Sample records for asian particle accelerator

  1. Accelerating Particles with Plasma

    SciTech Connect (OSTI)

    Litos, Michael; Hogan, Mark

    2014-11-05T23:59:59.000Z

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  2. Entanglement of Accelerating Particles

    E-Print Network [OSTI]

    W. L. Ku; M. -C. Chu

    2007-09-03T23:59:59.000Z

    We study how the entanglement of a maximally entangled pair of particles is affected when one or both of the pair are uniformly accelerated, while the detector remains in an inertial frame. We find that the entanglement is unchanged if all degrees of freedom are considered. However, particle pairs are produced, and the entanglements of different bipartite systems may change with the acceleration. In particular, the entanglement between accelerating fermions is transferred preferentially to the produced antiparticles when the acceleration is large, and the entanglement transfer is complete when the acceleration approaches infinity. However, for scalar particles, no entanglement transfer to the antiparticles is observed.

  3. Charged particle accelerator grating

    DOE Patents [OSTI]

    Palmer, Robert B. (Shoreham, NY)

    1986-01-01T23:59:59.000Z

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  4. Charged particle accelerator grating

    DOE Patents [OSTI]

    Palmer, R.B.

    1985-09-09T23:59:59.000Z

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  5. Particle Acceleration by MHD Turbulence

    E-Print Network [OSTI]

    Jungyeon Cho; A. Lazarian

    2005-10-21T23:59:59.000Z

    Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of particle acceleration. We make use of the recently established scaling of slow and fast MHD modes in strong and weak MHD turbulence to provide a systematic study of particle acceleration in magnetic pressure (low-$\\beta$) and gaseous pressure (high-$\\beta$) dominated plasmas. We consider the acceleration by large scale compressions in both slow and fast particle diffusion limits. We compare the results with the acceleration rate that arises from resonance scattering and Transit-Time Damping (TTD). We establish that fast modes accelerate particles more efficiently than slow modes. We find that particle acceleration by pitch-angle scattering and TTD dominates acceleration by slow or fast modes when the spatial diffusion rate is small. When the rate of spatial diffusion of particles is high, we establish an enhancement of the efficiency of particle acceleration by slow and fast modes in weak turbulence. We show that highly supersonic turbulence is an efficient agent for particle acceleration. We find that even incompressible turbulence can accelerate particles on the scales comparable with the particle mean free path.

  6. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, J.A.; Greenwald, S.

    1989-05-30T23:59:59.000Z

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  7. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

    1989-01-01T23:59:59.000Z

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  8. Particle Acceleration in Astrophysical Sources

    E-Print Network [OSTI]

    Amato, Elena

    2015-01-01T23:59:59.000Z

    Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest accelerators on Earth. Even more compelling evidence comes from the study of Cosmic Rays, charged relativistic particles that reach the Earth with incredibly high energies: at the highest energy end of their spectrum, these subatomic particles are carrying a macroscopic energy, up to a few Joules. Here I will address the best candidate sources and mechanisms as cosmic particle accelerators. I will mainly focus on Galactic sources such as Supernova Remnants and Pulsar Wind Nebulae, which being close and bright, are the best studied among astrophysical accelerators. These sources are held responsible for most of the energy that is put in relativistic particles in the Universe, but they are not thought to accelerate particles up to the highest individual energies, $\\approx 10^{20}$ eV...

  9. Particle Acceleration at Relativistic Shocks

    E-Print Network [OSTI]

    Yves A. Gallant

    2002-01-15T23:59:59.000Z

    I review the current status of Fermi acceleration theory at relativistic shocks. I first discuss the relativistic shock jump conditions, then describe the non-relativistic Fermi mechanism and the differences introduced by relativistic flows. I present numerical calculations of the accelerated particle spectrum, and examine the maximum energy attainable by this process. I briefly consider the minimum energy for Fermi acceleration, and a possible electron pre-acceleration mechanism.

  10. TOPICS IN THE PHYSICS OF PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    IN THE PHYSICS OF PARTICLE ACCELERATORS A.M. Sessler TWO-IN THE PHYSICS OF PARTICLE ACCELERATORS Andrew M. SesslerBruck, "Circular Particle Accelerators," PUF, Paris (1966).

