the commonly used Heidke skill score (HSS). In predicting flares over 24 hr, the maximum values of TSS achieved are 0.44 (C-class), 0.53 (M-class), 0.74 (X-class), 0.54 ({>=}M1.0), and 0.46 ({>=}C1.0). The maximum values of HSS are 0.38 (C-class), 0.27 (M-class), 0.14 (X-class), 0.28 ({>=}M1.0), and 0.41 ({>=}C1.0). These show that Poisson probabilities perform comparably to some more complex prediction systems, but the overall inaccuracy highlights the problem with using average values to represent flaring rate distributions.

  11. Continuum and line emission of flares on red dwarf stars

    E-Print Network [OSTI]

    Morchenko, Egor; Livshits, Moisey

    2015-01-01T23:59:59.000Z

    The emission spectrum has been calculated of a homogeneous pure hydrogen layer, which parameters are typical for a flare on a red dwarf. The ionization and excitation states were determined by the solution of steady-state equations taking into account the continuum and all discrete hydrogen levels. We consider the following elementary processes: electron-impact transitions, spontaneous and induced radiative transitions, and ionization by the bremsstrahlung and recombination radiation of the layer itself. The Biberman--Holstein approximation was used to calculate the scattering of line radiation. Asymptotic formulae for the escape probability are obtained for a symmetric line profile taking into account the Stark and Doppler effects. The approximation for the core of the H$-\\alpha$ line by a gaussian curve has been substantiated. The spectral intensity of the continuous spectrum, the intensity of the lines of the Balmer series and the magnitude of the Balmer jump have been calculated. The conditions have been ...

  12. Particle acceleration by slow modes in strong compressible MHD turbulence, with application to solar flares

    E-Print Network [OSTI]

    Benjamin D. G. Chandran

    2003-11-13T23:59:59.000Z

    Energetic particles that undergo strong pitch-angle scattering and diffuse through a plasma containing strong compressible MHD turbulence undergo diffusion in momentum space with diffusion coefficient Dp. In this paper, the contribution of slow modes to Dp is calculated assuming the rms turbulent velocity is of order the Alfven speed. The energy spectrum of accelerated particles is derived assuming slow modes make the dominant contribution to Dp, taking into account Coulomb losses and particle escape from the acceleration region with an energy-independent escape time. The results are applied to solar flares.

  13. IMPLICATIONS OF MASS AND ENERGY LOSS DUE TO CORONAL MASS EJECTIONS ON MAGNETICALLY ACTIVE STARS

    SciTech Connect (OSTI)

    Drake, Jeremy J.; Cohen, Ofer [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yashiro, Seiji [Interferometrics Inc., Herndon, VA 20171 (United States)] [Interferometrics Inc., Herndon, VA 20171 (United States); Gopalswamy, Nat, E-mail: jdrake@cfa.harvard.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-02-20T23:59:59.000Z

    Analysis of a database of solar coronal mass ejections (CMEs) and associated flares over the period 1996-2007 finds well-behaved power-law relationships between the 1-8 A flare X-ray fluence and CME mass and kinetic energy. We extrapolate these relationships to lower and higher flare energies to estimate the mass and energy loss due to CMEs from stellar coronae, assuming that the observed X-ray emission of the latter is dominated by flares with a frequency as a function of energy dn/dE = kE {sup -{alpha}}. For solar-like stars at saturated levels of X-ray activity, the implied losses depend fairly weakly on the assumed value of {alpha} and are very large: M-dot {approx}5 Multiplication-Sign 10{sup -10} M{sub sun} yr{sup -1} and E-dot {approx}0.1 L{sub sun}. In order to avoid such large energy requirements, either the relationships between CME mass and speed and flare energy must flatten for X-ray fluence {approx}> 10{sup 31} erg, or the flare-CME association must drop significantly below 1 for more energetic events. If active coronae are dominated by flares, then the total coronal energy budget is likely to be up to an order of magnitude larger than the canonical 10{sup -3} L {sub bol} X-ray saturation threshold. This raises the question of what is the maximum energy a magnetic dynamo can extract from a star? For an energy budget of 1% of L {sub bol}, the CME mass loss rate is about 5 Multiplication-Sign 10{sup -11} M {sub Sun} yr{sup -1}.

  14. Driving Major Solar Flares and Eruptions: Carolus J. Schrijver

    E-Print Network [OSTI]

    Schrijver, Karel

    Driving Major Solar Flares and Eruptions: A Review Carolus J. Schrijver Lockheed Martin Adv. Techn that energize and trigger M- and X-class so- lar flares and associated flux-rope destabilizations. Numerical modeling of specific solar regions is hampered by uncertain coronal-field reconstructions and by poorly

  15. Associated Shale Gas- From Flares to Rig Power 

    E-Print Network [OSTI]

    Wallace, Elizabeth Michelle

    2014-10-16T23:59:59.000Z

    /D, resulting in the flaring of approximately 266 MMcf/D. The Bakken area is one of the most produced shale oil and condensate formations in the US. Reported volumes for this formation suggest that the amount of associated gas flared is enough to power drilling...

  16. Relationships between physical and observational parameters during flares on

    E-Print Network [OSTI]

    Complutense de Madrid, Universidad

    for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. 3 Armagh Observatory, College Hill, Armagh BT61 9DG 2200 AG Noordwijk, The Netherlands. Summary. A great number of short and weak non white-light flares Solar flares were discovered by Carrington and Hodgson on September 1, 1859 [2, 19]. However

  17. Property Loss / Damage Report Damage Loss Details

    E-Print Network [OSTI]

    Ponce, V. Miguel

    Property Loss / Damage Report Damage Loss Details Date & Time of Damage / Loss: Type of damage / loss: Location - specific address / room: Project / Grant associated with damage / loss - grant Police: When was damage / loss first discovered - BY WHOM: Pictures available or attached? Was personal

  18. EVIDENCE FOR HOT FAST FLOW ABOVE A SOLAR FLARE ARCADE

    SciTech Connect (OSTI)

    Imada, S. [Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)] [Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Aoki, K.; Hara, H.; Watanabe, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan); Harra, L. K. [UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)] [UCL-Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Shimizu, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara-shi, Kanagawa 229-8510 (Japan)] [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara-shi, Kanagawa 229-8510 (Japan)

    2013-10-10T23:59:59.000Z

    Solar flares are one of the main forces behind space weather events. However, the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in the corona where hot fast flows are created. Some imaging or spectroscopic observations have indicated the presence of these hot fast flows, but there have been no spectroscopic scanning observations to date to measure the two-dimensional structure quantitatively. We analyzed a flare that occurred on the west solar limb on 2012 January 27 observed by the Hinode EUV Imaging Spectrometer (EIS) and found that the hot (?30MK) fast (>500 km s{sup –1}) component was located above the flare loop. This is consistent with magnetic reconnection taking place above the flare loop.

  19. Design Enhancements To Improve Flare Efficiency

    E-Print Network [OSTI]

    Dooley, K. A.; McLeod, G. M.; Lorenz, M. D.

    , to burn routine vent and purge gases. It was configured as a two-stage system with each stage consisting of multiple burners. The original burners were of a fin plate design. The flare system was designed to operate at low pressure due to venting... was reconfigured to accommodate the lower heat content via the addition of an alternate first stage. The new stage was comprised of three new burners designed for lower flowrates and for gases with lower heating values than the original fin-plate burners...

  20. Solar Flares and the Chromosphere A white paper for the Decadal Survey*

    E-Print Network [OSTI]

    California at Berkeley, University of

    detail the progression of flare energy re- lease. Flare chromo deserves attention in our attempts to find answers to the riddles of the corona, including flares flares radiate most of their lu- minous energy in the chromosphere. The chromosphere is where electrons

  1. 36Super-fast solar flares ! NASA's Ramaty High Energy Solar

    E-Print Network [OSTI]

    36Super-fast solar flares ! NASA's Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite has been studying solar flares since 2002. The sequence of figures to the left shows a flaring region hr/3600 sec = 0.98 kilometers/sec. The solar flare blob was traveling at 207 kilometers per second

  2. Quasi-periodic Slipping Magnetic Reconnection During an X-class Solar Flare Observed by the Solar Dynamics Observatory and Interface Region Imaging Spectrograph

    E-Print Network [OSTI]

    Li, Ting

    2015-01-01T23:59:59.000Z

    We firstly report the quasi-periodic slipping motion of flare loops during an eruptive X-class flare on 2014 September 10. The slipping motion was investigated at a specific location along one of the two ribbons and can be observed throughout the impulsive phase of the flare. The apparent slipping velocity was 20-110 km/s and the associated period was 3$-$6 min. The footpoints of flare loops appeared as small-scale bright knots observed in 1400 {\\AA}, corresponding to fine structures of the flare ribbon. These bright knots were observed to move along the southern part of the longer ribbon and also exhibited a quasi-periodic pattern. The Si IV 1402.77 {\\AA} line was redshifted by 30-50 km/s at the locations of moving knots with a ~ 40-60 km/s line width, larger than other sites of the flare ribbon. We suggest that the quasi-periodic slipping reconnection is involved in this process and the redshift at the bright knots is probably indicative of reconnection downflow. The emission line of Si IV at the northern p...

  3. OBSERVATIONS OF THERMAL FLARE PLASMA WITH THE EUV VARIABILITY EXPERIMENT

    SciTech Connect (OSTI)

    Warren, Harry P.; Doschek, George A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Mariska, John T. [School of Physics, Astronomy, and Computational Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2013-06-20T23:59:59.000Z

    One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often predicated on the assumption that the flare plasma is isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory provides spectrally resolved observations of emission lines that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for thermal flare plasma to be studied in detail. In this paper we describe a method for computing the differential emission measure distribution in a flare using EVE observations and apply it to several representative events. We find that in all phases of the flare the differential emission measure distribution is broad. Comparisons of EVE spectra with calculations based on parameters derived from the Geostationary Operational Environmental Satellites soft X-ray fluxes indicate that the isothermal approximation is generally a poor representation of the thermal structure of a flare.

  4. Solar Flare Measurements with STIX and MiSolFA

    E-Print Network [OSTI]

    Casadei, Diego

    2014-01-01T23:59:59.000Z

    Solar flares are the most powerful events in the solar system and the brightest sources of X-rays, often associated with emission of particles reaching the Earth and causing geomagnetic storms, giving problems to communication, airplanes and even black-outs. X-rays emitted by accelerated electrons are the most direct probe of solar flare phenomena. The Micro Solar-Flare Apparatus (MiSolFA) is a proposed compact X-ray detector which will address the two biggest issues in solar flare modeling. Dynamic range limitations prevent simultaneous spectroscopy with a single instrument of all X-ray emitting regions of a flare. In addition, most X-ray observations so far are inconsistent with the high anisotropy predicted by the models usually adopted for solar flares. Operated at the same time as the STIX instrument of the ESA Solar Orbiter mission, at the next solar maximum (2020), they will have the unique opportunity to look at the same flare from two different directions: Solar Orbiter gets very close to the Sun wit...

  5. PROPERTIES OF SEQUENTIAL CHROMOSPHERIC BRIGHTENINGS AND ASSOCIATED FLARE RIBBONS

    SciTech Connect (OSTI)

    Kirk, Michael S.; Balasubramaniam, K. S.; Jackiewicz, Jason; McAteer, R. T. James [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Milligan, Ryan O., E-mail: mskirk@nmsu.edu [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road Belfast, BT7 1NN (United Kingdom)

    2012-05-10T23:59:59.000Z

    We report on the physical properties of solar sequential chromospheric brightenings (SCBs) observed in conjunction with moderate-sized chromospheric flares with associated Coronal mass ejections. To characterize these ephemeral events, we developed automated procedures to identify and track subsections (kernels) of solar flares and associated SCBs using high-resolution H{alpha} images. Following the algorithmic identification and a statistical analysis, we compare and find the following: SCBs are distinctly different from flare kernels in their temporal characteristics of intensity, Doppler structure, duration, and location properties. We demonstrate that flare ribbons are themselves made up of subsections exhibiting differing characteristics. Flare kernels are measured to have a mean propagation speed of 0.2 km s{sup -1} and a maximum speed of 2.3 km s{sup -1} over a mean distance of 5 Multiplication-Sign 10{sup 3} km. Within the studied population of SCBs, different classes of characteristics are observed with coincident negative, positive, or both negative and positive Doppler shifts of a few km s{sup -1}. The appearance of SCBs precedes peak flare intensity by Almost-Equal-To 12 minutes and decay Almost-Equal-To 1 hr later. They are also found to propagate laterally away from flare center in clusters at 45 km s{sup -1} or 117 km s{sup -1}. Given SCBs' distinctive nature compared to flares, we suggest a different physical mechanism relating to their origin than the associated flare. We present a heuristic model of the origin of SCBs.

  6. THE n-DISTRIBUTION OF ELECTRONS AND DOUBLE LAYERS IN THE ELECTRON-BEAM-RETURN-CURRENT SYSTEM OF SOLAR FLARES

    SciTech Connect (OSTI)

    Karlicky, Marian, E-mail: karlicky@asu.cas.cz [Astronomical Institute of the Academy of Sciences of the Czech Republic, CZ-25165 Ondrejov (Czech Republic)

    2012-05-01T23:59:59.000Z

    We investigate processes in the electron-beam-return-current system in the impulsive phase of solar flares to answer a question about the formation of the n-electron distribution detected in this phase of solar flares. An evolution of the electron-beam-return-current system with an initial local density depression is studied using a three-dimensional electromagnetic particle-in-cell model. In the system the strong double layer is formed. Its electric field potential increases with the electron beam flux. In this electric field potential, the electrons of background plasma are strongly accelerated and propagate in the return-current direction. The high-energy part of their distribution at the high-potential side of the strong double layer resembles that of the n-distribution. Thus, the detection of the n-distributions, where a form of the high-energy part of the distribution is the most important, can indicate the presence of strong double layers in solar flares. The similarity between processes in solar flare loops and those in the downward current region of the terrestrial aurora, where the double layers were observed by FAST satellite, supports this idea.

  7. Sub-GeV flashes in $\\gamma-$ray burst afterglows as probes of underlying bright UV flares

    E-Print Network [OSTI]

    Fan, Y; Fan, Yizhong; Piran, Tsvi

    2006-01-01T23:59:59.000Z

    Bright optical and X-ray flares have been observed in many Gamma-ray Burst (GRB) afterglows. These flares have been attributed to late activity of the central engine. In most cases the peak energy is not known and it is possible and even likely that there is a significant far-ultraviolet component. These far-UV photons escape our detection because they are absorbed by the neutral hydrogen before reaching Earth. However, these photons cross the blast wave produced by the ejecta that have powered the initial GRB. They can be inverse Compton upscattered by hot electrons within this blast wave. This process will produce a strong sub-GeV flare that can be detected by the upcoming {\\em Gamma-Ray Large Area Telescope} (GLAST) satellite. This signature can be used to probe the spectrum of the underlying far-ultraviolet flare. The extra cooling produced by this inverse Compton process can lower the X-ray emissivity of the forward shock and explain the unexpected low early X-ray flux seen in many GRBs.

  8. Sign singularity and flares in solar active region NOAA 11158

    E-Print Network [OSTI]

    Sorriso-Valvo, Luca; Kazachenko, Maria D; Krucker, Sam; Primavera, Leonardo; Servidio, Sergio; Vecchio, Antonio; Welsch, Brian T; Fisher, George H; Lepreti, Fabio; Carbone, Vincenzo

    2015-01-01T23:59:59.000Z

    Solar Active Region NOAA 11158 has hosted a number of strong flares, including one X2.2 event. The complexity of current density and current helicity are studied through cancellation analysis of their sign-singular measure, which features power-law scaling. Spectral analysis is also performed, revealing the presence of two separate scaling ranges with different spectral index. The time evolution of parameters is discussed. Sudden changes of the cancellation exponents at the time of large flares, and the presence of correlation with EUV and X-ray flux, suggest that eruption of large flares can be linked to the small scale properties of the current structures.

  9. PRE-FLARE ACTIVITY AND MAGNETIC RECONNECTION DURING THE EVOLUTIONARY STAGES OF ENERGY RELEASE IN A SOLAR ERUPTIVE FLARE

    SciTech Connect (OSTI)

    Joshi, Bhuwan [Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313 001 (India); Veronig, Astrid M. [IGAM/Institute of Physics, University of Graz, A-8010 Graz (Austria); Lee, Jeongwoo [Physics Department, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Bong, Su-Chan; Cho, Kyung-Suk [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Tiwari, Sanjiv Kumar [Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany)

    2011-12-20T23:59:59.000Z

    In this paper, we present a multi-wavelength analysis of an eruptive white-light M3.2 flare that occurred in active region NOAA 10486 on 2003 November 1. The excellent set of high-resolution observations made by RHESSI and the TRACE provides clear evidence of significant pre-flare activities for {approx}9 minutes in the form of an initiation phase observed at EUV/UV wavelengths followed by an X-ray precursor phase. During the initiation phase, we observed localized brightenings in the highly sheared core region close to the filament and interactions among short EUV loops overlying the filament, which led to the opening of magnetic field lines. The X-ray precursor phase is manifested in RHESSI measurements below {approx}30 keV and coincided with the beginning of flux emergence at the flaring location along with early signatures of the eruption. The RHESSI observations reveal that both plasma heating and electron acceleration occurred during the precursor phase. The main flare is consistent with the standard flare model. However, after the impulsive phase, an intense hard X-ray (HXR) looptop source was observed without significant footpoint emission. More intriguingly, for a brief period, the looptop source exhibited strong HXR emission with energies up to {approx}50-100 keV and significant non-thermal characteristics. The present study indicates a causal relation between the activities in the pre-flare and the main flare. We also conclude that pre-flare activities, occurring in the form of subtle magnetic reorganization along with localized magnetic reconnection, played a crucial role in destabilizing the active region filament, leading to a solar eruptive flare and associated large-scale phenomena.

  10. Solar Flare Chromospheric Line Emission: Comparison Between IBIS High-resolution Observations and Radiative Hydrodynamic Simulations

    E-Print Network [OSTI]

    da Costa, Fatima Rubio; Petrosian, Vahé; Dalda, Alberto Sainz; Liu, Wei

    2014-01-01T23:59:59.000Z

    Solar flares involve impulsive energy release, which results in enhanced radiation in a broad spectral and at a wide height range. In particular, line emission from the chromosphere (lower atmosphere) can provide critical diagnostics of plasma heating processes. Thus, a direct comparison between high-resolution spectroscopic observations and advanced numerical modeling results can be extremely valuable, but has not been attempted so far. We present in this paper such a self-consistent investigation of an M3.0 flare observed by the Dunn Solar Telescope's (DST) Interferometric Bi-dimensional Spectrometer (IBIS) on 2011 September 24 that we have modeled with the radiative hydrodynamic code RADYN (Carlsson & Stein 1992, 1997; Abbett & Hawley 1999; Allred et al. 2005). We obtained images and spectra of the flaring region with IBIS in H$\\alpha$ 6563 \\AA\\ and Ca II 8542 \\AA, and with the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) in X-rays. The latter was used to infer the non-thermal elect...

  11. Obscuration of Flare Emission by an Eruptive Prominence

    E-Print Network [OSTI]

    Gopalswamy, Nat

    2013-01-01T23:59:59.000Z

    We report on the eclipsing of microwave flare emission by an eruptive prominence from a neighboring region as observed by the Nobeyama Radioheliograph at 17 GHz. The obscuration of the flare emission appears as a dimming feature in the microwave flare light curve. We use the dimming feature to derive the temperature of the prominence and the distribution of heating along the length of the filament. We find that the prominence is heated to a temperature above the quiet Sun temperature at 17 GHz. The duration of the dimming is the time taken by the eruptive prominence in passing over the flaring region. We also find evidence for the obscuration in EUV images obtained by the Solar and Heliospheric Observatory (SOHO) mission.

  12. 4Predicting CMEs and Flares Solar flares are violent releases of energy from the sun that last 10 to 20

    E-Print Network [OSTI]

    to predict flares. This means that you have a better chance of predicting when an electrical outage (caused Lights and sometimes result in electrical power blackouts. During a particular month of solar activity

  13. ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG, HINODE, AND RHESSI

    SciTech Connect (OSTI)

    Matthews, S. A.; Zharkov, S. [UCL Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, RH5 6NT UK (United Kingdom); Zharkova, V. V. [Horton D Building, Department of Mathematics, University of Bradford, Bradford, BD7 1DP (United Kingdom)

    2011-10-01T23:59:59.000Z

    Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its impact in the photosphere and the solar interior. Using data from Hinode, TRACE, RHESSI, and GONG we study the temporal and spatial evolution of the 2006 December 14 X-class flare in the chromosphere, photosphere, and the solar interior. We investigate the connections between the emission at various atmospheric depths, including acoustic signatures obtained by time-distance and holography methods from the GONG data. We report the horizontal displacements observed in the photosphere linked to the timing and locations of the acoustic signatures we believe to be associated with this flare, their vertical and horizontal displacement velocities, and their potential implications for current models of flare dynamics.

  14. AUTOMATED SOLAR FLARE STATISTICS IN SOFT X-RAYS OVER 37 YEARS OF GOES OBSERVATIONS: THE INVARIANCE OF SELF-ORGANIZED CRITICALITY DURING THREE SOLAR CYCLES

    SciTech Connect (OSTI)

    Aschwanden, Markus J.; Freeland, Samuel L., E-mail: aschwanden@lmsal.com [Lockheed Martin Advanced Technology Center, Solar and Astrophysics Laboratory, Org. ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

    2012-08-01T23:59:59.000Z

    We analyzed the soft X-ray light curves from the Geostationary Operational Environmental Satellites over the last 37 years (1975-2011) and measured with an automated flare detection algorithm over 300,000 solar flare events (amounting to Almost-Equal-To 5 times higher sensitivity than the NOAA flare catalog). We find a power-law slope of {alpha}{sub F} = 1.98 {+-} 0.11 for the (background-subtracted) soft X-ray peak fluxes that is invariant through three solar cycles and agrees with the theoretical prediction {alpha}{sub F} = 2.0 of the fractal-diffusive self-organized criticality (FD-SOC) model. For the soft X-ray flare rise times, we find a power-law slope of {alpha}{sub T} = 2.02 {+-} 0.04 during solar cycle minima years, which is also consistent with the prediction {alpha}{sub T} = 2.0 of the FD-SOC model. During solar cycle maxima years, the power-law slope is steeper in the range of {alpha}{sub T} Almost-Equal-To 2.0-5.0, which can be modeled by a solar-cycle-dependent flare pile-up bias effect. These results corroborate the FD-SOC model, which predicts a power-law slope of {alpha}{sub E} = 1.5 for flare energies and thus rules out significant nanoflare heating. While the FD-SOC model predicts the probability distribution functions of spatio-temporal scaling laws of nonlinear energy dissipation processes, additional physical models are needed to derive the scaling laws between the geometric SOC parameters and the observed emissivity in different wavelength regimes, as we derive here for soft X-ray emission. The FD-SOC model also yields statistical probabilities for solar flare forecasting.

  15. Oilfield Flare Gas Electricity Systems (OFFGASES Project)

    SciTech Connect (OSTI)

    Rachel Henderson; Robert Fickes

    2007-12-31T23:59:59.000Z

    The Oilfield Flare Gas Electricity Systems (OFFGASES) project was developed in response to a cooperative agreement offering by the U.S. Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) under Preferred Upstream Management Projects (PUMP III). Project partners included the Interstate Oil and Gas Compact Commission (IOGCC) as lead agency working with the California Energy Commission (CEC) and the California Oil Producers Electric Cooperative (COPE). The project was designed to demonstrate that the entire range of oilfield 'stranded gases' (gas production that can not be delivered to a commercial market because it is poor quality, or the quantity is too small to be economically sold, or there are no pipeline facilities to transport it to market) can be cost-effectively harnessed to make electricity. The utilization of existing, proven distribution generation (DG) technologies to generate electricity was field-tested successfully at four marginal well sites, selected to cover a variety of potential scenarios: high Btu, medium Btu, ultra-low Btu gas, as well as a 'harsh', or high contaminant, gas. Two of the four sites for the OFFGASES project were idle wells that were shut in because of a lack of viable solutions for the stranded noncommercial gas that they produced. Converting stranded gas to useable electrical energy eliminates a waste stream that has potential negative environmental impacts to the oil production operation. The electricity produced will offset that which normally would be purchased from an electric utility, potentially lowering operating costs and extending the economic life of the oil wells. Of the piloted sites, the most promising technologies to handle the range were microturbines that have very low emissions. One recently developed product, the Flex-Microturbine, has the potential to handle the entire range of oilfield gases. It is deployed at an oilfield near Santa Barbara to run on waste gas that is only 4% the strength of natural gas. The cost of producing oil is to a large extent the cost of electric power used to extract and deliver the oil. Researchers have identified stranded and flared gas in California that could generate 400 megawatts of power, and believe that there is at least an additional 2,000 megawatts that have not been identified. Since California accounts for about 14.5% of the total domestic oil production, it is reasonable to assume that about 16,500 megawatts could be generated throughout the United States. This power could restore the cost-effectiveness of thousands of oil wells, increasing oil production by millions of barrels a year, while reducing emissions and greenhouse gas emissions by burning the gas in clean distributed generators rather than flaring or venting the stranded gases. Most turbines and engines are designed for standardized, high-quality gas. However, emerging technologies such as microturbines have increased the options for a broader range of fuels. By demonstrating practical means to consume the four gas streams, the project showed that any gases whose properties are between the extreme conditions also could be utilized. The economics of doing so depends on factors such as the value of additional oil recovered, the price of electricity produced, and the alternate costs to dispose of stranded gas.

  16. ROSAT Observations of the Flare Star CC Eri

    E-Print Network [OSTI]

    H. C. Pan; C. Jordan

    1994-09-16T23:59:59.000Z

    The flare/spotted spectroscopic binary star CC Eri was observed with the Position Sensitive Proportional Counter (PSPC) on the X-ray satellite ROSAT on 1990 July 9-11 and 1992 January 26-27. During the observations, the source was variable on time scales from a few minutes to several hours, with the X-ray (0.2-2 keV) luminosity in the range $\\sim 2.5-6.8\\times 10^{29} erg s^{-1}$. An X-ray flare-like event, which has a one hour characteristic rise time and a two hour decay time, was observed from CC Eri on 1990 July 10 16:14-21:34 (UT). The X-ray spectrum of the source can be described by current thermal plasma codes with two temperature components or with a continuous temperature distribution. The spectral results show that plasma at $Te\\sim 10^{7}$ K exists in the corona of CC Eri. The variations in the observed source flux and spectra can be reproduced by a flare, adopting a magnetic reconnection model. Comparisons with an unheated model, late in the flare, suggest that the area and volume of the flare are substantially larger than in a solar two ribbon flare, while the electron pressure is similar. The emission measure and temperature of the non-flaring emission, interpreted as the average corona, lead to an electron pressure similar to that in a well-developed solar active region. Rotational modulation of a spot related active region requires an unphysically large X-ray flux in a concentrated area.

  17. The Carina Flare: What can fragments in the wall tell us?

    E-Print Network [OSTI]

    Wunsch, Richard; Sidorin, Vojtech; Ehlerova, Sona; Palous, Jan; Dale, James; Dawson, Joanne R; Fukui, Yasuo

    2011-01-01T23:59:59.000Z

    $^{13}$CO(J=2--1) and C$^{18}$O(J=2--1) observations of the molecular cloud G285.90+4.53 (Cloud~16) in the Carina Flare supershell (GSH287+04-17) with the APEX telescope are presented. With an algorithm DENDROFIND we identify 51 fragments and compute their sizes and masses. We discuss their mass spectrum and interpret it as being the result of the shell fragmentation process described by the pressure assisted gravitational instability - PAGI. We conclude that the explanation of the clump mass function needs a combination of gravity with pressure external to the shell.

  18. Impulsive Heating of Solar Flare Ribbons Above 10 MK

    E-Print Network [OSTI]

    Simões, Paulo J A; Fletcher, Lyndsay

    2015-01-01T23:59:59.000Z

    The chromospheric response to the input of flare energy is marked by extended extreme ultraviolet (EUV) ribbons and hard X-ray (HXR) footpoints. These are usually explained as the result of heating and bremsstrahlung emission from accelerated electrons colliding in the dense chromospheric plasma. We present evidence of impulsive heating of flare ribbons above 10 MK in a two-ribbon flare. We analyse the impulsive phase of SOL2013-11-09T06:38, a C2.6 class event using data from Atmospheric Imaging Assembly (AIA) on board of Solar Dynamics Observatory (SDO) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to derive the temperature, emission measure and differential emission measure of the flaring regions and investigate the evolution of the plasma in the flaring ribbons. The ribbons were visible at all SDO/AIA EUV/UV wavelengths, in particular, at 94 and 131 \\AA\\ filters, sensitive to temperatures of 8 MK and 12 MK. Time evolution of the emission measure of the plasma above 10 MK at the ribb...

  19. Acceleration and Enrichment of 3He in Impulsive Solar Flares by Electron Firehose Waves

    E-Print Network [OSTI]

    G. Paesold; R. Kallenbach; A. O. Benz

    2002-09-08T23:59:59.000Z

    A new mechanism for acceleration and enrichment of 3He during impulsive solar flares is presented. Low-frequency electromagnetic plasma waves excited by the Electron Firehose Instability (EFI) can account for the acceleration of ions up to 1 MeV/amu energies as a single stage process. The EFI arises as a direct consequence of the free energy stored in a temperature anisotropy (T_parallel>T_perp) of the bulk energized electron population during the acceleration process. In contrast to other mechanisms which require special plasma properties, the EFI is an intrinsic feature of the acceleration process of the bulk electrons. Being present as a side effect in the flaring plasma, these waves can account for the acceleration of 3He and 4He while selectively enhancing 3He due to the spectral energy density built up from linear growth. Linearized kinetic theory, analytic models and test-particle simulations have been applied to investigate the ability of the waves to accelerate and fractionate. As waves grow in both directions parallel to the magnetic field, they can trap resonant ions and efficiently accelerate them to the highest energies. Plausible models have been found that can explain the observed energies, spectra and abundances of 3He and 4He.

  20. Simulations of Spectral Profiles Observed in a C5.6 Limb Flare

    E-Print Network [OSTI]

    Li, Hui

    , Nanjing 210008, China Abstract We obtained a complete set of H# , CaII 8542 Å¡ A and HeI 10830 Å¡ A spectra of the flare loop. Key words: limb flare, line profile, infrared PACS: 1 Introduction Solar flare spectra velocities, electron temperatures and densities [1--4]. Spectral lines are thought be wide in solar limb

  1. Solar Flare Intermittency and the Earth's Temperature Anomalies Nicola Scafetta1,2

    E-Print Network [OSTI]

    Scafetta, Nicola

    Solar Flare Intermittency and the Earth's Temperature Anomalies Nicola Scafetta1,2 and Bruce J; published 17 June 2003) We argue that Earth's short-term temperature anomalies and the solar flare data sets that corresponds to the one that would be induced by the solar flare intermittency. The mean

  2. Automatic Solar Flare Detection Using MLP, RBF and SVM , Frank Y. Shih1

    E-Print Network [OSTI]

    1 Automatic Solar Flare Detection Using MLP, RBF and SVM Ming Qu1 , Frank Y. Shih1 , Ju Jing2. The focus of the automatic solar flare detection is on the development of efficient feature methods for solar flare detection on the solar H (Hydrogen-Alpha) images obtained from the Big Bear Solar

  3. Observations of Electrons from the Decay of Solar Flare Neutrons

    E-Print Network [OSTI]

    W. Dröge; D. Ruffolo; B. Klecker

    1996-04-03T23:59:59.000Z

    We have found evidence for fluxes of energetic electrons in interplanetary space on board the ISEE-3 spacecraft which we interpret as the decay products of neutrons generated in a solar flare on 1980 June 21. The decay electrons arrived at the s/c shortly before the electrons from the flare and can be distinguished from the latter by their distinctive energy spectrum. The time profile of the decay electrons is in good agreement with the results from a simulation based on a scattering mean free path derived from a fit to the flare electron data. The comparison with simultaneously observed decay protons and a published direct measurement of high-energy neutrons places important constraints on the parent neutron spectrum.

  4. A Reconnecting Current Sheet Imaged in A Solar Flare

    E-Print Network [OSTI]

    Liu, Rui; Wang, Tongjiang; Stenborg, Guillermo; Liu, Chang; Wang, Haimin

    2010-01-01T23:59:59.000Z

    Magnetic reconnection changes the magnetic field topology and powers explosive events in astrophysical, space and laboratory plasmas. For flares and coronal mass ejections (CMEs) in the solar atmosphere, the standard model predicts the presence of a reconnecting current sheet, which has been the subject of considerable theoretical and numerical modeling over the last fifty years, yet direct, unambiguous observational verification has been absent. In this Letter we show a bright sheet structure of global length (>0.25 Rsun) and macroscopic width ((5 - 10)x10^3 km) distinctly above the cusp-shaped flaring loop, imaged during the flare rising phase in EUV. The sheet formed due to the stretch of a transequatorial loop system, and was accompanied by various reconnection signatures that have been dispersed in the literature. This unique event provides a comprehensive view of the reconnection geometry and dynamics in the solar corona.

  5. Energy Partitions and Evolution in a Purely Thermal Solar Flare

    E-Print Network [OSTI]

    Fleishman, Gregory D; Gary, Dale E

    2015-01-01T23:59:59.000Z

    This paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free-free emission it produced. An advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. When combined with observationally-deduced plasma density and temperature, these magnetic field measurements offer a straightforward way of tracking evolution of the magnetic and thermal energies in the flare. For the event described here, the magnetic energy density in the radio-emitting volume declines over the flare rise phase, then stays roughly constant during the extended peak phase, but recovers to the original level over the decay phase. At the stage where the magnetic energy density decreases, the thermal energy density increases; however, this increase is insufficient, by roughly an order of magnitude, to compensate for the magnetic energy decrease. When the magnetic energy release is over, the source parameters come back to ne...

  6. NEUTRINO-COOLED ACCRETION MODEL WITH MAGNETIC COUPLING FOR X-RAY FLARES IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Luo Yang; Gu Weimin; Liu Tong; Lu Jufu, E-mail: guwm@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

    2013-08-20T23:59:59.000Z

    The neutrino-cooled accretion disk, which was proposed to work as the central engine of gamma-ray bursts, encounters difficulty in interpreting the X-ray flares after the prompt gamma-ray emission. In this paper, the magnetic coupling (MC) between the inner disk and the central black hole (BH) is taken into consideration. For mass accretion rates around 0.001 {approx} 0.1 M{sub Sun} s{sup -1}, our results show that the luminosity of neutrino annihilation can be significantly enhanced due to the coupling effects. As a consequence, after the gamma-ray emission, a remnant disk with mass M{sub disk} {approx}< 0.5 M{sub Sun} may power most of the observed X-ray flares with the rest frame duration less than 100 s. In addition, a comparison between the MC process and the Blandford-Znajek mechanism is shown on the extraction of BH rotational energy.

  7. EVOLUTION OF SOLAR MAGNETIC FIELD AND ASSOCIATED MULTIWAVELENGTH PHENOMENA: FLARE EVENTS ON 2003 NOVEMBER 20

    SciTech Connect (OSTI)

    Kumar, Pankaj; Uddin, Wahab [Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263 129 (India); Manoharan, P. K., E-mail: pkumar@aries.res.i, E-mail: wahab@aries.res.i, E-mail: mano@ncra.tifr.res.i [Radio Astronomy Centre, Tata Institute of Fundamental Research, Udhagamandalam (Ooty) 643 001 (India)

    2010-02-20T23:59:59.000Z

    We analyze Halpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and, radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 2003 November 20 in the active region NOAA 10501 and study properties of reconnection between twisted filament systems, energy release, and associated launch of coronal mass ejections. During both events twisted filaments observed in Halpha approached each other and initiated the flare processes. However, the second event showed the formation of cusp as the filaments interacted. The rotation of sunspots of opposite polarities, inferred from the magnetograms likely powered the twisted filaments and injection of helicity. Along the current sheet between these two opposite polarity sunspots, the shear was maximum, which could have caused the twist in the filament. At the time of interaction between filaments, the reconnection took place and flare emission in thermal and nonthermal energy ranges attained the maximum. The radio signatures revealed the opening of field lines resulting from the reconnection. The Halpha images and radio data provide the inflow speed leading to reconnection and the scale size of the particle acceleration region. The first event produced a narrow and slow CME, whereas the later one was associated with a fast full halo CME. The halo CME signatures observed between the Sun and Earth using white-light and scintillation images and in situ measurements indicated the magnetic energy utilized in the expansion and propagation. The magnetic cloud signature at the Earth confirmed the flux rope ejected at the time of filament interaction and reconnection.

  8. Coronal Trapping of Energetic Flare Particles: Yohkoh/HXT Observations

    E-Print Network [OSTI]

    Metcalf, Thomas R.

    the energization of the solar corona. The most common interpretation for the production of the observed HXR fluxes Alexander Lockheed Martin Solar and Astrophysics Laboratory, Department H1­12, Bldg. 252, 3251 Hanover St in a search for spectral evidence of the coronal trapping of energetic particles during solar flares. Two

  9. Solar flare impulsive phase emission observed with SDO/EVE

    SciTech Connect (OSTI)

    Kennedy, Michael B.; Milligan, Ryan O.; Mathioudakis, Mihalis; Keenan, Francis P., E-mail: mkennedy29@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2013-12-10T23:59:59.000Z

    Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the temperature range log T{sub e} = 5.8-7.2 allow the evolution of the DEM to be studied over a wide temperature range at 10 s cadence. The technique was applied to several M- and X-class flares, where impulsive phase EUV emission is observable in the disk-integrated EVE spectra from emission lines formed up to 3-4 MK and we use spatially unresolved EVE observations to infer the thermal structure of the emitting region. For the nine events studied, the DEMs exhibited a two-component distribution during the impulsive phase, a low-temperature component with peak temperature of 1-2 MK, and a broad high-temperature component from 7 to 30 MK. A bimodal high-temperature component is also found for several events, with peaks at 8 and 25 MK during the impulsive phase. The origin of the emission was verified using Atmospheric Imaging Assembly images to be the flare ribbons and footpoints, indicating that the constructed DEMs represent the spatially average thermal structure of the chromospheric flare emission during the impulsive phase.

  10. The Solar Flare: A Strongly Turbulent Particle Accelerator

    E-Print Network [OSTI]

    California at Berkeley, University of

    Chapter 5 The Solar Flare: A Strongly Turbulent Particle Accelerator L. Vlahos, S. Krucker, and P) and particle acceleration during such an event are rarely discussed together in the same article. Many the topic of particle acceleration is often presented as an addi- tional complication to be addressed

  11. SOLAR FLARE CYCLES , M. D. POPESCU1, 2

    E-Print Network [OSTI]

    on the solar disk. They occur when magnetic field loops undergo reorganization, releasing energy into the solar of a large amount of magnetic energy, previously stored in the solar corona, and dissipated through magneticSOLAR FLARE CYCLES G. MARI1 , M. D. POPESCU1, 2 1 Astronomical Institute of the Romanian Academy

  12. Soft X-ray emission in flaring coronal loops

    E-Print Network [OSTI]

    Pinto, R F; Brun, A S

    2014-01-01T23:59:59.000Z

    Solar flares are associated with intense soft X-ray emission generated by the hot flaring plasma in coronal magnetic loops. Kink unstable twisted flux-ropes provide a source of magnetic energy which can be released impulsively and account for the heating of the plasma in flares. We investigate the temporal, spectral and spatial evolution of the properties of the thermal X-ray emission produced in such kink-unstable magnetic flux-ropes using a series of MHD simulations. We deduce emission diagnostics and their temporal evolution and discuss the results of the simulations with respect to observations. The numerical setup used consists of a highly twisted loop embedded in a region of uniform and untwisted background coronal magnetic field. We let the kink instability develop, compute the evolution of the plasma properties in the loop (density, temperature) and deduce the X-ray emission properties of the plasma during the whole flaring episode. During the initial phase of the instability plasma heating is mostly ...

  13. Global Energetics of Solar Flares: II. Thermal Energies

    E-Print Network [OSTI]

    Aschwanden, M J; Ryan, D; Caspi, A; McTiernan, J M; Warren, H P

    2015-01-01T23:59:59.000Z

    We present the second part of a project on the global energetics of solar flares and CMEs that includes about 400 M- and X-class flares observed with AIA/SDO during the first 3.5 years of its mission. In this Paper II we compute the differential emission measure (DEM) distribution functions and associated multi-thermal energies, using a spatially-synthesized Gaussian DEM forward-fitting method. The multi-thermal DEM function yields a significantly higher (by an average factor of $\\approx 14$), but more comprehensive (multi-)thermal energy than an isothermal energy estimate from the same AIA data. We find a statistical energy ratio of $E_{th}/E_{diss} \\approx 2\\%-40\\%$ between the multi-thermal energy $E_{th}$ and the magnetically dissipated energy $E_{diss}$, which is an order of magnitude higher than the estimates of Emslie et al.~2012. For the analyzed set of M and X-class flares we find the following physical parameter ranges: $L=10^{8.2}-10^{9.7}$ cm for the length scale of the flare areas, $T_p=10^{5.7}-...

  14. ARE CORONAE OF MAGNETICALLY ACTIVE STARS HEATED BY FLARES? II. EXTREME ULTRAVIOLET AND X-RAY FLARE STATISTICS AND THE

    E-Print Network [OSTI]

    Audard, Marc

    @astro.columbia.edu Vinay L. Kashyap and Jeremy J. Drake Harvard-Smithsonian Center for Astrophysics, 60 Garden Street distribution in radiated energy of the late-type active star AD Leo. Occurrence rates of solar flares have almost 2 orders of magnitude in their radiated energy. We compare the observed light curves with light

  15. GAMMA-RAY FLARES FROM RED GIANT/JET INTERACTIONS IN ACTIVE GALACTIC NUCLEI

    SciTech Connect (OSTI)

    Barkov, Maxim V.; Aharonian, Felix A.; Bosch-Ramon, ValentI, E-mail: bmv@mpi-hd.mpg.d [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2010-12-01T23:59:59.000Z

    Non-blazar active galactic nuclei (AGNs) have been recently established as a class of gamma-ray sources. M87, a nearby representative of this class, shows fast TeV variability on timescales of a few days. We suggest a scenario of flare gamma-ray emission in non-blazar AGNs based on a red giant (RG) interacting with the jet at the base. We solve the hydrodynamical equations that describe the evolution of the envelope of an RG blown by the impact of the jet. If the RG is at least slightly tidally disrupted by the supermassive black hole, enough stellar material will be blown by the jet, expanding quickly until a significant part of the jet is shocked. This process can render suitable conditions for energy dissipation and proton acceleration, which could explain the detected day-scale TeV flares from M87 via proton-proton collisions. Since the radiation produced would be unbeamed, such an event should be mostly detected from non-blazar AGNs. They may be frequent phenomena, detectable in the GeV-TeV range even up to distances of {approx}1 Gpc for the most powerful jets. The counterparts at lower energies are expected to be not too bright. M87, and nearby non-blazar AGNs in general, can be fast variable sources of gamma-rays through RG/jet interactions.

  16. Evaluating Transformer Losses

    E-Print Network [OSTI]

    Grun, R. L. Jr.

    therefore are a function of the load squared. No-load losses occur from energizing the transformer steel and fore are continuous regardless of the transformer load. TRANSFORMER DESIGN Both types of losses are a fun ce here ion of design. If losses...

  17. Diagnostics of stellar flares from X-ray observations: from the decay to the rise phase

    E-Print Network [OSTI]

    F. Reale

    2007-05-23T23:59:59.000Z

    The diagnostics of stellar flaring coronal loops have been so far largely based on the analysis of the decay phase. We derive new diagnostics from the analysis of the rise and peak phase of stellar flares. We release the assumption of full equilibrium of the flaring loop at the flare peak, according to the frequently observed delay between the temperature and the density maximum. From scaling laws and hydrodynamic simulations we derive diagnostic formulas as a function of observable quantities and times. We obtain a diagnostic toolset related to the rise phase, including the loop length, density and aspect ratio. We discuss the limitations of this approach and find that the assumption of loop equilibrium in the analysis of the decay leads to a moderate overestimate of the loop length. A few relevant applications to previously analyzed stellar flares are shown. The analysis of the flare rise and peak phase complements and completes the analysis of the decay phase.

  18. DISCOVERY OF 6.035 GHz HYDROXYL MASER FLARES IN IRAS 18566+0408

    SciTech Connect (OSTI)

    Al-Marzouk, A. A.; Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States); Hofner, P. [Physics Department, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 3-72, 58090, Morelia, Michoacan (Mexico); Linz, H. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Olmi, L. [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)

    2012-05-10T23:59:59.000Z

    We report the discovery of 6.035 GHz hydroxyl (OH) maser flares toward the massive star-forming region IRAS 18566+0408 (G37.55+0.20), which is the only region known to show periodic formaldehyde (4.8 GHz H{sub 2}CO) and methanol (6.7 GHz CH{sub 3}OH) maser flares. The observations were conducted between 2008 October and 2010 January with the 305 m Arecibo Telescope in Puerto Rico. We detected two flare events, one in 2009 March and one in 2009 September to November. The OH maser flares are not simultaneous with the H{sub 2}CO flares, but may be correlated with CH{sub 3}OH flares from a component at corresponding velocities. A possible correlated variability of OH and CH{sub 3}OH masers in IRAS 18566+0408 is consistent with a common excitation mechanism (IR pumping) as predicted by theory.

  19. Max '91: flare research at the next solar maximum

    SciTech Connect (OSTI)

    Dennis, B.; Canfield, R.; Bruner, M.; Emslie, G.; Hildner, E.; Hudson, H.; Hurford, G.; Lin, R.; Novick, R.; Tarbell, T.

    1988-01-01T23:59:59.000Z

    To address the central scientific questions surrounding solar flares, coordinated observations of electromagnetic radiation and energetic particles must be made from spacecraft, balloons, rockets, and ground-based observatories. A program to enhance capabilities in these areas in preparation for the next solar maximum in 1991 is recommended. The major scientific issues are described, and required observations and coordination of observations and analyses are detailed. A program plan and conceptual budgets are provided.

  20. Seismic Emissions from a Highly Impulsive M6.7 Solar Flare

    E-Print Network [OSTI]

    J. C. Martinez-Oliveros; H. Moradi; A-C. Donea

    2008-01-09T23:59:59.000Z

    On 10 March 2001 the active region NOAA 9368 produced an unusually impulsive solar flare in close proximity to the solar limb. This flare has previously been studied in great detail, with observations classifying it as a type 1 white-light flare with a very hard spectrum in hard X-rays. The flare was also associated with a type II radio burst and coronal mass ejection. The flare emission characteristics appeared to closely correspond with previous instances of seismic emission from acoustically active flares. Using standard local helioseismic methods, we identified the seismic signatures produced by the flare that, to date, is the least energetic (in soft X-rays) of the flares known to have generated a detectable acoustic transient. Holographic analysis of the flare shows a compact acoustic source strongly correlated with the impulsive hard X-ray, visible continuum, and radio emission. Time-distance diagrams of the seismic waves emanating from the flare region also show faint signatures, mainly in the eastern sector of the active region. The strong spatial coincidence between the seismic source and the impulsive visible continuum emission reinforces the theory that a substantial component of the seismic emission seen is a result of sudden heating of the low photosphere associated with the observed visible continuum emission. Furthermore, the low-altitude magnetic loop structure inferred from potential--field extrapolations in the flaring region suggests that there is a significant inverse correlation between the seismicity of a flare and the height of the magnetic loops that conduct the particle beams from the corona.

  1. SHORT-TERM SOLAR FLARE PREDICTION USING MULTIRESOLUTION PREDICTORS

    SciTech Connect (OSTI)

    Yu Daren; Huang Xin; Hu Qinghua; Zhou Rui [Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin, Heilongjiang Province (China); Wang Huaning [National Astronomical Observatories, 20A Datun Road, Chaoyang District, Beijing (China); Cui Yanmei, E-mail: huangxinhit@yahoo.com.c [Center for Space Science and Applied Research, No. 1 Nanertiao, Zhongguancun, Haidian District, Beijing (China)

    2010-01-20T23:59:59.000Z

    Multiresolution predictors of solar flares are constructed by a wavelet transform and sequential feature extraction method. Three predictors-the maximum horizontal gradient, the length of neutral line, and the number of singular points-are extracted from Solar and Heliospheric Observatory/Michelson Doppler Imager longitudinal magnetograms. A maximal overlap discrete wavelet transform is used to decompose the sequence of predictors into four frequency bands. In each band, four sequential features-the maximum, the mean, the standard deviation, and the root mean square-are extracted. The multiresolution predictors in the low-frequency band reflect trends in the evolution of newly emerging fluxes. The multiresolution predictors in the high-frequency band reflect the changing rates in emerging flux regions. The variation of emerging fluxes is decoupled by wavelet transform in different frequency bands. The information amount of these multiresolution predictors is evaluated by the information gain ratio. It is found that the multiresolution predictors in the lowest and highest frequency bands contain the most information. Based on these predictors, a C4.5 decision tree algorithm is used to build the short-term solar flare prediction model. It is found that the performance of the short-term solar flare prediction model based on the multiresolution predictors is greatly improved.

  2. Magnetic Energy Dissipation during the 2014 March 29 Solar Flares

    E-Print Network [OSTI]

    Aschwanden, Markus J

    2015-01-01T23:59:59.000Z

    We calculated the time evolution of the free magnetic energy during the 2014-Mar-29 flare (SOL2014-03-29T17:48), the first X-class flare detected by IRIS. The free energy was calculated from the difference between the nonpotential field, constrained by the geometry of observed loop structures, and the potential field. We use AIA/SDO and IRIS images to delineate the geometry of coronal loops in EUV wavelengths, as well as to trace magnetic field directions in UV wavelengths in the chromosphere and transition region. We find an identical evolution of the free energy for both the coronal and chromospheric tracers, as well as agreement between AIA and IRIS results, with a peak free energy of $E_{free}(t_{peak}) \\approx (45 \\pm 2) \\times 10^{30}$ erg, which decreases by an amount of $\\Delta E_{free} \\approx (29 \\pm 3) \\times 10^{30}$ erg during the flare decay phase. The consistency of free energies measured from different EUV and UV wavelengths for the first time here, demonstrates that vertical electric currents...

  3. Exploring the connection between coronal and footpoint sources in a thin-thick target solar flare model

    E-Print Network [OSTI]

    Marina Battaglia; Arnold O. Benz

    2007-02-12T23:59:59.000Z

    Context: Hard X-ray emission of coronal sources in solar flares has been observed and studied since its discovery in Yohkoh observations. Several models have been proposed to explain the physical mechanisms causing this emission and the relations between those sources and simultaneously observed footpoint sources. Aims: We investigate and test one of the models (intermediate thin-thick target model) developed on the basis of Yohkoh observations. The model makes precise predictions on the shape of coronal and footpoint spectra and the relations between them, that can be tested with new instruments such as RHESSI. Methods: RHESSI observations of well observed events are studied in imaging and spectroscopy and compared to the predictions from the intermediate thin-thick target model. Results: The results indicate that such a simple model cannot account for the observed relations between the non-thermal spectra of coronal and footpoint sources. Including non-collisional energy loss of the electrons in the flare loop due to an electric field can solve most of the inconsistencies.

  4. GeV-TeV and X-ray flares from gamma-ray bursts

    E-Print Network [OSTI]

    Xiang-Yu Wang; Zhuo Li; Peter Meszaros

    2006-03-13T23:59:59.000Z

    The recent detection of delayed X-ray flares during the afterglow phase of gamma-ray bursts (GRBs) suggests an inner-engine origin, at radii inside the deceleration radius characterizing the beginning of the forward shock afterglow emission. Given the observed temporal overlapping between the flares and afterglows, there must be inverse Compton (IC) emission arising from such flare photons scattered by forward shock afterglow electrons. We find that this IC emission produces GeV-TeV flares, which may be detected by GLAST and ground-based TeV telescopes. We speculate that this kind of emission may already have been detected by EGRET from a very strong burst--GRB940217. The enhanced cooling of the forward shock electrons by the X-ray flare photons may suppress the synchrotron emission of the afterglows during the flare period. The detection of GeV-TeV flares combined with low energy observations may help to constrain the poorly known magnetic field in afterglow shocks. We also consider the self-IC emission in the context of internal-shock and external-shock models for X-ray flares. The emission above GeV from internal shocks is low, while the external shock model can also produce GeV-TeV flares, but with a different temporal behavior from that caused by IC scattering of flare photons by afterglow electrons. This suggests a useful approach for distinguishing whether X-ray flares originate from late central engine activity or from external shocks.

  5. GRB 060714: No Clear Dividing Line Between Prompt Emission and X-Ray Flares

    SciTech Connect (OSTI)

    Krimm, Hans A.; /NASA, Goddard /Universities Space Research Assoc.; Granot, J.; /KIPAC, Menlo Park; Marshal, F.; /NASA, Goddard; Perri, M.; /ASDC, Frascati; Barthelmy, S.D.; /NASA, Goddard; Burrows, D.N.; /Penn State U., Astron. Astrophys.; Gehrels, N.; /NASA, Goddard; Meszaros, P.; Morris, D.; /Penn State U., Astron. Astrophys.; ,

    2007-02-26T23:59:59.000Z

    The long gamma-ray burst GRB 060714 was observed to exhibit a series of five X-ray flares beginning {approx} 70 s after the burst trigger T{sub 0} and continuing until {approx} T{sub 0} + 200 s. The first two flares were detected by the Burst Alert Telescope (BAT) on the Swift satellite, before Swift had slewed to the burst location, while the last three flares were strongly detected by the X-Ray Telescope (XRT) but only weakly detected by the BAT. This burst provides an unusual opportunity to track a complete sequence of flares over a wide energy range. The flares were very similar in their light curve morphology, showing power-law rise and fall components, and in most cases significant sub-structure. The flares also showed strong evolution with time, both spectrally and temporally. The small time scale and large amplitude variability observed are incompatible with an external shock origin for the flares, and support instead late time sporadic activity either of the central source or of localized dissipation events within the outflow. We show that the flares in GRB 060714 cannot be the result of internal shocks in which the contrast in the Lorentz factor of the colliding shells is very small, and that this mechanism faces serious difficulties in most Swift GRBs. The morphological similarity of the flares and the prompt emission and the gradual and continual evolution of the flares with time makes it difficult and arbitrary to draw a dividing line between the prompt emission and the flares.

  6. Unknown: Multifocal scalp hair loss

    E-Print Network [OSTI]

    Shamsadini, Sadollah; Esfandiarpoor, Iraj; Zeinali, Hamid; Kalantari, Behjat; Ebrahimi, Hoseiali

    2006-01-01T23:59:59.000Z

    Unknown: Multifocal scalp hair loss Sadllah Shamsadini 1 ,four patches of scalp hair loss. What is your diagnosis?

  7. Topology and current ribbons: A model for current, reconnection and flaring in a complex, evolving corona

    E-Print Network [OSTI]

    Longcope, Dana

    (MCC), for the build­up of magnetic energy in a three­dimensional corona of arbitrary geometry. The MCCTopology and current ribbons: A model for current, reconnection and flaring in a complex, evolving of energy from the Sun's chromosphere and corona. The build­up and release of energy in a flare has been

  8. Broadening Calculation of the HeI 10830 A Line in Solar Limb Flare

    E-Print Network [OSTI]

    Li, Hui

    Broadening Calculation of the HeI 10830 °A Line in Solar Limb Flare LI Hui and YOU Jianqi Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China Abstract The Doppler broadening, Stark broadening and various kinds of broadening param- eters of the HeI 10830 °A line in solar flare

  9. Broadening Calculation of the HeI 10830 A Line in Solar Limb Flare #

    E-Print Network [OSTI]

    Li, Hui

    Broadening Calculation of the HeI 10830 š A Line in Solar Limb Flare # LI Hui and YOU Jianqi Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China Abstract The Doppler broadening, Stark broadening and various kinds of broadening param­ eters of the HeI 10830 š A line in solar flare

  10. ACCELERATION AND ENRICHMENT OF 3 IMPULSIVE SOLAR FLARES BY ELECTRON FIREHOSE

    E-Print Network [OSTI]

    ACCELERATION AND ENRICHMENT OF 3 He IN IMPULSIVE SOLAR FLARES BY ELECTRON FIREHOSE WAVES G. Paesold A new mechanism for acceleration and enrichment of 3 He during impulsive solar flares is presented. Low of the free energy stored in a temperature anisotropy (Te > Te ) of the bulk energized electron population

  11. TRACE and YOHKOH Observations of a White Light Flare Thomas R. Metcalf1

    E-Print Network [OSTI]

    Metcalf, Thomas R.

    . Hudson 2 , and Dana W. Longcope3 ABSTRACT We present observations of a large solar white light flare at 400 km s-1 . This is evidence in favor of particle acceleration models which energize the electrons), are typically the most energetic of solar flares. "White light" refers to continuum emission in excess

  12. Free Magnetic Energy and Flare Productivity of Active Regions , Changyi Tan2,3

    E-Print Network [OSTI]

    Free Magnetic Energy and Flare Productivity of Active Regions Ju Jing1 , Changyi Tan2,3 , Yuan Yuan with which we are able to estimate the free magnetic energy stored in the active regions. The magnitude scaling correlation between the free magnetic energy and the soft X-ray flare index of active regions

  13. CONSERVATION OF BOTH CURRENT AND HELICITY IN A QUADRUPOLAR MODEL FOR SOLAR FLARES

    E-Print Network [OSTI]

    Melrose, Don

    is neglected. 1. Introduction Solar flares are attributed to magnetic energy release in the solar coronaCONSERVATION OF BOTH CURRENT AND HELICITY IN A QUADRUPOLAR MODEL FOR SOLAR FLARES DON MELROSE School of Physics,University of Sydney, NSW 2006, Australia (Received 25 Novemebr 2003; accepted 9

  14. PPPL-3450 PPPL-3450 Solar Flare Mechanism Based on Magnetic Arcade

    E-Print Network [OSTI]

    PPPL-3450 PPPL-3450 UC-70 Solar Flare Mechanism Based on Magnetic Arcade Reconnection and Island Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 Telephone: 1, 00, 000­000, 2000 Solar Flare Mechanism Based on Magnetic Arcade Reconnection and Island Merging C. Z

  15. Unveiling the origin of X-ray flares in Gamma-Ray Bursts

    E-Print Network [OSTI]

    Chincarini, G; Margutti, R; Bernardini, M G; Guidorzi, C; Pasotti, F; Giannios, D; Della Valle, M; Moretti, A; Romano, P; D'Avanzo, P; Cusumano, G; Giommi, P

    2010-01-01T23:59:59.000Z

    We present an updated catalog of 113 X-ray flares detected by Swift in the ~33% of the X-ray afterglows of Gamma-Ray Bursts (GRB). 43 flares have a measured redshift. For the first time the analysis is performed in 4 different X-ray energy bands, allowing us to constrain the evolution of the flare temporal properties with energy. We find that flares are narrower at higher energies: their width follows a power-law relation w~E^{-0.5} reminiscent of the prompt emission. Flares are asymmetric structures, with a decay time which is twice the rise time on average. Both time scales linearly evolve with time, giving rise to a constant rise-to-decay ratio: this implies that both time scales are stretched by the same factor. As a consequence, the flare width linearly evolves with time to larger values: this is a key point that clearly distinguishes the flare from the GRB prompt emission. The flare 0.3-10 keV peak luminosity decreases with time, following a power-law behaviour with large scatter: L_{pk}~ t_{pk}^{-2.7}....

  16. FLARE HEATING IN STELLAR CORONAE Vinay L. Kashyap and Jeremy J. Drake

    E-Print Network [OSTI]

    Audard, Marc

    for Astrophysics, 60 Garden Street, Cambridge, MA 02138; vkashyap@cfa.harvard.edu, jdrake 2002 March 25; accepted 2002 August 2 ABSTRACT An open question in the field of solar and stellar to flares that are increasingly less energetic but are more numerous. Previous analyses of flares in light

  17. Seismic Emissions from a Highly Impulsive M6.7 Solar Flare

    E-Print Network [OSTI]

    California at Berkeley, University of

    Seismic Emissions from a Highly Impulsive M6.7 Solar Flare J.C. Mart´inez-Oliveros, H. Moradi, A characteristics appeared to closely correspond with previous instances of seismic emission from acoustically active flares. Using standard local helioseismic methods, we identified the seismic sig- natures produced

  18. PUBLISHED ONLINE: 15 AUGUST 2010 | DOI: 10.1038/NPHYS1741 The effect of flares on total solar irradiance

    E-Print Network [OSTI]

    Loss, Daniel

    - quality space instrumentation has been purpose built. However, the total energy radiated by flares and itsLETTERS PUBLISHED ONLINE: 15 AUGUST 2010 | DOI: 10.1038/NPHYS1741 The effect of flares on total flares, from our own Sun, are the most energetic events in the solar system, in comparison to the total

  19. Using the Maximum X-ray Flux Ratio and X-ray Background to Predict Solar Flare Class

    E-Print Network [OSTI]

    Winter, Lisa M

    2015-01-01T23:59:59.000Z

    We present the discovery of a relationship between the maximum ratio of the flare flux (namely, 0.5-4 Ang to the 1-8 Ang flux) and non-flare background (namely, the 1-8 Ang background flux), which clearly separates flares into classes by peak flux level. We established this relationship based on an analysis of the Geostationary Operational Environmental Satellites (GOES) X-ray observations of ~ 50,000 X, M, C, and B flares derived from the NOAA/SWPC flares catalog. Employing a combination of machine learning techniques (K-nearest neighbors and nearest-centroid algorithms) we show a separation of the observed parameters for the different peak flaring energies. This analysis is validated by successfully predicting the flare classes for 100% of the X-class flares, 76% of the M-class flares, 80% of the C-class flares and 81% of the B-class flares for solar cycle 24, based on the training of the parametric extracts for solar flares in cycles 22-23.

  20. Flare Noise Reduction Exxon Chemical- Baytown Olefins Plant: 1994 CMA Energy Efficiency Award for "Flare Noise Reduction" in the category of "Public Outreach/Plant Site"

    E-Print Network [OSTI]

    Bradham, S.; Stephan, R.

    frequency noise that resembles the sound of a jet plane passing overhead. To supplement the qualitative data received from the community, quantitative noise data was collected at various flaring conditions, wind conditions, and steam rates. Additional...

  1. Patient stratification and genomics: flares, fizzlers and foxes

    E-Print Network [OSTI]

    Smith, Kenneth GC

    2012-11-28T23:59:59.000Z

    INVITED SPEAKER PRESENTATION Open Access Patient stratification and genomics: flares, fizzlers and foxes Kenneth GC Smith From 7th European Workshop on Immune-Mediated Inflammatory Diseases Noordwijk aan Zee, the Netherlands. 28-30 November 2012... , Rees AJ, Clayton DG, Smith KGC: Genetically distinct subsets within ANCA-associated vasculitis. N Engl J Med 2012, 367:214-223. 2. McKinney EF, Lyons PA, Carr EJ, Hollis JL, Jayne DRW, Willcocks LC, Koukoulaki M, Hatton A, MacAry PA, Brazma A, Chaudhry...

  2. Kentucky Natural Gas Vented and Flared (Million Cubic Feet)

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40 Buildingto China (Million Cubic Feet) Kenai,Feet)Year JanVented and Flared

  3. Extreme Ultra-Violet Spectroscopy of the Flaring Solar Chromosphere

    E-Print Network [OSTI]

    Milligan, Ryan O

    2015-01-01T23:59:59.000Z

    The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.

  4. Virginia Natural Gas Vented and Flared (Million Cubic Feet)

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40 Buildingto17 34 44Year JanDecade Year-0 Year-1 Year-2Feet)Vented and Flared

  5. Florida Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40CoalLease(Billion2,12803 Table A1.GasYear Jan Feb Mar AprVented and Flared

  6. Florida Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40CoalLease(Billion2,12803 Table A1.GasYear Jan Feb Mar AprVented and FlaredVented

  7. Illinois Natural Gas Vented and Flared (Million Cubic Feet)

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122 40CoalLease(Billion2,12803 TableTotal Consumption (MillionTotalVented and Flared

  8. Ohio Natural Gas Vented and Flared (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5 Tables July 1996 Energy Information Administration Office ofthroughYear Jan Feb Mar Apr May Jun Jul9 20102009Vented and Flared

  9. Ohio Natural Gas Vented and Flared (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5 Tables July 1996 Energy Information Administration Office ofthroughYear Jan Feb Mar Apr May Jun Jul9 20102009Vented and FlaredVented

  10. Oklahoma Natural Gas Vented and Flared (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5 Tables July 1996 Energy Information Administration Office ofthroughYear Jan Feb Mar Apr May JunFeet)TotalVented and Flared

  11. Oklahoma Natural Gas Vented and Flared (Million Cubic Feet)

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5 Tables July 1996 Energy Information Administration Office ofthroughYear Jan Feb Mar Apr May JunFeet)TotalVented and FlaredVented

  12. RAPID TeV GAMMA-RAY FLARING OF BL LACERTAE

    SciTech Connect (OSTI)

    Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)] [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States)] [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)] [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)] [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)] [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Feng, Q.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)] [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Dumm, J.; Fortson, L. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)] [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)] [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Falcone, A. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Federici, S. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany)] [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Finnegan, G., E-mail: qfeng@purdue.edu, E-mail: cui@purdue.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Collaboration: VERITAS Collaboration; and others

    2013-01-10T23:59:59.000Z

    We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 {+-} 0.6) Multiplication-Sign 10{sup -6} photons m{sup -2} s{sup -1}, roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 {+-} 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 {+-} 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.

  13. Heat loss from an open cavity

    SciTech Connect (OSTI)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01T23:59:59.000Z

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  14. Maximum gravitational-wave energy emissible in magnetar flares

    E-Print Network [OSTI]

    Alessandra Corsi; Benjamin J. Owen

    2011-02-16T23:59:59.000Z

    Recent searches of gravitational-wave (GW) data raise the question of what maximum GW energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (\\sim 10^{49} erg) predicted so far come from a model [K. Ioka, Mon. Not. Roy. Astron. Soc. 327, 639 (2001)] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10^{48}-10^{49} erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

  15. SLOW MAGNETOACOUSTIC OSCILLATIONS IN THE MICROWAVE EMISSION OF SOLAR FLARES

    SciTech Connect (OSTI)

    Kim, S.; Shibasaki, K. [Nobeyama Solar Radio Observatory/NAOJ, Nagano 384-1305 (Japan); Nakariakov, V. M., E-mail: sjkim@nro.nao.ac.jp [Physics Department, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2012-09-10T23:59:59.000Z

    Analysis of the microwave data, obtained in the 17 GHz channel of the Nobeyama Radioheliograph during the M1.6 flare on 2010 November 4, revealed the presence of 12.6 minute oscillations of the emitting plasma density. The oscillations decayed with the characteristic time of about 15 minutes. Similar oscillations with the period of about 13.8 minutes and the decay time of 25 minutes are also detected in the variation of EUV emission intensity measured in the 335 A channel of the Solar Dynamics Observatory/Atmospheric Imaging Assembly. The observed properties of the oscillations are consistent with the oscillations of hot loops observed by the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) in the EUV spectra in the form of periodic Doppler shift. Our analysis presents the first direct observations of the slow magnetoacoustic oscillations in the microwave emission of a solar flare, complementing accepted interpretations of SUMER hot loop oscillations as standing slow magnetoacoustic waves.

  16. MULTI-WAVELENGTH OBSERVATIONS OF THE SPATIO-TEMPORAL EVOLUTION OF SOLAR FLARES WITH AIA/SDO. II. HYDRODYNAMIC SCALING LAWS AND THERMAL ENERGIES

    SciTech Connect (OSTI)

    Aschwanden, Markus J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304 (United States); Shimizu, Toshifumi, E-mail: aschwanden@lmsal.com, E-mail: shimizu.toshifumi@isas.jaxa.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-10-20T23:59:59.000Z

    In this study we measure physical parameters of the same set of 155 M- and X-class solar flares observed with AIA/SDO as analyzed in Paper I, by performing a differential emission measure analysis to determine the flare peak emission measure EM{sub p} , peak temperature T{sub p} , electron density n{sub p} , and thermal energy E{sub th}, in addition to the spatial scales L, areas A, and volumes V measured in Paper I. The parameter ranges for M- and X-class flares are log (EM{sub p}) = 47.0-50.5, T{sub p} = 5.0-17.8 MK, n{sub p} = 4 × 10{sup 9}-9 × 10{sup 11} cm{sup –3}, and thermal energies of E{sub th} = 1.6 × 10{sup 28}-1.1 × 10{sup 32} erg. We find that these parameters obey the Rosner-Tucker-Vaiana (RTV) scaling law T{sub p}{sup 2}?n{sub p} L and H?T {sup 7/2} L {sup –2} during the peak time t{sub p} of the flare density n{sub p} , when energy balance between the heating rate H and the conductive and radiative loss rates is achieved for a short instant and thus enables the applicability of the RTV scaling law. The application of the RTV scaling law predicts power-law distributions for all physical parameters, which we demonstrate with numerical Monte Carlo simulations as well as with analytical calculations. A consequence of the RTV law is also that we can retrieve the size distribution of heating rates, for which we find N(H)?H {sup –1.8}, which is consistent with the magnetic flux distribution N(?)??{sup –1.85} observed by Parnell et al. and the heating flux scaling law F{sub H} ?HL?B/L of Schrijver et al.. The fractal-diffusive self-organized criticality model in conjunction with the RTV scaling law reproduces the observed power-law distributions and their slopes for all geometrical and physical parameters and can be used to predict the size distributions for other flare data sets, instruments, and detection algorithms.

  17. A Comprehensive Study of Gamma-Ray Burst Optical Emission: I. Flares and Early Shallow Decay Component

    E-Print Network [OSTI]

    Li, Liang; Tang, Qing-Wen; Chen, Jie-Min; Xi, Shao-Qiang; LV, Hou-Jun; Zhang, Bing; Zhang, Jin; Yi, Shuang-Xi; Lu, Rui-Jing; LV, Lian-Zhong; Wei, Jian-Yan

    2012-01-01T23:59:59.000Z

    Well-sampled optical lightcurves of 146 GRBs are complied from the literature. Fitting the lightcurves with the superposition of multiple broken power law functions, we identify eight possible emission components that may have distinct physical origins. We summarize the results in a "synthetic" optical lightcurve. In this paper we focus on a statistical analysis of optical flares and an early optical shallow-decay component, both are likely related to a long-term central engine activity. Twenty-four optical flares are obtained from 19 GRBs. The isotropic flare peak luminosity is correlated with that of gamma-rays. The flares peak at from tens of seconds to several days post the GRB trigger. Later flares tend to be wider and dimmer. The fraction of GRBs with detected optical flares is much smaller than that of X-ray flares. Associated X-ray flares are observed for 4 optical flares, and the optical flares usually lag behind the corresponding X-ray flares. An optical shallow decay segment is observed in 39 GRBs....

  18. Dynamics of Electric Currents, Magnetic Field Topology and Helioseismic Response of a Solar Flare

    E-Print Network [OSTI]

    Sharykin, I N

    2015-01-01T23:59:59.000Z

    The solar flare on July 30, 2011 was of a modest X-ray class (M9.3), but it made a strong photospheric impact and produced a "sunquake," observed with the Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamics Observatory (SDO). In addition to the helioseismic waves (also observed with the SDO/AIA instrument), the flare caused a large expanding area of white-light emission and was accompanied by substantial restructuring of magnetic fields, leading to the rapid formation of a sunspot structure in the flare region. The flare produced no significant hard X-ray emission and no coronal mass ejection. This indicates that the flare energy release was mostly confined to the lower atmosphere. The absence of significant coronal mass ejection rules out magnetic rope eruption as a mechanism of helioseismic waves. We discuss the connectivity of the flare energy release with the electric currents dynamics and show the potential importance of high-speed plasma flows in the lower solar atmosphere during the flare e...

  19. Impulsive phase flare energy transport by large-scale Alfven waves and the electron acceleration problem

    E-Print Network [OSTI]

    L. Fletcher; H. S. Hudson

    2007-12-20T23:59:59.000Z

    The impulsive phase of a solar flare marks the epoch of rapid conversion of energy stored in the pre-flare coronal magnetic field. Hard X-ray observations imply that a substantial fraction of flare energy released during the impulsive phase is converted to the kinetic energy of mildly relativistic electrons (10-100 keV). The liberation of the magnetic free energy can occur as the coronal magnetic field reconfigures and relaxes following reconnection. We investigate a scenario in which products of the reconfiguration - large-scale Alfven wave pulses - transport the energy and magnetic-field changes rapidly through the corona to the lower atmosphere. This offers two possibilities for electron acceleration. Firstly, in a coronal plasma with beta energies on the order of 10 keV and above, including by repeated interactions between electrons and wavefronts. Secondly, when they reflect and mode-convert in the chromosphere, a cascade to high wavenumbers may develop. This will also accelerate electrons by turbulence, in a medium with a locally high electron number density. This concept, which bridges MHD-based and particle-based views of a flare, provides an interpretation of the recently-observed rapid variations of the line-of-sight component of the photospheric magnetic field across the flare impulsive phase, and offers solutions to some perplexing flare problems, such as the flare "number problem" of finding and resupplying sufficient electrons to explain the impulsive-phase hard X-ray emission.

  20. RAPID SUNSPOT ROTATION ASSOCIATED WITH THE X2.2 FLARE ON 2011 FEBRUARY 15

    SciTech Connect (OSTI)

    Jiang Yunchun; Zheng Ruisheng; Yang Jiayan; Hong Junchao; Yi Bi; Yang Dan, E-mail: jyc@ynao.ac.cn [National Astronomical Observatory/Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

    2012-01-01T23:59:59.000Z

    We present observations of sunspot evolution associated with the first X-class flare of the present solar cycle 24, which occurred in AR 11158 on 2011 February 15. The active region consisted of four emerging bipoles that showed complicated sunspot motion. The preceding spot of a bipole underwent the fastest movement. It not only passed through the following end of another bipole, thus causing a shearing motion, but also merged with the same-polarity spots and formed a single, larger umbra. This led to the formation of a {delta} configuration with an S-shaped neutral line, above which an extreme ultraviolet filament channel and a sigmoid formed and erupted to produce the flare. Along with the development of a clockwise (CW) spiral penumbra-filament pattern, the merged spot started rapid CW rotation around its umbral center 20 hr before the flare. The rotation persisted throughout the flare but stopped sharply about 1 hr after the flare ended, maintaining the twisted penumbra-filament pattern. The moving spot also caused continuous flux cancellation; in particular, its outer penumbra directly collided with small opposite-polarity spots only 100 minutes before the flare. When the shearing and rotational motions are main contributors to the energy buildup and helicity injection for the flare, the cancellation and collision might act as a trigger. Our observations support the idea that the rotation can be attributed to the emergence of twisted magnetic fields, as proposed in recent theories. Finally, the cause of its sudden halt is discussed.

  1. Confined Flares in Solar Active Region 12192 from 2014 October 18 to 29

    E-Print Network [OSTI]

    Chen, Huadong; Ma, Suli; Yang, Shuhong; Li, Leping; Huang, Xin; Xiao, Junmin

    2015-01-01T23:59:59.000Z

    Using the observations from the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO), we investigate six X-class and twenty-nine M-class flares occurring in solar active region (AR) 12192 from October 18 to 29. Among them, thirty (including six X- and twenty-four M-class) flares originated from the AR core and the other five M-flares appeared at the AR periphery. Four of the X-flares exhibited similar flaring structures, indicating they were homologous flares with analogous triggering mechanism. The possible scenario is: photospheric motions of emerged magnetic fluxes lead to shearing of the associated coronal magnetic field, which then yields a tether-cutting favorable configuration. Among the five periphery M-flares, four were associated with jet activities. The HMI vertical magnetic field data show that the photospheric fluxes of opposite magnetic polarities emerged, converged and canceled with each other at the footpoints of the jets bef...

  2. A NEW CORRELATION BETWEEN GRB X-RAY FLARES AND THE PROMPT EMISSION

    SciTech Connect (OSTI)

    Sonbas, E. [Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey); MacLachlan, G. A.; Shenoy, A.; Dhuga, K. S.; Parke, W. C., E-mail: edasonbas@yahoo.com [Department of Physics, George Washington University, Washington, DC 20052 (United States)

    2013-04-20T23:59:59.000Z

    From a sample of gamma-ray bursts (GRBs) detected by the Fermi and Swift missions, we have extracted the minimum variability timescales for temporal structures in the light curves associated with the prompt emission and X-ray flares. A comparison of this variability timescale with pulse parameters such as rise times, determined via pulse-fitting procedures, and spectral lags, extracted via the cross-correlation function, indicates a tight correlation between these temporal features for both the X-ray flares and the prompt emission. These correlations suggest a common origin for the production of X-ray flares and the prompt emission in GRBs.

  3. Regularized energy-dependent solar flare hard x-ray spectral index

    E-Print Network [OSTI]

    Eduard P. Kontar; Alexander L. MacKinnon

    2005-06-05T23:59:59.000Z

    The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency of spectral index for a high resolution energy spectrum provided by Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The regularization technique produces much smoother derivatives while avoiding additional errors typical of finite differences. It is shown that observations imply a spectral index varying significantly with energy, in a way that also varies with time as the flare progresses. The implications of these findings are discussed in the solar flare context.

  4. Simbol-X capability of detecting the non-thermal emission of stellar flares

    E-Print Network [OSTI]

    C. Argiroffi; G. Micela; A. Maggio

    2008-01-16T23:59:59.000Z

    We investigate the capability of detecting, with Simbol-X, non-thermal emission during stellar flares, and distinguishing it from hot thermal emission. We find that flare non-thermal emission is detectable when at least ~20 cts are detected with the CZT detector in the 20-80 keV band. Therefore Simbol-X will detect the non-thermal emission from some of the X-ray brightest nearby stars, whether the thermal vs. non-thermal relation, derived for solar flares, holds.

  5. Neutrino Solar Flare detection for a saving alert system of satellites and astronauts

    E-Print Network [OSTI]

    Fargion, Daniele

    2011-01-01T23:59:59.000Z

    Largest Solar Neutrino Flare may be soon detectable by Deep Core neutrino detector immediately and comunicate to satellites or astronauts. Its detection is the fastest manifestation of a later (tens minutes,hours) dangerous cosmic shower. The precursor trigger maybe saving satellites and even long flight astronauts lives. We shall suggest how. Moreover their detection may probe the inner solar flare acceleration place as well as the neutrino flavor mixing in a new different parameter windows. We show the updated expected rate and signature of neutrinos and antineutrinos in largest solar flare for present tens Megaton Deep Core telescope at tens Gev range. Speculation for additional Icecube gigaton array signals are also considered.

  6. Neutrino Solar Flare detection for a saving alert system of satellites and astronauts

    E-Print Network [OSTI]

    Daniele Fargion

    2011-06-19T23:59:59.000Z

    Largest Solar Neutrino Flare may be soon detectable by Deep Core neutrino detector immediately and comunicate to satellites or astronauts. Its detection is the fastest manifestation of a later (tens minutes,hours) dangerous cosmic shower. The precursor trigger maybe saving satellites and even long flight astronauts lives. We shall suggest how. Moreover their detection may probe the inner solar flare acceleration place as well as the neutrino flavor mixing in a new different parameter windows. We show the updated expected rate and signature of neutrinos and antineutrinos in largest solar flare for present tens Megaton Deep Core telescope at tens Gev range. Speculation for additional Icecube gigaton array signals are also considered.

  7. Triggering of Remote Flares by Magnetic Flux Emergence

    E-Print Network [OSTI]

    Fu, Yixing

    2015-01-01T23:59:59.000Z

    We study the effect of new emerging solar active regions on the large-scale magnetic environment of existing regions. We first present a theoretical approach to quantify the "interaction energy" between new and pre-existing regions as the difference between (i) the summed magnetic energies of their individual potential fields and (ii) the energy of their superposed potential fields. We expect that this interaction energy can, depending upon the relative arrangements of newly emerged and pre-existing magnetic flux, indicate the existence of "topological" free magnetic energy in the global coronal field that is independent of any "internal" free magnetic energy due to coronal electric currents flowing within the newly emerged and pre-existing flux systems. We then examine the interaction energy in two well-studied cases of flux emergence, but find that the predicted energetic perturbation is relatively small compared to energies released in large solar flares. Next, we present an observational study on the infl...

  8. Optimal Electron Energies for Driving Chromospheric Evaporation in Solar Flares

    E-Print Network [OSTI]

    Reep, Jeffrey; Alexander, David

    2015-01-01T23:59:59.000Z

    In the standard model of solar flares, energy deposition by a beam of electrons drives strong chromospheric evaporation leading to a significantly denser corona and much brighter emission across the spectrum. Chromospheric evaporation was examined in great detail by Fisher, Canfield, & McClymont (1985a,b,c), who described a distinction between two different regimes, termed explosive and gentle evaporation. In this work, we examine the importance of electron energy and stopping depths on the two regimes and on the atmospheric response. We find that with explosive evaporation, the atmospheric response does not depend strongly on electron energy. In the case of gentle evaporation, lower energy electrons are significantly more efficient at heating the atmosphere and driving up-flows sooner than higher energy electrons. We also find that the threshold between explosive and gentle evaporation is not fixed at a given beam energy flux, but also depends strongly on the electron energy and duration of heating. Furt...

  9. Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. II. Inclusion of Radiative Transfer with RADYN

    E-Print Network [OSTI]

    da Costa, Fatima Rubio; Petrosian, Vahe'; Carlsson, Mats

    2015-01-01T23:59:59.000Z

    Solar flares involve complex processes that are coupled together and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present such a model to simulate the coupling of high-energy particle kinetics with hydrodynamics of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration, transport, and bremsstrahlung radiation with the RADYN hydrodynamic code that models the atmospheric response to collisional heating by non-thermal electrons through detailed radiative transfer calculations. We perform simulations using different injection electron spectra, including an {\\it ad hoc} power law and more realistic spectra predicted by the stochastic acceleration model due to turbulence or plasma waves. Surprisingly, stochastically accelerated electrons, even with energy flux $\\ll 10^{10}$ erg s$^{-1}$ cm$^{-2}$, cause "explosive" chromospheric evaporation and drive stronger up- an...