  11. 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

  12. Cosmic Particle Acceleration: Basic Issues

    E-Print Network [OSTI]

    T. W. Jones

    2000-12-22T23:59:59.000Z

    Cosmic-rays are ubiquitous, but their origins are surprisingly difficult to understand. A review is presented of some of the basic issues common to cosmic particle accelerators and arguments leading to the likely importance of diffusive shock acceleration as a general explanation. The basic theory of diffusive shock acceleration is outlined, followed by a discussion of some of the key issues that still prevent us from a full understanding of its outcomes. Some recent insights are mentioned at the end that may help direct ultimate resolution of our uncertainties.

  13. Cooled particle accelerator target

    DOE Patents [OSTI]

    Degtiarenko, Pavel V.

    2005-06-14T23:59:59.000Z

    A novel particle beam target comprising: a rotating target disc mounted on a retainer and thermally coupled to a first array of spaced-apart parallel plate fins that extend radially inwardly from the retainer and mesh without physical contact with a second array of spaced-apart parallel plate fins that extend radially outwardly from and are thermally coupled to a cooling mechanism capable of removing heat from said second array of spaced-apart fins and located within the first array of spaced-apart parallel fins. Radiant thermal exchange between the two arrays of parallel plate fins provides removal of heat from the rotating disc. A method of cooling the rotating target is also described.

  14. Relativistic Shocks: Particle Acceleration and Magnetization

    E-Print Network [OSTI]

    Sironi, Lorenzo; Lemoine, Martin

    2015-01-01T23:59:59.000Z

    We review the physics of relativistic shocks, which are often invoked as the sources of non-thermal particles in pulsar wind nebulae (PWNe), gamma-ray bursts (GRBs), and active galactic nuclei (AGN) jets, and as possible sources of ultra-high energy cosmic-rays. We focus on particle acceleration and magnetic field generation, and describe the recent progress in the field driven by theory advances and by the rapid development of particle-in-cell (PIC) simulations. In weakly magnetized or quasi parallel-shocks (where the magnetic field is nearly aligned with the flow), particle acceleration is efficient. The accelerated particles stream ahead of the shock, where they generate strong magnetic waves which in turn scatter the particles back and forth across the shock, mediating their acceleration. In contrast, in strongly magnetized quasi-perpendicular shocks, the efficiencies of both particle acceleration and magnetic field generation are suppressed. Particle acceleration, when efficient, modifies the turbulence ...

  15. Fermi National Accelerator Laboratory February 2014 Particle...

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

    accelerators to the World Wide Web, and from medical imaging techniques to high-performance computing, the bold and innovative ideas and technologies of particle physics have...

  16. Gerig to Chair Particle Accelerator School Board

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

    2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed Gerig to Chair Particle Accelerator School Board FEBRUARY 23, 2012 Bookmark and Share Rod Gerig (PSC), Deputy...

  17. Particle Acceleration by Electromagnetic-Dominated Outflows

    E-Print Network [OSTI]

    Edison Liang; Koichi Noguchi

    2006-04-19T23:59:59.000Z

    We review recent developments in particle acceleration by Poynting flux using plasma kinetic simulations, and discuss their potential applications to gamma-ray burst phenomenology

  18. Particle acceleration efficiencies in astrophysical shear flows

    E-Print Network [OSTI]

    F. M. Rieger; P. Duffy

    2005-02-04T23:59:59.000Z

    The acceleration of energetic particles in astrophysical shear flows is analyzed. We show that in the presence of a non-relativistic gradual velocity shear, power law particle momentum distributions $f(p) \\propto p^{-(3+\\alpha)}$ may be generated, assuming a momentum-dependent scattering time $\\tau \\propto p^{\\alpha}$, with $\\alpha > 0$. We consider possible acceleration sites in astrophysical jets and study the conditions for efficient acceleration. It is shown, for example, that in the presence of a gradual shear flow and a gyro-dependent particle mean free path, synchrotron radiation losses no longer stop the acceleration once it has started to work efficiently. This suggests that shear acceleration may naturally account for a second, non-thermal population of energetic particles in addition to a shock-accelerated one. The possible relevance of shear acceleration is briefly discussed with reference to the relativistic jet in the quasar 3C 273.

  19. Fermilab | Science | Particle Accelerators | Fermilab's Accelerator Complex

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

    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 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator Complex photo

  20. Fermilab | Science | Particle Accelerators | Leading Accelerator Technology

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

    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 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator ComplexLeading

  1. Particle accelerator employing transient space charge potentials

    DOE Patents [OSTI]

    Post, Richard F. (Walnut Creek, CA)

    1990-01-01T23:59:59.000Z

    The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles.

  2. Feature-based Analysis of Plasma-based Particle Acceleration Data

    E-Print Network [OSTI]

    Ruebel, Oliver

    2014-01-01T23:59:59.000Z

    Abstract Plasma-based particle accelerators can produce andconventional particle accelerators, providing a potentialcost of conventional particle accelerators. To facilitate

  3. COLLIMATING TOUSCHEK PARTICLES IN AN ENERGY RECOVERY LINEAR ACCELERATOR

    E-Print Network [OSTI]

    Hoffstaetter, Georg

    COLLIMATING TOUSCHEK PARTICLES IN AN ENERGY RECOVERY LINEAR ACCELERATOR Michael P. Ehrlichman- tum would usually be inconsequential to the trajectory of the particles through the accelerator to longitudinal momentum significant to the trajec- tory of scattered particles through the accelerator

  4. LONGITUDINAL RESISTIVE INSTABILITIES OF INTENSE COASTING BEAMS IN PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Neil, V. Kelvin

    2008-01-01T23:59:59.000Z

    COASTING BEAMS IN PARTICLE ACCELERATORS TWO-WEEK LOAN COpyCOASTING BEAMS IN PARTICLE ACCELERATORS v. Kelyin Neil andCOASTING BEAt\\1S nr PARTICLE ACCELERATORS* V. Kelvin Neil

  5. Acceleration statistics of heavy particles in turbulence

    E-Print Network [OSTI]

    J. Bec; L. Biferale; G. Boffetta; A. Celani; M. Cencini; A. Lanotte; S. Musacchio; F. Toschi

    2005-12-09T23:59:59.000Z

    We present the results of direct numerical simulations of heavy particle transport in homogeneous, isotropic, fully developed turbulence, up to resolution $512^3$ ($R_\\lambda\\approx 185$). Following the trajectories of up to 120 million particles with Stokes numbers, $St$, in the range from 0.16 to 3.5 we are able to characterize in full detail the statistics of particle acceleration. We show that: ({\\it i}) The root-mean-squared acceleration $a_{\\rm rms}$ sharply falls off from the fluid tracer value already at quite small Stokes numbers; ({\\it ii}) At a given $St$ the normalised acceleration $a_{\\rm rms}/(\\epsilon^3/\

  6. Particle acceleration in electron-ion jets

    E-Print Network [OSTI]

    K. -I. Nishikawa; P. Hardee; C. B. Hededal; G. Richardson; R. Preece; H. Sol; G. J. Fishman; C. Kouvelioutou; Y. Mizuno

    2005-09-20T23:59:59.000Z

    Weibel instability created in collisionless shocks is responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic electron-ion jet fronts propagating into an ambient plasma without initial magnetic fields with a longer simulation system in order to investigate nonlinear stage of the Weibel instability and its acceleration mechanism. The current channels generated by the Weibel instability induce the radial electric fields. The z component of the Poynting vector (E x B) become positive in the large region along the jet propagation direction. This leads to the acceleration of jet electrons along the jet. In particular the E x B drift with the large scale current channel generated by the ion Weibel instability accelerate electrons effectively in both parallel and perpendicular directions.

  7. International Particle Accelerator Community Prepares for May...

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

    International Particle Accelerator Community Prepares for May 3-8 Gathering in Richmond NEWPORT NEWS, VA - April 29, 2015 - Scientists, engineers and students from across U.S. and...

  8. Twisted waveguides for particle accelerator applications

    E-Print Network [OSTI]

    Wilson, Joshua L.

    A novel microwave device for accelerating charged particles based on twisted waveguide is presented. Twisted guides support slow-wave TM modes whose phase velocity could reach the speed of light c. The axial electric field ...

  9. Acceleration of trapped particles and beams

    E-Print Network [OSTI]

    Er'el Granot; Boris Malomed

    2011-07-30T23:59:59.000Z

    The dynamics of a quantum particle bound by an accelerating delta-functional potential is investigated. Three cases are considered, using the reference frame moving along with the {\\delta}-function, in which the acceleration is converted into the additional linear potential. (i) A stationary regime, which corresponds to a resonance state, with a minimum degree of delocalization, supported by the accelerating potential trap. (ii) A pulling scenario: an initially bound particle follows the accelerating delta-functional trap, within a finite time. (iii) The pushing scenario: the particle, which was initially localized to the right of the repulsive delta-function, is shoved to the right by the accelerating potential. For the two latter scenarios, the life time of the trapped particle, and the largest velocity to which it can be accelerated while staying trapped, are found. Analytical approximations are developed for the cases of small and large accelerations in the pulling regime, and also for a small acceleration in the stationary situation, and in the regime of pushing. The same regimes may be realized by Airy-like planar optical beams guided by a narrow bending potential channel or crest. Physical estimates are given for an atom steered by a stylus of a scanning tunneling microscope (STM), and for the optical beam guided by a bending stripe.