  10. X-ray flares from dense shells formed in gamma-ray burst explosions

    E-Print Network [OSTI]

    Hascoet, R; Daigne, F; Mochkovitch, R

    2015-01-01T23:59:59.000Z

    Bright X-ray flares are routinely detected by the Swift satellite during the early afterglow of gamma-ray bursts, when the explosion ejecta drives a blast wave into the external medium. We suggest that the flares are produced as the reverse shock propagates into the tail of the ejecta. The ejecta is expected to contain a few dense shells formed at an earlier stage of the explosion. We show an example of how such dense shells form and describe how the reverse shock interacts with them. A new reflected shock is generated in this interaction, which produces a short-lived X-ray flare. The model provides a natural explanation for the main observed features of the X-ray flares --- the fast rise, the steep power-law decline, and the characteristic peak duration \\Delta t /t= (0.1-0.3).

  11. Catalogue of a Loss

    E-Print Network [OSTI]

    Berger, Larisa (Larisa A.)

    2012-01-01T23:59:59.000Z

    Catalogue of a Loss is a collection of sixty-two prose poems written within the past year and half. The work is printed on 4x6 cards. Each poem may be read individually from a single card or the poems can be read in ...

  12. High-temperature phase transition in a plasma and the mechanism of powerful solar flares

    E-Print Network [OSTI]

    Fedor V. Prigara

    2006-05-04T23:59:59.000Z

    It is shown that the high- temperature phase transition in a plasma gives the mechanism of transition from the highly conductive state to the highly resistive state of a plasma in the `electric circuit' model of solar flares which was first introduced by H.Alfven and P.Carlqvist in 1967. With this addendum, the modern version of the electric circuit model can explain both the fast dissipation of energy and the acceleration of particles in a solar flare.

  13. IMPLOSION OF CORONAL LOOPS DURING THE IMPULSIVE PHASE OF A SOLAR FLARE

    SciTech Connect (OSTI)

    Simões, P. J. A.; Fletcher, L.; Hudson, H. S.; Russell, A. J. B., E-mail: paulo.simoes@glasgow.ac.uk, E-mail: lyndsay.fletcher@glasgow.ac.uk, E-mail: arussell@maths.dundee.ac.uk, E-mail: hhudson@ssl.berkeley.edu [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-11-10T23:59:59.000Z

    We study the relationship between implosive motions in a solar flare, and the energy redistribution in the form of oscillatory structures and particle acceleration. The flare SOL2012-03-09T03:53 (M6.4) shows clear evidence for an irreversible (stepwise) coronal implosion. Extreme-ultraviolet (EUV) images show at least four groups of coronal loops at different heights overlying the flaring core undergoing fast contraction during the impulsive phase of the flare. These contractions start around a minute after the flare onset, and the rate of contraction is closely associated with the intensity of the hard X-ray and microwave emissions. They also seem to have a close relationship with the dimming associated with the formation of the coronal mass ejection and a global EUV wave. Several studies now have detected contracting motions in the corona during solar flares that can be interpreted as the implosion necessary to release energy. Our results confirm this, and tighten the association with the flare impulsive phase. We add to the phenomenology by noting the presence of oscillatory variations revealed by Geostationary Operational Environmental Satellite soft X-rays (SXR) and spatially integrated EUV emission at 94 and 335 Å. We identify pulsations of ?60 s in SXR and EUV data, which we interpret as persistent, semi-regular compressions of the flaring core region which modulate the plasma temperature and emission measure. The loop oscillations, observed over a large region, also allow us to provide rough estimates of the energy temporarily stored in the eigenmodes of the active-region structure as it approaches its new equilibrium.

  14. Plasma Heating to Super-Hot Temperatures (>30 MK) in the August 9, 2011 Solar Flare

    E-Print Network [OSTI]

    Sharykin, I N; Zimovets, I V

    2015-01-01T23:59:59.000Z

    We investigate the August 9, 2011 solar flare of X-ray class X6.9, the "hottest" flare from 2000 to 2012, with a peak plasma temperature according to GOES data of 32.5 MK. Our goal is to determine the cause of such an anomalously high plasma temperature and to investigate the energy balance in the flare region with allowance made for the presence of a super-hot plasma (>30 MK). We analyze the RHESSI, GOES, AIA/SDO, and EVE/SDO data and discuss the spatial structure of the flare region and the results of our spectral analysis of its X-ray emission. Our analysis of the RHESSI X-ray spectra is performed in the one-temperature and two-temperature approximations by taking into account the emission of hot (20 MK) and super-hot (45 MK) plasmas. The hard X-ray spectrum in both models is fitted by power laws. The observed peculiarities of the flare are shown to be better explained in terms of the two-temperature model, in which the super-hot plasma is located at the flare loop tops (or in the magnetic cusp region). Th...

  15. Radiative hydrodynamic modelling and observations of the X-class solar flare on 2011 March 9

    E-Print Network [OSTI]

    Kennedy, Michael B; Allred, Joel C; Mathioudakis, Mihalis; Keenan, Francis P

    2015-01-01T23:59:59.000Z

    We investigated the response of the solar atmosphere to non-thermal electron beam heating using the radiative transfer and hydrodynamics modelling code RADYN. The temporal evolution of the parameters that describe the non-thermal electron energy distribution were derived from hard X-ray observations of a particular flare, and we compared the modelled and observed parameters. The evolution of the non-thermal electron beam parameters during the X1.5 solar flare on 2011 March 9 were obtained from analysis of RHESSI X-ray spectra. The RADYN flare model was allowed to evolve for 110 seconds, after which the electron beam heating was ended, and was then allowed to continue evolving for a further 300s. The modelled flare parameters were compared to the observed parameters determined from extreme-ultraviolet spectroscopy. The model produced a hotter and denser flare loop than that observed and also cooled more rapidly, suggesting that additional energy input in the decay phase of the flare is required. In the explosi...

  16. Hinode Observations of Vector Magnetic Field Change Associated with a Flare on 2006 December 13

    E-Print Network [OSTI]

    Masahito Kubo; Takaaki Yokoyama; Yukio Katsukawa; Bruce W Lites; Saku Tsuneta; Yoshinori Suematsu; Kiyoshi Ichimoto; Toshifumi Shimizu; Shin'ichi Nagata; Theodore D Tarbell; Richard A Shine; Alan M Title; David Elmore

    2007-09-17T23:59:59.000Z

    Continuous observations of a flare productive active region 10930 were successfully carried out with the Solar Optical Telescope onboard the Hinode spacecraft during 2007 December 6 to 19. We focus on the evolution of photospheric magnetic fields in this active region, and magnetic field properties at the site of the X3.4 class flare, using a time series of vector field maps with high spatial resolution. The X3.4 class flare occurred on 2006 December 13 at the apparent collision site between the large, opposite polarity umbrae. Elongated magnetic structures with alternatingly positive and negative polarities resulting from flux emergence appeared one day before the flare in the collision site penumbra. Subsequently, the polarity inversion line at the collision site became very complicated. The number of bright loops in Ca II H increased during the formation of these elongated magnetic structures. The flare ribbons and bright loops evolved along the polarity inversion line and one footpoint of the bright loop was located in a region having a large departure of field azimuth angle with respect to its surroundings. The SOT observations with high spatial resolution and high polarization precision reveal temporal change in fine structure of magnetic fields at the flare site: some parts of the complicated polarity inversion line then disappeared, and in those regions the azimuth angle of photospheric magnetic field changed by about 90 degrees, becoming more spatially uniform within the collision site.

  17. Probing the Flare Atmospheres of M dwarfs Using Infrared Emission Lines

    E-Print Network [OSTI]

    Schmidt, Sarah J; Hawley, Suzanne L; Hilton, Eric J; Wisniewski, John P; Tofflemire, Benjamin M

    2011-01-01T23:59:59.000Z

    We present the results of a campaign to monitor active M dwarfs using infrared spectroscopy, supplemented with optical photometry and spectroscopy. We detected 16 flares during nearly 50 hours of observations on EV Lac, AD Leo, YZ CMi, and VB8. The three most energetic flares also showed infrared emission, including the first reported detections of P\\beta, P\\gamma, He I 10830\\AA and Br\\gamma during an M dwarf flare. The strongest flare (\\Delta u = 4.02 on EV Lac) showed emission from H\\gamma, H\\delta, He I 4471\\AA, and Ca II K in the UV/blue and P\\beta, P\\gamma, P\\delta, Br\\gamma, and He I 10830\\AA in the infrared. The weaker flares (\\Delta u = 1.68 on EV Lac and \\Delta U = 1.38 on YZ CMi) were only observed with photometry and infrared spectroscopy; both showed emission from P\\beta, P\\gamma, and He I 10830\\AA. The strongest infrared emission line, P\\beta, occurred in the active mid-M dwarfs with a duty cycle of ~3-4%. To examine the most energetic flare, we used the static NLTE radiative transfer code RH to ...

  18. Fermi Large Area Telescope observations of high-energy gamma-ray emission from behind-the-limb solar flares

    E-Print Network [OSTI]

    Pesce-Rollins, Melissa; Petrosian, Vahe'; Liu, Wei; da Costa, Fatima Rubio; Allafort, Alice

    2015-01-01T23:59:59.000Z

    Fermi-LAT >30 MeV observations have increased the number of detected solar flares by almost a factor of 10 with respect to previous space observations. These sample both the impulsive and long duration phases of GOES M and X class flares. Of particular interest is the recent detections of three solar flares whose position behind the limb was confirmed by the STEREO-B spacecraft. While gamma-ray emission up to tens of MeV resulting from proton interactions has been detected before from occulted solar flares, the significance of these particular events lies in the fact that these are the first detections of >100 MeV gamma-ray emission from footpoint-occulted flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss the various emission scenarios for these sources and implications for the particle acceleration mechanisms.

  19. 2 Solar flare signatures of the ionospheric GPS total electron content 3 J. Y. Liu,1,2

    E-Print Network [OSTI]

    Chen, Yuh-Ing

    2 Solar flare signatures of the ionospheric GPS total electron content 3 J. Y. Liu,1,2 C. H. Lin,1, ionospheric solar flare effects on the total electron content (TEC) and 7 associated time rate of change (r. The occurrence times and 9 locations of 11 solar flares are isolated from the 1­8 A° X-ray radiations of the 10

  20. The evolution of the width of X-ray flares with time in Gamma-ray bursts

    SciTech Connect (OSTI)

    Bernardini, Maria Grazia [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); ICRANet, P.le della Repubblica 10, I-65100 Pescara (Italy); Chincarini, Guido; Margutti, Raffaella [INAF-Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy); University of Milano Bicocca, Physics Dept., P.zza della Scienza 3, I-20126 Milano (Italy)

    2010-10-15T23:59:59.000Z

    We present one of the most intriguing results obtained with an updated catalog of 113 early time (i.e. t{sub pk} < or approx. 1000 s) and 36 late time (i.e. t{sub pk} > or approx. 1000 s) X-ray flares detected by Swift in the afterglows of Gamma-Ray Bursts (GRB): the evolution of the width of the flares with time. This result, together with other properties investigated on early and late time flares and bright flares, provides a clear observational property that every model aiming at explaining the GRB emission has to face.

  1. Full Stokes observations in the He I 1083 nm spectral region covering an M3.2 flare

    E-Print Network [OSTI]

    Kuckein, C; Sainz, R Manso; Ramos, A Asensio

    2015-01-01T23:59:59.000Z

    We present an exceptional data set acquired with the Vacuum Tower Telescope (Tenerife, Spain) covering the pre-flare, flare, and post-flare stages of an M3.2 flare. The full Stokes spectropolarimetric observations were recorded with the Tenerife Infrared Polarimeter in the He I 1083.0 nm spectral region. The object under study was active region NOAA 11748 on 2013 May 17. During the flare the chomospheric He I 1083.0 nm intensity goes strongly into emission. However, the nearby photospheric Si I 1082.7 nm spectral line profile only gets shallower and stays in absorption. Linear polarization (Stokes Q and U) is detected in all lines of the He I triplet during the flare. Moreover, the circular polarization (Stokes V) is dominant during the flare, being the blue component of the He I triplet much stronger than the red component, and both are stronger than the Si I Stokes V profile. The Si I inversions reveal enormous changes of the photospheric magnetic field during the flare. Before the flare magnetic field conc...

  2. Neutron star blackbody contraction during flaring in X1624-490

    E-Print Network [OSTI]

    M. Balucinska-Church; R. Barnard; M. J. Church; A. P. Smale

    2001-10-01T23:59:59.000Z

    We present results of an investigation of the physical changes taking place in the emission regions of the LMXB X1624-490 during strong flaring in RXTE observations. Based on the detailed light curve, we propose that the flaring consists of a superposition of X-ray bursts. It is shown that major changes take place in the blackbody emission component, the temperature kT_BB increasing to ~2.2 keV in flaring. Remarkably, the blackbody area decreases by a factor of ~5 in flaring. During flare evolution, the blackbody luminosity remains approximately constant, constituting a previously unknown Eddington limiting effect which we propose is due to radiation pressure of the blackbody as kT_BB increases affecting the inner disk or accretion flow resulting in a decreased emitting area on the star. We argue that the large decrease in area cannot be explained in terms of modification of the blackbody spectrum by electron scattering in the atmosphere of the neutron star. The height of the emitting region on the non-flaring neutron star is shown to agree with the height of the inner radiatively-supported disk as found for sources in the ASCA survey of LMXB of Church & Balucinska-Church (2001). The decrease in height during flaring is discussed in terms of possible models, including radial accretion flow onto the stellar surface and the theory of accretion flow spreading on the neutron star surface of Inogamov & Sunyaev (1999). We demonstrate that the intensity of the broad iron line at 6.4 keV is strongly correlated with the luminosity of the blackbody emission from the neutron star, and discuss the probable origin of this line in the ADC. Finally, possible reasons for non-detection of a reflection component in this source, and LMXB in general, are discussed.

  3. CONTINUUM CONTRIBUTIONS TO THE SDO/AIA PASSBANDS DURING SOLAR FLARES

    SciTech Connect (OSTI)

    Milligan, Ryan O.; McElroy, Sarah A., E-mail: r.milligan@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2013-11-01T23:59:59.000Z

    Data from the Multiple EUV Grating Spectrograph component of the Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) were used to quantify the contribution of continuum emission to each of the extreme ultraviolet (EUV) channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during an X-class solar flare that occurred on 2011 February 15. Both the pre-flare-subtracted EVE spectra and fits to the associated free-free continuum were convolved with the AIA response functions of the seven EUV passbands at 10 s cadence throughout the course of the flare. It was found that 10%-25% of the total emission in the 94 Å, 131 Å, 193 Å, and 335 Å passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171 Å channel, while the continuum contribution to the 304 Å channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211 Å channel was found to be due to free-free emission around the peak of the flare, while an additional 20% was due to the recombination continuum of He II. The analysis was extended to a number of M- and X-class flares and it was found that the level of free-free emission contributing to both the 171 Å and 211 Å passbands increased with increasing GOES class. These results suggest that the amount of continuum emission that contributes to AIA observations during flares is more significant than stated in previous studies which used synthetic, rather than observed, spectra. These findings highlight the importance of spectroscopic observations carried out in conjunction with those from imaging instruments so that the data are interpreted correctly.

  4. Measurements of Beam Ion Loss from the Compact Helical System

    SciTech Connect (OSTI)

    D. S. Darrow, M. Isobe, Takashi Kondo, M. Sasao, and the CHS Group National Institute for Fusion Science, Toki, Gifu, Japan

    2010-02-03T23:59:59.000Z

    Beam ion loss from the Compact Helical System (CHS) has been measured with a scintillator-type probe. The total loss to the probe, and the pitch angle and gyroradius distributions of that loss, have been measured as various plasma parameters were scanned. Three classes of beam ion loss were observed at the probe position: passing ions with pitch angles within 10o of those of transition orbits, ions on transition orbits, and ions on trapped orbits, typically 15o or more from transition orbits. Some orbit calculations in this geometry have been performed in order to understand the characteristics of the loss. Simulation of the detector signal based upon the following of orbits from realistic beam deposition profiles is not able to reproduce the pitch angle distribution of the losses measured. Consequently it is inferred that internal plasma processes, whether magnetohydrodynamic modes, radial electric fields, or plasma turbulence, move previously confined beam ions to transition orbits, resulting in their loss.

  5. High-sensitivity observations of solar flare decimeter radiation

    E-Print Network [OSTI]

    Arnold O. Benz; Peter Messmer; Christian Monstein

    2000-12-05T23:59:59.000Z

    A new acousto-optic radio spectrometer has observed the 1 - 2 GHz radio emission of solar flares with unprecedented sensitivity. The number of detected decimeter type III bursts is greatly enhanced compared to observations by conventional spectrometers observing only one frequency at the time. The observations indicate a large number of electron beams propagating in dense plasmas. For the first time, we report weak, reversed drifting type III bursts at frequencies above simultaneous narrowband decimeter spikes. The type III bursts are reliable signatures of electron beams propagating downward in the corona, apparently away from the source of the spikes. The observations contradict the most popular spike model that places the spike sources at the footpoints of loops. Conspicuous also was an apparent bidirectional type U burst forming a fish-like pattern. It occurs simultaneously with an intense U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated with strong terrestrial interference (cellular phones) causing a spurious symmetric pattern in the spectrogram at 1.4 GHz. Symmetric features in the 1 - 2 GHz range, some already reported in the literature, therefore must be considered with utmost caution.

  6. Soot and SO[subscript 2] contribution to the supersites in the MILAGRO campaign from elevated flares in the Tula Refinery

    E-Print Network [OSTI]

    Molina, Luisa Tan

    This work presents a simulation of the plume trajectory emitted by flaring activities of the Miguel Hidalgo Refinery in Mexico. The flame of a representative sour gas flare is modeled with a CFD combustion code in order ...

  7. FLARE-GENERATED TYPE II BURST WITHOUT ASSOCIATED CORONAL MASS EJECTION

    SciTech Connect (OSTI)

    Magdalenic, J.; Marque, C.; Zhukov, A. N. [Solar-Terrestrial Center of Excellence, SIDC, Royal Observatory of Belgium, Avenue Circulaire 3, B-1180 Brussels (Belgium); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, Kaciceva 26, HR-10000 Zagreb (Croatia); Veronig, A., E-mail: Jasmina.Magdalenic@oma.be [IGAM/Kanzelhoehe Observatory, Institut of Physics, Universitaet Graz, Universitaetsplatz 5, A-8010 Graz (Austria)

    2012-02-20T23:59:59.000Z

    We present a study of the solar coronal shock wave on 2005 November 14 associated with the GOES M3.9 flare that occurred close to the east limb (S06 Degree-Sign E60 Degree-Sign ). The shock signature, a type II radio burst, had an unusually high starting frequency of about 800 MHz, indicating that the shock was formed at a rather low height. The position of the radio source, the direction of the shock wave propagation, and the coronal electron density were estimated using Nancay Radioheliograph observations and the dynamic spectrum of the Green Bank Solar Radio Burst Spectrometer. The soft X-ray, H{alpha}, and Reuven Ramaty High Energy Solar Spectroscopic Imager observations show that the flare was compact, very impulsive, and of a rather high density and temperature, indicating a strong and impulsive increase of pressure in a small flare loop. The close association of the shock wave initiation with the impulsive energy release suggests that the impulsive increase of the pressure in the flare was the source of the shock wave. This is supported by the fact that, contrary to the majority of events studied previously, no coronal mass ejection was detected in association with the shock wave, although the corresponding flare occurred close to the limb.

  8. X-ray flares, neutrino cooled disks, and the dynamics of late accretion in GRB engines

    E-Print Network [OSTI]

    Davide Lazzati; Rosalba Perna; Mitchell C. Begelman

    2008-05-01T23:59:59.000Z

    We compute the average luminosity of X-ray flares as a function of time, for a sample of 10 long-duration gamma-ray burst afterglows. The mean luminosity, averaged over a timescale longer than the duration of the individual flares, declines as a power-law in time with index ~-1.5. We elaborate on the properties of the central engine that can produce such a decline. Assuming that the engine is an accreting compact object, and for a standard conversion factor between accretion rate and jet luminosity, the switch between a neutrino-cooled thin disk and a non-cooled thick disk takes place at the transition from the prompt to the flaring phase. We discuss the implications of this coincidence under different scenarios for the powering of the GRB outflow. We also show that the interaction of the outflow with the envelope of the progenitor star cannot produce flares out of a continuous relativistic flow, and conclude that it is the dynamics of the disk or the jet-launching mechanism that generates an intrinsically unsteady outflow on timescales much longer than the dynamical timescale of the system. This is consistent with the fact that X-ray flares are observed in short-duration GRBs as well as in long-duration ones.

  9. Constraints on the Bulk Lorentz Factors of GRB X-Ray Flares

    E-Print Network [OSTI]

    Yi, Shuang-Xi; Wang, Fa-Yin; Dai, Zi-Gao

    2015-01-01T23:59:59.000Z

    X-ray flares were discovered in the afterglow phase of gamma-ray bursts (GRBs) by the {\\em Swift} satellite a decade ago and known as a canonical component in GRB X-ray afterglows. In this paper, we constrain the Lorentz factors of GRB X-ray flares using two different methods. For the first method, we estimate the lower limit on the bulk Lorentz factor with the flare duration and jet break time. In the second method, the upper limit on the Lorentz factor is derived by assuming that the X-ray flare jet has undergone saturated acceleration. We also re-estimate the initial Lorentz factor with GRB afterglow onsets, and find the coefficient of the theoretical Lorentz factor is 1.67 rather than the commonly used 2 for interstellar medium (ISM) and 1.44 for the wind case. We find that the correlation between the limited Lorentz factor and the isotropic radiation energy of X-ray flares in the ISM case is more consistent with that of prompt emission than the wind case in a statistical sense. For a comparison, the lowe...

  10. The Confined X-class Flares of Solar Active Region 2192

    E-Print Network [OSTI]

    Thalmann, J K; Temmer, M; Veronig, A M

    2015-01-01T23:59:59.000Z

    The unusually large NOAA active region 2192, observed in October 2014, was outstanding in its productivity of major two-ribbon flares without coronal mass ejections. On a large scale, a predominantly north-south oriented magnetic system of arcade fields served as a strong, also lateral, confinement for a series of large two-ribbon flares originating from the core of the active region. The large initial separation of the flare ribbons, together with an almost absent growth in ribbon separation, suggests a confined reconnection site high up in the corona. Based on a detailed analysis of the confined X1.6 flare on October 22, we show how exceptional the flaring of this active region was. We provide evidence for repeated energy release, indicating that the same magnetic field structures were repeatedly involved in magnetic reconnection. We find that a large number of electrons was accelerated to non-thermal energies, revealing a steep power law spectrum, but that only a small fraction was accelerated to high ener...

  11. MAGNETIC NONPOTENTIALITY IN PHOTOSPHERIC ACTIVE REGIONS AS A PREDICTOR OF SOLAR FLARES

    SciTech Connect (OSTI)

    Yang Xiao; Lin Ganghua; Zhang Hongqi; Mao Xinjie, E-mail: yangx@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012 (China)

    2013-09-10T23:59:59.000Z

    Based on several magnetic nonpotentiality parameters obtained from the vector photospheric active region magnetograms obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station over two solar cycles, a machine learning model has been constructed to predict the occurrence of flares in the corresponding active region within a certain time window. The Support Vector Classifier, a widely used general classifier, is applied to build and test the prediction models. Several classical verification measures are adopted to assess the quality of the predictions. We investigate different flare levels within various time windows, and thus it is possible to estimate the rough classes and erupting times of flares for particular active regions. Several combinations of predictors have been tested in the experiments. The True Skill Statistics are higher than 0.36 in 97% of cases and the Heidke Skill Scores range from 0.23 to 0.48. The predictors derived from longitudinal magnetic fields do perform well, however, they are less sensitive in predicting large flares. Employing the nonpotentiality predictors from vector fields improves the performance of predicting large flares of magnitude {>=}M5.0 and {>=}X1.0.

  12. Optical Spectral Observations of a Flickering White-Light Kernel in a C1 Solar Flare

    E-Print Network [OSTI]

    Kowalski, Adam F; Fletcher, Lyndsay

    2014-01-01T23:59:59.000Z

    We analyze optical spectra of a two-ribbon, long duration C1.1 flare that occurred on 18 Aug 2011 within AR 11271 (SOL2011-08-18T15:15). The impulsive phase of the flare was observed with a comprehensive set of space-borne and ground-based instruments, which provide a range of unique diagnostics of the lower flaring atmosphere. Here we report the detection of enhanced continuum emission, observed in low-resolution spectra from 3600 \\AA\\ to 4550 \\AA\\ acquired with the Horizontal Spectrograph at the Dunn Solar Telescope. A small, $\\le$0''.5 ($10^{15}$ cm$^2$) penumbral/umbral kernel brightens repeatedly in the optical continuum and chromospheric emission lines, similar to the temporal characteristics of the hard X-ray variation as detected by the Gamma-ray Burst Monitor (GBM) on the Fermi spacecraft. Radiative-hydrodynamic flare models that employ a nonthermal electron beam energy flux high enough to produce the optical contrast in our flare spectra would predict a large Balmer jump in emission, indicative of h...

  13. An explanation for long flares from extragalactic globular cluster X-ray sources

    E-Print Network [OSTI]

    Thomas J. Maccarone

    2005-09-21T23:59:59.000Z

    Repeatedly flaring X-ray binaries have recently been discovered in NGC 4697 by Sivakoff and collaborators. We show that these flares can be explained as the result of eccentric binaries in globular clusters which accrete more rapidly at periastron than during the rest of the binary orbit. We show that theoretical timescales for producing eccentricities and circularising the binaries are consistent with what is needed to produce the observed population of flaring sources, although the circularisation timescales are highly uncertain on both observational and theoretical grounds. This model makes two clear theoretical predictions (1) the flares should be seen to be strictly periodic if adequate sampling is provided, and that periodicity should be of approximately 15 hours (2) this class of flaring behaviour should be seen only in globular cluster sources, and predominantly in the densest globular clusters. We also test the model for producing eccentricities through fly-by's of a third star near the binary in a globular cluster against a much larger database of millisecond pulsar observations than has been used in past work, and find that the theoretical cross sections for producing eccentricity in binaries are in reasonable agreement with most of the data, provided that the pulsar ages are about $4\\times10^9$ years.

  14. PRIOR FLARING AS A COMPLEMENT TO FREE MAGNETIC ENERGY FOR FORECASTING SOLAR ERUPTIONS

    SciTech Connect (OSTI)

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F. [ZP13 MSFC/NASA, Huntsville, AL 35812 (United States); Khazanov, Igor [CSPAR, Cramer Hall/NSSTC, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2012-09-20T23:59:59.000Z

    From a large database of (1) 40,000 SOHO/MDI line-of-sight magnetograms covering the passage of 1300 sunspot active regions across the 30 Degree-Sign radius central disk of the Sun, (2) a proxy of each active region's free magnetic energy measured from each of the active region's central-disk-passage magnetograms, and (3) each active region's full-disk-passage history of production of major flares and fast coronal mass ejections (CMEs), we find new statistical evidence that (1) there are aspects of an active region's magnetic field other than the free energy that are strong determinants of the active region's productivity of major flares and fast CMEs in the coming few days; (2) an active region's recent productivity of major flares, in addition to reflecting the amount of free energy in the active region, also reflects these other determinants of coming productivity of major eruptions; and (3) consequently, the knowledge of whether an active region has recently had a major flare, used in combination with the active region's free-energy proxy measured from a magnetogram, can greatly alter the forecast chance that the active region will have a major eruption in the next few days after the time of the magnetogram. The active-region magnetic conditions that, in addition to the free energy, are reflected by recent major flaring are presumably the complexity and evolution of the field.

  15. Solar Flare Element Abundances from the Solar Assembly for X-rays (SAX) on MESSENGER

    E-Print Network [OSTI]

    Dennis, B R; Schwartz, R A; Tolbert, A K; Starr, R D; Nittler, L R

    2015-01-01T23:59:59.000Z

    X-ray spectra in the range $1.5-8.5$~keV have been analyzed for 526 large flares detected with the Solar Assembly for X-rays (SAX) on the Mercury {\\em MESSENGER} spacecraft between 2007 and 2013. For each flare, the temperature and emission measure of the emitting plasma were determined from the spectrum of the continuum. In addition, with the SAX energy resolution of 0.6 keV (FWHM) at 6~keV, the intensities of the clearly resolved Fe-line complex at 6.7~keV and the Ca-line complex at 3.9~keV were determined, along with those of unresolved line complexes from S, Si, and Ar at lower energies. Comparisons of these line intensities with theoretical spectra allow the abundances of these elements relative to hydrogen to be derived, with uncertainties due to instrument calibration and the unknown temperature distribution of the emitting plasma. While significant deviations are found for the abundances of Fe and Ca from flare to flare, the abundances averaged over all flares are found to be enhanced over photospheri...

  16. Midlatitude Ozone: Loss and Trends

    E-Print Network [OSTI]

    Toohey, Darin W.

    1 Lecture 17 Midlatitude Ozone: Loss and Trends ATOC/CHEM 5151 #12;2 Importance of midlatitude ozone · Covers most of the world's populated areas · Provides protection from UV #12;3 Ozone loss picture, c. 1988 #12;4 Lower vs. Upper stratosphere #12;5 Ozone loss, post 1988 · Discovery of ozone hole

  17. Detection of Li i enhancement during a longduration flare in the recenltly discovered Xray/EUV selected, chromospher

    E-Print Network [OSTI]

    Complutense de Madrid, Universidad

    of this behavior as an unusual long­duration flare. ­ 1) The temporal evolution of the event is similar to the observed in other solar and stellar flares, with an initial impulsive phase characterized by a strong of the event. A two Gaussian components fit to the subtracted spectra is displayed in the right panel of Fig. 1

  18. Turbulence in the Solar Atmosphere: Manifestations and Diagnostics via Solar Image Processing

    E-Print Network [OSTI]

    Manolis K. Georgoulis

    2005-11-15T23:59:59.000Z

    Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of solar magnetic fields. While these techniques advance our understanding of the physical system at work, it is unclear whether they can be used to predict solar eruptions, thus obtaining a practical significance for space weather. We address part of this problem by focusing on solar active regions and by investigating the usefulness of scaling and multi-scaling image-processing techniques in solar flare prediction. Since solar flares exhibit spatial and temporal intermittency, we suggest that they are the products of instabilities subject to a critical threshold in a turbulent magnetic configuration. The identification of this threshold in scaling and multi-scaling spectra would then contribute meaningfully to the prediction of solar flares. We find that the fractal dimension of solar magnetic fields and their multi-fractal spectrum of generalized correlation dimensions do not have significant predictive ability. The respective multi-fractal structure functions and their inertial-range scaling exponents, however, probably provide some statistical distinguishing features between flaring and non-flaring active regions. More importantly, the temporal evolution of the above scaling exponents in flaring active regions probably shows a distinct behavior starting a few hours prior to a flare and therefore this temporal behavior may be practically useful in flare prediction. The results of this study need to be validated by more comprehensive works over a large number of solar active regions.

  19. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Refinements to flare energy estimates -a follow-up to "Energy

    E-Print Network [OSTI]

    California at Berkeley, University of

    flare/CME events, using as much reliable data as was available, not only on radiative output, but also estimates - a follow-up to "Energy Partition in Two Solar Flare/CME Events" A. G. Emslie, 1 B. R. Dennis 2 in the different flare and CME components of two major solar events with unprecedented observational coverage, one

  20. SIMULATIONS OF PARTICLE ACCELERATION BEYOND THE CLASSICAL SYNCHROTRON BURNOFF LIMIT IN MAGNETIC RECONNECTION: AN EXPLANATION OF THE CRAB FLARES

    SciTech Connect (OSTI)

    Cerutti, B.; Werner, G. R.; Uzdensky, D. A. [Center for Integrated Plasma Studies, Physics Department, University of Colorado, UCB 390, Boulder, CO 80309-0390 (United States); Begelman, M. C., E-mail: benoit.cerutti@colorado.edu, E-mail: greg.werner@colorado.edu, E-mail: uzdensky@colorado.edu, E-mail: mitch@jila.colorado.edu [JILA, University of Colorado and National Institute of Standards and Technology, UCB 440, Boulder, CO 80309-0440 (United States)

    2013-06-20T23:59:59.000Z

    It is generally accepted that astrophysical sources cannot emit synchrotron radiation above 160 MeV in their rest frame. This limit is given by the balance between the accelerating electric force and the radiation reaction force acting on the electrons. The discovery of synchrotron gamma-ray flares in the Crab Nebula, well above this limit, challenges this classical picture of particle acceleration. To overcome this limit, particles must accelerate in a region of high electric field and low magnetic field. This is possible only with a non-ideal magnetohydrodynamic process, like magnetic reconnection. We present the first numerical evidence of particle acceleration beyond the synchrotron burnoff limit, using a set of two-dimensional particle-in-cell simulations of ultra-relativistic pair plasma reconnection. We use a new code, Zeltron, that includes self-consistently the radiation reaction force in the equation of motion of the particles. We demonstrate that the most energetic particles move back and forth across the reconnection layer, following relativistic Speiser orbits. These particles then radiate >160 MeV synchrotron radiation rapidly, within a fraction of a full gyration, after they exit the layer. Our analysis shows that the high-energy synchrotron flux is highly variable in time because of the strong anisotropy and inhomogeneity of the energetic particles. We discover a robust positive correlation between the flux and the cut-off energy of the emitted radiation, mimicking the effect of relativistic Doppler amplification. A strong guide field quenches the emission of >160 MeV synchrotron radiation. Our results are consistent with the observed properties of the Crab flares, supporting the reconnection scenario.

  1. Long term flaring activity of XRF 011030 observed with BeppoSAX

    E-Print Network [OSTI]

    Piro, A G L

    2005-01-01T23:59:59.000Z

    We present the spectral and temporal analysis of the X-ray flash XRF 011030 observed with BeppoSAX. This event is characterized by a very long X-ray bursting activity that lasts about 1500 s, the longest ever observed by BeppoSAX. In particular a precursor and a late flare are present in the light curve. We connect the late X-ray flare observed at about 1300 s to the afterglow emission observed by Chandra and associate it with the onset of the afterglow emission in the framework of external shock by a long duration engine activity. We find that the late X-ray flare and the broad-band afterglow data, including optical and radio measurements, are consistent either with a fireball expanding in a wind environment or with a jetted fireball in a ISM.

  2. VERITAS OBSERVATIONS OF DAY-SCALE FLARING OF M 87 IN 2010 APRIL

    SciTech Connect (OSTI)

    Aliu, E.; Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Bradbury, S. M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Duke, C. [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); Falcone, A., E-mail: cmhui@physics.utah.edu [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); and others

    2012-02-20T23:59:59.000Z

    VERITAS has been monitoring the very-high-energy (VHE; > 100 GeV) gamma-ray activity of the radio galaxy M 87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 {+-} 0.16) Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 {+-} 0.68) Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} for E > 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90{sup +0.22}{sub -0.15} days. The shortest detected exponential rise time is three times as long, at 2.87{sup +1.65}{sub -0.99} days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 {+-} 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region.

  3. OCCULTATION OF THE QUIESCENT EMISSION FROM Sgr A* BY IR FLARES

    SciTech Connect (OSTI)

    Yusef-Zadeh, F. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Wardle, M. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Bushouse, H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dowell, C. D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Roberts, D. A. [Adler Planetarium and Astronomy Museum, 1300 South Lake Shore Drive, Chicago, IL 60605 (United States)

    2010-11-20T23:59:59.000Z

    We have investigated the nature of flare emission from Sgr A* during multi-wavelength observations of this source that took place in 2004, 2005, and 2006. We present evidence for dimming of submillimeter and radio flux during the peak of near-IR flares. This suggests that the variability of Sgr A* across its wavelength spectrum is phenomenologically related. The model explaining this new behavior of flare activity could be consistent with adiabatically cooling plasma blobs that are expanding but also partially eclipsing the background quiescent emission from Sgr A*. When a flare is launched, the plasma blob is most compact and is brightest in the optically thin regime whereas the emission in radio/submillimeter wavelengths has a higher opacity. Absorption in the observed light curve of Sgr A* at radio/submillimeter flux is due to the combined effects of lower brightness temperature of plasma blobs with respect to the quiescent brightness temperature and high opacity of plasma blobs. This implies that plasma blobs are mainly placed in the magnetosphere of a disk-like flow or further out in the flow. The depth of the absorption being larger in submillimeter than in radio wavelengths implies that the intrinsic size of the quiescent emission increases with increasing wavelength which is consistent with previous size measurements of Sgr A*. Lastly, we believe that occultation of the quiescent emission of Sgr A* at radio/submillimeter by IR flares can be used as a powerful tool to identify flare activity at its earliest phase of its evolution.

  4. Modeling Non-Confined Coronal Flares: Dynamics and X-Ray Diagnostics

    E-Print Network [OSTI]

    F. Reale; F. Bocchino; G. Peres

    2001-12-14T23:59:59.000Z

    Long-lasting, intense, stellar X-ray flares may approach conditions of breaking magnetic confinement and evolving in open space. We explore this hypothesis with hydrodynamic simulations of flares occurring in a non-confined corona: model flares are triggered by a transient impulsive heating injected in a plane-parallel stratified corona. The plasma evolution is described by means of a numerical 2-D model in cylindrical geometry R,Z. We explore the space of fundamental parameters. As a reference model, we consider a flare triggered by a heating pulse that would cause a 20 MK flare if delivered in a 40000 km long closed loop. The modeled plasma evolution is described. The X-ray emission, spectra and light curves at the ASCA/SIS focal plan, and in two intense X-ray lines (Mg XI at 9.169 A and Fe XXI at 128.752 A), have been synthesized from the models. The results are discussed and compared to features of confined events, and scaling laws are derived. The light curves invariably show a very rapid rise, a constant phase as long as the constant heating is on, and then a very fast decay, on time scales of few seconds, followed by a more gradual one (few minutes). We show that this evolution of the emission, and especially the fast decay, together with other potentially observable effects, are intrinsic to the assumption of non-confinement. Their lack indicates that observed long-lasting stellar X-ray flares should involve plasma strongly confined by magnetic fields.

  5. Lag-luminosity relation in gamma-ray burst X-ray flares

    SciTech Connect (OSTI)

    Margutti, R.

    2010-10-15T23:59:59.000Z

    In strict analogy to prompt pulses, X-ray flares observed by Swift-XRT in long Gamma-Ray Bursts define a lag-luminosity relation: L{sub p,iso}{sup 0.3-10} k{sup eV} {infinity}t{sub lag}{sup -0.95{+-}0.23}. The lag-luminosity is proven to be a fundamental law extending {approx}5 decades in time and {approx}5 in energy. This is direct evidence that GRB X-ray flares and prompt gamma-ray pulses are produced by the same mechanism.

  6. Plastic damping of Alfv\\'en waves in magnetar flares and delayed afterglow emission

    E-Print Network [OSTI]

    Li, Xinyu

    2015-01-01T23:59:59.000Z

    Magnetar flares generate Alfv\\'en waves bouncing in the closed magnetosphere with energy up to $\\sim 10^{46}$ erg. We show that on a 10-ms timescale the waves are transmitted into the star and form a compressed packet of high energy density. This packet strongly shears the stellar crust and initiates a plastic flow, heating the crust and melting it hundreds of meters below the surface. A fraction of the deposited plastic heat is eventually conducted to the stellar surface, contributing to the surface afterglow months to years after the flare. A large fraction of heat is lost to neutrino emission or conducted into the core of the neutron star.

  7. Search for correlations between solar flares and decay rate of radioactive nuclei

    E-Print Network [OSTI]

    E. Bellotti; C. Broggini; G. Di Carlo; M. Laubenstein; R. Menegazzo

    2013-02-05T23:59:59.000Z

    The deacay rate of three different radioactive sources 40K, 137Cs and natTh has been measured with NaI and Ge detectors. Data have been analyzed to search for possible variations in coincidence with the two strongest solar flares of the years 2011 and 2012. No significant deviations from standard expectation have been observed, with a few 10-4 sensitivity. As a consequence, we could not find any effect like that recently reported by Jenkins and Fischbach: a few per mil decrease in the decay rate of 54Mn during solar flares in December 2006.

  8. Loan Loss Reserve Fund Impacts on Standard Residential Underwriting Guidelines

    Broader source: Energy.gov [DOE]

    State and local governments can use loan loss reserve (LLR) funds to persuade lenders to offer more flexible terms during the underwriting process. The availability of an LLR can have the following...

  9. Written emotional expression: Effects on weight loss and maintenance

    E-Print Network [OSTI]

    Hockemeyer, Jill Renee

    2007-10-16T23:59:59.000Z

    the negative effects of distress on weight loss and maintenance through improved emotional self-regulatory processes. This study examined the effects of expressive writing on weight regain, stress, and emotional eating among individuals who have recently lost...