  10. Non-accelerator Particle Physics

    E-Print Network [OSTI]

    Wechsler, Risa H.

    · Surface science: Prof Gratta #12;Sept 16, 09 Grad Sudent Orientation: Non Accel Particle Physics 4;Sept 16, 09 Grad Sudent Orientation: Non Accel Particle Physics 5 Composition of the Cosmos WIMPs WMAP best fit #12;Sept 16, 09 Grad Sudent Orientation: Non Accel Particle Physics 6 What is the dark matter

  11. Superconducting Magnets for Particle Accelerators

    E-Print Network [OSTI]

    Rossi, L

    2012-01-01T23:59:59.000Z

    Superconductivity has been the most influential technology in the field of accelerators in the last 30 years. Since the commissioning of the Tevatron, which demonstrated the use and operability of superconductivity on a large scale, superconducting magnets and rf cavities have been at the heart of all new large accelerators. Superconducting magnets have been the invariable choice for large colliders, as well as cyclotrons and large synchrotrons. In spite of the long history of success, superconductivity remains a difficult technology, requires adequate R&D and suitable preparation, and has a relatively high cost. Hence, it is not surprising that the development has also been marked by a few setbacks. This article is a review of the main superconducting accelerator magnet projects; it highlights the main characteristics and main achievements, and gives a perspective on the development of superconducting magnets for the future generation of very high energy colliders.

  12. A Maxwellian Perspective on Particle Acceleration

    E-Print Network [OSTI]

    McDonald, Kirk

    A Maxwellian Perspective on Particle Acceleration K.T. McDonald Princeton U. (with Max Zolotorev, LBNL) March 31, 1998 http://puhep1.princeton.edu/~mcdonald/accel/ 1 #12;The Newtonian View A charge e and B change the particle's momentum, but only E can change it's energy. Integrate equation of motion

  13. A Maxwellian Perspective on Particle Acceleration

    E-Print Network [OSTI]

    McDonald, Kirk

    A Maxwellian Perspective on Particle Acceleration K.T. McDonald Princeton U. (with Max Zolotorev, LBNL) March 31, 1998 http://puhep1.princeton.edu/~mcdonald/accel/ 1 #12; The Newtonian View A charge e): ) Both E and B change the particle's momentum, but only E can change it's energy. ) Integrate equation

  14. A Maxwellian Perspective on Particle Acceleration

    E-Print Network [OSTI]

    McDonald, Kirk

    A Maxwellian Perspective on Particle Acceleration K.T. McDonald Princeton U. (with Max Zolotorev, LBNL) April 19, 1998 http://puhep1.princeton.edu/~mcdonald/accel/ 1 #12;The Newtonian View A charge e and B change the particle's momentum, but only E can change it's energy. Integrate equation of motion

  15. A Maxwellian Perspective on Particle Acceleration

    E-Print Network [OSTI]

    McDonald, Kirk

    A Maxwellian Perspective on Particle Acceleration K.T. McDonald Princeton U. (with Max Zolotorev, LBNL) April 19, 1998 http://puhep1.princeton.edu/~mcdonald/accel/ 1 #12; The Newtonian View A charge e): ) Both E and B change the particle's momentum, but only E can change it's energy. ) Integrate equation

  16. Nonlinear Particle Acceleration in Relativistic Shocks

    E-Print Network [OSTI]

    Donald C. Ellison; Glen P. Double

    2002-04-22T23:59:59.000Z

    Monte Carlo techniques are used to model nonlinear particle acceleration in parallel collisionless shocks of various speeds, including mildly relativistic ones. When the acceleration is efficient, the backreaction of accelerated particles modifies the shock structure and causes the compression ratio, r, to increase above test-particle values. Modified shocks with Lorentz factors less than about 3 can have compression ratios considerably greater than 3 and the momentum distribution of energetic particles no longer follows a power law relation. These results may be important for the interpretation of gamma-ray bursts if mildly relativistic internal and/or afterglow shocks play an important role accelerating particles that produce the observed radiation. For shock Lorentz factors greater than about 10, r approaches 3 and the so-called `universal' test-particle result of N(E) proportional to E^{-2.3} is obtained for sufficiently energetic particles. In all cases, the absolute normalization of the particle distribution follows directly from our model assumptions and is explicitly determined.

  17. Particle acceleration in astrophysical shear flows

    E-Print Network [OSTI]

    Frank M. Rieger; Peter Duffy

    2005-01-10T23:59:59.000Z

    We consider the acceleration of particles due to a velocity shear in relativistic astrophysical flows. The basic physical picture and the formation of power law momentum spectra is discussed for a non-relativistic velocity field using a microscopic approach. We identify possible sites for shear acceleration in relativistic astrophysical jets and analyze their associated acceleration timescales. It is shown in particular that for a mean scattering time $\\tau$ scaling with the gyro-radius, the acceleration timescale for gradual shear scales in the same manner as the synchrotron cooling timescale, so that losses may no longer be able to stop the acceleration once it has started to work efficiently. Finally, the possible role of shear acceleration is discussed with reference to the relativistic jet in the quasar 3C~273.

  18. Machine Protection: Availability for Particle Accelerators

    E-Print Network [OSTI]

    Apollonio, Andrea; Schmidt, Ruediger

    2015-03-16T23:59:59.000Z

    Machine availability is a key indicator for the performance of the next generation of particle accelerators. Availability requirements need to be carefully considered during the design phase to achieve challenging objectives in different fields, as e.g. particle physics and material science. For existing and future High-Power facilities, such as ESS (European Spallation Source) and HL-LHC (High-Luminosity LHC), operation with unprecedented beam power requires highly dependable Machine Protection Systems (MPS) to avoid any damage-induced downtime. Due to the high complexity of accelerator systems, finding the optimal balance between equipment safety and accelerator availability is challenging. The MPS architecture, as well as the choice of electronic components, have a large influence on the achievable level of availability. In this thesis novel methods to address the availability of accelerators and their protection systems are presented. Examples of studies related to dependable MPS architectures are given i...

  19. Particle Acceleration at High-$?$ Shock Waves

    E-Print Network [OSTI]

    Jacek Niemiec

    2005-09-22T23:59:59.000Z

    First-order Fermi acceleration processes at ultrarelativistic shocks are studied with Monte Carlo simulations. The accelerated particle spectra are obtained by integrating the exact particle trajectories in a turbulent magnetic field near the shock, with a few ``realistic'' features of the field structure included. We show that the main acceleration process at oblique shocks is the particle compression at the shock. Formation of energetic spectral tails is possible in a limited energy range for highly perturbed magnetic fields. Cut-offs in the spectra occur at low energies in the resonance range considered. We relate this feature to the structure of the magnetic field downstream of the shock, where field compression produces effectively 2D turbulence in which cross-field diffusion is very small. Because of the field compression downstream, the acceleration process is inefficient also in parallel high-$\\gamma$ shocks for larger turbulence amplitudes, and features observed in oblique shocks are recovered. For small-amplitude perturbations, particle spectra are formed in a wide energy range and modifications of the acceleration process due to the existence of long-wave perturbations are observed. The critical turbulence amplitude for efficient acceleration at parallel shocks decreases with shock Lorentz factor. We also study the influence of strong short-wave perturbations downstream of the shock on the particle acceleration processes. The spectral indices obtained do not converge to the ``universal'' value . Our results indicate inefficiency of the first-order Fermi process to generate high-energy cosmic rays at ultrarelativistic shocks with the considered perturbed magnetic field structures.

  20. 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

  1. Energetic particle acceleration in shear layers

    E-Print Network [OSTI]

    M. Ostrowski

    1999-11-05T23:59:59.000Z

    A plasma velocity shear layer and/or a tangential flow discontinuity provide conditions allowing for energetic particle acceleration. We review such acceleration processes acting both in non-relativistic and in relativistic flows. In heliospheric conditions shear layers can provide particles with energies compatible with the observed values (from several keV up to MeV), while in relativistic extragalactic jets proton energies even in excess of 10^{19} eV can be obtained. Application of the discussed theory to particular astrophysical objects is severely limited by inadequate knowledge of local physical conditions.

  2. Stochastic Particle Acceleration in Parallel Relativistic Shocks

    E-Print Network [OSTI]

    Joni J. P. Virtanen; Rami Vainio

    2005-03-03T23:59:59.000Z

    We present results of test-particle simulations on both the first- and the second-order Fermi acceleration for relativistic parallel shock waves. Our studies suggest that the role of the second-order mechanism in the turbulent downstream of a relativistic shock may have been underestimated in the past, and that the stochastic mechanism may have significant effects on the form of the particle spectra and its time evolution.