  10. Tax aspects of casualty losses

    E-Print Network [OSTI]

    Lehmann, August Herman

    1960-01-01T23:59:59.000Z

    sudden, unex- 1 pected or unusual nature. The word also signifies an accident, a mishap, or some sudden invasion by a hostile agency. It excludes the progressive deterioration of property through a steadily operating cause, and the loss of an article.... F. T, R. 432, rulings and Court decisions indicate that there may be a tendency to dis- regard suddenness as a requirement for a casualty loss deduction. The casualty loss deduction is allowed only for the loss of pro- 3 perty and the property...

  11. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect (OSTI)

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M. [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 Zagreb (Croatia)

    2012-08-10T23:59:59.000Z

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  12. CHARACTERISTIC SIZE OF FLARE KERNELS IN THE VISIBLE AND NEAR-INFRARED CONTINUA

    SciTech Connect (OSTI)

    Xu, Yan; Jing, Ju; Wang, Haimin [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States); Cao, Wenda, E-mail: yx2@njit.edu [Big Bear Solar Observatory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States)

    2012-05-01T23:59:59.000Z

    In this Letter, we present a new approach to estimate the formation height of visible and near-infrared emission of an X10 flare. The sizes of flare emission cores in three wavelengths are accurately measured during the peak of the flare. The source size is the largest in the G band at 4308 A and shrinks toward longer wavelengths, namely the green continuum at 5200 A and NIR at 15600 A, where the emission is believed to originate from the deeper atmosphere. This size-wavelength variation is likely explained by the direct heating model as electrons need to move along converging field lines from the corona to the photosphere. Therefore, one can observe the smallest source, which in our case is 0.''65 {+-} 0.''02 in the bottom layer (represented by NIR), and observe relatively larger kernels in upper layers of 1.''03 {+-} 0.''14 and 1.''96 {+-} 0.''27, using the green continuum and G band, respectively. We then compare the source sizes with a simple magnetic geometry to derive the formation height of the white-light sources and magnetic pressure in different layers inside the flare loop.

  13. Observational Evidence of Changing Photospheric Vector Magnetic Fields Associated with Solar Flares

    E-Print Network [OSTI]

    of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012, China 3. Key Laboratory of Solar ActivityObservational Evidence of Changing Photospheric Vector Magnetic Fields Associated with Solar Flares University, Beijing 100875, China sjt@bao.ac.cn Received ; accepted Not to appear in Nonlearned J., 45. #12

  14. NO FLARES FROM GAMMA-RAY BURST AFTERGLOW BLAST WAVES ENCOUNTERING SUDDEN CIRCUMBURST DENSITY CHANGE

    SciTech Connect (OSTI)

    Gat, Ilana; Van Eerten, Hendrik; MacFadyen, Andrew [Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)

    2013-08-10T23:59:59.000Z

    Afterglows of gamma-ray bursts are observed to produce light curves with the flux following power-law evolution in time. However, recent observations reveal bright flares at times on the order of minutes to days. One proposed explanation for these flares is the interaction of a relativistic blast wave with a circumburst density transition. In this paper, we model this type of interaction computationally in one and two dimensions, using a relativistic hydrodynamics code with adaptive mesh refinement called RAM, and analytically in one dimension. We simulate a blast wave traveling in a stellar wind environment that encounters a sudden change in density, followed by a homogeneous medium, and compute the observed radiation using a synchrotron model. We show that flares are not observable for an encounter with a sudden density increase, such as a wind termination shock, nor for an encounter with a sudden density decrease. Furthermore, by extending our analysis to two dimensions, we are able to resolve the spreading, collimation, and edge effects of the blast wave as it encounters the change in circumburst medium. In all cases considered in this paper, we find that a flare will not be observed for any of the density changes studied.

  15. The Temporal Behaviour of Lyman-alpha Emission During Solar Flares From SDO/EVE

    E-Print Network [OSTI]

    Milligan, Ryan O

    2015-01-01T23:59:59.000Z

    Despite being the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Lyman-alpha (Ly$\\alpha$) emission during solar flares in recent years. The few examples that do exist, however, have shown Ly$\\alpha$ emission to be a substantial radiator of the total energy budget of solar flares (on the order of 10%). It is also a known driver of fluctuations in earth's ionosphere. The EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory now provides broadband, photometric Ly$\\alpha$ data at 10 s cadence, and has observed scores of solar flares in the 5 years since it was launched. However, the time profiles appear to display a rise time of tens of minutes around the time of the flare onset. This is in stark contrast to the rapid, impulsive increase observed in other intrinsically chromospheric features (H$\\alpha$, Ly$\\beta$, LyC, C III, etc.). Furthermore, the Ly$\\alpha$ emission peaks around the time of the peak of thermal soft X-ray e...

  16. Temporal evolution of multiple evaporating ribbon sources in a solar flare

    E-Print Network [OSTI]

    Graham, D R

    2015-01-01T23:59:59.000Z

    We present new results from the Interface Region Imaging Spectrograph showing the dynamic evolution of chromospheric evaporation and condensation in a flare ribbon, with the highest temporal and spatial resolution to date. IRIS observed the entire impulsive phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 second cadence `sit-and-stare' mode. As the ribbon brightened successively at new positions along the slit, a unique impulsive phase evolution was observed for many tens of individual pixels in both coronal and chromospheric lines. Each activation of a new footpoint displays the same initial coronal up-flows of up to ~300 km/s, and chromospheric downflows up to 40 km/s. Although the coronal flows can be delayed by over 1 minute with respect to those in the chromosphere, the temporal evolution of flows is strikingly similar between all pixels, and consistent with predictions from hydrodynamic flare models. Given the large sample of independent footpoints, we conclude that each flaring pixel can be c...

  17. LETTER Earth Planets Space, 61, 577580, 2009 Flares and the chromosphere

    E-Print Network [OSTI]

    Hudson, Hugh

    LETTER Earth Planets Space, 61, 577­580, 2009 Flares and the chromosphere Hugh S. Hudson1 limited to the "semi-empirical" models, based on 1D radiative-transfer physics. Such an approach omits dy energetics (Section 2), en- ergy build-up (Section 3), and energy release (Section 4), attempting to use

  18. Accretion, fluorescent X-ray emission and flaring magnetic structures in YSOs

    E-Print Network [OSTI]

    F. Favata

    2004-12-20T23:59:59.000Z

    I present some recent developments on high-energy phenomena in YSOs, concentrating on the new evidence for accretion-induced X-ray emission in YSOs, for Fe 6.4 keV fluorescent emission from the disks of YSOs and for very long magnetic structures responsible for intense X-ray flares, likely connecting the star and the circumstellar disk.

  19. Hard X-ray Emission During Flares and Photospheric Field Changes

    E-Print Network [OSTI]

    Burtseva, O; Petrie, G J D; Pevtsov, A A

    2015-01-01T23:59:59.000Z

    We study the correlation between abrupt permanent changes of magnetic field during X-class flares observed by the GONG and HMI instruments, and the hard X-ray (HXR) emission observed by RHESSI, to relate the photospheric field changes to the coronal restructuring and investigate the origin of the field changes. We find that spatially the early RHESSI emission corresponds well to locations of the strong field changes. The field changes occur predominantly in the regions of strong magnetic field near the polarity inversion line (PIL). The later RHESSI emission does not correspond to significant field changes as the flare footpoints are moving away from the PIL. Most of the field changes start before or around the start time of the detectable HXR signal, and they end at about the same time or later than the detectable HXR flare emission. Some of the field changes propagate with speed close to that of the HXR footpoint at a later phase of the flare. The propagation of the field changes often takes place after the...

  20. The Sun as an X-ray Star: III. Flares F. Reale, G. Peres

    E-Print Network [OSTI]

    distribution vs. temperature and its evolution during some selected solar ares, representative of the wideThe Sun as an X-ray Star: III. Flares F. Reale, G. Peres Dip. di Scienze Fisiche & Astronomiche class C5.8) to very intense ones (X9) are selected as representative of the aring Sun. The emission

  1. CHARGE-EXCHANGE LIMITS ON LOW-ENERGY {alpha}-PARTICLE FLUXES IN SOLAR FLARES

    SciTech Connect (OSTI)

    Hudson, H. S. [SSL, UC Berkeley, CA 94720 (United States); Fletcher, L.; MacKinnon, A. L. [School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Woods, T. N., E-mail: hhudson@ssl.berkeley.edu [Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Dr., Boulder, CO 80303 (United States)

    2012-06-20T23:59:59.000Z

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Ly{alpha} line of He II at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary {alpha} particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He II bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment on board the Solar Dynamics Observatory gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV nucleon{sup -1}. We study 10 events in total, including the {gamma}-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic particles. The absence of charge-exchange line wings may point to a need for more complete theoretical work. Some of the events do have broadband signatures, which could correspond to continua from other origins, but these do not have the spectral signatures expected from the Orrall-Zirker mechanism.

  2. Very fast optical flaring from a possible new Galactic A. Stefanescu1

    E-Print Network [OSTI]

    Cai, Long

    1 , A. Slowikowska2,3 , J. Greiner1 , S. McBreen1 & G. Sala1 Highly luminous rapid flares fibre, plus one additional, more distant background fibre to determine and subtract the sky background. All apertures are of 300 mm diameter, corresponding to 6 arcsec on the sky with the SKO 1.3m telescope

  3. Particle acceleration and radiation by direct electric fields in flaring complex solar active regions

    E-Print Network [OSTI]

    Anastasiadis, Anastasios

    Particle acceleration and radiation by direct electric fields in flaring complex solar active-Meudon, 92195 Meudon Cedex, FRANCE Abstract The acceleration and radiation of solar energetic particles with the existing observations. 1 Introduction The approach used for particle acceleration models proposed for solar

  4. GEOMAGNETIC CONSEQUENCES OF THE SOLAR FLARES DURING THE LAST HALE SOLAR CYCLE (II)

    E-Print Network [OSTI]

    GEOMAGNETIC CONSEQUENCES OF THE SOLAR FLARES DURING THE LAST HALE SOLAR CYCLE (II) Georgeta Maris@aira.astro.ro ABSTRACT/RESUME The effects of the solar energetic phenomena cover the entire terrestrial environment, from is the solar plasma that may originate from solar eruptive phenomena that take their energy from magnetic field

  5. The shock reprocessing model of electron acceleration in impulsive solar flares

    E-Print Network [OSTI]

    Selkowitz, R; Selkowitz, Robert; Blackman, Eric G.

    2005-01-01T23:59:59.000Z

    We propose a new two-stage model for acceleration of electrons in solar flares. In the first stage, electrons are accelerated stochastically in a post-reconnection turbulent downflow. The second stage is the reprocessing of a subset of these electrons as they pass through a weakly compressive fast shock above the apex of the closed flare loop on their way to the chromosphere. We call this the "shock reprocessing" model. The model reproduces the energy dependent arrival time delays observed for both the pulsed and smooth components of impulsive solar flare x-rays with physically reasonable parameters for the downflow region. The model also predicts an emission site above the loop-top, as seen in the Masuda flare. The loop-top source distinguishes the shock reprocessing model from previous models. The model makes testable predictions for the energy dependence of footpoint pulse strengths and the location and spectrum of the loop-top emission, and can account for the observed soft-hard-soft trend in the spectral...

  6. Toward magnetic field dissipation during the 23 July 2002 solar flare measured with Solar

    E-Print Network [OSTI]

    Zharkova, Valentina V.

    and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) and Reuven Ramaty High Energy Solar Spectroscopic] It is widely accepted that the source of primary energy release in solar flares is associated with magnetic

  7. DIFFERENT PATTERNS OF CHROMOSPHERIC EVAPORATION IN A FLARING REGION OBSERVED WITH HINODE/EIS

    SciTech Connect (OSTI)

    Li, Y.; Ding, M. D., E-mail: dmd@nju.edu.cn [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

    2011-02-01T23:59:59.000Z

    We investigate the chromospheric evaporation in the flare of 2007 January 16 using line profiles observed by the Exterme-UV Imaging Spectrometer on board Hinode. Three points at flare ribbons of different magnetic polarities are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The spectral lines at the first point are mostly blueshifted, with the hotter lines showing a dominant blueshifted component over the stationary one. At the second point, however, only weak upflows are detected; instead, notable downflows appear at high temperatures (up to 2.5-5.0 MK). The third point is similar to the second one only in that it shows evidence of multi-component downflows. While the evaporated plasma falling back down as warm rain is a possible cause of the redshifts at the second and third points, the different patterns of chromospheric evaporation at the three points imply the existence of different heating mechanisms in the flaring active region.

  8. Energy loss of fast quarks in nuclei

    SciTech Connect (OSTI)

    Garvey, G. T. (Gerald T.); Johnson, Mikkel B.; Leitch, M. J.; McGaughey, P. L. (Patrick L.); Peng, J. C. (Jen-Chieh); Kopeliovich, B. Z.; Potashnikova, I. K.; Moss, J. M. (Joel Marshall)

    2001-01-01T23:59:59.000Z

    We report an analysis of the nuclear dependence of the yield of Drell-Yan (DY) dimuons from the 800 GeV/c proton bombardment of {sup 2}H, C, Ca, Fe, and W targets. A light-cone formulation of the DY process is employed in the rest frame of the nucleus. In this frame, for x{sub 2} <loss and shadowing, in a consistent formulation. Shadowing, involving no free parameters, is calculated within the light-cone dipole formalism. Initial-state energy loss, the only unknown in the problem, is determined from afit to the nuclear-dependence ratio versus x{sub 1}. With the assumption of constant energy loss per unit path length, we find -dE/dz = 2.32 {+-} 0.52 {+-} 0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in nuclear environment.

  9. A COMPREHENSIVE STUDY OF GAMMA-RAY BURST OPTICAL EMISSION. I. FLARES AND EARLY SHALLOW-DECAY COMPONENT

    SciTech Connect (OSTI)

    Li Liang; Liang Enwei; Tang Qingwen; Chen Jiemin; Xi Shaoqiang; Zhang Bing; Lu Ruijing; Lue Lianzhong [Department of Physics and GXU-NAOC, Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Lue Houjun; Gao He [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States); Zhang Jin; Wei Jianyan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Yi Shuangxi, E-mail: lew@gxu.edu.cn, E-mail: zhang@physics.unlv.edu [College of Astronomy and Space Sciences, Nanning University, Nanjing 210093 (China)

    2012-10-10T23:59:59.000Z

    Well-sampled optical light curves of 146 gamma-ray bursts (GRBs) are compiled from the literature. By empirical fitting, we identify eight possible emission components and summarize the results in a 'synthetic' light curve. Both optical flare and early shallow-decay components are likely related to long-term central engine activities. We focus on their statistical properties in this paper. Twenty-four optical flares are obtained from 19 GRBs. The isotropic R-band energy is smaller than 1% of E{sub {gamma},iso}. The relation between the isotropic luminosities of the flares and gamma rays follows L{sup F}{sub R,iso}{proportional_to}L {sup 1.11{+-}0.27}{sub {gamma},iso}. Later flares tend to be wider and dimmer, i.e., w{sup F} {approx} t{sup F}{sub p}/2 and L{sup F}{sub R,iso}{proportional_to}[t{sup F}{sub p}/(1 + z)]{sup -1.15{+-}0.15}. The detection probability of the optical flares is much smaller than that of X-ray flares. An optical shallow-decay segment is observed in 39 GRBs. The relation between the break time and break luminosity is a power law, with an index of -0.78 {+-} 0.08, similar to that derived from X-ray flares. The X-ray and optical breaks are usually chromatic, but a tentative correlation is found. We suggest that similar to the prompt optical emission that tracks {gamma}-rays, the optical flares are also related to the erratic behavior of the central engine. The shallow-decay component is likely related to a long-lasting spinning-down central engine or piling up of flare materials onto the blast wave. Mixing of different emission components may be the reason for the diverse chromatic afterglow behaviors.

  10. Upper limits on the solar-neutron flux at the Yangbajing neutron monitor from BATSE-detected solar flares

    E-Print Network [OSTI]

    H. Tsuchiya; H. Miyasaka; E. Takahashi; S. Shimoda; Y. Yamada; I. Kondo; K. Makishima; F. Zhu; Y. Tan; H. Hu; Y. Tang; J. Zhang; H. Lu; X. Meng

    2007-03-16T23:59:59.000Z

    The purpose of this work is to search the Yangbajing neutron monitor data obtained between 1998 October and 2000 June for solar neutrons associated with solar flares. Using the onset times of 166 BATSE-detected flares with the GOES peak flux (1 -- 8 \\AA) higher than $1.0 \\times 10^{-5}$ $\\mathrm{Wm^{-2}}$, we prepare for each flare a light curve of the Yangbajing neutron monitor, spanning $\\pm$ 1.5 hours from the BATSE onset time. Based on the light curves, a systematic search for solar neutrons in energies above 100 MeV from the 166 flares was performed. No statistically significant signals due to solar neutrons were found in the present work. Therefore, we put upper limits on the $>$ 100 MeV solar-neutron flux for 18 events consisting of 2 X and 16 M class flares. The calculation assumed a power-law shaped neutron energy spectrum and three types of neutron emission profiles at the Sun. Compared with the other positive neutron detections associated with X-class flares, typical 95% confidence level upper limits for the two X-class flares are found to be comparable to the lowest and second lowest neutron fluxes at the top of the atmosphere.In addition, the upper limits for M-class flares scatter in the range of $10^{-2}$ to 1 neutrons $\\mathrm{cm^{-2}s^{-1}}$. This provides the first upper limits on the solar-neutron flux from M-class solar flares, using space observatories as well as ground-based neutron monitors.

  11. Structure and Design a Finance Program with Loan Loss Reserve Funds

    Broader source: Energy.gov [DOE]

    The process for structuring and designing a finance program with a loan loss reserve (LLR) fund typically includes research and preparing a finance program design document.

  12. Beam Cooling with ionisation losses

    E-Print Network [OSTI]

    C. Rubbia; A. Ferrari; Y. Kadi; V. Vlachoudis

    2006-02-03T23:59:59.000Z

    A novel type of particle "cooling", called Ionization Cooling, is applicable to slow (v of the order of 0.1c) ions stored in a small ring. The many traversals through a thin foil enhance the nuclear reaction probability, in a steady configuration in which ionisation losses are recovered at each turn by a RF-cavity. For a uniform target "foil" the longitudinal momentum spread diverges exponentially since faster (slower) particles ionise less (more) than the average. In order to "cool" also longitudinally, a chromaticity has to be introduced with a wedge shaped "foil". Multiple scattering and straggling are then "cooled" in all three dimensions, with a method similar to the one of synchrotron cooling, but valid for low energy ions. Particles then stably circulate in the beam indefinitely, until they undergo for instance nuclear processes in the thin target foil. This new method is under consideration for the nuclear production of a few MeV/A ion beams. Simple reactions, for instance Li 7 + D Li 8 + p, are more favourably exploited with the heavier ion colliding against a gas-jet D2 target. Kinematics is generally very favourable, with emission angles in a narrow angular cone and a relatively concentrated outgoing energy spectrum which allows an efficient collection as a neutral gas in a tiny volume with a technology at high temperatures perfected at ISOLDE. It is however of a much more general applicability. The method appears capable of producing a "table top" storage ring with an accumulation rate in excess of 10**14 Li-8 radioactive ion/s for possible use for radioactive beams for physics studies (for example for beta-beams) or for therapy.

  13. High Energy Neutrino Flashes from Far-Ultraviolet and X-ray Flares in Gamma-Ray Bursts

    E-Print Network [OSTI]

    Kohta Murase; Shigehiro Nagataki

    2006-08-07T23:59:59.000Z

    The recent observations of bright optical and x-ray flares by the Swift satellite suggest these are produced by the late activities of the central engine. We study the neutrino emission from far-ultraviolet and x-ray flares under the late internal shock model. We show that the efficiency of pion production in the highest energy is comparable to or higher than the unity, and the contribution from such neutrino flashes to a diffuse very high energy neutrino background can be larger than that of prompt bursts if the total baryonic energy input into flares is comparable to the radiated energy of prompt bursts. These signals may be detected by IceCube and are very important because they have possibilities to probe the nature of flares (the baryon loading, the photon field, the magnetic field and so on).

  14. Physics of ion acceleration in the solar flare on 2005 September 7 determines c-ray and neutron production

    E-Print Network [OSTI]

    California at Berkeley, University of

    de San Andre´s, La Paz, Bolivia m Department of Physics, Tokyo Institute of Technology, Meguro. Angular and energy-dependent neutron emission from solar flare magnetic loops, Astrophys. J. Sup- pl. Ser

  15. Turbine tip clearance loss mechanisms

    E-Print Network [OSTI]

    Mazur, Steven (Steven Andrew)

    2013-01-01T23:59:59.000Z

    Three-dimensional numerical simulations (RANS and URANS) were used to assess the impact of two specific design features, and of aspects of the actual turbine environment, on turbine blade tip loss. The calculations were ...

  16. OBSERVATIONAL STUDY OF THE QUASI-PERIODIC FAST-PROPAGATING MAGNETOSONIC WAVES AND THE ASSOCIATED FLARE ON 2011 MAY 30

    SciTech Connect (OSTI)

    Shen Yuandeng; Liu Yu, E-mail: ydshen@ynao.ac.cn [Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

    2012-07-01T23:59:59.000Z

    On 2011 May 30, quasi-periodic fast-propagating (QFP) magnetosonic waves accompanied by a C2.8 flare were directly imaged by the Atmospheric Imaging Assembly instrument on board the Solar Dynamics Observatory. The QFP waves successively emanated from the flare kernel, they propagated along a cluster of open coronal loops with a phase speed of {approx}834 km s{sup -1} during the flare's rising phase, and the multiple arc-shaped wave trains can be fitted with a series of concentric circles. We generate the k - {omega} diagram of the Fourier power and find a straight ridge that represents the dispersion relation of the waves. Along the ridge, we find a lot of prominent nodes which represent the available frequencies of the QFP waves. On the other hand, the frequencies of the flare are also obtained by analyzing the flare light curves using the wavelet technique. The results indicate that almost all the main frequencies of the flare are consistent with those of the QFP waves. This suggests that the flare and the QFP waves were possibly excited by a common physical origin. On the other hand, a few low frequencies (e.g., 2.5 mHz (400 s) and 0.7 mHz (1428 s)) revealed by the k - {omega} diagram cannot be found in the accompanying flare. We propose that these low frequencies were possibly due to the leakage of the pressure-driven p-mode oscillations from the photosphere into the low corona, which should be a noticeable mechanism for driving the QFP waves observed in the corona.

  17. Associated Shale Gas- From Flares to Rig Power

    E-Print Network [OSTI]

    Wallace, Elizabeth Michelle

    2014-10-16T23:59:59.000Z

    , compressed natural gas (CNG), or liquefied natural gas (LNG) (Soares 2008). Another option that can be considered to use natural gas and meet power load requirements is to convert diesel generators to a dual-fuel engines. Using both diesel and natural gas...-scale gas process could provide the solution to variable gas quality from different locations for use in power sources using natural gas. This micro-scale process is comparable to full scale LNG and CNG processing, first separating the liquids...

  18. Radio Flares of Compact Binary Mergers: the Effect of Non-Trivial Outflow Geometry

    E-Print Network [OSTI]

    Margalit, Ben

    2015-01-01T23:59:59.000Z

    The next generation gravitational waves (GW) detectors are most sensitive to GW emitted by compact (neutron star/black hole) binary mergers. If one of those is a neutron star the merger will also emit electromagnetic radiation via three possible channels: Gamma-ray bursts and their (possibly orphan) afterglows (Eichler et al. 1989), Li-Paczynski Macronovae (Li & Paczynski 1998) and radio flares (Nakar & Piran 2011). This accompanying electromagnetic radiation is vitally important in confirming the GW detections (Kochanek & Piran 1993). It could also reveal a wealth of information regarding the merger and will open a window towards multi-messenger astronomy. Identifying and characterizing these counterparts is therefore of utmost importance. In this work we explore late time radio flares emitted by the dynamically ejected outflows. We build upon previous work and consider the effect of the outflow's non-trivial geometry. Using an approximate method we estimate the radio light-curves for several eje...

  19. Power Laws in Solar Flares: Self-Organized Criticality or Turbulence?

    E-Print Network [OSTI]

    Guido Boffetta; Vincenzo Carbone; Paolo Giuliani; Pierluigi Veltri; Angelo Vulpiani

    1999-04-23T23:59:59.000Z

    We study the time evolution of Solar Flares activity by looking at the statistics of quiescent times $\\tau_{L}$ between successive bursts. The analysis of 20 years of data reveals a power law distribution with exponent $\\alpha \\simeq 2.4$ which is an indication of complex dynamics with long correlation times. The observed scaling behavior is in contradiction with the Self-Organized Criticality models of Solar Flares which predict Poisson-like statistics. Chaotic models, including the destabilization of the laminar phases and subsequent restabilization due to nonlinear dynamics, are able to reproduce the power law for the quiescent times. In the case of the more realistic Shell Model of MHD turbulence we are able to reproduce all the observed distributions.

  20. The synchrotron peak shift during high-energy flares of blazars

    E-Print Network [OSTI]

    M. Boettcher

    1999-02-10T23:59:59.000Z

    A prediction for the energy shift of the synchrotron spectrum of flat-spectrum radio quasars (FSRQs) during high-energy flares is presented. If the $\\gamma$-ray emission of FSRQs is produced by Comptonization of external radiation, then the peak of the synchrotron spectrum is predicted to move to lower energies in the flare state. This is opposite to the well-known broadband spectral behavior of high-frequency peaked BL-Lac objects where the external radiation field is believed to be weak and synchrotron-self Compton scattering might be the dominant $\\gamma$-ray radiation mechanism. The synchrotron peak shift, if observed in FSRQs, can thus be used as a diagnostic to determine the dominant radiation mechanism in these objects. I suggest a few FSRQs as promising candidates to test the prediction of the external-Comptonization model.

  1. Numerical Study of a Propagating Non-Thermal Microwave Feature in a Solar Flare Loop

    E-Print Network [OSTI]

    T. Minoshima; T. Yokoyama

    2008-06-24T23:59:59.000Z

    We analytically and numerically study the motion of electrons along a magnetic loop, to compare with the observation of the propagating feature of the non-thermal microwave source in the 1999 August 28 solar flare reported by Yokoyama et al. (2002). We model the electron motion with the Fokker-Planck equation and calculate the spatial distribution of the gyrosynchrotron radiation. We find that the microwave propagating feature does not correspond to the motion of electrons with a specific initial pitch angle. This apparent propagating feature is a consequence of the motion of an ensemble of electrons with different initial pitch angles, which have different time and position to produce strong radiation in the loop. We conclude that the non-thermal electrons in the 1999 August 28 flare were isotropically accelerated and then are injected into the loop.

  2. QUASI-PERIODIC FORMALDEHYDE MASER FLARES IN THE MASSIVE PROTOSTELLAR OBJECT IRAS 18566+0408

    SciTech Connect (OSTI)

    Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States); Hofner, P.; Goss, W. M. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Kurtz, S. [Centro de RadioastronomIa y Astrofisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 3-72, 58089 Morelia, Michoacan (Mexico); Richards, A. M. S. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Linz, H. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Olmi, L. [University of Puerto Rico at Rio Piedras, Physics Department, P.O. Box 23343, San Juan, PR 00931 (Puerto Rico); Sewilo, M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2010-07-10T23:59:59.000Z

    We report results of an extensive observational campaign of the 6 cm formaldehyde maser in the young massive stellar object IRAS 18566+0408 (G37.55+0.20) conducted from 2002 to 2009. Using the Arecibo Telescope, the Very Large Array, and the Green Bank Telescope, we discovered quasi-periodic formaldehyde flares (P {approx} 237 days). Based on Arecibo observations, we also discovered correlated variability between formaldehyde (H{sub 2}CO) and methanol (CH{sub 3}OH) masers. The H{sub 2}CO and CH{sub 3}OH masers are not spatially coincident, as demonstrated by different line velocities and high angular resolution MERLIN observations. The flares could be caused by variations in the infrared radiation field, possibly modulated by periodic accretion onto a young binary system.

  3. Hadronic Production of TeV Gamma Ray Flares from Blazars

    E-Print Network [OSTI]

    Arnon Dar; Ari Laor

    1997-01-13T23:59:59.000Z

    We propose that TeV $\\gamma$-ray emission from blazars is produced by collisions near the line of sight of high energy jet protons with gas targets (``clouds'') from the broad emission-line region (BLR). Intense TeV $\\gamma$-ray flares (GRFs) are produced when BLR clouds cross the line of sight close to the black hole. The model reproduces the observed properties of the recently reported very short and intense TeV GRFs from the blazar Markarian 421. Hadronic production of TeV GRF from blazars implies that it is accompanied by a simultaneous emission of high energy neutrinos, and of electrons and positrons with similar intensities, light curves and energy spectra. Cooling of these electrons and positrons by emission of synchrotron radiation and inverse Compton scattering produces delayed optical, X-ray and $\\gamma$-ray flares.

  4. Strongly Blueshifted Phenomena Observed with {\\it Hinode}/EIS in the 2006 December 13 Solar Flare

    E-Print Network [OSTI]

    Ayumi Asai; Hirohisa Hara; Tetsuya Watanabe; Shinsuke Imada; Taro Sakao; Noriyuki Narukage; J. L. Culhane; G. A. Doschek

    2008-05-29T23:59:59.000Z

    We present a detailed examination of strongly blueshifted emission lines observed with the EUV Imaging Spectrometer on board the {\\it Hinode} satellite. We found two kinds of blueshifted phenomenon associated with the X3.4 flare that occurred on 2006 December 13. One was related to a plasmoid ejection seen in soft X-rays. It was very bright in all the lines used for the observations. The other was associated with the faint arc-shaped ejection seen in soft X-rays. The soft X-ray ejection is thought to be an MHD fast-mode shock wave. This is therefore the first spectroscopic observation of an MHD fast-mode shock wave associated with a flare.

  5. Efficiency loss in resource allocation games

    E-Print Network [OSTI]

    Xu, Yunjian

    2012-01-01T23:59:59.000Z

    The overarching goals of this thesis are to quantify the efficiency loss due to market participant strategic behavior, and to design proper pricing mechanisms that reduce the efficiency loss. The concept of efficiency loss ...

  6. Cancer Vulnerabilities Unveiled by Genomic Loss

    E-Print Network [OSTI]

    Nijhawan, Deepak

    Due to genome instability, most cancers exhibit loss of regions containing tumor suppressor genes and collateral loss of other genes. To identify cancer-specific vulnerabilities that are the result of copy number losses, ...

  7. EVOLUTION OF CURRENTS OF OPPOSITE SIGNS IN THE FLARE-PRODUCTIVE SOLAR ACTIVE REGION NOAA 10930

    SciTech Connect (OSTI)

    Ravindra, B. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Venkatakrishnan, P.; Tiwari, Sanjiv Kumar; Bhattacharyya, R., E-mail: ravindra@iiap.res.in, E-mail: pvk@prl.res.in, E-mail: tiwari@mps.mpg.de, E-mail: ramit@prl.res.in [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur 313 001 (India)

    2011-10-10T23:59:59.000Z

    Analysis of a time series of high spatial resolution vector magnetograms of the active region NOAA 10930 available from the Solar Optical Telescope SpectroPolarimeter on board Hinode revealed that there is a mixture of upward and downward currents in the two footpoints of an emerging flux rope. The flux emergence rate is almost the same in both the polarities. We observe that along with an increase in magnetic flux, the net current in each polarity increases initially for about three days after which it decreases. This net current is characterized by having exactly opposite signs in each polarity while its magnitude remains almost the same most of the time. The decrease of the net current in both the polarities is due to the increase of current having a sign opposite to that of the net current. The dominant current, with the same sign as the net current, is seen to increase first and then decreases during the major X-class flares. Evolution of non-dominant current appears to be a necessary condition for flare initiation. The above observations can be plausibly explained in terms of the superposition of two different force-free states resulting in a non-zero Lorentz force in the corona. This Lorentz force then pushes the coronal plasma and might facilitate the magnetic reconnection required for flares. Also, the evolution of the net current is found to follow the evolution of magnetic shear at the polarity inversion line.

  8. On the 2012 October 23 circular ribbon flare: emission features and magnetic topology

    E-Print Network [OSTI]

    Yang, Kai; Ding, M D

    2015-01-01T23:59:59.000Z

    Circular ribbon flares are usually related to spine-fan type magnetic topology containing null-points. In this paper, we investigate an X-class circular ribbon flare on 2012 October 23, using the multi-wavelength data from the \\textit{Solar Dynamics Observatory}, \\textit{Hinode}, and the \\textit{Ramaty High Energy Solar Spectroscopic Imager}. In \\ion{Ca}{2} H emission, the flare showed three ribbons with two highly elongated ones inside and outside a quasi-circular one, respectively. A hot channel was displayed in the extreme ultraviolet (EUV) emissions that infers the existence of a magnetic flux rope. Two hard X-ray (HXR) sources in the 12--25 keV energy band were located at the footpoints of this hot channel. Using a nonlinear force-free magnetic field extrapolation, we identify three topological structures: (1) a 3D null-point, (2) a flux rope below the fan of the null-point, and (3) a large-scale quasi-separatrix layers (QSL) induced by the quadrupolar-like magnetic field of the active region. We find th...

  9. MODELING OF GYROSYNCHROTRON RADIO EMISSION PULSATIONS PRODUCED BY MAGNETOHYDRODYNAMIC LOOP OSCILLATIONS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2012-04-01T23:59:59.000Z

    A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

  10. Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare

    E-Print Network [OSTI]

    Tian, Hui; Reeves, Katharine K; Raymond, John C; Guo, Fan; Liu, Wei; Chen, Bin; Murphy, Nicholas A

    2014-01-01T23:59:59.000Z

    Magnetic reconnection is believed to be the dominant energy release mechanism in solar flares. The standard flare model predicts both downward and upward outflow plasmas with speeds close to the coronal Alfv\\'{e}n speed. Yet, spectroscopic observations of such outflows, especially the downflows, are extremely rare. With observations of the newly launched Interface Region Imaging Spectrograph (IRIS), we report the detection of greatly redshifted ($\\sim$125 km s$^{-1}$ along line of sight) Fe {\\sc{xxi}} 1354.08\\AA{} emission line with a $\\sim$100 km s$^{-1}$ nonthermal width at the reconnection site of a flare. The redshifted Fe {\\sc{xxi}} feature coincides spatially with the loop-top X-Ray source observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We interpret this large redshift as the signature of downward-moving reconnection outflow/hot retracting loops. Imaging observations from both IRIS and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) also...

  11. Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare

    E-Print Network [OSTI]

    T. Minoshima; T. Yokoyama; N. Mitani

    2007-10-02T23:59:59.000Z

    We study the non-thermal emissions in a solar flare occurring on 2003 May 29 by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This flare shows several typical behaviors of the HXR and microwave emissions: time delay of microwave peaks relative to HXR peaks, loop-top microwave and footpoint HXR sources, and a harder electron energy distribution inferred from the microwave spectrum than from the HXR spectrum. In addition, we found that the time profile of the spectral index of the higher-energy ($\\gsim 100$ keV) HXRs is similar to that of the microwaves, and is delayed from that of the lower-energy ($\\lsim 100$ keV) HXRs. We interpret these observations in terms of an electron transport model called {\\TPP}. We numerically solved the spatially-homogeneous {\\FP} equation to determine electron evolution in energy and pitch-angle space. By comparing the behaviors of the HXR and microwave emissions predicted by the model with the observations, we discuss the pitch-angle distribution of the electrons injected into the flare site. We found that the observed spectral variations can qualitatively be explained if the injected electrons have a pitch-angle distribution concentrated perpendicular to the magnetic field lines rather than isotropic distribution.

  12. X-ray flare in XRF 050406: evidence for prolonged engine activity

    E-Print Network [OSTI]

    Romano, P; Banat, P L; Burrows, D N; Campana, S; Chincarini, G; Covino, S; Malesani, D; Tagliaferri, G; Kobayashi, S; Zhang, B; Falcone, A D; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Cusumano, G; Giommi, P; Goad, M R; Godet, O; Grupe, D; Hill, J E; Kennea, J A; La Parola, V; Mangano, V; Mészáros, P; Morris, D C; Nousek, J A; O'Brien, P T; Osborne, J P; Parsons, A; Perri, M; Pagani, C; Page, K L; Wells, A A; Gehrels, N

    2006-01-01T23:59:59.000Z

    We present observations of XRF 050406, the first burst detected by Swift showing a flare in its X-ray light curve. During this flare, which peaks at t_peak ~210s after the BAT trigger, a flux variation of (delta F)/F~6 in a very short time (delta t)/t_peak<<1 was observed. Its measured fluence in the 0.2-10 keV band was ~1.4x10^-8 erg cm^-2, which corresponds to 1-15% of the prompt fluence. We present indications of spectral variations during the flare. We argue that the producing mechanism is late internal shocks, which implies that the central engine is still active at 210s, though with a reduced power with respect to the prompt emission. The X-ray light curve flattens to a very shallow slope with decay index of ~0.5 after ~4400s, which also supports continued central engine activity at late times. This burst is classified as an X-ray flash, with a relatively low fluence (~10^-7 erg cm^-2 in the 15-350 keV band, E_iso~10^51 erg), a soft spectrum (photon index 2.65), no significant flux above ~50 keV a...

  13. Study of multi-periodic coronal pulsations during an X-class solar flare

    E-Print Network [OSTI]

    Chowdhury, Partha; Dwivedi, B N; Sych, Robert; Moon, Y -J

    2015-01-01T23:59:59.000Z

    We investigate quasi-periodic coronal pulsations during the decay phase of an X 3.2 class flare on 14 May 2013, using soft X-ray data from the RHESSI satellite. Periodogram analyses of soft X-ray light curves show that 53 s and 72 s periods co-exist in the 3-6, 6-12 and 12-25 KeV energy bands. Considering the typical length of the flaring loop system and observed periodicities, we find that they are associated with multiple (first two harmonics) of fast magnetoacoustic sausage waves. The phase relationship of soft X-ray emissions in different energy bands using cross-correlation technique show that these modes are standing in nature as we do not find the phase lag. Considering the period ratio, we diagnose the local plasma conditions of the flaring region by invoking MHD seismology. The period ratio P1/2P2 is found to be 0.65, which indicates that such oscillations are most likely excited in longitudinal density stratified loops.

  14. Collisional relaxation of electrons in a warm plasma and accelerated nonthermal electron spectra in solar flares

    E-Print Network [OSTI]

    Kontar, E P; Emslie, A G; Bian, N H

    2015-01-01T23:59:59.000Z

    Extending previous studies of nonthermal electron transport in solar flares which include the effects of collisional energy diffusion and thermalization of fast electrons, we present an analytic method to infer more accurate estimates of the accelerated electron spectrum in solar flares from observations of the hard X-ray spectrum. Unlike for the standard cold-target model, the spatial characteristics of the flaring region, especially the necessity to consider a finite volume of hot plasma in the source, need to be taken into account in order to correctly obtain the injected electron spectrum from the source-integrated electron flux spectrum (a quantity straightforwardly obtained from hard X-ray observations). We show that, for a given source-integrated electron flux spectrum, the overall power in the injected electrons could be reduced by an order of magnitude or more relative to its cold-target value. Indeed, the extent of electron thermalization can be significant enough to nullify the need to introduce an...

  15. RESIK Solar X-ray flare element abundances on a non-isothermal assumption

    E-Print Network [OSTI]

    Sylwester, B; Sylwester, J; Kepa, A

    2015-01-01T23:59:59.000Z

    Solar X-ray spectra from the RESIK crystal spectrometer on the {\\em CORONAS-F} spacecraft (spectral range $3.3-6.1$~\\AA) are analyzed for thirty-three flares using a method to derive abundances of Si, S, Ar, and K, emission lines of which feature prominently in the spectra. For each spectrum, the method first optimizes element abundances then derives the differential emission measure as a function of temperature based on a procedure given by Sylwester et al. and Withbroe. This contrasts with our previous analyses of RESIK spectra in which an isothermal assumption was used. The revised abundances (on a logarithmic scale with $A({\\rm H}) = 12$) averaged for all the flares in the analysis are $A({\\rm Si}) = 7.53 \\pm 0.08$ (previously $7.89 \\pm 0.13$), $A({\\rm S}) = 6.91 \\pm 0.07$ ($7.16 \\pm 0.17$), $A({\\rm Ar}) = 6.47 \\pm 0.08$ ($6.45 \\pm 0.07$), and $A({\\rm K}) = 5.73 \\pm 0.19$ ($5.86 \\pm 0.20$), with little evidence for time variations of abundances within the evolution of each flare. Our previous estimates of...

  16. Fermilab experience of post-annealing losses in SRF niobium cavities due to furnace contamination and the ways to its mitigation: a pathway to processing simplification and quality factor improvement

    E-Print Network [OSTI]

    Grassellino, A; Crawford, A; Melnychuk, O; Rowe, A; Wong, M; Cooper, C; Sergatskov, D; Bice, D; Trenikhina, Y; Cooley, L D; Ginsburg, C; Kephart, R D

    2013-01-01T23:59:59.000Z

    We investigate the effect of high temperature treatments followed by only high-pressure water rinse (HPR) of superconducting radio frequency (SRF) niobium cavities. The objective is to provide a cost effective alternative to the typical cavity processing sequence, by eliminating the material removal step post furnace treatment while preserving or improving the RF performance. The studies have been conducted in the temperature range 800-1000C for different conditions of the starting substrate: large grain and fine grain, electro-polished (EP) and centrifugal barrel polished (CBP) to mirror finish. An interesting effect of the grain size on the performances is found. Cavity results and samples characterization show that furnace contaminants cause poor cavity performance, and a practical solution is found to prevent surface contamination. Extraordinary values of residual resistances ~ 1 nOhm and below are then consistently achieved for the contamination-free cavities. These results lead to a more cost-effective ...

  17. Adjustable Speed- A Tool for Saving Energy Losses in Pumps, Fans, Fans, Blowers and Compressors

    E-Print Network [OSTI]

    Hickok, H. N.

    Petroleum and chemical plants of today are effectively cutting energy losses in their plants thermally, electrically, and mechanically in their process equipment. In rotating process equipment such as pumps, fans, compressors, and blowers, much...

  18. DATA ACQUISITION FOR SNS BEAM LOSS MONITOR SYSTEM

    SciTech Connect (OSTI)

    YENG,Y.GASSNER,D.HOFF,L.WITKOVER,R.

    2003-10-13T23:59:59.000Z

    The Spallation Neutron Source (SNS) beam loss monitor system uses VME based electronics to measure the radiation produced by lost beam. Beam loss signals from cylindrical argon-filled ion chambers and neutron detectors will be conditioned in analog front-end (AFE) circuitry. These signals will be digitized and further processed in a dedicated VME crate. Fast beam inhibit and low-level, long-term loss warnings will be generated to provide machine protection. The fast loss data will have a bandwidth of 35kHz. While the low level, long-term loss data will have much higher sensitivity. This is further complicated by the 3 decade range of intensity as the Ring accumulates beam. Therefore a bandwidth of 100kHz and dynamic range larger than 21 bits data acquisition system will be required for this purpose. Based on the evaluation of several commercial ADC modules in preliminary design phase, a 24 bits Sigma-Delta data acquisition VME bus card was chosen as the SNS BLM digitizer. An associated vxworks driver and EPICS device support module also have been developed at BNL. Simulating test results showed this system is fully qualified for both fast loss and low-level, long-term loss application. The first prototype including data acquisition hardware setup and EPICS software (running database and OPI clients) will be used in SNS Drift Tube Linac (DTL) system commissioning.

  19. Stopping and time reversing a light pulse using dynamic loss tuning of coupled-resonator

    E-Print Network [OSTI]

    Fan, Shanhui

    Stopping and time reversing a light pulse using dynamic loss tuning of coupled-resonator delay. ID 85496); published November 12, 2007 We introduce a light-stopping process that uses dynamic loss processing [1,2]. For this pur- pose, dynamically tuned delay lines based on cas- caded optical resonators

  20. HELIOPHYSICS II. ENERGY CONVERSION PROCESSES

    E-Print Network [OSTI]

    Hudson, Hugh

    and radiation page 2 2 Observations of solar and stellar eruptions, flares, and jets 3 2.1 Introduction 3 2 of a solar flare 11 2.3.1 Flare luminosity and mechanical energy 11 2.3.2 The impulsive phase (hard X Energization of trapped particles 46 10 In situ detection of energetic particles 47 11 Radiative signatures

  1. Thermochemical processing of digested sludge and its implications in the United States Jennifer Lawrence, Ruth Reed, Sara Tischhauser, Casey Zak

    E-Print Network [OSTI]

    Iglesia, Enrique

    , or biomethane) for meeting onsite heat #12;and power needs. Biogas is a methanerich byproduct of this process, or biomethane, is produced as a result of this process and can either be flared off to reduce greenhouse gas of anaerobic digestion (AD) to reduce sludge volumes as well as produce digester gas (also known as biogas

  2. RELATIVISTIC SHOCK BREAKOUTS-A VARIETY OF GAMMA-RAY FLARES: FROM LOW-LUMINOSITY GAMMA-RAY BURSTS TO TYPE Ia SUPERNOVAE

    SciTech Connect (OSTI)

    Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Sari, Re'em [Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)

    2012-03-10T23:59:59.000Z

    The light from a shock breakout of stellar explosions, which carries a wealth of information, strongly depends on the shock velocity at the time of the breakout. The emission from Newtonian breakouts, typical in regular core-collapse supernovae (SNe), has been explored extensively. However, a large variety of explosions result in mildly or ultrarelativistic breakouts, where the observed signature is unknown. Here we calculate the luminosity and spectrum produced by relativistic breakouts. In order to do so, we improve the analytic description of relativistic radiation-mediated shocks and follow the system from the breakout itself, through the planar phase and into the spherical phase. We limit our calculation to cases where the post-breakout acceleration of the gas ends during the planar phase (i.e., the final gas Lorentz factor {approx}< 30). We find that spherical relativistic breakouts produce a flash of gamma rays with energy, E{sub bo}, temperature, T{sub bo}, and duration, t{sup obs} b{sub o}, that provide the breakout radius ( Almost-Equal-To 5 R{sub Sun }(t{sup obs}{sub bo}/10 s)(T{sub bo}/50 keV){sup 2}) and the Lorentz factor ( Almost-Equal-To T{sub bo}/50 keV). They also always satisfy a relativistic breakout relation (t{sup obs}{sub bo}/20 s) {approx} (E{sub bo}/10{sup 46} erg){sup 1/2}(T{sub bo}/50 keV){sup -2.68}. The breakout flare is typically followed, on longer timescales, by X-rays that carry a comparable energy. We apply our model to a variety of explosions, including Type Ia and .Ia SNe, accretion-induced collapse, energetic SNe, and gamma-ray bursts (GRBs). We find that all these events produce detectable gamma-ray signals, some of which may have already been seen. Some particular examples are: (1) relativistic shock breakouts provide a natural explanation to the energy, temperature, and timescales of low-luminosity GRBs. Indeed, all observed low-luminosity GRBs satisfy the relativistic breakout relation. (2) Nearby broad-line Type Ib/c (like SN 2002ap) may produce a detectable {gamma}-ray signal. (3) Galactic Type Ia SNe may produce detectable {gamma}-ray flares. We conclude that relativistic shock breakouts provide a generic process for the production of gamma-ray flares.

  3. Solar Flare Prediction Using SDO/HMI Vector Magnetic Field Data with a Machine-Learning Algorithm

    E-Print Network [OSTI]

    Bobra, Monica G

    2014-01-01T23:59:59.000Z

    We attempt to forecast M-and X-class solar flares using a machine-learning algorithm, called Support Vector Machine (SVM), and four years of data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager, the first instrument to continuously map the full-disk photospheric vector magnetic field from space. Most flare forecasting efforts described in the literature use either line-of-sight magnetograms or a relatively small number of ground-based vector magnetograms. This is the first time a large dataset of vector magnetograms has been used to forecast solar flares. We build a catalog of flaring and non-flaring active regions sampled from a database of 2,071 active regions, comprised of 1.5 million active region patches of vector magnetic field data, and characterize each active region by 25 parameters. We then train and test the machine-learning algorithm and we estimate its performances using forecast verification metrics with an emphasis on the True Skill Statistic (TSS). We obtain relatively h...

  4. Charm Quark Energy Loss in QCD Matter

    E-Print Network [OSTI]

    W. C. Xiang; H. T. Ding; D. C. Zhou; D. Rohrich

    2005-07-13T23:59:59.000Z

    The energy loss of heavy quarks in a quark-gluon plasma of finite size is studied within the light-cone integral approach. A simple analytical formulation of the radiative energy loss of heavy quarks is derived. This provides a convenient way to quantitatively estimate the quark energy loss. Our results show that if the energy of a heavy quark is much larger than its mass, the radiative energy loss approaches the radiative energy loss of light quarks.

  5. Flare Ribbons Observed with G-band and FeI 6302A Filters of the Solar Optical Telescope on Board Hinode

    E-Print Network [OSTI]

    H. Isobe; M. Kubo; T. Minoshima; K. Ichimoto; Y. Katsukawa; T. D. Tarbell; S. Tsuneta; T. E. Berger; B. W. Lites; S. Nagata; T. Shimizu; R. A. Shine; Y. Suematsu; A. Title

    2007-11-26T23:59:59.000Z

    The Solar Optical Telescope (SOT) on board Hinode satellite observed an X3.4 class flare on 2006 December 13. Typical two-ribbon structure was observed, not only in the chromospheric CaII H line but also in G-band and FeI 6302A line. The high-resolution, seeing-free images achieved by SOT revealed, for the first time, the sub-arcsec fine structures of the "white light" flare. The G-band flare ribbons on sunspot umbrae showed a sharp leading edge followed by a diffuse inside, as well as previously known core-halo structure. The underlying structures such as umbral dots, penumbral filaments and granules were visible in the flare ribbons. Assuming that the sharp leading edge was directly heated by particle beam and the diffuse parts were heated by radiative back-warming, we estimate the depth of the diffuse flare emission using the intensity profile of the flare ribbon. We found that the depth of the diffuse emission is about 100 km or less from the height of the source of radiative back-warming. The flare ribbons were also visible in the Stokes-V images of FeI 6302A, as a transient polarity reversal. This is probably related to "magnetic transient" reported in the literature. The intensity increase in Stokes-I images indicates that the FeI 6302A line was significantly deformed by the flare, which may cause such a magnetic transient.

  6. PROBING DYNAMICS OF ELECTRON ACCELERATION WITH RADIO AND X-RAY SPECTROSCOPY, IMAGING, AND TIMING IN THE 2002 APRIL 11 SOLAR FLARE

    SciTech Connect (OSTI)

    Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Kontar, Eduard P. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-05-10T23:59:59.000Z

    Based on detailed analysis of radio and X-ray observations of a flare on 2002 April 11 augmented by realistic three-dimensional modeling, we have identified a radio emission component produced directly at the flare acceleration region. This acceleration region radio component has distinctly different (1) spectrum, (2) light curves, (3) spatial location, and, thus, (4) physical parameters from those of the separately identified trapped or precipitating electron components. To derive evolution of physical parameters of the radio sources we apply forward fitting of the radio spectrum time sequence with the gyrosynchrotron source function with five to six free parameters. At the stage when the contribution from the acceleration region dominates the radio spectrum, the X-ray- and radio-derived electron energy spectral indices agree well with each other. During this time the maximum energy of the accelerated electron spectrum displays a monotonic increase with time from {approx}300 keV to {approx}2 MeV over roughly one minute duration indicative of an acceleration process in the form of growth of the power-law tail; the fast electron residence time in the acceleration region is about 2-4 s, which is much longer than the time of flight and so requires a strong diffusion mode there to inhibit free-streaming propagation. The acceleration region has a relatively strong magnetic field, B {approx} 120 G, and a low thermal density, n{sub e} {approx}< 2 Multiplication-Sign 10{sup 9} cm{sup -3}. These acceleration region properties are consistent with a stochastic acceleration mechanism.

  7. ANALYSIS AND MODELING OF TWO FLARE LOOPS OBSERVED BY AIA AND EIS

    SciTech Connect (OSTI)

    Li, Y.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Qiu, J. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2012-10-10T23:59:59.000Z

    We analyze and model an M1.0 flare observed by SDO/AIA and Hinode/EIS to investigate how flare loops are heated and evolve subsequently. The flare is composed of two distinctive loop systems observed in extreme ultraviolet (EUV) images. The UV 1600 A emission at the feet of these loops exhibits a rapid rise, followed by enhanced emission in different EUV channels observed by the Atmospheric Imaging Assembly (AIA) and the EUV Imaging Spectrometer (EIS). Such behavior is indicative of impulsive energy deposit and the subsequent response in overlying coronal loops that evolve through different temperatures. Using the method we recently developed, we infer empirical heating functions from the rapid rise of the UV light curves for the two loop systems, respectively, treating them as two big loops with cross-sectional area of 5'' by 5'', and compute the plasma evolution in the loops using the EBTEL model. We compute the synthetic EUV light curves, which, with the limitation of the model, reasonably agree with observed light curves obtained in multiple AIA channels and EIS lines: they show the same evolution trend and their magnitudes are comparable by within a factor of two. Furthermore, we also compare the computed mean enthalpy flow velocity with the Doppler shift measurements by EIS during the decay phase of the two loops. Our results suggest that the two different loops with different heating functions as inferred from their footpoint UV emission, combined with their different lengths as measured from imaging observations, give rise to different coronal plasma evolution patterns captured both in the model and in observations.

  8. Dimensioning hospital wards using the Erlang loss model Corresponding author

    E-Print Network [OSTI]

    -2006. Finally, we demonstrate the efficiency of merging departments. Keywords: hospital resource allocationDimensioning hospital wards using the Erlang loss model Corresponding author: A.M. de Bruin (MSc of Sciences Department of Mathematics Assistant professor Optimization of Business Processes L. van Zanten

  9. Analysis of the Impulsive Phase of Solar Flares with Pass 8 LAT data

    E-Print Network [OSTI]

    Desiante, R; Omodei, N; Pesce-Rollins, M

    2015-01-01T23:59:59.000Z

    We show the results of analyses performed on high-energy gamma-ray emission during the impulsive phase of solar flares detected by the LAT using Pass 8 data. We compare results obtained with Pass 7 and Pass 8 data sets, using both LAT Low Energy and standard data classes. With a dedicated event selection, Pass 8 allows standard analysis during the impulsive phase: it has been designed to be less susceptible to pile-up in the LAT Anti-Coincidence Detector caused by the intense hard X-ray emission at early times.

  10. PROPERTIES OF A SOLAR FLARE KERNEL OBSERVED BY HINODE AND SDO

    SciTech Connect (OSTI)

    Young, P. R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)] [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Doschek, G. A.; Warren, H. P. [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States)] [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Hara, H. [National Astronomical Observatory of Japan/NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan/NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2013-04-01T23:59:59.000Z

    Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare in active region AR 11158 observed on 2011 February 16 07:44 UT for which the location of the upflow region seen by EUV Imaging Spectrometer (EIS) can be precisely aligned to high spatial resolution images obtained by the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). A string of bright flare kernels is found to be aligned with a ridge of strong magnetic field, and one kernel site is highlighted for which an upflow speed of Almost-Equal-To 400 km s{sup -1} is measured in lines formed at 10-30 MK. The line-of-sight magnetic field strength at this location is Almost-Equal-To 1000 G. Emission over a continuous range of temperatures down to the chromosphere is found, and the kernels have a similar morphology at all temperatures and are spatially coincident with sizes at the resolution limit of the AIA instrument ({approx}<400 km). For temperatures of 0.3-3.0 MK the EIS emission lines show multiple velocity components, with the dominant component becoming more blueshifted with temperature from a redshift of 35 km s{sup -1} at 0.3 MK to a blueshift of 60 km s{sup -1} at 3.0 MK. Emission lines from 1.5-3.0 MK show a weak redshifted component at around 60-70 km s{sup -1} implying multi-directional flows at the kernel site. Significant non-thermal broadening corresponding to velocities of Almost-Equal-To 120 km s{sup -1} is found at 10-30 MK, and the electron density in the kernel, measured at 2 MK, is 3.4 Multiplication-Sign 10{sup 10} cm{sup -3}. Finally, the Fe XXIV {lambda}192.03/{lambda}255.11 ratio suggests that the EIS calibration has changed since launch, with the long wavelength channel less sensitive than the short wavelength channel by around a factor two.

  11. Detecting Flaring Structures in Sagittarius A* with (Sub)Millimeter VLBI

    E-Print Network [OSTI]

    Vincent L. Fish; Sheperd S. Doeleman; Avery E. Broderick; Abraham Loeb; Alan E. E. Rogers

    2008-07-15T23:59:59.000Z

    Multiwavelength monitoring observations of Sagittarius A* exhibit variability on timescales of minutes to hours, indicating emission regions localized near the event horizon. (Sub)Millimeter-wavelength VLBI is uniquely suited to probe the environment of the assumed black hole on these scales. We consider a range of orbiting hot-spot and accretion-disk models and find that periodicity in Sgr A* flares is detectable using closure quantities. Our methods are applicable to any model producing source structure changes near the black hole, including jets and magnetohydrodynamic disk instabilities, and suggest that (sub)millimeter VLBI will play a prominent role in investigating Sgr A* near the event horizon.

  12. Quantum cryptographic system with reduced data loss

    DOE Patents [OSTI]

    Lo, Hoi-Kwong (1309, Low Block, Lei Moon House Ap Lei Chau Estate, Hong Kong, HK); Chau, Hoi Fung (Flat C, 42nd Floor, Tower 1, University Heights 23 Pokfield Road, Pokfulam, Hong Kong, HK)

    1998-01-01T23:59:59.000Z

    A secure method for distributing a random cryptographic key with reduced data loss. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically.

  13. Quantum cryptographic system with reduced data loss

    DOE Patents [OSTI]

    Lo, H.K.; Chau, H.F.

    1998-03-24T23:59:59.000Z

    A secure method for distributing a random cryptographic key with reduced data loss is disclosed. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically. 23 figs.

  14. Simulation and optimization of beam losses during continuous transfer extraction at the CERN Proton Synchrotron

    E-Print Network [OSTI]

    Garcia, J B

    2011-01-01T23:59:59.000Z

    The proton beams used for the fixed target physics at the Super Proton Synchrotron (SPS) are extracted from the Proton Synchrotron ( PS) by a multiturn technique called continuous transfer (CT). During the CT extraction, large losses are observed in locations where the machine aperture should be large enough to accommodate the circulating beam. This limits the maximum intensity deliverable due to the induced stray radiation outside the PS tunnel. Scattered particles from the interaction with the electrostatic septum are identified as the possible source of these losses. This article presents a detailed study aiming to understand the origin of losses and propose possible cures. The simulations could reproduce accurately the beam loss pattern measured in real machine operation and determine the beam shaving, intrinsic to the extraction process, as the cause for the unexpected losses. Since these losses are unavoidable, the proposed solution implies a new optics scheme displacing the losses to a region with bett...

  15. Low-energy cutoffs in electron spectra of solar flares: statistical survey

    E-Print Network [OSTI]

    E. P. Kontar; E. Dickson; J. Kasparova

    2008-05-21T23:59:59.000Z

    The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) X-ray data base (February 2002 -- May 2006) has been searched to find solar flares with weak thermal components and flat photon spectra. Using a regularised inversion technique, we determine the mean electron flux distribution from count spectra of a selection of events with flat photon spectra in the 15--20 keV energy range. Such spectral behaviour is expected for photon spectra either affected by photospheric albedo or produced by electron spectra with an absence of electrons in a given energy range, e.g. a low-energy cutoff in the mean electron spectra of non-themal particles. We have found 18 cases which exhibit a statistically significant local minimum (a dip) in the range of 10--20 keV. The positions and spectral indices of events with low-energy cutoff indicate that such features are likely to be the result of photospheric albedo. It is shown that if the isotropic albedo correction was applied, all low-energy cutoffs in the mean electron spectrum were removed and hence the low energy cutoffs in the mean electron spectrum of solar flares above $\\sim$12 keV cannot be viewed as real features in the electron spectrum. If low-energy cutoffs exist in the mean electron spectra, the energy of low energy cutoffs should be less than $\\sim$12 keV.

  16. Constraints on Blazar Jet Conditions During Gamma-Ray Flaring from Radiative Transfer Modeling

    E-Print Network [OSTI]

    Aller, Margo F; Aller, Hugh D; Hovatta, Talvikki

    2013-01-01T23:59:59.000Z

    As part of a program to investigate jet flow conditions during GeV gamma-ray flares detected by Fermi, we are using UMRAO multi-frequency, centimeter-band total flux density and linear polarization monitoring observations to constrain radiative transfer models incorporating propagating shocks orientated at an arbitrary angle to the flow direction. We describe the characteristics of the model, illustrate how the data are used to constrain the models, and present results for three program sources with diverse characteristics: PKS 0420-01, OJ 287, and 1156+295. The modeling of the observed spectral behavior yields information on the sense, strength and orientation of the shocks producing the radio-band flaring; on the energy distribution of the radiating particles; and on the observer's viewing angle with respect to the jet independent of VLBI data. We present evidence that, while a random component dominates the jet magnetic field, a distinguishing feature of those radio events with an associated gamma-ray flar...

  17. Recovery Act: ArcelorMittal USA Blast Furnace Gas Flare Capture

    SciTech Connect (OSTI)

    Seaman, John

    2013-01-14T23:59:59.000Z

    The U.S. Department of Energy (DOE) awarded a financial assistance grant under the American Recovery and Reinvestment Act of 2009 (Recovery Act) to ArcelorMittal USA, Inc. (ArcelorMittal) for a project to construct and operate a blast furnace gas recovery boiler and supporting infrastructure at ArcelorMittal’s Indiana Harbor Steel Mill in East Chicago, Indiana. Blast furnace gas (BFG) is a by-product of blast furnaces that is generated when iron ore is reduced with coke to create metallic iron. BFG has a very low heating value, about 1/10th the heating value of natural gas. BFG is commonly used as a boiler fuel; however, before installation of the gas recovery boiler, ArcelorMittal flared 22 percent of the blast furnace gas produced at the No. 7 Blast Furnace at Indiana Harbor. The project uses the previously flared BFG to power a new high efficiency boiler which produces 350,000 pounds of steam per hour. The steam produced is used to drive existing turbines to generate electricity and for other requirements at the facility. The goals of the project included job creation and preservation, reduced energy consumption, reduced energy costs, environmental improvement, and sustainability.

  18. Characterization of the Inner Knot of the Crab: The Site of the Gamma-ray Flares?

    E-Print Network [OSTI]

    Rudy, A; DeLuca, A; Kolodziejczak, J; Tennant, A; Yuan, Y; Buehler, R; Arons, J; Blandford, R; Caraveo, P; Costa, E; Funk, S; Hays, E; Lobanov, A; Max, C; Mayer, M; Mignani, R; O'Dell, S L; Romani, R; Tavani, M; Weisskopf, M C

    2015-01-01T23:59:59.000Z

    One of the most intriguing results from the gamma-ray instruments in orbit has been the detection of powerful flares from the Crab Nebula. These flares challenge our understanding of pulsar wind nebulae and models for particle acceleration. We report on the portion of a multiwavelength campaign using Keck, HST, and Chandra concentrating on a small emitting region, the Crab's inner knot, located a fraction of an arcsecond from the pulsar. We find that the knot's radial size, tangential size, peak flux, and the ratio of the flux to that of the pulsar are correlated with the projected distance of the knot from the pulsar. A new approach, using singular value decomposition for analyzing time series of images, was introduced yielding results consistent with the more traditional methods while some uncertainties were substantially reduced. We exploit the characterization of the knot to discuss constraints on standard shock-model parameters that may be inferred from our observations assuming the inner knot lies near ...

  19. PROPAGATION OF ALFVENIC WAVES FROM CORONA TO CHROMOSPHERE AND CONSEQUENCES FOR SOLAR FLARES

    SciTech Connect (OSTI)

    Russell, A. J. B.; Fletcher, L. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom)

    2013-03-10T23:59:59.000Z

    How do magnetohydrodynamic waves travel from the fully ionized corona, into and through the underlying partially ionized chromosphere, and what are the consequences for solar flares? To address these questions, we have developed a two-fluid model (of plasma and neutrals) and used it to perform one-dimensional simulations of Alfven waves in a solar atmosphere with realistic density and temperature structure. Studies of a range of solar features (faculae, plage, penumbra, and umbra) show that energy transmission from corona to chromosphere can exceed 20% of incident energy for wave periods of 1 s or less. Damping of waves in the chromosphere depends strongly on wave frequency: waves with periods 10 s or longer pass through the chromosphere with relatively little damping, however, for periods of 1 s or less, a substantial fraction (37%-100%) of wave energy entering the chromosphere is damped by ion-neutral friction in the mid- and upper chromosphere, with electron resistivity playing some role in the lower chromosphere and in umbras. We therefore conclude that Alfvenic waves with periods of a few seconds or less are capable of heating the chromosphere during solar flares, and speculate that they could also contribute to electron acceleration or exciting sunquakes.

  20. Imaging and Spectral Observations of Quasi-Periodic Pulsations in a Solar Flare

    E-Print Network [OSTI]

    Li, D; Zhang, Q M

    2015-01-01T23:59:59.000Z

    We explore the Quasi-Periodic Pulsations (QPPs) in a solar flare observed by Fermi Gamma-ray Burst Monitor (GBM), Solar Dynamics Observatory (SDO), Solar Terrestrial Relations Observatory (STEREO), and Interface Region Imaging Spectrograph (IRIS) on 2014 September 10. QPPs are identified as the regular and periodic peaks on the rapidly-varying components, which are the light curves after removing the slowly-varying components. The QPPs display only three peaks at the beginning on the hard X-ray (HXR) emissions, but ten peaks on the chromospheric and coronal line emissions, and more than seven peaks (each peak is corresponding to a type III burst on the dynamic spectra) at the radio emissions. An uniform quasi-period about 4 minutes are detected among them. AIA imaging observations exhibit that the 4-min QPPs originate from the flare ribbon, and tend to appear on the ribbon front. IRIS spectral observations show that each peak of the QPPs tends to a broad line width and a red Doppler velocity at C I, O IV, Si ...

  1. Stochastic Fermi Acceleration of sub-Relativistic Electrons and Its Role in Impulsive Solar Flares

    E-Print Network [OSTI]

    Selkowitz, R; Selkowitz, Robert; Blackman, Eric G.

    2004-01-01T23:59:59.000Z

    We reexamine stochastic Fermi acceleration (STFA) in the low energy (Newtonian) regime in the context of solar flares. The particle energization rate depends a dispersive term and a coherent gain term. The energy dependence of pitch angle scattering is important for determining the electron energy spectrum. For scattering by whistler wave turbulence, STFA produces a quasi-thermal spectrum. A second well-constrained scattering mechanism is needed for STFA to match the observed 10-100keV non-thermal spectrum. We suggest that STFA most plausibly acts as phase one of a two phase particle acceleration engine in impulsive flares: STFA can match the thermal spectrum below 10kev, and possibly the power law spectrum between 10 and 100keV, given the proper pitch angle scattering. However, a second phase, such as shock acceleration at loop tops, is likely required to match the spectrum above the observed knee at 100keV. Understanding this knee, if it survives further observations, is tricky.

  2. Stochastic Fermi Acceleration of sub-Relativistic Electrons and Its Role in Impulsive Solar Flares

    E-Print Network [OSTI]

    Robert Selkowitz; Eric G. Blackman

    2004-07-23T23:59:59.000Z

    We reexamine stochastic Fermi acceleration (STFA) in the low energy (Newtonian) regime in the context of solar flares. The particle energization rate depends a dispersive term and a coherent gain term. The energy dependence of pitch angle scattering is important for determining the electron energy spectrum. For scattering by whistler wave turbulence, STFA produces a quasi-thermal spectrum. A second well-constrained scattering mechanism is needed for STFA to match the observed 10-100keV non-thermal spectrum. We suggest that STFA most plausibly acts as phase one of a two phase particle acceleration engine in impulsive flares: STFA can match the thermal spectrum below 10kev, and possibly the power law spectrum between 10 and 100keV, given the proper pitch angle scattering. However, a second phase, such as shock acceleration at loop tops, is likely required to match the spectrum above the observed knee at 100keV. Understanding this knee, if it survives further observations, is tricky.

  3. Heating and Dynamics of Two Flare Loop Systems Observed by AIA and EIS

    E-Print Network [OSTI]

    Li, Y; Ding, M D

    2013-01-01T23:59:59.000Z

    We investigate heating and evolution of flare loops in a C4.7 two-ribbon flare on 2011 February 13. From SDO/AIA imaging observations, we can identify two sets of loops. Hinode/EIS spectroscopic observations reveal blueshifts at the feet of both sets of loops. The evolution and dynamics of the two sets are quite different. The first set of loops exhibits blueshifts for about 25 minutes followed by redshifts, while the second set shows stronger blueshifts, which are maintained for about one hour. The UV 1600 observation by AIA also shows that the feet of the second set of loops brighten twice. These suggest that continuous heating may be present in the second set of loops. We use spatially resolved UV light curves to infer heating rates in the few tens of individual loops comprising the two loop systems. With these heating rates, we then compute plasma evolution in these loops with the "enthalpy-based thermal evolution of loops" (EBTEL) model. The results show that, for the first set of loops, the synthetic EU...

  4. Loss mechanisms in turbine tip clearance flows

    E-Print Network [OSTI]

    Huang, Arthur (Arthur C.)

    2011-01-01T23:59:59.000Z

    Numerical simulations of tip clearance ow have been carried out to dene the loss generation mechanisms associated with tip leakage in unshrouded axial turbines. Mix- ing loss between the leakage, which takes the form of a ...

  5. Loss of coordination in competitive supply chains

    E-Print Network [OSTI]

    Teo, Koon Soon

    2009-01-01T23:59:59.000Z

    The loss of coordination in supply chains quantifies the inefficiency (i.e. the loss of total profit) due to the presence of competition in the supply chain. In this thesis, we discuss four models: one model with multiple ...

  6. 7, 1009710129, 2007 Chemical ozone loss

    E-Print Network [OSTI]

    ACPD 7, 10097­10129, 2007 Chemical ozone loss in the Arctic winter 1991­1992 S. Tilmes et al. Title Chemistry and Physics Discussions Chemical ozone loss in the Arctic winter 1991­1992 S. Tilmes 1 , R. M Chemical ozone loss in the Arctic winter 1991­1992 S. Tilmes et al. Title Page Abstract Introduction

  7. 4, 21672238, 2004 Ozone loss and

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 4, 2167­2238, 2004 Ozone loss and chlorine activation in the Arctic winters 1991­2003 S Union 2004 Atmospheric Chemistry and Physics Discussions Ozone loss and chlorine activation Correspondence to: S. Tilmes (simone.tilmes@t-online.de) 2167 #12;ACPD 4, 2167­2238, 2004 Ozone loss and chlorine

  8. Technical report Minimizing Calibrated Loss using

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Technical report Minimizing Calibrated Loss using Stochastic Low-Rank Newton Descent for large algorithm (SGD) for the minimization of classical Hinge Loss in the primal space. Although com- plexity- imization of any calibrated loss in the primal space. SLND approximates the inverse Hessian by the best low

  9. Configuration and Validation of the LHC Beam Loss Monitoring System

    E-Print Network [OSTI]

    Zamantzas, C; Emery, J; Fitzek, J; Follin, F; Jackson, S; Kain, V; Kruk, G; Misiowiec, M; Roderick, C; Sapinski, M

    2009-01-01T23:59:59.000Z

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. As well as protecting the machine, the system is also used as a means of diagnosing machine faults, and providing feedback of losses to the control room and several systems such as the Collimation, the Beam Dump and the Post-Mortem. The system has to transmit and process signals from over 4’000 monitors, and has approaching 3 million configurable parameters. This paper describes the types of configuration data needed, the means used to store and deploy all the parameters in such a distributed system and how operators are able to alter the operating parameters of the system, particularly with regard to the loss threshold values. The various security mechanisms put in place, both at the hardware and software level, to avoid accidental or malicious modification of these BLM parameters are also shown for each case.

  10. Global analysis of active longitudes of solar X-ray flares L. Zhang a,b,c

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    Observatories, Chinese Academy of Sciences, Beijing, China c Key Laboratory of Solar Activity, Chinese AcademyGlobal analysis of active longitudes of solar X-ray flares L. Zhang a,b,c , K. Mursula a,Ã, I of Sciences, Beijing, China d University of Oulu, Sodankyl¨a Geophysical Observatory, Oulu, Finland a r t i c

  11. Stellar flares observed by LOFT: implications for the physics of coronae and for the "space weather" environment of extrasolar planets

    E-Print Network [OSTI]

    Drake, S A; Doyle, J G; Güdel, M; Hamaguchi, K; Kowalski, A F; Maccarone, T; Osten, R A; Peretz, U; Wolk, S J

    2015-01-01T23:59:59.000Z

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of stellar flares. For a summary, we refer to the paper.

  12. First detection of >100 MeV gamma rays associated with a behind-the-limb solar flare

    E-Print Network [OSTI]

    Pesce-Rollins, Melissa; Petrosian, Vahe'; Liu, Wei; da Costa, Fatima Rubio; Allafort, Alice; Chen, Qingrong

    2015-01-01T23:59:59.000Z

    We report the first detection of >100 MeV gamma rays associated with a behind-the-limb solar flare, which presents a unique opportunity to probe the underlying physics of high-energy flare emission and particle acceleration. On 2013 October 11 a GOES M1.5 class solar flare occurred ~ 9.9 degrees behind the solar limb as observed by STEREO-B. RHESSI observed hard X-ray emission above the limb, most likely from the flare loop-top, as the footpoints were occulted. Surprisingly, the Fermi Large Area Telescope (LAT) detected >100 MeV gamma-rays for ~30 minutes with energies up to GeV. The LAT emission centroid is consistent with the RHESSI hard X-ray source, but its uncertainty does not constrain the source to be located there. The gamma-ray spectra can be adequately described by bremsstrahlung radiation from relativistic electrons having a relatively hard power-law spectrum with a high-energy exponential cutoff, or by the decay of pions produced by accelerated protons and ions with an isotropic pitch-angle distri...

  13. Acceleration of the Greenland ice sheet mass loss as observed by GRACE: Confidence and sensitivity

    E-Print Network [OSTI]

    Acceleration of the Greenland ice sheet mass loss as observed by GRACE: Confidence and sensitivity: Greenland mass loss acceleration confidence intervals GRACE a b s t r a c t We examine the scale and spatial distribution of the mass change acceleration in Greenland and its statistical significance, using processed

  14. Influence of parasitic resistances on the mismatch relative power loss of solar cell modules

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    689 Influence of parasitic resistances on the mismatch relative power loss of solar cell modules P, which originate from the manufacturing process. In order to enhance the array output power, the cells, to a limited extent, for mmRPL of a parallel-connected module. 1. Introduction. Loss of output power from

  15. QCD Collisional Energy Loss Reexamined

    SciTech Connect (OSTI)

    Peshier, A. [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany)

    2006-11-24T23:59:59.000Z

    It is shown that at a large temperature and E{yields}{infinity} the QCD collisional energy loss reads dE/dx{approx}{alpha}(m{sub D}{sup 2})T{sup 2}. Compared to previous approaches, which led to dE{sup B}/dx{approx}{alpha}{sup 2}T{sup 2}ln(ET/m{sub D}{sup 2}) similar to the Bethe-Bloch formula in QED, we take into account the running of the strong coupling. As one significant consequence, due to asymptotic freedom, dE/dx becomes E independent for large parton energies. Some implications with regard to heavy ion collisions are pointed out.

  16. Genomic Responses to the Loss of LRPPRC MITOCHONDRIAL AND NUCLEAR GENOMIC RESPONSES TO LOSS OF LRPPRC

    E-Print Network [OSTI]

    Mootha, Vamsi K.

    of Systems Biology, Harvard Medical School, Boston, MA 02446 USA Running head: Genomic Responses to the LossGenomic Responses to the Loss of LRPPRC 1 MITOCHONDRIAL AND NUCLEAR GENOMIC RESPONSES TO LOSS with the loss of LRPPRC. Using this strategy, we discovered a specific role for LRPPRC in the expression of all

  17. ON THE CAUSE OF SUPRA-ARCADE DOWNFLOWS IN SOLAR FLARES

    SciTech Connect (OSTI)

    Cassak, P. A.; Shepherd, L. S. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States)] [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Drake, J. F. [Department of Physics and the Institute for Physical Science and Technology and the Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States)] [Department of Physics and the Institute for Physical Science and Technology and the Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Gosling, J. T. [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO 80303 (United States)] [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO 80303 (United States); Phan, T.-D. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)] [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Shay, M. A., E-mail: Paul.Cassak@mail.wvu.edu, E-mail: lshephe1@mix.wvu.edu, E-mail: drake@umd.edu, E-mail: Jack.Gosling@lasp.colorado.edu, E-mail: phan@ssl.berkeley.edu, E-mail: shay@udel.edu [Department of Physics and Astronomy, University of Delaware, Newark, DE 20742 (United States)

    2013-09-20T23:59:59.000Z

    A model of supra-arcade downflows (SADs), dark low density regions also known as tadpoles that propagate sunward during solar flares, is presented. It is argued that the regions of low density are flow channels carved by sunward-directed outflow jets from reconnection. The solar corona is stratified, so the flare site is populated by a lower density plasma than that in the underlying arcade. As the jets penetrate the arcade, they carve out regions of depleted plasma density which appear as SADs. The present interpretation differs from previous models in that reconnection is localized in space but not in time. Reconnection is continuous in time to explain why SADs are not filled in from behind as they would if they were caused by isolated descending flux tubes or the wakes behind them due to temporally bursty reconnection. Reconnection is localized in space because outflow jets in standard two-dimensional reconnection models expand in the normal (inflow) direction with distance from the reconnection site, which would not produce thin SADs as seen in observations. On the contrary, outflow jets in spatially localized three-dimensional reconnection with an out-of-plane (guide) magnetic field expand primarily in the out-of-plane direction and remain collimated in the normal direction, which is consistent with observed SADs being thin. Two-dimensional proof-of-principle simulations of reconnection with an out-of-plane (guide) magnetic field confirm the creation of SAD-like depletion regions and the necessity of density stratification. Three-dimensional simulations confirm that localized reconnection remains collimated.

  18. THE BURSTY NATURE OF SOLAR FLARE X-RAY EMISSION. II. THE NEUPERT EFFECT

    SciTech Connect (OSTI)

    McAteer, R. T. James [Department of Astronomy, New Mexico State University, MSC 4500, NM 88003-8001 (United States); Bloomfield, D. Shaun, E-mail: mcateer@nmsu.edu [Astrophysics Research Group, School of Physics, Trinity College Dublin, College Green, Dublin 2 (Ireland)

    2013-10-20T23:59:59.000Z

    We carry out a novel statistical test of the Neupert effect based on multifractal spectra. The multifractal spectrum is the number distribution of the strengths (i.e., the Hölder exponents) of bursts in a signal. This is tested on simulations and carried out on RHESSI X-ray data from a well observed GOES X4.8 magnitude flare. The multifractal spectra is ideally suited to quantifying the relative smooth and bursty signals typically found in (thermal) soft X-ray and (non-thermal) hard X-ray data of solar flares. We show that light curves from all energies between 3 keV and 25 keV are statistically similar, suggesting that all these signals are dominated by the same (presumably thermal) emission. Emission lying between 25 keV and 100 keV probably contains some contribution from both thermal and non-thermal sources. The multifractal spectrum of a signal and that of its (cumulative) temporal integration are statistically similar (i.e., low residuals upon subtraction), but shifted by one in the peak Hölder exponent. We find the pairs of 3-6 keV and 100-300 keV emissions, the 6-12 keV and 100-300 keV emissions and the 12-25 keV and 100-300 keV emissions are all consistent with the Neupert effect. The best agreement with the Neupert effect is between the 12-25 keV and 100-300 keV pair, although possibly with some secondary source of thermal emission present.

  19. Multilayer Platform for Ultra-Low-Loss Waveguide Applications

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    1, 2012 Multilayer Platform for Ultra-Low-Loss Waveguidepreviously demonstrated ultra-low-loss technologies. Groupet al. : MULTILAYER PLATFORM FOR ULTRA-LOW-LOSS WAVEGUIDE

  20. CHROMOSPHERIC EVAPORATION IN AN M1.8 FLARE OBSERVED BY THE EXTREME-ULTRAVIOLET IMAGING SPECTROMETER ON HINODE

    SciTech Connect (OSTI)

    Doschek, G. A.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Young, P. R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)] [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2013-04-10T23:59:59.000Z

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s{sup -1} upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s{sup -1} upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s{sup -1}. We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive tests of models of chromospheric evaporation as envisaged in the Standard Flare Model.

  1. Reduce Radiation Losses from Heating Equipment

    SciTech Connect (OSTI)

    Not Available

    2006-01-01T23:59:59.000Z

    This DOE Industrial Technologies Program tip sheet describes how to save energy and costs by reducing expensive heat losses from industrial heating equipment, such as furnaces.

  2. Analysis of TPV Network Losses (a Presentation)

    SciTech Connect (OSTI)

    DM DePoy; MW Dashiell; DD Rahner; LR Danielson; JE Oppenlander; JL Vell; RJ Wehrer

    2004-12-08T23:59:59.000Z

    This talk focuses on the theoretical analysis of electrical losses associated with electrically networking large numbers of TPV cells to produce high power TPV power generators.

  3. Statistical methods for detecting loss of materials using NRTA data

    SciTech Connect (OSTI)

    Burr, T.; Coulter, A.; Hakkila, A. [Los Alamos National Lab., NM (United States); Ai, H.; Kadokura, I.; Fujimaki, K. [Japan Nuclear Fuel Ltd., Tokyo (Japan)

    1995-12-31T23:59:59.000Z

    The authors selected eight sequential statistical tests and studied their performance on near-real-time-accounting (NRTA) data that is nominally what is expected from the proposed Rokkasho Reprocessing Plant in Japan. The effort divided into three main activities: (1) use process-flow information to determine process vessel inventories and transfers at the time of material balance closure, (2) use variance propagation methods to estimate the variance-covariance matrix of a sequence of material balances, and (3) study the performance of eight sequential tests on a variety of loss scenarios. This paper describes the results of these three activities.

  4. Method for reducing energy losses in laser crystals

    DOE Patents [OSTI]

    Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.

    1992-03-24T23:59:59.000Z

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.