  3. Automatic beam path analysis of laser wakefield particle acceleration data

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Automatic beam path analysis of laser wakefield particle acceleration data Oliver Rübel1 particle accelerators play a key role in the understanding of the complex acceleration process in a pipeline fashion to automatically locate and analyze high-energy particle bunches undergoing acceleration

  4. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Knowles, David William

    Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data Oliver R¨ubel1 particle accelerators play a key role in the understanding of the complex acceleration process in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration

  5. US Particle Accelerator School Cyclotrons: Old but Still New

    E-Print Network [OSTI]

    Dai, Pengcheng

    US Particle Accelerator School Cyclotrons: Old but Still New The history of accelerators is a history of inventions William A. Barletta Director, US Particle Accelerator School Dept. of Physics, MIT Economics Faculty, University of Ljubljana #12;US Particle Accelerator School ~ 650 cyclotrons operating

  6. Test particle acceleration by rotating jet magnetospheres

    E-Print Network [OSTI]

    F. M. Rieger; K. Mannheim

    2000-11-01T23:59:59.000Z

    Centrifugal acceleration of charged test particles at the base of a rotating jet magnetosphere is considered. Based on an analysis of forces we derive the equation for the radial accelerated motion and present an analytical solution. It is shown that for particles moving outwards along rotating magnetic field lines, the energy gain is in particular limited by the breakdown of the bead-on-the-wire approximation which occurs in the vicinity of the light cylinder $r_{L}$. The corresponding upper limit for the maximum Lorentz factor $\\gamma_{max}$ for electrons scales $\\propto B^{2/3} r_{L}^{2/3}$, with $B$ the magnetic field strength at $r_{L}$, and is at most of the order of a $10^2-10^3$ for the conditions regarded to be typical for BL Lac objects. Such values suggest that this mechanism may provide pre-accelerated seed particles which are required for efficient Fermi-type particle acceleration at larger scales in radio jets.

  7. Seventy Five Years of Particle Accelerators

    ScienceCinema (OSTI)

    Andy Sessler

    2013-06-11T23:59:59.000Z

    Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe. His talk was presented July 26, 2006.

  8. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    E-Print Network [OSTI]

    Geddes, Cameron G.R.

    2010-01-01T23:59:59.000Z

    of high- gradient, laser plasma particle accelerators.accelerators that use laser-driven plasma waves. Theseleft) showing the laser (red), plasma wake density (purple-

  9. Non-accelerator particle physics

    SciTech Connect (OSTI)

    Steinberg, R.I.; Lane, C.E.

    1991-09-01T23:59:59.000Z

    The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos: the {nu}IMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiment using a kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments. 21 refs., 19 figs., 6 tabs.

  10. RFQ device for accelerating particles

    DOE Patents [OSTI]

    Shepard, K.W.; Delayen, J.R.

    1995-06-06T23:59:59.000Z

    A superconducting radio frequency quadrupole (RFQ) device includes four spaced elongated, linear, tubular rods disposed parallel to a charged particle beam axis, with each rod supported by two spaced tubular posts oriented radially with respect to the beam axis. The rod and post geometry of the device has four-fold rotation symmetry, lowers the frequency of the quadrupole mode below that of the dipole mode, and provides large dipole-quadrupole mode isolation to accommodate a range of mechanical tolerances. The simplicity of the geometry of the structure, which can be formed by joining eight simple T-sections, provides a high degree of mechanical stability, is insensitive to mechanical displacement, and is particularly adapted for fabrication with superconducting materials such as niobium. 5 figs.

  11. 9/16/2009 Andy Haas Stanford Student Orientation: Accelerator based Particle Physics 1 Accelerator-based Particle Physics

    E-Print Network [OSTI]

    Wechsler, Risa H.