  5. Kalman Filtering in Correlated Losses Sachin Adlakha

    E-Print Network [OSTI]

    Adlakha, Sachin

    Kalman Filtering in Correlated Losses Sachin Adlakha Department of Electrical Engineering Stanford in presence of correlated losses using a Kalman Filter . This scenario arises in performing vehicle tracking for the Kalman estimator to lose some observations. We study the behavior of Kalman filter in such correlated

  6. > MEPS06 Preprint Version Transmission Loss

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    .phulpin@supelec.fr Abstract - In the deregulated electrical power system, the allocation of transmission losses is becoming a key issue. The electric transmission power system is more and more constrained due to the increasing electrical power system, the allocation of transmission losses is becoming a key issue. The electric

  7. MANAGING JOB LOSS and FINANCIAL STRESS

    E-Print Network [OSTI]

    MANAGING JOB LOSS and FINANCIAL STRESS a Personal and Family Guide CENTER ON THE FAMILY #12;2 Managing Job Loss and Financial Stress The issues associated with losing one's job or having hours cut also have other assistance (e.g., job placement, resume preparation, retraining), of which you should

  8. Compton backscattered and primary X-rays from solar flares: angle dependent Green's function correction for photospheric albedo

    E-Print Network [OSTI]

    Eduard P. Kontar; Alec L. MacKinnon; Richard A. Schwartz; John C. Brown

    2005-10-06T23:59:59.000Z

    The observed hard X-ray (HXR) flux spectrum $I(\\epsilon)$ from solar flares is a combination of primary bremsstrahlung photons $I_P(\\epsilon)$ with a spectrally modified component from photospheric Compton backscatter of downward primary emission. The latter can be significant, distorting or hiding the true features of the primary spectrum which are key diagnostics for acceleration and propagation of high energy electrons and of their energy budget. For the first time in solar physics, we use a Green's function approach to the backscatter spectral deconvolution problem, constructing a Green's matrix including photoelectric absorption. This approach allows spectrum-independent extraction of the primary spectrum for several HXR flares observed by the {\\it Ramaty High Energy Solar Spectroscopic Imager} (RHESSI). We show that the observed and primary spectra differ very substantially for flares with hard spectra close to the disk centre. We show in particular that the energy dependent photon spectral index $\\gamma (\\epsilon)=-d \\log I/d \\log \\epsilon$ is very different for $I_P(\\epsilon)$ and for $I(\\epsilon)$ and that inferred mean source electron spectra ${\\bar F}(E)$ differ greatly. Even for a forward fitting of a parametric ${\\bar F}(E)$ to the data, a clear low-energy cutoff required to fit $I(\\epsilon)$ essentially disappears when the fit is to $I_P(\\epsilon)$ - i.e. when albedo correction is included. The self-consistent correction for backscattered photons is thus shown to be crucial in determining the energy spectra of flare accelerated electrons, and hence their total number and energy.

  9. A JOINT ANALYSIS OF HIGH-ENERGY NEUTRONS AND NEUTRON-l)ECAY PROTONS FROM A FLARE

    E-Print Network [OSTI]

    Usoskin, Ilya G.

    A JOINT ANALYSIS OF HIGH-ENERGY NEUTRONS AND NEUTRON-l)ECAY PROTONS FROM A FLARE I.. G. KOCI'l.I)elel:sl~zHg 194021. RHs.ffa (Received ll April, 19%; in final form 19.1uly., 1996) Abstract. A .joint. analysis of the 1990 May 24 neutron event provided an oppor u ~ ly to delect neu[ron decay prolons of higher energies

  10. CLASSICAL CEPHEIDS REQUIRE ENHANCED MASS LOSS

    SciTech Connect (OSTI)

    Neilson, Hilding R.; Langer, Norbert; Izzard, Robert [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Engle, Scott G.; Guinan, Ed, E-mail: neilsonh@etsu.edu [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Ave. Villanova, PA 19085 (United States)

    2012-11-20T23:59:59.000Z

    Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools for measuring the Hubble constant. Our recent study of the period change of the nearest Cepheid, Polaris, suggested that it is undergoing enhanced mass loss when compared to canonical stellar evolution model predictions. In this work, we expand the analysis to rates of period change measured for about 200 Galactic Cepheids and compare them to population synthesis models of Cepheids including convective core overshooting and enhanced mass loss. Rates of period change predicted from stellar evolution models without mass loss do not agree with observed rates, whereas including enhanced mass loss yields predicted rates in better agreement with observations. This is the first evidence that enhanced mass loss as suggested previously for Polaris and {delta} Cephei must be a ubiquitous property of Classical Cepheids.

  11. Hydrogen H$?$ line polarization in solar flares. Theoretical investigation of atomic polarization by proton beams considering self-consistent NLTE polarized radiative transfer

    E-Print Network [OSTI]

    Jiri Stepan; Petr Heinzel; Sylvie Sahal-Brechot

    2007-01-22T23:59:59.000Z

    Context. We present a theoretical review of the effect of impact polarization of a hydrogen H$\\alpha$ line due to an expected proton beam bombardment in solar flares. Aims. Several observations indicate the presence of the linear polarization of the hydrogen H$\\alpha$ line observed near the solar limb above 5% and preferentially in the radial direction. We theoretically review the problem of deceleration of the beam originating in the coronal reconnection site due to its interaction with the chromospheric plasma, and describe the formalism of the density matrix used in our description of the atomic processes and the treatment of collisional rates. Methods. We solve the self-consistent NLTE radiation transfer problem for the particular semiempirical chromosphere models for both intensity and linear polarization components of the radiation field. Results. In contrast to recent calculations, our results show that the energy distribution of the proton beam at H$\\alpha$ formation levels and depolarizing collisions by background electrons and protons cause a significant reduction of the effect below 0.1%. The radiation transfer solution shows that tangential resonance-scattering polarization dominates over the impact polarization effect in all considered models. Conclusions. In the models studied, proton beams are unlikely to be a satisfying explanation for the observed linear polarization of the H$\\alpha$ line.

  12. Sender-Based Heuristics for Distinguishing Congestion Losses from Wireless Transmission Losses

    E-Print Network [OSTI]

    Vaidya, Nitin

    Sender-Based Heuristics for Distinguishing Congestion Losses from Wireless Transmission Losses Saad-3112, USA E-mail: saadb@cs.tamu.edu Phone : (409) 845-5007 Fax : (409) 847-8578 Technical Report #98-013 Abstract TCP is a popular transport protocol used in present-day internet. When packet losses occur, TCP

  13. Differentiated Services: A New Direction for Distinguishing Congestion Losses from Wireless Losses

    E-Print Network [OSTI]

    Differentiated Services: A New Direction for Distinguishing Congestion Losses from Wireless Losses Sa^ad Biaz Nitin H. Vaidya ¡£¢ sbiaz@eng.auburn.edu nhv@crhc.uiuc.edu February 21, 2003 Technical Report # CSSE03-02 Abstract Currently, a TCP sender considers all losses as congestion signals and reacts

  14. High energy astrophysical processes

    E-Print Network [OSTI]

    Todor Stanev

    2005-04-18T23:59:59.000Z

    We briefly review the high energy astrophysical processes that are related to the production of high energy $\\gamma$-ray and neutrino signals and are likely to be important for the energy loss of high and ultrahigh energy cosmic rays. We also give examples for neutrino fluxes generated by different astrophysical objects and describe the cosmological link provided by cosmogenic neutrinos.

  15. Excessive loss of information by the power-law ansatz for complex systems

    E-Print Network [OSTI]

    Tsai, Sun-Ting; Chang, Ching-Hao; Tsai, Meng-Xue; Hsu, Nan-Jung; Hong, Tzay-Ming

    2015-01-01T23:59:59.000Z

    Physicists love simple laws and uncovering common causes among seemingly unrelated phenomena. An example is the connection between earthquakes and crumpling of a paper, built through the simple power law (SPL) believed to exist between the occurrence rate of their crackling noise and the pulse intensity. We provide, however, evidence to weaken such a link by showing that both systems in fact obey different and more complex laws. Our analyses are based on the Akaike information criterion (AIC) that is a direct measurement of information loss and emphasizes the need to strike a balance between model simplicity and goodness of fit. AIC found that a shifted power law retains more information than SPL in the cases of crumpling sound, duration-time frequency of solar flare, web link, protein-domain frequency, and stock-market fluctuations. In the mean time, double power laws (DPL) should replace the Gutenberg-Richter law for earthquake, and the scale-free model for brain functional network, two-dimensional sandpile...

  16. AC Losses of Prototype HTS Transmission Cables

    SciTech Connect (OSTI)

    Demko, J.A.; Dresner, L.; Hughey, R.L.; Lue, J.W.; Olsen, S.K.; Sinha, U.; Tolbert, J.C.

    1998-09-13T23:59:59.000Z

    Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and with theory developed by Dresner. Losses were measured with both a calorimetric and an electrical technique. Because of the broad resistive transition of the HTS tapes, the cables can be operated stably beyond their critical currents. The AC losses were measured in this region as well as below critical currents. Dresner's theory takes into account the broad resistive transition of the HTS tapes and calculates the AC losses both below and above the critical current. The two sets of AC 10SS data agree with each other and with the theory quite welL In particular, at low currents of incomplete penetration, the loss data agree with the theoretical prediction of hysteresis loss based on only the outer two Iayers carrying the total current.

  17. Modeling particle loss in ventilation ducts

    SciTech Connect (OSTI)

    Sippola, Mark R.; Nazaroff, William W.

    2003-04-01T23:59:59.000Z

    Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

  18. PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS FROM THE SWIFT X-RAY TELESCOPE OBSERVATIONS

    E-Print Network [OSTI]

    Zhang, Bing

    PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS August 15; accepted 2005 December 19 ABSTRACT With the successful launch of the Swift Gamma-Ray Burst component is consistent with the tail emission of the prompt gamma-ray bursts and/or the X-ray flares

  19. Energy Loss Distribution in the Taylor-Couette Flow between Concentric Rotating Cylinders

    E-Print Network [OSTI]

    Dou, H S; Phan-Thien, N; Yeo, K S; Dou, Hua-Shu; Khoo, Boo Cheong; Phan-Thien, Nhan; Yeo, Khoon Seng

    2005-01-01T23:59:59.000Z

    The distribution of energy loss due to viscosity friction in plane Couette flow and Taylor-Couette Flow between concentric rotating cylinders are studied in detail for various flow conditions. The energy loss is related to the industrial processes in some fluid delivery devices and has significant influence on the flow efficiency, flow stability, turbulent transition, mixing, and heat transfer behaviours, etc. Therefore, it is very helpful to know about the energy loss distribution in the flow domain and to know its influence on the flow for understanding the flow physics. The calculation method of the energy loss distribution in the Taylor-Couette Flow between concentric rotating cylinders has not been found in open literature. In this note, the principle and the calculation are given for single cylinder rotating of inner or outer cylinder, and counter and same direction rotating of two cylinders. For comparison, the distribution of energy loss in a plane Couette flow is also derived for various flow conditi...

  20. Optimization of quantum interferometric metrological sensors in the presence of photon loss

    E-Print Network [OSTI]

    Tae-Woo Lee; Sean D. Huver; Hwang Lee; Lev Kaplan; Steven B. McCracken; Changjun Min; Dmitry B. Uskov; Christoph F. Wildfeuer; Georgios Veronis; Jonathan P. Dowling

    2009-08-20T23:59:59.000Z

    We optimize two-mode, entangled, number states of light in the presence of loss in order to maximize the extraction of the available phase information in an interferometer. Our approach optimizes over the entire available input Hilbert space with no constraints, other than fixed total initial photon number. We optimize to maximize the Fisher information, which is equivalent to minimizing the phase uncertainty. We find that in the limit of zero loss the optimal state is the so-called N00N state, for small loss, the optimal state gradually deviates from the N00N state, and in the limit of large loss the optimal state converges to a generalized two-mode coherent state, with a finite total number of photons. The results provide a general protocol for optimizing the performance of a quantum optical interferometer in the presence of photon loss, with applications to quantum imaging, metrology, sensing, and information processing.

  1. A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the Rho Ophiuchi Star-Forming Region with Chandra

    E-Print Network [OSTI]

    K. Imanishi; H. Nakajima; M. Tsujimoto; K. Koyama; Y. Tsuboi

    2003-05-10T23:59:59.000Z

    We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using Chandra observations of the main region of the Rho Oph. From 195 X-ray sources, including class I-III sources and some young brown dwarfs, we detected a total of 71 X-ray flares. Most of the flares have the typical profile of solar and stellar flares, fast rise and slow decay. We derived the time-averaged temperature (kT), luminosity (L_X), rise and decay timescales (tau_r and tau_d) of the flares, finding that (1) class I-II sources tend to have a high kT, (2) the distribution of L_X during flares is nearly the same for all classes, and (3) positive and negative log-linear correlations are found between tau_r and tau_d, and kT and tau_r. In order to explain these relations, we used the framework of magnetic reconnection model to formulate the observational parameters as a function of the half-length of the reconnected magnetic loop (L) and magnetic field strength (B). The estimated L is comparable to the typical stellar radius of these objects (10^{10-11} cm), which indicates that the observed flares are triggered by solar-type loops, rather than larger ones (10^{12} cm) connecting the star with its inner accretion disk. The higher kT observed for class I sources may be explained by a higher magnetic field strength (about 500 G) than for class II-III sources (200-300 G).

  2. Bulk Energization of Electrons in Solar Flares by Alfv\\'en Waves

    E-Print Network [OSTI]

    Melrose, D B

    2013-01-01T23:59:59.000Z

    Bulk energization of electrons to $10\\,-\\,20\\,$keV in solar flares is attributed to dissipation of Alfv\\'en waves that transport energy and potential downward to an acceleration region near the chromosphere. The acceleration involves the parallel electric field that develops in the limit of inertial Alfv\\'en waves (IAWs). A two-potential model for IAWs is used to relate the parallel potential to the cross-field potential transported by the waves. We identify a maximum parallel potential in terms of a maximum current density that corresponds to the threshold for the onset of anomalous resistivity. This maximum is of order $10\\,$kV when the threshold is that for the Buneman instability. We argue that this restricts the cross-field potential in an Alfv\\'en wave to about $10\\,$kV. Effective dissipation requires a large number of up- and down-current paths associated with multiple Alfv\\'en waves. The electron acceleration occurs in localized, transient, anomalously-conducting regions (LTACRs) and is associated wit...

  3. Optical polarization map of the Polaris Flare with RoboPol

    E-Print Network [OSTI]

    Panopoulou, G V; Blinov, D; Pavlidou, V; King, O G; Paleologou, E; Ramaprakash, A; Angelakis, E; Balokovic, M; Das, H K; Feiler, R; Hovatta, T; Khodade, P; Kiehlmann, S; Kus, A; Kylafis, N; Liodakis, I; Modi, D; Myserlis, I; Papadakis, I; Papamastorakis, I; Pazderska, B; Pazderski, E; Pearson, T J; Rajarshi, C; Readhead, A C S; Reig, P; Zensus, J A

    2015-01-01T23:59:59.000Z

    The stages before the formation of stars in molecular clouds are poorly understood. Insights can be gained by studying the properties of quiescent clouds, such as their magnetic field structure. The plane-of-the-sky orientation of the field can be traced by polarized starlight. We present the first extended, wide-field ($\\sim$10 $\\rm deg^2$) map of the Polaris Flare cloud in dust-absorption induced optical polarization of background stars, using the RoboPol polarimeter at the Skinakas Observatory. This is the first application of the wide-field imaging capabilities of RoboPol. The data were taken in the R-band and analysed with the automated reduction pipeline of the instrument. We present in detail optimizations in the reduction pipeline specific to wide-field observations. Our analysis resulted in reliable measurements of 648 stars with median fractional linear polarization 1.3%. The projected magnetic field shows a large scale ordered pattern. At high longitudes it appears to align with faint striations se...

  4. KAPPA DISTRIBUTION MODEL FOR HARD X-RAY CORONAL SOURCES OF SOLAR FLARES

    SciTech Connect (OSTI)

    Oka, M.; Ishikawa, S.; Saint-Hilaire, P.; Krucker, S.; Lin, R. P. [Space Sciences Laboratory, University of California Berkeley (United States)] [Space Sciences Laboratory, University of California Berkeley (United States)

    2013-02-10T23:59:59.000Z

    Solar flares produce hard X-ray emission, the photon spectrum of which is often represented by a combination of thermal and power-law distributions. However, the estimates of the number and total energy of non-thermal electrons are sensitive to the determination of the power-law cutoff energy. Here, we revisit an 'above-the-loop' coronal source observed by RHESSI on 2007 December 31 and show that a kappa distribution model can also be used to fit its spectrum. Because the kappa distribution has a Maxwellian-like core in addition to a high-energy power-law tail, the emission measure and temperature of the instantaneous electrons can be derived without assuming the cutoff energy. Moreover, the non-thermal fractions of electron number/energy densities can be uniquely estimated because they are functions of only the power-law index. With the kappa distribution model, we estimated that the total electron density of the coronal source region was {approx}2.4 Multiplication-Sign 10{sup 10} cm{sup -3}. We also estimated without assuming the source volume that a moderate fraction ({approx}20%) of electrons in the source region was non-thermal and carried {approx}52% of the total electron energy. The temperature was 28 MK, and the power-law index {delta} of the electron density distribution was -4.3. These results are compared to the conventional power-law models with and without a thermal core component.

  5. Correlated optical and X-ray flares in the afterglow of XRF 071031

    E-Print Network [OSTI]

    Krühler, T; McBreen, S; Klose, S; Rossi, A; Afonso, P; Clemens, C; Filgas, R; Yoldas, A Küpcü; Szokoly, G P; Yoldas, A

    2009-01-01T23:59:59.000Z

    We present a densely sampled early light curve of the optical/near-infrared (NIR) afterglow of the X-Ray Flash (XRF) 071031 at z=2.692. Simultaneous and continuous observations in seven photometric bands from g' to K with GROND at the 2.2 m MPI/ESO telescope on LaSilla were performed between 4 minutes and 7 hours after the burst. The light curve consists of 547 individual points which allows us to study the early evolution of the optical transient associated with XRF 071031 in great detail. The optical/NIR light curve is dominated by an early increase in brightness which can be attributed to the apparent onset of the forward shock emission. There are several bumps which are superimposed onto the overall rise and decay. Significant flaring is also visible in the Swift X-Ray Telescope (XRT) light curve from early to late times. The availability of high quality, broadband data enables detailed studies of the connection between the X-ray and optical/NIR afterglow and its colour evolution during the first night po...

  6. Report on fuel pool water loss tests

    SciTech Connect (OSTI)

    Zalenski, R.F. [West Valley Nuclear Services Co., West Valley, NY (United States)

    1995-12-31T23:59:59.000Z

    To resolve potential concerns on the integrity of the fuel storage pool at the West Valley Demonstration Project (WVDP), a highly accurate testing technique was developed to quantify water losses from the pool. The fuel pool is an unlined, single wall, reinforced concrete structure containing approximately 818,000 gallons of water. Since an initial test indicated that water losses could possibly be attributed solely to evaporation, a cover was suspended and sealed over the pool to block evaporation losses. High accuracy water level and temperature instrumentation was procured and installed. The conclusions of this report indicate that unaccounted-for water losses from the pool are insignificant and there is no detectable leakage within the range of test accuracy.

  7. Telling Absence: War Widows, Loss and Memory 

    E-Print Network [OSTI]

    Loipponen, Jaana

    2009-01-01T23:59:59.000Z

    This thesis concerns feminist sociological analysis of war loss and its consequences as experienced and told by Finnish Karelian war widows of World War 2. They lost their partners and had to leave their homes by force, ...

  8. Corona losses in HVdc bipolar lines

    SciTech Connect (OSTI)

    Corbellini, U.; Pelacchi, P. [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation] [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation

    1996-07-01T23:59:59.000Z

    The problem related to the prediction of corona losses in HVdc bipolar lines has been solved, in the past, by means of semi-empirical monomial formulae. However, the proposed formulae that are simpler to use do not always give adequate calculation precision, while the formulae that provide the closest results require implicit functions of different complexity, which are difficult to apply; moreover, it is not possible to understand clearly what influence the variations of the different line parameters have on the losses themselves. The new monomial semi-empirical relationship, proposed to predict the corona losses in HVdc bipolar lines, is very simple to use; it highlights the dependence of power losses due to the corona effect by the different line parameters. The formula has been developed by elaborating a considerable amount of available experimental data.

  9. RCS pressure under reduced inventory conditions following a loss of residual heat removal

    SciTech Connect (OSTI)

    Palmrose, D.E.; Hughes, E.D.; Johnsen, G.W.

    1992-01-01T23:59:59.000Z

    The thermal-hydraulic response of a closed-reactor coolant system to loss of residual heat removal (RHR) cooling is investigated. The processes examined include: core coolant boiling and steam generator reflux condensation, pressure increase on the primary side, heat transfer mechanisms on the steam generator primary and secondary sides, and effects of noncondensible gas on heat transfer processes.

  10. RCS pressure under reduced inventory conditions following a loss of residual heat removal

    SciTech Connect (OSTI)

    Palmrose, D.E.; Hughes, E.D.; Johnsen, G.W.

    1992-08-01T23:59:59.000Z

    The thermal-hydraulic response of a closed-reactor coolant system to loss of residual heat removal (RHR) cooling is investigated. The processes examined include: core coolant boiling and steam generator reflux condensation, pressure increase on the primary side, heat transfer mechanisms on the steam generator primary and secondary sides, and effects of noncondensible gas on heat transfer processes.

  11. Reducing Livestock Losses To Toxic Plants

    E-Print Network [OSTI]

    McGinty, Allan; Machen, Richard V.

    2000-04-25T23:59:59.000Z

    TexasAgriculturalExtensionService The Texas A&M University System Reducing Livestock Losses to Toxic Plants B-1499 Sand Shinnery L Perennial Broomweed Texas Agricultural Extension Service a71 Zerle L. Carpenter, Director a71 The Texas A&M University... ................... ...... ... 6 BehaviorModification.................................. 7 Management Techniques forReducingToxic Plant Losses... 8 LiteratureCited........................................ 9 Poisonous Plants ofTexas...............................10 Editor: Judy Winn...

  12. Reducing Livestock Losses To Toxic Plants 

    E-Print Network [OSTI]

    McGinty, Allan; Machen, Richard V.

    2000-04-25T23:59:59.000Z

    TexasAgriculturalExtensionService The Texas A&M University System Reducing Livestock Losses to Toxic Plants B-1499 Sand Shinnery L Perennial Broomweed Texas Agricultural Extension Service a71 Zerle L. Carpenter, Director a71 The Texas A&M University... ................... ...... ... 6 BehaviorModification.................................. 7 Management Techniques forReducingToxic Plant Losses... 8 LiteratureCited........................................ 9 Poisonous Plants ofTexas...............................10 Editor: Judy Winn...

  13. Nuclear parton distribution functions and energy loss effect in the Drell-Yan reaction off nuclei

    E-Print Network [OSTI]

    ChunGui Duan; LiHua Song; ShuoHe Wang; GuangLie Li

    2006-01-23T23:59:59.000Z

    The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process. By means of two typical kinds of quark energy loss parametrization and the different sets of nuclear parton distribution functions, we present a analysis of the E866 experiments on the nuclear dependence of Drell-Yan lepton pair production resulting from the bombardment of Be, Fe and W targets by 800GeV protons at Fermilab. It is found that the quark energy loss in cold nuclei is strongly dependent on the used nuclear parton distribution functions. The further prospects of using relatively low energy proton incident on nuclear targets are presented by combining the quark energy loss rate determined from a fit to the E866 nuclear-dependent ratios versus $x_1$, with the nuclear parton distribution functions given from lA deep inelastic scattering (DIS) data. The experimental study of the relatively low energy nuclear Drell-Yan process can give valuable insight in the enengy loss of fast quark propagating a cold nuclei and help to pin down nuclear parton distributions functions.

  14. Running Head: The Autonomic Nervous System's responses to losses Loss aversion in the eye and in the heart: The

    E-Print Network [OSTI]

    Yechiam, Eldad

    Running Head: The Autonomic Nervous System's responses to losses Loss aversion in the eye and in the heart: The Autonomic Nervous System's responses to losses Guy Hochman and Eldad Yechiam Technion@tx.technion.ac.il #12;ANS responses to losses 2 Loss aversion in the eye and in the heart: The Autonomic Nervous System

  15. ac loss measurement: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tape, tem- perature dependence, total ac loss, transport loss. I. INTRODUCTION HIGH 6 Heat Loss Measurement Using Infrared Imaging Texas A&M University - TxSpace Summary: in...

  16. 2002 AUGUST 24 LIMB FLARE LOOP: DYNAMICS OF MICROWAVE BRIGHTNESS DISTRIBUTION

    SciTech Connect (OSTI)

    Reznikova, V. E.; Ji, H. [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Melnikov, V. F.; Gorbikov, S. P.; Pyatakov, N. P. [Radiophysical Research Institute (NIRFI), Nizhny Novgorod 603950 (Russian Federation); Shibasaki, K. [Nobeyama Solar Radio Observatory/NAOJ, Nagano 384-1305 (Japan); Myagkova, I. N. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation)], E-mail: vreznikova@nirfi.sci-nnov.ru

    2009-05-20T23:59:59.000Z

    High-resolution radio observation of Nobeyama Radioheliograph at 17 and 34 GHz allowed studying the dynamics of microwave brightness distribution along the giant limb flaring loop in the event of 2002 August 24. It is found that on the rising phase of the radio burst the brightness distribution was highly asymmetric, with a strong maximum near the southern footpoint (SFP) and much weaker brightness enhancements near the loop top (LT) and northern footpoint. On the decay phase, the LT gradually became most bright. The similar dynamics of brightness distribution are shown to happen for all major temporal subpeaks of the burst. Results of our diagnostics show two important properties: (1) the number density of mildly relativistic electrons in the LT is much higher than near the footpoints (FPs) during rise, maximum and decay of each major peak; and (2) the ratio of the electron number densities in the LT and an FP increases from the maximum to decay phase. Model simulations with making use of the nonstationary Fokker-Planck equation have allowed us to find the model explaining the major properties of the microwave brightness distribution and dynamics. The model is characterized by a compact source of electrons located near the center of an asymmetric magnetic loop; the source is nonstationary, long lasting, and injecting high-energy electrons with the pitch-angle distribution mostly directed toward the SFP but also having a very weak isotropic component. This easily explains the observed brightness asymmetry. The observed dynamics comes due to two reasons: faster precipitation of electrons having their mirror points near the ends of the magnetic trap, and relatively faster decay of the lower energy electrons responsible for the gyrosynchrotron emission near the FPs with higher magnetic field.

  17. Electron-Electron Bremsstrahlung Emission and the Inference of Electron Flux Spectra in Solar Flares

    E-Print Network [OSTI]

    Eduard P. Kontar; A. Gordon Emslie; Anna Maria Massone; Michele Piana; John C. Brown; Marco Prato

    2007-07-28T23:59:59.000Z

    Although both electron-ion and electron-electron bremsstrahlung contribute to the hard X-ray emission from solar flares, the latter is normally ignored. Such an omission is not justified at electron (and photon) energies above $\\sim 300$ keV, and inclusion of the additional electron-electron bremsstrahlung in general makes the electron spectrum required to produce a given hard X-ray spectrum steeper at high energies. Unlike electron-ion bremsstrahlung, electron-electron bremsstrahlung cannot produce photons of all energies up to the maximum electron energy involved. The maximum possible photon energy depends on the angle between the direction of the emitting electron and the emitted photon, and this suggests a diagnostic for an upper cutoff energy and/or for the degree of beaming of the accelerated electrons. We analyze the large event of January 17, 2005 observed by RHESSI and show that the upward break around 400 keV in the observed hard X-ray spectrum is naturally accounted for by the inclusion of electron-electron bremsstrahlung. Indeed, the mean source electron spectrum recovered through a regularized inversion of the hard X-ray spectrum, using a cross-section that includes both electron-ion and electron-electron terms, has a relatively constant spectral index $\\delta$ over the range from electron kinetic energy $E = 200$ keV to $E = 1$ MeV. However, the level of detail discernible in the recovered electron spectrum is not sufficient to determine whether or not any upper cutoff energy exists.

  18. Lithographic measurement of EUV flare in the 0.3-NA Micro ExposureTool optic at the Advanced Light Source

    SciTech Connect (OSTI)

    Cain, Jason P.; Naulleau, Patrick; Spanos, Costas J.

    2005-01-01T23:59:59.000Z

    The level of flare present in a 0.3-NA EUV optic (the MET optic) at the Advanced Light Source at Lawrence Berkeley National Laboratory is measured using a lithographic method. Photoresist behavior at high exposure doses makes analysis difficult. Flare measurement analysis under scanning electron microscopy (SEM) and optical microscopy is compared, and optical microscopy is found to be a more reliable technique. In addition, the measured results are compared with predictions based on surface roughness measurement of the MET optical elements. When the fields in the exposure matrix are spaced far enough apart to avoid influence from surrounding fields and the data is corrected for imperfect mask contrast and aerial image proximity effects, the results match predicted values quite well. The amount of flare present in this optic ranges from 4.7% for 2 {micro}m features to 6.8% for 500 nm features.

  19. Fermi Guest Investigator Program Cycle 2 Project Final Report Albedo Polarimetry of Gamma-Ray Bursts and Solar Flares with GBM

    SciTech Connect (OSTI)

    Kippen, Richard Marc [Los Alamos National Laboratory

    2012-08-27T23:59:59.000Z

    Several key properties of GRBs remain poorly understood and are difficult or even impossible to infer with the information currently being collected. Polarization measurements will probe the precise nature of the central engine. For solar flares, high-energy polarization measurements are expected to be useful in determining the beaming (or directivity) of solar flare electrons - a quantity that may provide important clues about electron acceleration and transport. We propose to investigate the viability of using the Fermi Gamma-ray Burst Monitor (GBM) to measure the polarization of GRBs and solar flares using the albedo photon flux. This approach was previously developed for use with BATSE data. We will conduct a careful study of this technique using a modified version of the GRESS simulation tools developed by the GBM team.

  20. TIME DELAYS IN QUASI-PERIODIC PULSATIONS OBSERVED DURING THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15

    SciTech Connect (OSTI)

    Dolla, L.; Marque, C.; Seaton, D. B.; Dominique, M.; Berghmans, D.; Cabanas, C.; De Groof, A.; Verdini, A.; West, M. J.; Zhukov, A. N. [Solar-Terrestrial Center of Excellence, Royal Observatory of Belgium, Avenue Circulaire 3, B-1180 Brussels (Belgium); Van Doorsselaere, T. [Centrum voor Plasma-Astrofysica, Department of Mathematics, KULeuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Schmutz, W. [Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos Dorf (Switzerland); Zender, J., E-mail: dolla@sidc.be [European Space Agency, ESTEC, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands)

    2012-04-10T23:59:59.000Z

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on timescale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the extreme-ultraviolet (EUV) channels of the Euv SpectroPhotometer (ESP) on board the Solar Dynamic Observatory. The zirconium and aluminum filter channels of the Large Yield Radiometer on board the Project for On-Board Autonomy satellite and the soft X-ray (SXR) channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite, where the channel at 1-8 A leads the 0.5-4 A channel by several seconds. The time lags between the first and last channels is up to Almost-Equal-To 9 s. We identified at least two distinct time intervals during the flare impulsive phase, during which the QPPs were associated with two different sources in the Nobeyama RadioHeliograph at 17 GHz. The radio as well as the hard X-ray channels showed different lags during these two intervals. To our knowledge, this is the first time that time lags are reported between EUV and SXR fluctuations on these timescales. We discuss possible emission mechanisms and interpretations, including flare electron trapping.

  1. A FAST FLARE AND DIRECT REDSHIFT CONSTRAINT IN FAR-ULTRAVIOLET SPECTRA OF THE BLAZAR S5 0716+714

    SciTech Connect (OSTI)

    Danforth, Charles W.; Nalewajko, Krzysztof; France, Kevin; Keeney, Brian A., E-mail: danforth@casa.colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States)

    2013-02-10T23:59:59.000Z

    The BL Lacertae object S5 0716+714 is one of the most studied blazars on the sky due to its active variability and brightness in many bands, including very-high-energy gamma rays. We present here two serendipitous results from recent far-ultraviolet spectroscopic observations by the Cosmic Origins Spectrograph onboard the Hubble Space Telescope (HST). First, during the course of our 7.3 hr HST observations, the blazar increased in flux rapidly by {approx}40% (-0.45 mag hr{sup -1}) followed by a slower decline (+0.36 mag hr{sup -1}) to previous FUV flux levels. We model this flare using asymmetric flare templates and constrain the physical size and energetics of the emitting region. Furthermore, the spectral index of the object softens considerably during the course of the flare from {alpha}{sub {nu}} Almost-Equal-To -1.0 to {alpha}{sub {nu}} Almost-Equal-To -1.4. Second, we constrain the source redshift directly using the {approx}30 intervening absorption systems. A system at z = 0.2315 is detected in Ly{alpha}, Ly{beta}, O VI, and N V and defines the lower bound on the source redshift. No absorbers are seen in the remaining spectral coverage (0.2315 < z {sub Ly{alpha}} {approx}< 0.47) and we set a statistical upper bound of z < 0.322 (95% confidence) on the blazar. This is the first direct redshift limit for this object and is consistent with literature estimates of z = 0.31 {+-} 0.08 based on the detection of a host galaxy.

  2. HIGH-RESOLUTION IMAGING OF SOLAR FLARE RIBBONS AND ITS IMPLICATION ON THE THICK-TARGET BEAM MODEL

    SciTech Connect (OSTI)

    Krucker, Saem; Hudson, H. S.; Lin, R. P. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Jeffrey, N. L. S.; Battaglia, M.; Kontar, E. P. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Benz, A. O.; Csillaghy, A., E-mail: krucker@ssl.berkeley.edu [Institute of 4D Technologies, School of Engineering, University of Applied Sciences Northwestern Switzerland, 5210 Windisch (Switzerland)

    2011-10-01T23:59:59.000Z

    We report on high-resolution optical and hard X-ray observations of solar flare ribbons seen during the GOES X6.5 class white-light flare of 2006 December 6. The data consist of imaging observations at 430 nm (the Fraunhofer G band) taken by the Hinode Solar Optical Telescope with the hard X-rays observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager. The two sets of data show closely similar ribbon structures, strongly suggesting that the flare emissions in white light and in hard X-rays have physically linked emission mechanisms. While the source structure along the ribbons is resolved at both wavelengths (length {approx} 30''), only the G-band observations resolve the width of the ribbon, with values between {approx}0.''5 and {approx}1.''8. The unresolved hard X-ray observations reveal an even narrower ribbon in hard X-rays (the main footpoint has a width perpendicular to the ribbon of <1.''1 compared to the G-band width of {approx}1.''8) suggesting that the hard X-ray emission comes from the sharp leading edge of the G-band ribbon. Applying the thick-target beam model, the derived energy deposition rate is >5 x 10{sup 12} erg s{sup -1} cm{sup -2} provided by an electron flux of 1 x 10{sup 20} electrons s{sup -1} cm{sup -2} above 18 keV. This requires that the beam density of electrons above 18 keV be at least 1 x 10{sup 10} cm{sup -3}. Even if field lines converge toward the chromospheric footpoints, the required beam in the corona has too high a density to be described as a dilute tail population on top of a Maxwellian core. We discuss this issue and others associated with this extreme event, which poses serious questions to the standard thick target beam interpretation of solar flares.

  3. Draft "Michigan Saves" Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample loan loss reserve agreement between a state or local government and a financial institution setting the terms and conditions of the loan loss reserve fund.

  4. ac loss characteristics: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and solar heat gain characteristics of a home's windows performance by reducing heat loss (in the winter), and cooling loss and solar heat gain (in the summer 86...

  5. Energy Use Loss and Opportunities Analysis: U.S. Manufacturing...

    Energy Savers [EERE]

    Use Loss and Opportunities Analysis: U.S. Manufacturing & Mining Energy Use Loss and Opportunities Analysis: U.S. Manufacturing & Mining energyuselossopportunitiesanalysis.pdf...

  6. Understanding Collection-Related Losses in Organic Solar Cells...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Understanding Collection-Related Losses in Organic Solar Cells Home > Research > ANSER Research Highlights > Understanding Collection-Related Losses in Organic Solar Cells...

  7. Factors affect offshore production loss control

    SciTech Connect (OSTI)

    Ash, C.S.

    1986-05-12T23:59:59.000Z

    Many aspects of petroleum measurement on an offshore production platform are the same as at an onshore facility, but there are some unique differences. Before going into them it should be noted that even in today's climate of low or declining oil prices that stock loss control is still important. Improving measurement of the quantity of oil transfers can help reduce the amount of stock that is ''unaccounted for'' or lost. As stock loss is reduced, the salable quantity increases, the gross revenue increases, and the net revenue increases. Even in cases where transfers are between two departments of the same company, accurate measurement and proper accountability are required because they often are the basis for determining costs and can thus affect the price that is charged on a later custody transfer. Inefficiencies in intracompany transfers can often hide real losses which may occur during intercompany transfers.

  8. Rethinking the QCD collisional energy loss

    E-Print Network [OSTI]

    A. Peshier

    2006-07-25T23:59:59.000Z

    It is shown that to leading order the collisional energy loss of an energetic parton in the hot quark gluon plasma reads $dE/dx \\sim \\alpha(m_D^2)T^2$, where the scale of the coupling is determined by the (parametrically soft) Debye screening mass. Compared to previous expressions derived by Bjorken and other authors, $dE^B/dx \\sim \\alpha^2 T^2 \\ln(ET/m_D^2)$, the rectified result takes into account the running of the coupling, as dictated by quantum corrections beyond tree level. As one significant consequence, due to asymptotic freedom, the QCD collisional energy loss becomes independent of the jet energy in the limit $E \\gg T$. It is advocated that this resummation improved perturbative result might be useful to (re-)estimate the collisional energy loss for temperatures relevant in heavy ion phenomenology.

  9. On Optimal Sequential Prediction for General Processes Andrew B. Nobel

    E-Print Network [OSTI]

    Nobel, Andrew

    -stationary processes under p-th power loss p(u, v) = |u-v|p , 1 'th power loss. Andrew Nobel is with the Department of Statistics, University of North Carolina, Chapel'th power loss of the form p(u, v) = |u - v|p, with 1

  10. Reducing the losses of optical metamaterials

    SciTech Connect (OSTI)

    Fang, Anan

    2010-12-15T23:59:59.000Z

    The field of metamaterials is driven by fascinating and far-reaching theoretical visions, such as perfect lenses, invisibility cloaking, and enhanced optical nonlinearities. However, losses have become the major obstacle towards real world applications in the optical regime. Reducing the losses of optical metamaterials becomes necessary and extremely important. In this thesis, two approaches are taken to reduce the losses. One is to construct an indefinite medium. Indefinite media are materials where not all the principal components of the permittivity and permeability tensors have the same sign. They do not need the resonances to achieve negative permittivity, {var_epsilon}. So, the losses can be comparatively small. To obtain indefinite media, three-dimensional (3D) optical metallic nanowire media with different structures are designed. They are numerically demonstrated that they are homogeneous effective indefinite anisotropic media by showing that their dispersion relations are hyperbolic. Negative group refraction and pseudo focusing are observed. Another approach is to incorporate gain into metamaterial nanostructures. The nonlinearity of gain is included by a generic four-level atomic model. A computational scheme is presented, which allows for a self-consistent treatment of a dispersive metallic photonic metamaterial coupled to a gain material incorporated into the nanostructure using the finite-difference time-domain (FDTD) method. The loss compensations with gain are done for various structures, from 2D simplified models to 3D realistic structures. Results show the losses of optical metamaterials can be effectively compensated by gain. The effective gain coefficient of the combined system can be much larger than the bulk gain counterpart, due to the strong local-field enhancement.

  11. Parton Energy Loss with Detailed Balance

    E-Print Network [OSTI]

    Enke Wang; Xin-Nian Wang

    2001-06-28T23:59:59.000Z

    Stimulated gluon emission and thermal absorption in addition to induced radiation are considered for an energetic parton propagating inside a quark- gluon plasma. In the presence of thermal gluons, stimulated emission reduces while absorption increases the parton's energy. The net effect is a reduction of the parton energy loss. Though decreasing asymptotically as $T/E$ with the parton energy, the relative reduction is found to be important for intermediate energies. The modified energy dependence of the energy loss will affect the shape of suppression of moderately high $p_T$ hadrons due to jet quenching in high-energy heavy-ion collisions.

  12. The QCD collisional energy loss revised

    E-Print Network [OSTI]

    A. Peshier

    2006-05-29T23:59:59.000Z

    It is shown that to leading order the QCD collisional energy loss reads $dE/dx \\sim \\alpha(m_D^2)T^2$. Compared to prevalent expressions, $dE^B/dx \\sim \\alpha^2 T^2 \\ln(ET/m_D^2)$, which could be considered adaptions of the (QED) Bethe-Bloch formula, the rectified result takes into account the running coupling, as dictated by renormalization. As one significant consequence, due to asymptotic freedom, the collisional energy loss becomes independent of the jet energy $E$. Some implications with regard to heavy ion collisions are pointed out.