    9/16/2009 Andy Haas Stanford Student Orientation: Accelerator based Particle Physics 1 Accelerator, 2009 #12;9/16/2009 Andy Haas Stanford Student Orientation: Accelerator based Particle Physics 2 Stanford Student Orientation: Accelerator based Particle Physics 5 Super B (to be built near Frascati lab

  12. Particle acceleration at perpendicular shock waves: Model and observations

    E-Print Network [OSTI]

    Sanahuja, Blai

    Particle acceleration at perpendicular shock waves: Model and observations G. P. Zank,1 Gang Li,1 V the transport of energetic particles, we construct a model for diffusive particle acceleration at highly excitation at quasiparallel shocks in evaluating the particle acceleration timescale ensures

  13. Particles accelerate the detachment of viscous liquids

    E-Print Network [OSTI]

    Merlijn S. van Deen; Thibault Bertrand; Nhung Vu; David Quéré; Eric Clément; Anke Lindner

    2013-01-31T23:59:59.000Z

    During detachment of a viscous fluid extruded from a nozzle a filament linking the droplet to the latter is formed. Under the effect of surface tension the filament thins until pinch off and final detachment of the droplet. In this paper we study the effect of the presence of individual particles trapped in the filament on the detachment dynamics using granular suspensions of small volume fractions ({\\phi} particle strongly modifies the detachment dynamics. The particle perturbs the thinning of the thread and a large droplet of fluid around the particle is formed. This perturbation leads to an acceleration of the detachment of the droplet compared to the detachment ob- served for a pure fluid. We quantify this acceleration for single particles of different sizes and link it to similar ob- servations for suspensions of small volume fractions. Our study also gives more insight into particulate effects on de- tachment of more dense suspensions and allows to explain the accelerated detachment close to final pinch off observed previously (Bonnoit et al 2012)

  14. On particle acceleration around shocks. I

    E-Print Network [OSTI]

    Mario Vietri

    2003-03-28T23:59:59.000Z

    We derive a relativistically covariant (although not manifestly so) equation for the distribution function of particles accelerated at shocks, which applies also to extremely relativistic shocks, and arbitrarily anisotropic particle distributions. The theory is formulated for arbitrary pitch angle scattering, and reduces to the well--known case for small angle scatterings via a Fokker--Planck approximation. The boundary conditions for the problem are completely reformulated introducing a physically motivated Green's function; the new formulation allows derivation of the particle spectrum both close and far away from the injection energy in an exact way, while it can be shown to reduce to a power--law at large particle energies. The particle spectral index is also recovered in a novel way. Contact is made with the Newtonian treatment.

  15. Self force on an accelerated particle

    E-Print Network [OSTI]

    Thomas M. Linz; John L. Friedman; Alan G. Wiseman

    2014-04-28T23:59:59.000Z

    We calculate the singular field of an accelerated point particle (scalar charge, electric charge or small gravitating mass) moving on an accelerated (non-geodesic) trajectory in a generic background spacetime. Using a mode-sum regularization scheme, we obtain explicit expressions for the self-force regularization parameters. In the electromagnetic and gravitational case, we use a Lorenz gauge. This work extends the work of Barack and Ori [1] who demonstrated that the regularization parameters for a point particle in geodesic motion in a Schwarzschild spacetime can be described solely by the leading and subleading terms in the mode-sum (commonly known as the $A$ and $B$ terms) and that all terms of higher order in $\\ell$ vanish upon summation (later they showed the same behavior for geodesic motion in Kerr [2], [3]). We demonstrate that these properties are universal to point particles moving through any smooth spacetime along arbitrary (accelerated) trajectories. Our renormalization scheme is based on, but not identical to, the Quinn-Wald axioms. As we develop our approach, we review and extend work showing that that different definitions of the singular field used in the literature are equivalent to our approach. Because our approach does not assume geodesic motion of the perturbing particle, we are able use our mode-sum formalism to explicitly recover a well-known result: The self-force on static scalar charges near a Schwarzschild black hole vanishes.

  16. uge particle accelerators have been at the vanguard of research in particle

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    H uge particle accelerators have been at the vanguard of research in particle physics for more than counterparts, positrons, can then `surf' the electric field of a wave's wake. Particles have been accelerated accelerator, charged particles such as electrons, protons or their antiparticles are accelerated by an alterna

  17. Neutron Sciences Staff Give Back, Teach US Particle Accelerator...

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

    Neutron Sciences Staff Give Back, Teach US Particle Accelerator School Courses Katie Bethea - March 13, 2014 Neutron Science Directorate staff hosted students from the US Particle...

  18. Channeled particle acceleration by plasma waves in metals

    SciTech Connect (OSTI)

    Chen, P.; Noble, R.J.

    1987-01-01T23:59:59.000Z

    A solid state accelerator concept utilizing particle acceleration along crystal channels by longitudinal electron plasma waves in a metal is presented. Acceleration gradients of order 100 GV/cm are theoretically possible. Particle dechanneling due to electron multiple scattering can be eliminated with a sufficiently high acceleration gradient. Plasma wave dissipation and generation in metals are also discussed.