  13. Obesity & Weight Loss Therapy Krakauer and Krakauer, J Obes Weight Loss Ther 2014, 4:2

    E-Print Network [OSTI]

    Krakauer, Nir Y.

    Obesity & Weight Loss Therapy Krakauer and Krakauer, J Obes Weight Loss Ther 2014, 4:2 http the original author and source are credited. Keywords: Waist circumference; Body shape index; Obesity Introduction Obesity has historically been a sign of good health, except at the greatestexcess[1

  14. Collisional parton energy loss in a finite size QCD medium revisited: Off mass-shell effects

    E-Print Network [OSTI]

    Alejandro Ayala; J. Magnin; Luis Manuel Montano; Eduardo Rojas

    2008-03-25T23:59:59.000Z

    We study the collisional energy loss mechanism for particles produced off mass-shell in a finite size QCD medium. The off mass-shell effects introduced are to consider particles produced in wave packets instead of plane waves and the length scale associated to an in-medium particles' life-time. We show that these effects reduce the energy loss as compared to the case when the particles are described as freely propagating from the source. The reduction of the energy loss is stronger as this scale becomes of the order or smaller than the medium size. We discuss possible consequences of the result on the description of the energy loss process in the parton recombination scenario.

  15. Endocortical bone loss in osteoporosis: the role of bone surface availability

    E-Print Network [OSTI]

    Buenzli, Pascal R; Clement, John G; Pivonka, Peter

    2012-01-01T23:59:59.000Z

    Age-related bone loss and postmenopausal osteoporosis are disorders of bone remodelling, in which less bone is reformed than resorbed. Yet, this dysregulation of bone remodelling does not occur equally in all bone regions. Loss of bone is more pronounced near the endocortex, leading to cortical wall thinning and medullary cavity expansion, a process sometimes referred to as "trabecularisation" or "cancellisation". Cortical wall thinning is of primary concern in osteoporosis due to the strong reduction in bone mechanical properties that it is associated with. In this paper, we examine the possibility that the nonuniformity of microscopic bone surface availability could explain the nonuniformity of bone loss in osteoporosis. We use a simple computational model of bone remodelling, in which microscopic bone surface availability influences bone turnover rate, to simulate the evolution of the bone volume fraction profile across the midshaft of a long bone. We find that bone loss is accelerated near the endocortica...

  16. Loss and thermal noise in plasmonic waveguides

    SciTech Connect (OSTI)

    Syms, R. R. A., E-mail: r.syms@imperial.ac.uk; Solymar, L. [Optical and Semiconductor Devices Group, EEE Department, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2014-06-07T23:59:59.000Z

    Rytov's theory of thermally generated radiation is used to find the noise in two-dimensional passive guides based on an arbitrary distribution of lossy isotropic dielectric. To simplify calculations, the Maxwell curl equations are approximated using difference equations that also permit a transmission-line analogy, and material losses are assumed to be low enough for modal losses to be estimated using perturbation theory. It is shown that an effective medium representation of each mode is valid for both loss and noise and, hence, that a one-dimensional model can be used to estimate the best achievable noise factor when a given mode is used in a communications link. This model only requires knowledge of the real and imaginary parts of the modal dielectric constant. The former can be found by solving the lossless eigenvalue problem, while the latter can be estimated using perturbation theory. Because of their high loss, the theory is most relevant to plasmonic waveguides, and its application is demonstrated using single interface, slab, and slot guide examples. The best noise performance is offered by the long-range plasmon supported by the slab guide.

  17. Queues with simultaneous loss on Dave Thornley

    E-Print Network [OSTI]

    Ould-Khaoua, Mohamed

    London SW7 2BZ England djt@doc.ic.ac.uk #12; 2 Breakdowns and repairs In a uniform multi-processor serverQueues with simultaneous loss on breakdowns Dave Thornley #3; June 15, 2002 Abstract We take a queue with breakdowns and repairs of processors in which the queue length does not change

  18. Queues with simultaneous loss on Dave Thornley

    E-Print Network [OSTI]

    Imperial College, London

    of Computing Imperial College of Science, Technology and Medicine Huxley Building 180 Queen's Gate London SW7 2BZ England djt@doc.ic.ac.uk #12; 2 Breakdowns and repairs In a uniform multi-processor server, weQueues with simultaneous loss on breakdowns Dave Thornley #3; Abstract We take a queue

  19. Report of Refrigerated Medication Loss UConn Health

    E-Print Network [OSTI]

    Oliver, Douglas L.

    Report of Refrigerated Medication Loss UConn Health Please complete form & return to John Dempsey Other (Specify): Phone: E-mail: Address: Location of Refrigerator Affected: Date/time refrigerator was out of temperature range: Describe the event below: How long was the refrigerator out of range (hours

  20. Standby and Off-Mode Energy Losses

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Standby and Off-Mode Energy Losses In New Appliances Measured in Shops #12;ISBN: 978 with the University of Coimbra. Its research interests include energyefficient technologies, renewable energies, and energy planning. Recent work includes the coordination of several European projects on market

  1. Revolving Loan Funds and Loan Loss Reserves

    Broader source: Energy.gov [DOE]

    U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) State Energy Program (SEP) guidance to states, Indian tribes, and overseas U.S. territories receiving SEP grants under the 209 Recovery Act dealing with loan loss reserves for revolving loan funds.

  2. Direct observation of the energy release site in a solar flare by SDO/AIA, Hinode/EIS and RHESSI

    E-Print Network [OSTI]

    Simões, Paulo J A; Fletcher, Lyndsay

    2015-01-01T23:59:59.000Z

    We present direct evidence for the detection of the main energy release site in a non-eruptive solar flare, SOL2013-11-09T06:38UT. This GOES C2.7 event was characterised by two flaring ribbons and a compact, bright coronal source located between them, which is the focus of our study. We use imaging from SDO/AIA, and imaging spectroscopy from RHESSI to characterise the thermal and non-thermal emission from the coronal source, and EUV spectroscopy from the Hinode/EIS, which scanned the coronal source during the impulsive peak, to analyse Doppler shifts in Fe XII and Fe XXIV emission lines, and determine the source density. The coronal source exhibited an impulsive emission lightcurve in all AIA filters during the impulsive phase. RHESSI hard X-ray images indicate both thermal and non-thermal emission at the coronal source, and its plasma temperature derived from RHESSI imaging spectroscopy shows an impulsive rise, reaching a maximum at 12-13 MK about 10 seconds prior to the hard X-ray peak. High redshifts assoc...

  3. FLOWS AND MOTIONS IN MOSS IN THE CORE OF A FLARING ACTIVE REGION: EVIDENCE FOR STEADY HEATING

    SciTech Connect (OSTI)

    Brooks, David H.; Warren, Harry P., E-mail: dhbrooks@ssd5.nrl.navy.mi [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2009-09-20T23:59:59.000Z

    We present new measurements of the time variability of intensity, Doppler, and nonthermal velocities in moss in an active region core observed by the EUV Imaging Spectrometer on Hinode in 2007 June. The measurements are derived from spectral profiles of the Fe XII 195 A line. Using the 2'' slit, we repeatedly scanned 150'' by 150'' in a few minutes. This is the first time it has been possible to make such velocity measurements in the moss, and the data presented are the highest cadence spatially resolved maps of moss Doppler and nonthermal velocities ever obtained in the corona. The observed region produced numerous C- and M-class flares with several occurring in the core close to the moss. The magnetic field was therefore clearly changing in the active region core, so we ought to be able to detect dynamic signatures in the moss if they exist. Our measurements of moss intensities agree with previous studies in that a less than 15% variability is seen over a period of 16 hr. Our new measurements of Doppler and nonthermal velocities reveal no strong flows or motions in the moss, nor any significant variability in these quantities. The results confirm that moss at the bases of high temperature coronal loops is heated quasi-steadily. They also show that quasi-steady heating can contribute significantly even in the core of a flare productive active region. Such heating may be impulsive at high frequency, but if so it does not give rise to large flows or motions.

  4. EVIDENCE FOR INTERNAL TETHER-CUTTING IN A FLARE/CORONAL MASS EJECTION OBSERVED BY MESSENGER, RHESSI, AND STEREO

    SciTech Connect (OSTI)

    Raftery, Claire L.; Gallagher, Peter T.; McAteer, R. T. James; Delahunt, Gareth; Lin, Chia-Hsien, E-mail: claire@ssl.berkeley.ed [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2010-10-01T23:59:59.000Z

    The relationship between eruptive flares and coronal mass ejections (CMEs) is a topic of ongoing debate, especially regarding the possibility of a common initiation mechanism. We studied the kinematic and hydrodynamic properties of a well-observed event that occurred on 2007 December 31 using data from MESSENGER, RHESSI, and STEREO in order to gain new physical insight into the evolution of the flare and CME. The initiation mechanism was determined by comparing observations to the internal tether-cutting, breakout, and ideal magnetohydrodynamic (MHD) models. Evidence of pre-eruption reconnection immediately eliminated the ideal MHD model. The timing and location of the soft and hard X-ray sources led to the conclusion that the event was initiated by the internal tether-cutting mechanism. In addition, a thermal source was observed to move in a downward direction during the impulsive phase of the event, followed by upward motion during the decay phase, providing evidence for X- to Y-type magnetic reconnection.

  5. Magnetically enhanced centrifugation for continuous biopharmaceutical processing

    E-Print Network [OSTI]

    Chen, Fei, Ph. D. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    Effective separation and purification of biopharmaceutical products from the media in which they are produced continues to be a challenging task. Such processes usually involve multiple steps and the overall product loss ...

  6. Understanding Loss Mechanisms and Efficiency Improvement Options for HCCI Engines Using Detailed Exergy Analysis

    E-Print Network [OSTI]

    Saxena, Samveg

    2013-01-01T23:59:59.000Z

    Exergy Loss from Cylinder Gases Combustion Heat Loss Exhaustheptane and Natural Gas blends Combustion in HCCI Engines,”from Cylinder Gases (%) Loss Mechanisms Combustion Heat Loss

  7. Fifteen years of XMM-Newton and Chandra monitoring of Sgr A*: Evidence for a recent increase in the bright flaring rate

    E-Print Network [OSTI]

    Ponti, G; Morris, M R; Merloni, A; Munoz-Darias, T; Clavel, M; Haggard, D; Zhang, S; Nandra, K; Gillessen, S; Mori, K; Neilsen, J; Rea, N; Degenaar, N; Terrier, R; Goldwurm, A

    2015-01-01T23:59:59.000Z

    We present a study of the X-ray flaring activity of Sgr A* during all the 150 XMM-Newton and Chandra observations pointed at the Milky Way center over the last 15 years. This includes the latest XMM-Newton and Chandra campaigns devoted to monitoring the closest approach of the very red Br-Gamma emitting object called G2. The entire dataset analysed extends from September 1999 through November 2014. We employed a Bayesian block analysis to investigate any possible variations in the characteristics (frequency, energetics, peak intensity, duration) of the flaring events that Sgr A* has exhibited since their discovery in 2001. We observe that the total bright-or-very bright flare luminosity of Sgr A* increased between 2013-2014 by a factor of 2-3 (~3.5 sigma significance). We also observe an increase (~99.9% significance) from 0.27+-0.04 to 2.5+-1.0 day^-1 of the bright-or-very bright flaring rate of Sgr A*, starting in late summer 2014, which happens to be about six months after G2's peri-center passage. This mi...

  8. Solar activity can be surprisingly good for Last month, the sun went haywire. Almost every day for two weeks in early September, solar flares

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Solar activity can be surprisingly good for astronauts Last month, the sun went haywire. Almost every day for two weeks in early September, solar flares issued from a giant sunspot named "active region 798/808." X-rays ionized Earth's upper atmosphere. Solar protons peppered the Moon

  9. Scannerless laser range imaging using loss modulation

    DOE Patents [OSTI]

    Sandusky, John V. (Albuquerque, NM)

    2011-08-09T23:59:59.000Z

    A scannerless 3-D imaging apparatus is disclosed which utilizes an amplitude modulated cw light source to illuminate a field of view containing a target of interest. Backscattered light from the target is passed through one or more loss modulators which are modulated at the same frequency as the light source, but with a phase delay .delta. which can be fixed or variable. The backscattered light is demodulated by the loss modulator and detected with a CCD, CMOS or focal plane array (FPA) detector to construct a 3-D image of the target. The scannerless 3-D imaging apparatus, which can operate in the eye-safe wavelength region 1.4-1.7 .mu.m and which can be constructed as a flash LADAR, has applications for vehicle collision avoidance, autonomous rendezvous and docking, robotic vision, industrial inspection and measurement, 3-D cameras, and facial recognition.

  10. Tuneable dielectric films having low electrical losses

    DOE Patents [OSTI]

    Dimos, Duane Brian (Albuquerque, NM); Schwartz, Robert William (Albuquerque, NM); Raymond, Mark Victor (Albuquerque, NM); Al-Shareef, Husam Niman (Boise, ID); Mueller, Carl (Lakewood, CO); Galt, David (Denver, CO)

    2000-01-01T23:59:59.000Z

    The present invention is directed to a method for forming dielectric thin films having substantially reduced electrical losses at microwave and millimeter wave frequencies relative to conventional dielectric thin films. The reduction in losses is realized by dramatically increasing the grain sizes of the dielectric films, thereby minimizing intergranular scattering of the microwave signal due to grain boundaries and point defects. The increase in grain size is realized by heating the film to a temperature at which the grains experience regrowth. The grain size of the films can be further increased by first depositing the films with an excess of one of the compoents, such that a highly mobile grain boundary phase is formed.

  11. Recent Stirling engine loss - understanding results

    SciTech Connect (OSTI)

    Tew, R.C.; Thieme, L.G.; Dudenhoefer, J.E.

    1994-09-01T23:59:59.000Z

    For several years, the National Aeronautics and Space Administration and other US Government agencies have been funding experimental and analytical efforts to improve the understanding of Stirling thermodynamic losses. NASA`s objective is to improve Stirling engine design capability to support the development of new engines for space power. An overview of these efforts was last given at the 1988 IECEC. Recent results of this research are reviewed.

  12. REGULAR ARTICLE Soil erosion, runoff and nutrient losses in an avocado (Persea

    E-Print Network [OSTI]

    Lehmann, Johannes

    REGULAR ARTICLE Soil erosion, runoff and nutrient losses in an avocado (Persea americana Mill management systems on erosion and runoff processes associated with extremely steep hillside avocado (Persea several groundcover manage- ment systems at a steep hillside avocado planting in a three-year study: 1

  13. Exploiting the Quantum Zeno effect to beat photon loss in linear optical quantum information processors

    E-Print Network [OSTI]

    Dowling, Jonathan P.

    to the loss of photons caused by the inter- action between the fiber and the electromagnetic field. By frequently monitoring the presence of the photon through a quantum non-demolition (QND) measurement), and the processing is accomplished by sending the photon through a system of linear optical elements and using

  14. In Situ Electron Energy Loss Spectroscopy in Liquids

    E-Print Network [OSTI]

    Holtz, Megan E; Gao, Jie; Abruña, Héctor D; Muller, David A

    2012-01-01T23:59:59.000Z

    In situ scanning transmission electron microscopy (STEM) through liquids is a promising approach for exploring biological and materials processes. However, options for in situ chemical identification are limited: X-ray analysis is precluded because the holder shadows the detector, and electron energy loss spectroscopy (EELS) is degraded by multiple scattering events in thick layers. Here, we explore the limits of EELS for studying chemical reactions in their native environments in real time and on the nanometer scale. The determination of the local electron density, optical gap and thickness of the liquid layer by valence EELS is demonstrated for liquids. By comparing theoretical and experimental plasmon energies, we find that liquids appear to follow the free-electron model that has been previously established for solids. Signals at energies below the optical gap and plasmon energy of the liquid provide a high signal-to-background ratio as demonstrated for LiFePO4 in aqueous solution. The potential for using...

  15. FLARE-ASSOCIATED TYPE III RADIO BURSTS AND DYNAMICS OF THE EUV JET FROM SDO/AIA AND RHESSI OBSERVATIONS

    SciTech Connect (OSTI)

    Chen Naihwa; Ip, Wing-Huen [Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China); Innes, Davina, E-mail: d949001@astro.ncu.edu.tw, E-mail: wingip@astro.ncu.edu.tw, E-mail: innes@mps.mpg.de [Max-Planck-Institut fuer Sonnensystemforschung, D-37191 Katlenburg-Lindau (Germany)

    2013-06-01T23:59:59.000Z

    We present a detailed description of the interrelation between the Type III radio bursts and energetic phenomena associated with the flare activities in active region AR11158 at 07:58 UT on 2011 February 15. The timing of the Type III radio burst measured by the radio wave experiment on Wind/WAVE and an array of ground-based radio telescopes coincided with an extreme-ultraviolet (EUV) jet and hard X-ray (HXR) emission observed by SDO/AIA and RHESSI, respectively. There is clear evidence that the EUV jet shares the same source region as the HXR emission. The temperature of the jet, as determined by multiwavelength measurements by Atmospheric Imaging Assembly, suggests that Type III emission is associated with hot, 7 MK, plasma at the jet's footpoint.

  16. Spectral Studies of Flaring FSRQs at GeV Energies Using Pass 8 Fermi-LAT Data

    E-Print Network [OSTI]

    Britto, Richard J G; Lott, Benoît

    2015-01-01T23:59:59.000Z

    Flat spectrum radio quasars (FSRQs) are bright active galactic nuclei surrounded by gas clouds within a UV-visible intense radiation field that form the so-called broad line region (BLR). These objects emit relativistic jets from a region close to the central supermassive black hole and through the BLR. The Fermi-Large Area Telescope (Fermi-LAT) is sensitive to gamma-ray photons from $\\sim$30 MeV to more than 300 GeV. We have performed spectral analysis of bright FSRQs in a 5.5 year (2008-2014) data sample collected by Fermi-LAT, using the new Pass 8 event selection and instrument response function. Also, our study of flaring episodes in a limited time range brings interesting results while compared to the full 5.5 year data samples.

  17. Suzaku Detection of an Intense X-Ray Flare from an A-type Star HD161084

    E-Print Network [OSTI]

    Junichiro Miura; Masahiro Tsujimoto; Yohko Tsuboi; Yoshitomo Maeda; Yasuharu Sugawara; Katsuji Koyama; Shigeo Yamauchi

    2007-11-08T23:59:59.000Z

    We report a serendipitous detection of an intense X-ray flare from the Tycho reference source HD 161084 during a Suzaku observation of the Galactic Center region for 20 ks. The X-ray Imaging Spectrometer (XIS) recorded a flare from this A1-type dwarf or subgiant star with a flux of 1.4x10^{-12} erg s^{-1} cm^{-2} (0.5--10 keV) and a decay time scale of 0.5 hr. The spectrum is hard with a prominent Fe XXV K alpha emission line at 6.7 keV, which is explained by a 5 keV thin-thermal plasma model attenuated by a 1.4x10^{21} cm^{-2} extinction. The low extinction, which is consistent with the optical reddening, indicates that the source is a foreground star toward the Galactic Center region. Based on the spectroscopic parallax distance of 530 pc, the peak X-ray luminosity amounts to 1x10^{32} erg s^{-1} (0.5--10 keV). This is much larger than the X-ray luminosity of ordinary late-type main-sequence stars, and the X-ray emission is unattributable to a hidden late-type companion that comprises a wide binary system with the A-star. We discuss possible natures of HD 161084 and suggest that it is most likely an interacting binary with elevated magnetic activity in the companion such as the Algol-type system. The flux detected by Suzaku during the burst is 100 times larger than the quiescent level measured using the archived XMM-Newton and Chandra data. The large flux amplification makes this star a unique example among sources of this class.

  18. Energy loss and (de)coherence effects beyond eikonal approximation

    E-Print Network [OSTI]

    Liliana Apolinário; Néstor Armesto; Guilherme Milhano; Carlos A. Salgado

    2014-10-21T23:59:59.000Z

    The parton branching process is known to be modified in the presence of a medium. Colour decoherence processes are known to determine the process of energy loss when the density of the medium is large enough to break the correlations between partons emitted from the same parent. In order to improve existing calculations that consider eikonal trajectories for both the emitter and the hardest emitted parton, we provide in this work, the calculation of all finite energy corrections for the gluon radiation off a quark in a QCD medium that exist in the small angle approximation and for static scattering centres. Using the path integral formalism, all particles are allowed to undergo Brownian motion in the transverse plane and the offspring allowed to carry an arbitrary fraction of the initial energy. The result is a general expression that contains both coherence and decoherence regimes that are controlled by the density of the medium and by the amount of broadening that each parton acquires independently.

  19. System Losses and Assessment Trade Study

    SciTech Connect (OSTI)

    David Shropshire; Steve Piet; Nick Soelberg; Robert Cherry; Roger Henry; David Meikrantz; Greg Teske; Eric Shaber; Candido Pereira

    2009-09-01T23:59:59.000Z

    This Advanced Fuel Cycle Initiative (AFCI) study has developed new analysis methods to examine old and new technology options toward the goal of improving fuel cycle systems. We have integrated participants and information from AFCI Systems Analysis, Transmutation Fuels, Separations, and Waste Form Campaigns in the Systems Losses and Assessment Trade Study. The initial objectives of this study were to 1) increase understanding of system interdependencies and thereby identify system trade-offs that may yield important insights, 2) define impacts of separations product purity on fuel manufacture and transmutation reactivity, 3) define impacts from transuranic (TRU) losses to waste, 4) identify the interrelationships involved in fuels and separations technology performance, and 5) identify system configuration adjustments with the greatest potential for influencing system losses. While bounding and analyzing this initial problem, we also identified significantly higher-level programmatic drivers with broad implications to the current fuel cycle research charter and the general issue of a DOE complex wide need for a comprehensive and integrated nuclear material management as addressed by the new DOE Order 410.2 titled “Management of Nuclear Materials”. The initial modeling effort developed in this study for a much smaller subset of material (i.e., commercial fuel) and a selected transmutation scheme (i.e., fast reactor recycling) is a necessary first step towards examining a broader set of nuclear material management options, dispositioning strategies and integrated waste management options including potential areas of research leverage. The primary outcome from this initial study has been an enhanced integration among Campaigns and associated insights and analysis methods. Opportunities for improved understanding between the groups abound. The above lanthanide-actinide example highlights the importance of evaluating options via integration across the Campaigns. Plans for Fiscal Year 2010 are being made in a coordinated fashion such that the knowledge gained from the research performed by the Campaigns can benefit on-going work of the study, and that improved understanding of the system relationships can be used to guide the specific research and development (R&D) activities within the Campaigns. In FY-10, the System Losses and Assessment Trade Study will carry-over activities from FY-09. We will continue to refine impurity and loss estimates and impurity limits on fuels by incorporating results from ongoing R&D. And we will begin work on an enhanced nuclear material management model to allow us to continue to improve our overall system understanding of the trade-offs between separations, fuel fabrication, waste forms, waste disposition, SNM losses, reactor performance, and proliferation resistance. In the future, we can also better understand how used fuel and other forms of remote-handled SNM can be better integrated into an overall nuclear material management program that will evolve for the DOE complex via Order 410.2 (DOE 2009).

  20. Collisional energy loss of heavy quarks

    E-Print Network [OSTI]

    Alex Meistrenko; Andre Peshier; Jan Uphoff; Carsten Greiner

    2013-04-13T23:59:59.000Z

    We develop a transport approach for heavy quarks in a quark-gluon plasma, which is based on improved binary collision rates taking into account quantum statistics, the running of the QCD coupling and an effective screening mass adjusted to hard-thermal loop calculations. We quantify the effects of in-medium collisions by calculating the heavy flavor nuclear modification factor and the elliptic flow for RHIC energies, which are comparable to radiative effects. We also derive an analytic formula for the mean collisional energy loss of an energetic heavy quark in a streaming quark gluon plasma.

  1. Reducing Energy Loss | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMay 2015 < prevQuick Guide:U.N.June 8,PastRadiation LossesReducingReducing

  2. Methane/nitrogen separation process

    DOE Patents [OSTI]

    Baker, R.W.; Lokhandwala, K.A.; Pinnau, I.; Segelke, S.

    1997-09-23T23:59:59.000Z

    A membrane separation process is described for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. The authors have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen. 11 figs.

  3. Methane/nitrogen separation process

    DOE Patents [OSTI]

    Baker, Richard W. (Palo Alto, CA); Lokhandwala, Kaaeid A. (Menlo Park, CA); Pinnau, Ingo (Palo Alto, CA); Segelke, Scott (Mountain View, CA)

    1997-01-01T23:59:59.000Z

    A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

  4. CHARACTERIZING LOSSES IN MICROSTRIP TRANSMISSION LINES Rashmi Pathak

    E-Print Network [OSTI]

    Timbie, Peter

    CHARACTERIZING LOSSES IN MICROSTRIP TRANSMISSION LINES by Rashmi Pathak A dissertation submitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Transmission Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Engineering) at the UNIVERSITY OF WISCONSIN­MADISON Summer 2005 #12;i Characterizing Losses in Transmission

  5. Draft 'Michigan Saves' Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample loan loss reserve agreement between a state or local government and a financial institution setting the terms and conditions of the loan loss reserve fund. Author: State of Michigan

  6. abrupt mass loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of two SNe, 2002ap and 2006jc, for Wolf-Rayet star mass-loss rates and long Gamma-ray bursts. John Eldridge 5 Mass loss and supernova progenitors Astrophysics (arXiv)...

  7. Characterizing Shading Losses on Partially Shaded PV Systems (Presentation)

    SciTech Connect (OSTI)

    Deline, C.

    2010-09-23T23:59:59.000Z

    Presentation on shaded PV power loss, practical issues with modeling shaded PV, and methods of implementing partially shaded PV modeling.

  8. Status of wake and array loss research

    SciTech Connect (OSTI)

    Elliott, D.L.

    1991-09-01T23:59:59.000Z

    In recent years, many projects have evaluated wind turbine wake effects and resultant array losses in both Europe and the United States. This paper examines the status of current knowledge about wake effects and array losses and suggests future research. Single-turbine wake characteristics have been studied extensively and are generally described well by existing theoretical models. Field measurements of wake effects in wind turbine arrays are largely limited to small arrays, with 2 to 4 rows of turbines. Few data have been published on wake effects within large arrays. Measurements of wake deficits downwind of large arrays that deficits are substantially larger and extend farther downwind than expected. Although array design models have been developed, these models have been tested and verified using only limited data from a few rows of wind turbines in complex terrain, whereas some of the largest arrays have more than 40 rows of wind turbines. Planned cooperative efforts with the wind industry will obtain existing data relevant to analyzing energy deficits within large arrays and identifying data sets for potential use in array model verification efforts. Future research being considered include a cooperative research experiment to obtain more definitive data on wake deficits and turbulence within and downwind of large arrays. 16 refs., 9 figs., 1 tab.

  9. An investigation of simplified loss formula evaluation of total and incremental power system losses

    E-Print Network [OSTI]

    Malinowski, James Henry

    1962-01-01T23:59:59.000Z

    of the requirements i' or the degree of NASTER OF SCIENCE NaF~ 1962 Na)or Sub)ect: Electrical Engineering AN INVESTIGlLTION OF SIMPLIFIED LOSS FORMULA EVALUATION OF TOTAL AND INCREMENTAL POWER SYSTEM LOSSES A Thesis JAMES HENRY MALINOWSKI Approved as to style... e o o o e 0 e 32 BIBLIOGRAPHY ~ e o ~ o ~ a o ~ a a o ~ o o o o o o 37 CHAPTER I IRTRODUCTZOH The past decade, l9$0-1960, has seen the electric power industry of the United States more than double its installed capacity and annual energy...

  10. MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS

    E-Print Network [OSTI]

    Mi, Chunting "Chris"

    MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS IN PERMANENT MAGNET MACHINES@umich.edu Received 24 November 2010 Accepted 16 June 2011 The eddy current loss in the magnets of permanent magnet- mium-iron-boron (NdFeB), and slot/tooth harmonics, there is eddy current loss generated inside

  11. Arctic ozone loss and climate sensitivity: Updated threedimensional model study

    E-Print Network [OSTI]

    Feng, Wuhu

    Arctic ozone loss and climate sensitivity: Updated three­dimensional model study Chipperfield winter­spring chemical ozone loss from 1991 2003, its observed correlation with low temperatures. CTM throughout studied. The model reproduces large column winters also captures shape of ozone loss profile

  12. The Capacity Loss of Dense Constellations Tobias Koch

    E-Print Network [OSTI]

    high SNR, our results recover the power loss of 1.53dB for square signal constellations without-noise channels for suitably high signal- to-noise ratio. Our expression for the capacity loss recovers the power loss of 1.53dB for square signal constellations. I. INTRODUCTION As it is well known, the channel

  13. Silicon on ultra-low-loss waveguide photonic integration platform

    E-Print Network [OSTI]

    Bauters, Jared; Davenport, Michael; Heck, Martijn; Doylend, Jonathan; Chen, Arnold; Fang, Alexander

    2013-01-01T23:59:59.000Z

    and J. E. Bowers, “Ultra-low-loss high-aspect-ratio Si 3 N 4and K. J. Vahala, “Ultra-low-loss optical delay line on aspiral is 78 mm long. 3. Ultra-low-loss waveguides with and

  14. Loss Factor of the PEP-II Rings

    SciTech Connect (OSTI)

    Novokhatski, A; Sullivan, M.; /SLAC

    2008-07-11T23:59:59.000Z

    An RF power balance method is used to measure the synchrotron radiation losses and the wake field losses. We present the history of the losses in the Low Energy Ring (LER) and the High Energy Ring (HER) during the last several runs of PEP-II.

  15. Greed, Leverage, and Potential Losses: A Prospect Theory Perspective

    E-Print Network [OSTI]

    and losses, reference point, portfolio choice 1 Introduction "Greed" as a non-technical term is fairlyGreed, Leverage, and Potential Losses: A Prospect Theory Perspective Hanqing Jin and Xun Yu Zhou with leverage and potential losses, in the context of a continuous-time behavioral portfolio choice model under

  16. Controlling internal barrier in low loss BaTiO3 supercapacitors U-C. Chung, C. Elissalde, S. Mornet and M. Maglione

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Controlling internal barrier in low loss BaTiO3 supercapacitors U-C. Chung, C. Elissalde, S Supercapacitor behavior has been reported in a number of oxides including reduced BaTiO3 ferroelectric ceramics to process bulk composites having supercapacitor features with low dielectric losses and temperature

  17. A New Loss Control Management System; Assimilating Loss Control Methodology in Reducing the Overall Quality Losses in XYZ Chemical Corporation

    E-Print Network [OSTI]

    Shaikh, Sameer

    2011-05-20T23:59:59.000Z

    . Many programs are being implemented to support high quality products and chief amongst them is the use of Statistical Process Control software called “STATPRO”. STATPRO not only helps in computing and analyzing SPC but also track a record of changes...

  18. Particle-in-cell simulations of particle energization via shock drift acceleration from low Mach number quasi-perpendicular shocks in solar flares

    E-Print Network [OSTI]

    Park, Jaehong; Workman, Jared C; Blackman, Eric G

    2012-01-01T23:59:59.000Z

    Low Mach number, high beta fast mode shocks can occur in the magnetic reconnection outflows of solar flares. These shocks, which occur above flare loop tops, may provide the electron energization responsible for some of the observed hard X-rays and contemporaneous radio emission. Here we present new 2D particle-in-cell simulations of low Mach number/high beta quasi-perpendicular shocks. The simulations show that electrons above a certain energy threshold experience shock-drift-acceleration. The transition energy between the thermal and non-thermal spectrum and the spectral index from the simulations are consistent with some of the X-ray spectra from RHESSI in the energy regime, $E\\lesssim 40\\sim 100$ keV. Plasma instabilities associated with the shock structure such as the modified-two-stream and the electron whistler/mirror instabilities are examined and compared with the numerical solutions of the kinetic dispersion relations.

  19. Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992

    SciTech Connect (OSTI)

    Boden, T.A.; Marland, G. [Oak Ridge National Lab., TN (United States); Andres, R.J. [University of Alaska, Fairbanks, AK (United States). Inst. of Northern Engineering

    1995-12-01T23:59:59.000Z

    This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, provides estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.

  20. Global warming, insurance losses and financial industry

    SciTech Connect (OSTI)

    Low, N.C. [UOB Life Assurance Limited, Singapore (Singapore)

    1996-12-31T23:59:59.000Z

    Global warming causes extremely bad weather in the near term. They have already caught the attention of the insurance industry, as they suffered massive losses in the last decade. Twenty-one out of the 25 largest catastrophes in the US, mainly in the form of hurricanes have occurred in the last decade. The insurance industry has reacted by taking the risk of global warming in decisions as to pricing and underwriting decisions. But they have yet to take a more active role in regulating the factors that contributes to global warming. How global warming can impact the financial industry and the modern economy is explored. Insurance and modern financial derivatives are key to the efficient functioning of the modern economy, without which the global economy can still function but will take a giant step backward. Any risk as global warming that causes economic surprises will hamper the efficient working of the financial market and the modern economy.

  1. Non-linear force-free field modeling of a solar active region around the time of a major flare and coronal mass ejection

    E-Print Network [OSTI]

    C. J. Schrijver; M. L. DeRosa; T. Metcalf; G. Barnes; B. Lites; T. Tarbell; J. McTiernan; G. Valori; T. Wiegelmann; M. S. Wheatland; T. Amari; G. Aulanier; P. Demoulin; M. Fuhrmann; K. Kusano; S. Regnier; J. K. Thalmann

    2007-11-30T23:59:59.000Z

    Solar flares and coronal mass ejections are associated with rapid changes in field connectivity and powered by the partial dissipation of electrical currents in the solar atmosphere. A critical unanswered question is whether the currents involved are induced by the motion of pre-existing atmospheric magnetic flux subject to surface plasma flows, or whether these currents are associated with the emergence of flux from within the solar convective zone. We address this problem by applying state-of-the-art nonlinear force-free field (NLFFF) modeling to the highest resolution and quality vector-magnetographic data observed by the recently launched Hinode satellite on NOAA Active Region 10930 around the time of a powerful X3.4 flare. We compute 14 NLFFF models with 4 different codes and a variety of boundary conditions. We find that the model fields differ markedly in geometry, energy content, and force-freeness. We discuss the relative merits of these models in a general critique of present abilities to model the coronal magnetic field based on surface vector field measurements. For our application in particular, we find a fair agreement of the best-fit model field with the observed coronal configuration, and argue (1) that strong electrical currents emerge together with magnetic flux preceding the flare, (2) that these currents are carried in an ensemble of thin strands, (3) that the global pattern of these currents and of field lines are compatible with a large-scale twisted flux rope topology, and (4) that the ~10^32 erg change in energy associated with the coronal electrical currents suffices to power the flare and its associated coronal mass ejection.

  2. LATERAL OFFSET OF THE CORONAL MASS EJECTIONS FROM THE X-FLARE OF 2006 DECEMBER 13 AND ITS TWO PRECURSOR ERUPTIONS

    SciTech Connect (OSTI)

    Sterling, Alphonse C.; Moore, Ronald L. [Space Science Office, VP62, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Harra, Louise K., E-mail: alphonse.sterling@nasa.gov, E-mail: ron.moore@nasa.gov, E-mail: lkh@mssl.ucl.ac.uk [UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2011-12-10T23:59:59.000Z

    Two GOES sub-C-class precursor eruptions occurred within {approx}10 hr prior to and from the same active region as the 2006 December 13 X4.3-class flare. Each eruption generated a coronal mass ejection (CME) with center laterally far offset ({approx}> 45 Degree-Sign ) from the co-produced bright flare. Explaining such CME-to-flare lateral offsets in terms of the standard model for solar eruptions has been controversial. Using Hinode/X-Ray Telescope (XRT) and EUV Imaging Spectrometer (EIS) data, and Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) and Michelson Doppler Imager (MDI) data, we find or infer the following. (1) The first precursor was a 'magnetic-arch-blowout' event, where an initial standard-model eruption of the active region's core field blew out a lobe on one side of the active region's field. (2) The second precursor began similarly, but the core-field eruption stalled in the side-lobe field, with the side-lobe field erupting {approx}1 hr later to make the CME either by finally being blown out or by destabilizing and undergoing a standard-model eruption. (3) The third eruption, the X-flare event, blew out side lobes on both sides of the active region and clearly displayed characteristics of the standard model. (4) The two precursors were offset due in part to the CME originating from a side-lobe coronal arcade that was offset from the active region's core. The main eruption (and to some extent probably the precursor eruptions) was offset primarily because it pushed against the field of the large sunspot as it escaped outward. (5) All three CMEs were plausibly produced by a suitable version of the standard model.

  3. The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf

    E-Print Network [OSTI]

    Segura, Antígona; Meadows, Victoria; Kasting, James; Hawley, Suzanne

    2010-01-01T23:59:59.000Z

    Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwarf, AD Leonis (AD Leo), simulating the effects from both UV radiation and protons on the atmospheric chemistry of a hypothetical, Earth-like planet located within its habitable zone. Based on observations of solar proton events and the Neupert effect we estimated a proton flux associated with the flare of $5.9\\times 10^{8}$ protons cm$^{-2}$ sr$^{-1}$ s$^{-1}$ for particles with energies >10 MeV. Then we calculated the abundance of nitrogen oxides produced by the flare by scaling the production of these compounds during a large solar proton event called the "Carrington event". The simulations were performed using a 1-D photochemical model coupled to a 1-D radiative/co...

  4. Plasmoid Ejections and Loop Contractions in an Eruptive M7.7 Solar Flare: Evidence of Particle Acceleration and Heating in Magnetic Reconnection Outflows

    E-Print Network [OSTI]

    Liu, Wei; Petrosian, Vahe'

    2013-01-01T23:59:59.000Z

    Where particle acceleration and plasma heating take place in relation to magnetic reconnection is a fundamental question for solar flares. We report analysis of an M7.7 flare on 2012 July 19 observed by SDO/AIA and RHESSI. Bi-directional outflows in forms of plasmoid ejections and contracting cusp-shaped loops originate between an erupting flux rope and underlying flare loops at speeds of typically 200-300 km/s up to 1050 km/s. These outflows are associated with spatially separated double coronal X-ray sources with centroid separation decreasing with energy. The highest temperature is located near the nonthermal X-ray loop-top source well below the original heights of contracting cusps near the inferred reconnection site. These observations suggest that the primary loci of particle acceleration and plasma heating are in the reconnection outflow regions, rather than the reconnection site itself. In addition, there is an initial ascent of the X-ray and EUV loop-top source prior to its recently recognized descen...

  5. Processing Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Processing Science Related to the Electron Beam Melting Additive Manufacturing Process October 14 th , 2014 Ryan Dehoff Metal Additive Manufacturing Thrust Lead Manufacturing...

  6. Selection Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Selection Process Selection Process Fellowships will be awarded based on academic excellence, relevance of candidate's research to the laboratory mission in fundamental nuclear...

  7. Proposal Process

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Proposal Process Network R&D Overview Experimental Network Testbeds 100G SDN Testbed Testbed Description Testbed Results Current Testbed Research Proposal Process Terms and...

  8. NEUTRINO ANALYSIS OF THE 2010 SEPTEMBER CRAB NEBULA FLARE AND TIME-INTEGRATED CONSTRAINTS ON NEUTRINO EMISSION FROM THE CRAB USING ICECUBE

    SciTech Connect (OSTI)

    Abbasi, R.; Aguilar, J. A.; Andeen, K.; Baker, M. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Abdou, Y. [Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium); Abu-Zayyad, T. [Department of Physics, University of Wisconsin, River Falls, WI 54022 (United States); Adams, J. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Ahlers, M. [Department of Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Altmann, D. [III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen (Germany); Auffenberg, J.; Becker, K.-H. [Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany); Bai, X. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Barwick, S. W. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Bay, R. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Bazo Alba, J. L.; Benabderrahmane, M. L. [DESY, D-15735 Zeuthen (Germany); Beattie, K. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Beatty, J. J. [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Bechet, S. [Science Faculty CP230, Universite Libre de Bruxelles, B-1050 Brussels (Belgium); Becker, J. K. [Fakultaet fuer Physik and Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); and others

    2012-01-20T23:59:59.000Z

    We present the results of a search for high-energy muon neutrinos with the IceCube detector in coincidence with the Crab Nebula flare reported on 2010 September by various experiments. Due to the unusual flaring state of the otherwise steady source we performed a prompt analysis of the 79-string configuration data to search for neutrinos that might be emitted along with the observed {gamma}-rays. We performed two different and complementary data selections of neutrino events in the time window of 10 days around the flare. One event selection is optimized for discovery of E{sup -2}{sub {nu}} neutrino spectrum typical of first-order Fermi acceleration. A similar event selection has also been applied to the 40-string data to derive the time-integrated limits to the neutrino emission from the Crab. The other event selection was optimized for discovery of neutrino spectra with softer spectral index and TeV energy cutoffs as observed for various Galactic sources in {gamma}-rays. The 90% confidence level (CL) best upper limits on the Crab flux during the 10 day flare are 4.73 Multiplication-Sign 10{sup -11} cm{sup -2} s{sup -1} TeV{sup -1} for an E{sup -2}{sub {nu}} neutrino spectrum and 2.50 Multiplication-Sign 10{sup -10} cm{sup -2} s{sup -1} TeV{sup -1} for a softer neutrino spectra of E{sup -2.7}{sub {nu}}, as indicated by Fermi measurements during the flare. In this paper, we also illustrate the impact of the time-integrated limit on the Crab neutrino steady emission. The limit obtained using 375.5 days of the 40-string configuration is compared to existing models of neutrino production from the Crab and its impact on astrophysical parameters is discussed. The most optimistic predictions of some models are already rejected by the IceCube neutrino telescope with more than 90% CL.

  9. STELLAR CORONAE, SOLAR FLARES: A DETAILED COMPARISON OF {sigma} GEM, HR 1099, AND THE SUN IN HIGH-RESOLUTION X-RAYS

    SciTech Connect (OSTI)

    Huenemoerder, David P. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Phillips, Kenneth J. H. [Visiting Scientist, Space Research Center, Polish Academy of Sciences, 51-622, Kopernika 11, Wroclaw (Poland); Sylwester, Janusz; Sylwester, Barbara, E-mail: dph@space.mit.edu, E-mail: kennethjhphillips@yahoo.com, E-mail: js@cbk.pan.wroc.pl, E-mail: bs@cbk.pan.wroc.pl [Space Research Center, Polish Academy of Sciences, 51-622, Kopernika 11, Wroclaw (Poland)

    2013-05-10T23:59:59.000Z

    The Chandra High Energy Transmission Grating Spectrometer (HETG) spectra of the coronally active binary stars {sigma} Gem and HR 1099 are among the highest fluence observations for such systems taken at high spectral resolution in X-rays with this instrument. This allows us to compare their properties in detail to solar flare spectra obtained with the Russian CORONAS-F spacecraft's RESIK instrument at similar resolution in an overlapping bandpass. Here we emphasize the detailed comparisons of the 3.3-6.1 A region (including emission from highly ionized S, Si, Ar, and K) from solar flare spectra to the corresponding {sigma} Gem and HR 1099 spectra. We also model the larger wavelength range of the HETG, from 1.7 to 25 A - having emission lines from Fe, Ca, Ar, Si, Al, Mg, Ne, O, and N-to determine coronal temperatures and abundances. {sigma} Gem is a single-lined coronally active long-period binary which has a very hot corona. HR 1099 is a similar, but shorter period, double-lined system. With very deep HETG exposures we can even study emission from some of the weaker species, such as K, Na, and Al, which are important since they have the lowest first ionization potentials, a parameter well known to be correlated with elemental fractionation in the solar corona. The solar flare temperatures reach Almost-Equal-To 20 MK, comparable to the {sigma} Gem and HR 1099 coronae. During the Chandra exposures, {sigma} Gem was slowly decaying from a flare and its spectrum is well characterized by a collisional ionization equilibrium plasma with a broad temperature distribution ranging from 2 to 60 MK, peaking near 25 MK, but with substantial emission from 50 MK plasma. We have detected K XVIII and Na XI emission which allow us to set limits on their abundances. HR 1099 was also quite variable in X-rays, also in a flare state, but had no detectable K XVIII. These measurements provide new comparisons of solar and stellar coronal abundances, especially at the lowest first ionization potential (FIP) values. The low FIP elements do not show enhancement in the stellar coronae as they do in the Sun, except perhaps for K in {sigma} Gem. While {sigma} Gem and HR 1099 differ in their emission measure distributions, they have very similar elemental abundances.

  10. Detonation propagation in a high loss configuration

    SciTech Connect (OSTI)

    Jackson, Scott I [Los Alamos National Laboratory; Shepherd, Joseph E [CALTECH

    2009-01-01T23:59:59.000Z

    This work presents an experimental study of detonation wave propagation in tubes with inner diameters (ID) comparable to the mixture cell size. Propane-oxygen mixtures were used in two test section tubes with inner diameters of 1.27 mm and 6.35 mm. For both test sections, the initial pressure of stoichiometric mixtures was varied to determine the effect on detonation propagation. For the 6.35 mm tube, the equivalence ratio {phi} (where the mixture was {phi} C{sub 3}H{sub 8} + 50{sub 2}) was also varied. Detonations were found to propagate in mixtures with cell sizes as large as five times the diameter of the tube. However, under these conditions, significant losses were observed, resulting in wave propagation velocities as slow as 40% of the CJ velocity U{sub CJ}. A review of relevant literature is presented, followed by experimental details and data. Observed velocity deficits are predicted using models that account for boundary layer growth inside detonation waves.

  11. Cool horizons lead to information loss

    E-Print Network [OSTI]

    Borun D. Chowdhury

    2013-07-29T23:59:59.000Z

    There are two evidences for information loss during black hole evaporation: (i) a pure state evolves to a mixed state and (ii) the map from the initial state to final state is non-invertible. Any proposed resolution of the information paradox must address both these issues. The firewall argument focuses only on the first and this leads to order one deviations from the Unruh vacuum for maximally entangled black holes. The nature of the argument does not extend to black holes in pure states. It was shown by Avery, Puhm and the author that requiring the initial state to final state map to be invertible mandates structure at the horizon even for pure states. The proof works if black holes can be formed in generic states and in this paper we show that this is indeed the case. We also demonstrate how models proposed by Susskind, Papadodimas et al. and Maldacena et al. end up making the initial to final state map non-invertible and thus make the horizon "cool" at the cost of unitarity.

  12. Importance of Biologically Active Aurora-like Ultraviolet Emission: Stochastic Irradiation of Earth and Mars by Flares and Explosions

    E-Print Network [OSTI]

    David S. Smith; John Scalo; J. Craig Wheeler

    2003-07-30T23:59:59.000Z

    (Abridged) We show that sizeable fractions of incident ionizing radiation from stochastic astrophysical sources can be redistributed to biologically and chemically important UV wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption, with energies low enough to excite atmospheric molecules and atoms, resulting in a rich aurora-like spectrum. We calculate the fraction of energy redistributed into biologically and chemically important wavelength regions for spectra characteristic of stellar flares and supernovae using a Monte-Carlo transport code written for this problem and then estimate the fraction of this energy that is transmitted from the atmospheric altitudes of redistribution to the surface for a few illustrative cases. Redistributed fractions are found to be of order 1%, even in the presence of an ozone shield. This result implies that planetary organisms will be subject to mutationally significant, if intermittent, fluences of UV-B and harder radiation even in the presence of a narrow-band UV shield like ozone. We also calculate the surficial transmitted fraction of ionizing radiation and redistributed ultraviolet radiation for two illustrative evolving Mars atmospheres whose initial surface pressures were 1 bar. Our results suggest that coding organisms on planets orbiting low-mass stars (and on the early Earth) may evolve very differently than on contemporary Earth, with diversity and evolutionary rate controlled by a stochastically varying mutation rate and frequent hypermutation episodes.

  13. Time delays in quasi-periodic pulsations observed during the X2.2 solar flare on 2011 February 15

    E-Print Network [OSTI]

    Dolla, L; Seaton, D B; Van Doorsselaere, T; Dominique, M; Berghmans, D; Cabanas, C; De Groof, A; Schmutz, W; Verdini, A; West, M J; Zender, J; Zhukov, A N

    2012-01-01T23:59:59.000Z

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on time scale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the Extreme Ultra-Violet (EUV) channels of the Euv SpectroPhotometer (ESP) onboard the Solar Dynamic Observatory (SDO). The Zirconium and Aluminum filter channels of the Large Yield Radiometer (LYRA) onboard the Project for On-Board Autonomy (PROBA2) satellite and the SXR channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite (GOES), where the channel at 1-8 {\\AA} leads the 0.5-4 {\\AA} channel by several seconds. The time lags between the first and last channels is up to 9 ...

  14. Moreton Waves and EIT Waves Related to the Flare Events of June 3, 2012 and July 6, 2012

    E-Print Network [OSTI]

    Admiranto, A G; Yus'an, U; Puspitaningrum, E

    2015-01-01T23:59:59.000Z

    We present geometrical and kinematical analysis of Moreton waves and EIT waves observed on June 3, 2012 and Moreton waves observed on July 6, 2012. The Moreton waves were recorded in H$\\alpha$ images of Global Oscillation Network Group (GONG) archive and EIT waves obtained from SDO/AIA observations, especially in 193 nm channel. The observed wave of June 3 has angular span of about $70^{\\circ}$ with a broad wave front associated to NOAA active region 11496. It was found that the speed of the wave that started propagating at 17.53 UT is between 950 to 1500 km/s. Related to this wave occurrence, there was solar type II and III radio bursts. The speed of the EIT in this respect about 247 km/sec. On the other hand, the wave of July 6 may be associated to X1.1 class flare that occurred at 23.01 UT around the 11514 active region. From the kinematical analysis, the wave propagated with the initial velocity of about 1180 km/s which is in agreement with coronal shock velocity derived from type II radio burst observati...

  15. Bright X-ray flares in XRF 050406 and GRB 050502B provide evidence for extended central engine activity

    E-Print Network [OSTI]

    Burrows, D N; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'Brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S D; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-01-01T23:59:59.000Z

    Gamma-ray bursts (GRBs) are the most powerful explosions since the Big Bang, with typical energies around 10**51 ergs. Long GRBs (duration > 2 s) are thought to signal the creation of black holes, most likely by collapse of massive stars. The detected signals from the resulting highly relativistic fireball consist of prompt gamma-ray emission (from internal shocks in the fireball) lasting for several seconds to minutes, followed by afterglow emission (from external shocks as the fireball encounters surrounding material) covering a broad range of frequencies from radio through X-rays. Because of the time needed to determine the GRB position, most afterglow measurements have been made hours after the burst, and little is known about the characteristics of afterglows in the minutes following a burst, when the afterglow emission is actively responding to inhomogeneities in both the fireball and the circumburst environment. Here we report our discovery of two bright X-ray flares peaking a few minutes after the bur...

  16. 4, 50455074, 2004 Arctic ozone loss in

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , Germany 4 Central Aerological Observatory (CAO), Moscow, Russia 5 Institute of Atmospheric Sciences and Climate (ISAC), Italian National Research Council, Bologna, Italy 6 Alfred Wegener Institute, Potsdam changes to the CTM have improved the model's ability to reproduce polar chemical and dynamical processes.5

  17. Report on the Loss of the Mars Polar Lander and

    E-Print Network [OSTI]

    Leveson, Nancy

    ........................................................................................... 1 1.2.1 Investigation of the MCO Loss .................................................................................................................. 1 1.2.2 Post-MCO Corrective Actions for Mars Polar Lander

  18. Correlation Of Surface Heat Loss And Total Energy Production...

    Open Energy Info (EERE)

    Correlation Of Surface Heat Loss And Total Energy Production For Geothermal Systems Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Correlation...

  19. Draft Michigan SAVES Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    A sample LRF agreement between a grantee and an financial institution setting the terms and conditions of the loan loss reserve fund.

  20. Polarization Losses under Accelerated Stress Test Using Multiwalled...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Accelerated Stress Test Using Multiwalled Carbon Nanotube Supported Pt Catalyst in PEM Fuel Cells. Polarization Losses under Accelerated Stress Test Using Multiwalled Carbon...

  1. Analysis of beam loss induced abort kicker instability

    SciTech Connect (OSTI)

    Zhang W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Pai, C.; Tan, Y.

    2012-05-20T23:59:59.000Z

    Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

  2. ac losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    23 24 25 Next Page Last Page Topic Index 1 Transport AC loss in high temperature superconducting coils University of Cambridge - Dspace Summary: 's electromagnetic properties and...

  3. Process Modeling for Process Improvement A Process Conformance Approach

    E-Print Network [OSTI]

    Process Modeling for Process Improvement - A Process Conformance Approach Sigurd Thunem September processes. In order to improve these processes, knowledge about them is necessary. To support process improve- ment the organization should collect process data, transform process data into knowledge

  4. Efficient gas-separation process to upgrade dilute methane stream for use as fuel

    DOE Patents [OSTI]

    Wijmans, Johannes G. (Menlo Park, CA); Merkel, Timothy C. (Menlo Park, CA); Lin, Haiqing (Mountain View, CA); Thompson, Scott (Brecksville, OH); Daniels, Ramin (San Jose, CA)

    2012-03-06T23:59:59.000Z

    A membrane-based gas separation process for treating gas streams that contain methane in low concentrations. The invention involves flowing the stream to be treated across the feed side of a membrane and flowing a sweep gas stream, usually air, across the permeate side. Carbon dioxide permeates the membrane preferentially and is picked up in the sweep air stream on the permeate side; oxygen permeates in the other direction and is picked up in the methane-containing stream. The resulting residue stream is enriched in methane as well as oxygen and has an EMC value enabling it to be either flared or combusted by mixing with ordinary air.

  5. Processing alternatives for glandless cottonseed oil

    E-Print Network [OSTI]

    Chamkasem, Narong

    1981-01-01T23:59:59.000Z

    to contamination of the two oils at processing facilities. This practice results in increased refining costs and increased oil loss. In many oil processing plants it would be economically advantageous to process all cotton- seed oils in the same manner as soy... with various levels of glanded cottonseed were quantified. Generally conventional refining of oil from glandless cottonseed containing up to 10% glanded seed contamination produced refined and bleached oils as good in color as extraction-site miscella-refined...

  6. Basic TRUEX process for Rocky Flats Plant

    SciTech Connect (OSTI)

    Leonard, R.A.; Chamberlain, D.B.; Dow, J.A.; Farley, S.E.; Nunez, L.; Regalbuto, M.C.; Vandegrift, G.F.

    1994-08-01T23:59:59.000Z

    The Generic TRUEX Model was used to develop a TRUEX process flowsheet for recovering the transuranics (Pu, Am) from a nitrate waste stream at Rocky Flats Plant. The process was designed so that it is relatively insensitive to changes in process feed concentrations and flow rates. Related issues are considered, including solvent losses, feed analysis requirements, safety, and interaction with an evaporator system for nitric acid recycle.

  7. Thermal Processes

    Broader source: Energy.gov [DOE]

    Some thermal processes use the energy in various resources, such as natural gas, coal, or biomass, to release hydrogen, which is part of their molecular structure. In other processes, heat, in...

  8. Photolytic Processes

    Broader source: Energy.gov [DOE]

    Photolytic processes use the energy in sunlight to separate water into hydrogen and oxygen. These processes are in the very early stages of research but offer long-term potential for sustainable...

  9. Heat Loss Measurement Using Infrared Imaging

    E-Print Network [OSTI]

    Seeber, S. A.

    1983-01-01T23:59:59.000Z

    levels for objects seen in the CRT. (Radiance levels refer to the amount of infrared energy produced by an object.) The conversion of these radiance compari sons to temperatures and heat flows will be discussed below. Infrared images may be recorded... radiance level comparisons since colors may be associated with particular temperature ranges. Black and white images may be colorized during the inspection process. Alternatively, the black and white images may be stored on magnetic tape and color...

  10. The effects of R/X ratios on power system minimum loss 

    E-Print Network [OSTI]

    Denison, John Scott

    1949-01-01T23:59:59.000Z

    Presentation of Data Summary e ~ ~ ~ ~ ~ Appendix . Bibliography ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ S5 ~ ~ ~ ~ ~ ~ ~ ~ ~ 89 Case I, Loss vs ~ Angle ~ Case II, Loss vs. Angle Case III, Loss vs ~ Angle Case IV ~ Loss vso Angle... ~ ~ ~ Case V, Line Impedances . . . . . , ~ 17 20 23 27 33 Case V (a), Loss vs. Angle . . ~ Case V (b), Loss vs. Voltage Case V (c), Loss vs. Angle Case VI, Line Impedances ~ Case VI, Loss vs. &ngle ~ Case VII (a), Line Impedances Case VII (a...

  11. Energy Upgrade California in Los Angeles County, Loan Loss Reserve Fund Agreement

    Broader source: Energy.gov [DOE]

    Energy Upgrade California in Los Angeles County, Loan Loss Reserve Fund Agreement. Example of loan loss reserve agreement.

  12. Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3

    E-Print Network [OSTI]

    Nebot Del Busto, E; Branger, E; Holzer, E B; Doebert, S; Lillestol, R L; Welsch, C P

    2013-01-01T23:59:59.000Z

    The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the bea...

  13. SPOT PRICING FRAMEWORK FOR LOSS GUARANTEED INTERNET SERVICE CONTRACTS

    E-Print Network [OSTI]

    Kalyanaraman, Shivkumar

    . In a two-component approach to pricing, a nonlinear pricing scheme is used for cost recovery and a utility for cost recovery, and (ii) an options-based approach to price the risk of deviations in the loss based QoSPOT PRICING FRAMEWORK FOR LOSS GUARANTEED INTERNET SERVICE CONTRACTS Aparna Gupta Decision

  14. average energy losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    average energy losses First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Comparing energy loss...

  15. additional energy losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    additional energy losses First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Comparing energy loss...

  16. How Compatible is Perfect Competition with Transmission Loss Allocation Methods?

    E-Print Network [OSTI]

    Boyer, Edmond

    the problem of transmission loss allocation in a power system where the generators, the demands and the system. INTRODUCTION IN power systems where generation and transmission are unbundled, the transmission operationalHow Compatible is Perfect Competition with Transmission Loss Allocation Methods? Jing Dai, Yannick

  17. Estimation of Convection Loss from Paraboloidal Dish Cavity Receivers

    E-Print Network [OSTI]

    In general, cavity receivers employed in the sun-tracking paraboloidal dish concentrator are subjected the numerical investigation of natural and combined convection loss from cavity receivers employed in solar is a significant source of energy loss from thermal receivers used with dish solar concentrators. This paper

  18. Modelling and Computation of AC Fields and Losses in

    E-Print Network [OSTI]

    Sóbester, András

    electricity but inherently has energy losses associated with (joule) heating. Fault current limiters would be installed in transmission and distribution systems, especially for electric utilities and large energy users. High-Tc superconductors experience energy loss when exposed to time-varying magnetic fields or carrying

  19. Linear-optics manipulations of photon-loss codes

    E-Print Network [OSTI]

    Konrad Banaszek; Wojciech Wasilewski

    2007-02-09T23:59:59.000Z

    We discuss codes for protecting logical qubits carried by optical fields from the effects of amplitude damping, i.e. linear photon loss. We demonstrate that the correctability condition for one-photon loss imposes limitations on the range of manipulations than can be implemented with passive linear-optics networks.

  20. Advanced EL inspection with predictive estimation of module power loss

    E-Print Network [OSTI]

    with no relation to its significance on potential power degradation 7pi4_robotics GmbH #12;The idea: Estimate power photovoltaic modules due to micro-cracks" #12;Three step approach to estimate power loss PL1 : power loss

  1. Legal Access to Geographic Information: Measuring Losses or Developing Responses?

    E-Print Network [OSTI]

    Onsrud, Harlan J.

    are obvious and a focus on measuring losses in such situations seems misplaced when energies might be better and measurements those in power positions are often able to divert attention and energy away from the goals digital data environments. As a result, widespread loss of access to information and works of knowledge

  2. Analysis of partial loss reward models and its application

    E-Print Network [OSTI]

    Telek, Miklós

    Analysis of partial loss reward models and its application #3; M. Telek 1 , S. R#19;acz 2 1. The applicability of partial loss re- ward models and the proposed numerical analysis methods are demonstrated via the performance analysis of a computer system executing long running batch programs with checkpointing. Keywords

  3. Losses in superconducting Niobium Films caused by Interface Tunnel Exchange

    E-Print Network [OSTI]

    Junginger, Tobias; Welsch, Carsten

    2012-01-01T23:59:59.000Z

    Identifying the loss mechanisms of niobium film cavities enables an accurate determination of applications for future accelerator projects and points to research topics required to mitigate their limitations. Measurements on samples show that the electric field is a dominant loss mechanism for niobium films, acting through interface tunneling between localized states in surface oxides and delocalized states in the superconducting niobium.

  4. Predicting Performance of PESQ in Case of Single Frame Losses

    E-Print Network [OSTI]

    Wichmann, Felix

    Predicting Performance of PESQ in Case of Single Frame Losses Christian Hoene, Enhtuya Dulamsuren-Lalla Technical University of Berlin, Germany Fax: +49 30 31423819 Email: hoene@ieee.org Abstract ITU's objective can measure the impact of single frame losses ­ a source of impairment for which PESQ has not been

  5. Technical note Insertion loss testing of active noise reduction

    E-Print Network [OSTI]

    Wong, Willy

    Technical note Insertion loss testing of active noise reduction headsets using acoustic fixture Jie. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, ON measured insertion losses of four types of commercially avail- able ANR headsets using an Acoustic Test

  6. Chemical Biology Chemical Screening for Hair Cell Loss and Protection

    E-Print Network [OSTI]

    Rubel, Edwin

    Chemical Biology Chemical Screening for Hair Cell Loss and Protection in the Zebrafish Lateral Line Rubel,1,2 and David W. Raible1,4 Abstract In humans, most hearing loss results from death of hair cells, the mechanosensory receptors of the inner ear. Two goals of current hearing research are to protect hair cells from

  7. Mechanical Loss in Tantala/Silica Dielectric Mirror Coatings

    E-Print Network [OSTI]

    Steven D. Penn; Peter H. Sneddon; Helena Armandula; Joseph C. Betzwieser; Gianpietro Cagnoli; Jordan Camp; D. R. M. Crooks; Martin M. Fejer; Andri M. Gretarsson; Gregory M. Harry; Jim Hough; Scott E. Kittelberger; Michael J. Mortonson; Roger Route; Sheila Rowan; Christophoros C. Vassiliou

    2003-02-24T23:59:59.000Z

    Current interferometric gravitational wave detectors use test masses with mirror coatings formed from multiple layers of dielectric materials, most commonly alternating layers of SiO2 (silica) and Ta2O5 (tantala). However, mechanical loss in the Ta2O5/SiO2 coatings may limit the design sensitivity for advanced detectors. We have investigated sources of mechanical loss in the Ta2O5/SiO2 coatings, including loss associated with the coating-substrate interface, with the coating-layer interfaces, and with the bulk material. Our results indicate that the loss is associated with the bulk coating materials and that the loss of Ta2O5 is substantially larger than that of SiO2.

  8. Fuel Saving Ideas for Metal and Ceramic Processing

    E-Print Network [OSTI]

    Reed, R. J.

    1982-01-01T23:59:59.000Z

    An easy method is presented for analyzing sources of heat loss from industrial processing furnaces, kilns, and ovens; and thus for recognizing opportunities for fuel saving. This will relate to melting, heat treating and hot forming of metals...

  9. TOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER THE THIN LINE BETWEEN GAIN AND LOSS

    E-Print Network [OSTI]

    Kik, Pieter

    and waveguide. If the pump laser could somehow be eliminated from this scheme, the fabrication of low-cost SiTOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER ­ THE THIN LINE BETWEEN GAIN AND LOSS-doped SiO2, a composite material that can potentially be fabricated using a VLSI compatible process

  10. The uncertainties due to quark energy loss on determining nuclear sea quark distribution from nuclear Drell-Yan data

    E-Print Network [OSTI]

    C. G. Duan; N. Liu; G. L. Li

    2008-11-05T23:59:59.000Z

    By means of two different parametrizations of quark energy loss and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order phenomenological analysis is performed on the nuclear Drell-Yan differential cross section ratios as a function of the quark momentum fraction in the beam proton and target nuclei for E772 experimental data. It is shown that there is the quark energy loss effect in nuclear Drell-Yan process apart from the nuclear effects on the parton distribution as in deep inelastic scattering. The uncertainties due to quark energy loss effect is quantified on determining nuclear sea quark distribution by using nuclear Drell-Yan data. It is found that the quark energy loss effect on nuclear Drell-Yan cross section ratios make greater with the increase of quark momentum fraction in the target nuclei. The uncertainties from quark energy loss become bigger as the nucleus A come to be heavier. The Drell-Yan data on proton incident middle and heavy nuclei versus deuterium would result in an overestimate for nuclear modifications on sea quark distribution functions with neglecting the quark energy loss. Our results are hoped to provide good directional information on the magnitude and form of nuclear modifications on sea quark distribution functions by means of the nuclear Drell-Yan experimental data.

  11. Quantum plasmonic excitation in graphene and robust-to-loss propagation

    E-Print Network [OSTI]

    Hanson, George W; Lee, Changhyoup; Angelakis, Dimitris G; Tame, Mark

    2015-01-01T23:59:59.000Z

    We investigate the excitation of quantum plasmonic states of light in graphene using end-fire and prism coupling. In order to model the excitation process quantum mechanically we quantize the transverse-electric and transverse-magnetic surface plasmon polariton (SPP) modes in graphene. A selection of regimes are then studied that enable the excitation of SPPs by photons and we show that efficient coupling of photons to graphene SPPs is possible at the quantum level. Futhermore, we study the excitation of quantum states and their propagation under the effects of loss induced from the electronic degrees of freedom in the graphene. Here, we investigate whether it is possible to protect quantum information using quantum error correction techniques. We find that these techniques provide a robust-to-loss method for transferring quantum states of light in graphene over large distances.

  12. MHD Induced Neutral Beam Ion Loss from NSTX Plasmas

    SciTech Connect (OSTI)

    D.S. Darrow, E.D. Fredrickson, N.N. Gorelenkov, A.L. Roquemore, and K. Shinohara

    2007-12-13T23:59:59.000Z

    Bursts of ~60 kHz activity on Mirnov coils occur frequently in NSTX plasmas and these are accompanied by bursts of neutral beam ion loss over a range in pitch angles. These losses have been measured with a scintillator type loss probe imaged with a high speed (>10,000 frames/s) video camera, giving the evolution of the energy and pitch angle distributions of the lost neutral beam ions over the course of the events. The instability occurs below the TAE frequency in NSTX (~100 kHz) in high beta plasmas and may be a beta driven Alfvén acoustic (BAAE) mode.

  13. Elucidating Jet Energy Loss Using Jets: Prospects from ATLAS

    E-Print Network [OSTI]

    N. Grau; for the ATLAS Collaboration

    2009-10-20T23:59:59.000Z

    Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet $R_{AA}$, the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

  14. Impacts of the Venezuelan Crude Oil Production Loss

    Reports and Publications (EIA)

    2003-01-01T23:59:59.000Z

    This assessment of the Venezuelan petroleum loss examines two areas. The first part of the analysis focuses on the impact of the loss of Venezuelan crude production on crude oil supply for U.S. refiners who normally run a significant fraction of Venezuelan crude oil. The second part of the analysis looks at the impact of the Venezuelan production loss on crude markets in general, with particular emphasis on crude oil imports, refinery crude oil throughput levels, stock levels, and the changes in price differences between light and heavy crude oils.

  15. Mode imaging and loss evaluation of semiconductor waveguides

    SciTech Connect (OSTI)

    Mochizuki, Toshimitsu [Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba (Japan); Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, 2-2-9 Machiike-dai, Koriyama, Fukushima (Japan); Kim, Changsu; Yoshita, Masahiro; Nakamura, Takahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba (Japan); Pfeiffer, Loren N.; West, Ken W. [Department of Electrical Engineering, Princeton University, New Jersey 08544 (United States)

    2014-05-15T23:59:59.000Z

    An imaging and loss evaluation method for semiconductor waveguides coupled with non-doped quantum wells is presented. Using the internal emission of the wells as a probe light source, the numbers and widths of the modes of waveguides with various ridge sizes were evaluated by CCD imaging, and the obtained values were consistent with effective index method calculation. Waveguide internal losses were obtained from analyses of the Fabry-Pérot fringes of waveguide emission spectra. We quantified the quality of 29 single-mode waveguide samples as an internal loss and variation of 10.2 ± 0.6??cm{sup ?1}.

  16. THE LOSS, RECOVERY, AND REINVENTION OF SELF: A CONCEPTUAL FRAMEWORK FOR THE PROCESS OF TRANSFORMATION

    E-Print Network [OSTI]

    Zoellner, Kendra Pennington

    2009-12-08T23:59:59.000Z

    and in the family, and ultimately, the continuation of all forms of violence against women. Moreover, society?s failure to offer widespread prevention programs for high risk children is likely contributing to the intergenerational transmission of violence... articles addressing ?family violence? (Gelles, 1974; Straus, 1973). Straus (1973) and Gelles (1974) approach IPV from a 21 general systems theory perspective and study all forms of violence within the family, not just the incidence of wife abuse...

  17. Process and apparatus for reducing the loss of hydrogen from Stirling engines

    SciTech Connect (OSTI)

    Alger, D.L.

    1987-03-24T23:59:59.000Z

    A Stirling engine assembly is described which defines a working gas volume therein, the Stirling engine assembly comprising: a working gas reservoir for storing a working gas at a pressure greater than pressure of the working gas in the working volume of the Stirling engine; a trap cell operatively connected between an outlet of the reservoir and the Stirling engine working volume. The trap cell includes an enclosure having porous windows at either end thereof and a sorbent with an affinity for water vapor therein, such that water vapor adsorbed on the sorbent diffuses into the hydrogen passing from the reservoir into the working engine; a compressor means for drawing working gas from the Stirling engine working volume, through the trap cell and pumping the working gas into the hydrogen reservoir. The sorbent in the trap cell at the reduced pressure caused by the compressor adsorbs water vapor from the working gas such that substantially dry working gas is pumped by the compressor into the reservoir. The working gas is doped with water vapor by the tank cell as it passes into the Stirling engine and is dried by the trap cell as it is removed from the working engine for storage in the reservoir to prevent condensation of water vapor in the reservoir.

  18. The effect of stress cracked and broken corn kernels on alkaline processing losses

    E-Print Network [OSTI]

    Jackson, David Scott

    1986-01-01T23:59:59.000Z

    (~. 70, P&. 06). There were significant differences in COD and DML (KRATIO= 100) between highly damaged corn and the less damaged counterpart of the same hybrid. Stress cracked corn, however, only slightly increased COD and DML. The ease of pericarp... Sigruficance of Com and Cooking Parameters . . . LIST OF FIGURES Page Stress Crack, Pericarp, and Broken Kernel Damage of Corn . . Flow Chart of Procedutes and Differences Between Cook Methods I and H 21 24 Correlation between Thousand Kernel Weight...

  19. Investigating late stage biopharmaceutical product loss using novel analytical and process technology

    E-Print Network [OSTI]

    Hunnicutt, Leigh Anne

    2008-01-01T23:59:59.000Z

    The biopharmaceutical industry uses recombinant protein technologies to provide novel therapeutics to patients around the world. These technologies have presented exciting opportunities for breakthrough medical treatments ...

  20. Reordering an index to speed query processing without loss of effectiveness.

    E-Print Network [OSTI]

    Hawking, David

    Funnelback Pty Ltd. Canberra ACT 2602, Australia, and RsCS, Australian National University david.hawking@acm.org Timothy Jones Funnelback Pty Ltd. Melbourne VIC 3066, Australia tjones@funnelback.com ABSTRACT Following been gathered and indexed, we build a tool for reordering an ex- isting index and show that it operates

  1. In Situ Energy Loss Instruments for Insulation Economy and Process Control

    E-Print Network [OSTI]

    Hauser, R. L.; McKeever, R. B.; Stull, D. P.

    and follow changes off ambient weather conditions for indoor, outdoor, buried and downhole applications. A variation of this instrument can be placed on columns under insulation to act as control sensor for adiabatic operation....

  2. LOSS OF PLASMA MEMBRANE PROTEINS OF BULL SPERMATOZOA THROUGH THE FREEZING -THAWING PROCESS

    E-Print Network [OSTI]

    Zaragoza, Universidad de

    Molecular y Celular Facultad de Veterinaria, Zaragoza, Spain Received for publication: July 24, 1996

  3. Cladding embrittlement during postulated loss-of-coolant accidents.

    SciTech Connect (OSTI)

    Billone, M.; Yan, Y.; Burtseva, T.; Daum, R.; Nuclear Engineering Division

    2008-07-31T23:59:59.000Z

    The effect of fuel burnup on the embrittlement of various cladding alloys was examined with laboratory tests conducted under conditions relevant to loss-of-coolant accidents (LOCAs). The cladding materials tested were Zircaloy-4, Zircaloy-2, ZIRLO, M5, and E110. Tests were performed with specimens sectioned from as-fabricated cladding, from prehydrided (surrogate for high-burnup) cladding, and from high-burnup fuel rods which had been irradiated in commercial reactors. The tests were designed to determine for each cladding material the ductile-to-brittle transition as a function of steam oxidation temperature, weight gain due to oxidation, hydrogen content, pre-transient cladding thickness, and pre-transient corrosion-layer thickness. For short, defueled cladding specimens oxidized at 1000-1200 C, ring compression tests were performed to determine post-quench ductility at {le} 135 C. The effect of breakaway oxidation on embrittlement was also examined for short specimens oxidized at 800-1000 C. Among other findings, embrittlement was found to be sensitive to fabrication processes--especially surface finish--but insensitive to alloy constituents for these dilute zirconium alloys used as cladding materials. It was also demonstrated that burnup effects on embrittlement are largely due to hydrogen that is absorbed in the cladding during normal operation. Some tests were also performed with longer, fueled-and-pressurized cladding segments subjected to LOCA-relevant heating and cooling rates. Recommendations are given for types of tests that would identify LOCA conditions under which embrittlement would occur.

  4. Geologic controls influencing CO2 loss from a leaking well.

    SciTech Connect (OSTI)

    Hopkins, Polly L.; Martinez, Mario J.; McKenna, Sean Andrew; Klise, Katherine A.

    2010-12-01T23:59:59.000Z

    Injection of CO2 into formations containing brine is proposed as a long-term sequestration solution. A significant obstacle to sequestration performance is the presence of existing wells providing a transport pathway out of the sequestration formation. To understand how heterogeneity impacts the leakage rate, we employ two dimensional models of the CO2 injection process into a sandstone aquifer with shale inclusions to examine the parameters controlling release through an existing well. This scenario is modeled as a constant-rate injection of super-critical CO2 into the existing formation where buoyancy effects, relative permeabilities, and capillary pressures are employed. Three geologic controls are considered: stratigraphic dip angle, shale inclusion size and shale fraction. In this study, we examine the impact of heterogeneity on the amount and timing of CO2 released through a leaky well. Sensitivity analysis is performed to classify how various geologic controls influence CO2 loss. A 'Design of Experiments' approach is used to identify the most important parameters and combinations of parameters to control CO2 migration while making efficient use of a limited number of computations. Results are used to construct a low-dimensional description of the transport scenario. The goal of this exploration is to develop a small set of parametric descriptors that can be generalized to similar scenarios. Results of this work will allow for estimation of the amount of CO2 that will be lost for a given scenario prior to commencing injection. Additionally, two-dimensional and three-dimensional simulations are compared to quantify the influence that surrounding geologic media has on the CO2 leakage rate.

  5. Energy-loss- and thickness-dependent contrast in atomic-scale electron energy-loss spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tan, Haiyan [Universit_e de Toulouse, Toulouse, France (Europe); National Institute of Standards Technology, Gaithersburg, MD (United States); Xin, Huolin L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhu, Ye [Monash Univ., Melbourne, VIC (Australia); Dwyer, Christian [Peter Grunberg Institute, Julich, Germany (Europe)

    2014-12-01T23:59:59.000Z

    Atomic-scale elemental maps of materials acquired by core-loss inelastic electron scattering often exhibit an undesirable sensitivity to the unavoidable elastic scattering, making the maps counter-intuitive to interpret. Here, we present a systematic study that scrutinizes the energy-loss and sample-thickness dependence of atomic-scale elemental maps acquired using 100 keV incident electrons in a scanning transmission electron microscope. For single-crystal silicon, the balance between elastic and inelastic scattering means that maps generated from the near-threshold Si-L signal (energy loss of 99 eV) show no discernible contrast for a thickness of 0.5? (? is the electron mean-free path, here approximately 110 nm). At greater thicknesses we observe a counter-intuitive “negative” contrast. Only at much higher energy losses is an intuitive “positive” contrast gradually restored. Our quantitative analysis shows that the energy-loss at which a positive contrast is restored depends linearly on the sample thickness. This behavior is in very good agreement with our double-channeling inelastic scattering calculations. We test a recently-proposed experimental method to correct the core-loss inelastic scattering and restore an intuitive “positive” chemical contrast. The method is demonstrated to be reliable over a large range of energy losses and sample thicknesses. The corrected contrast for near-threshold maps is demonstrated to be (desirably) inversely proportional to sample thickness. Implications for the interpretation of atomic-scale elemental maps are discussed.

  6. Mode conversation losses in overmolded millimeter wave transmission lines

    E-Print Network [OSTI]

    Tax, David S. (David Samuel)

    2008-01-01T23:59:59.000Z

    Millimeter wave transmission lines are integral components for many important applications like nuclear fusion and NMR spectroscopy. In low loss corrugated transmission lines propagating the HE,1 mode with a high waveguide ...

  7. altitudinal field loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Roe et al.'s model as DFT (decision field theory) and Usher and McClelland's model as the LCA (leaky, competing accumulator) model. Does Loss Aversion Pose a Problem for DFT? As...

  8. alloying element losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 141 Turbine tip clearance loss mechanisms MIT - DSpace Summary: Three-dimensional numerical...

  9. Applying thresholds to forecast potential biodiversity loss from human development

    E-Print Network [OSTI]

    Hilderbrand, Robert H.

    thresholds to projected increases in residential development in the Middle Patuxent River watershed by 2030 in the Potapsco River watershed of Maryland could result in the loss of nearly 60% of the benthic

  10. Rapid Spatial Distribution Seismic Loss Analysis for Multistory Buildings 

    E-Print Network [OSTI]

    Deshmukh, Pankaj Bhagvatrao

    2012-07-16T23:59:59.000Z

    and incremental dynamic analysis along with the commercial software SAP2000 are used to establish demands from which story damage and financial losses are computed directly and aggregated for the entire structure. Rigorous and simplified methods are developed...

  11. Habitat loss and the structure of plantanimal mutualistic networks

    E-Print Network [OSTI]

    Fortuna, Miguel A.

    LETTER Habitat loss and the structure of plant­animal mutualistic networks Miguel A. Fortuna Sevilla, Spain *Correspondence: E-mail: fortuna@ebd.csic.es Abstract Recent papers have described

  12. Loan Loss Reserves: Lessons from the Field (Text Version)

    Broader source: Energy.gov [DOE]

    Merrian Fuller: Hi, and welcome to the Department of Energy's webinar on using loan-loss reserves report financing programs. My name is Marian Fuller, I work with Lawrence Berkeley National...

  13. Ovarian hormone loss induces bioenergetic deficits and mitochondrial -amyloid

    E-Print Network [OSTI]

    Brinton, Roberta Diaz

    Ovarian hormone loss induces bioenergetic deficits and mitochondrial -amyloid Jia Yaoa , Ronald by ovariectomy (OVX) in nontransgenic mice significantly decreased brain bioenergetics, and induced mitochondrial. Treatment with E2 at OVX prevented OVX-induced mitochondrial deficits, sustained mitochondrial bioenergetic

  14. array wake losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 UZOL & CAMCI1 ENDWALL HEAT TRANSFER, TOTAL PRESSURE LOSS AND WAKE FLOW FIELD Engineering Websites Summary: . The...

  15. Optimizing hysteretic power loss of magnetic ferrite nanoparticles

    E-Print Network [OSTI]

    Chen, Ritchie

    2013-01-01T23:59:59.000Z

    This thesis seeks to correlate hysteretic power loss of tertiary ferrite nanoparticles in alternating magnetic fields to trends predicted by physical models. By employing integration of hysteresis loops simulated from ...

  16. apical support loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    bags. We instead consider the problem of predicting instance labels while learning from data labeled only at the bag level. We propose Rank-Loss Support Instance Machines, which...

  17. acute interneuron loss: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    sets for previously unseen bags. We instead consider the problem of predicting instance labels while learning from data labeled only at the bag level. We propose Rank-Loss...

  18. Control of cooling losses at high pulverized coal injection rates

    SciTech Connect (OSTI)

    Bonte, L.; Nieuwerburgh, H. Van [Sidmar N.V., Gent (Belgium)

    1996-12-31T23:59:59.000Z

    One of the problems which is encountered by many blast furnace operators is the appropriate control of the cooling losses of the blast furnace. This problem has been aggravated by the introduction of pulverized coal injection. Even with equal burden and coke composition, both Sidmar furnaces behave differently with respect to the cooling losses. This phenomenon is possibly attributable to the different profile and cooling circuitry of the furnaces. Among other parameters the angles of bosh and stack may favor the formation of scabs or not. Some operators experience a decrease of their cooling losses, other operators have problems to limit their cooling losses to an acceptable level. As a result, different operating practices exist with respect to the burden distribution. The increase of the ore to coke ratio with pulverized coal injection suggests that the coke and sinter quality has to be monitored very carefully in order to avoid permeability problems.

  19. appendix gap losses: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    kicker performance and its effect on the beam losses will be described. Kourbanis, I; Biggs, J; Brown, B; Capista, D; Jensen, C C; Krafczyk, G E; Morris, D K; Scott, D; Seiya, K;...

  20. ChitChat : making video chat robust to packet loss

    E-Print Network [OSTI]

    Wang, Jue, 1986-

    2010-01-01T23:59:59.000Z

    Video chat is increasingly popular among Internet users (e.g. Skype, Windows Live Messenger, Google Talk). Often, however, chatting sessions suffer from packet loss, which causes video outage and poor quality. Existing ...