  19. Jacobi equations and particle accelerator beam dynamics

    E-Print Network [OSTI]

    Ricardo Gallego Torrome

    2012-03-27T23:59:59.000Z

    A geometric formulation of the linear beam dynamics in accelerator physics is presented. In particular, it is proved that the linear transverse and longitudinal dynamics can be interpret geometrically as an approximation to the Jacobi equation of an affine averaged Lorentz connection. We introduce a specific notion reference trajectory as integral curves of the main velocity vector field. A perturbation caused by the statistical nature of the bunch of particles is considered.

  20. FASTBUS for the particle accelerator laboratories

    SciTech Connect (OSTI)

    Dawson, W.K.; Costrell, L.; Ikeda, H.; Ponting, P.J.; Walz, H.V.

    1985-05-01T23:59:59.000Z

    The FASTBUS modular high speed data acquisition and control system for high energy physics and other applications was described by Costrell and Dawson at the 1983 Particle Accelerator Conference. Both the specification and the implementation of this interlaboratory development have progressed considerably since that time. Because of its many attractive features, FASTBUS is currently in use in several major nuclear and high energy physics laboratories and is also finding application in other areas. 10 refs.

  1. Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics

    E-Print Network [OSTI]

    Zisman, Michael S.

    2008-01-01T23:59:59.000Z

    of 2006 European Particle Accelerator Conf. , Edinburgh,Proc. 1992 European Particle Accelerator Conference, Berlin,in Proc. 2007 Particle Accelerator Conf. , Albuquerque, June

  2. Query-driven Analysis of Plasma-based Particle Acceleration Data

    E-Print Network [OSTI]

    Ruebel, Oliver

    2014-01-01T23:59:59.000Z

    A BSTRACT Plasma-based particle accelerators can produce andof conventional particle accelerators. There is a pressingplasma-based particle accelerator designs. To address this

  3. Advanced Visualization Technology for Terascale Particle Accelerator Simulations

    E-Print Network [OSTI]

    Ma, Kwan-Liu

    Advanced Visualization Technology for Terascale Particle Accelerator Simulations Kwan-Liu Ma £ Greg-performance computing, particle accelerators, perception, point-based rendering, scientific visualization, field lines Introduction Particle accelerators have helped enable some of the most remarkable discoveries of the 20th

  4. 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

  5. PARTICLE ACCELERATION AT THE SUN AND IN THE HELIOSPHERE

    E-Print Network [OSTI]

    Reames, Donald V.

    PARTICLE ACCELERATION AT THE SUN AND IN THE HELIOSPHERE DONALD V. REAMES NASA/ Goddard Space Flight) Abstract. Energetic particles are accelerated in rich profusion at sites throughout the heliosphere. Printed in the Netherlands. #12;414 PARTICLE ACCELERATION AT THE SUN AND IN THE HELIOSPHERE 4. Impulsive

  6. 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

  7. Accelerated Particle Electrophoretic Motion and Separation in Converging-Diverging

    E-Print Network [OSTI]

    Xuan, Xiangchun "Schwann"

    Accelerated Particle Electrophoretic Motion and Separation in Converging-Diverging Microchannels of Toronto, 5 King's College Road, Toronto, Ontario, Canada M5S 3G8 Accelerated particle electrophoretic. The accelerated particle elec- trophoretic separation is highly desirable in on-chip flow cytometry and high

  8. Don Melrose Particle Acceleration and Nonthermal Radiation in

    E-Print Network [OSTI]

    Melrose, Don

    Don Melrose #12;Particle Acceleration and Nonthermal Radiation in Space Plasmas D.B. Melrose maser emission fi-om planets and stars. Key words: Acceleration of particles, plasma emission, electron mechanism is ' a process that increases the energy of nonthermal particles. Several different acceleration

  9. Microwaves and particle accelerators: a fundamental link

    SciTech Connect (OSTI)

    Chattopadhyay, Swapan [Universities of Lancaster, Liverpool and Manchester and Cockcroft Institute, Cheshire (United Kingdom)

    2011-07-01T23:59:59.000Z

    John Cockcroft's splitting of the atom and Ernest Lawrence's invention of the cyclotron in the first half of the twentieth century ushered in the grand era of ever higher energy particle accelerators to probe deeper into matter. It also forged a link, bonding scientific discovery with technological innovation that continues today in the twenty first century. The development of radar and high power vacuum electronics, especially microwave power tubes like the magnetrons and the klystrons in the pre-second world war era, was instrumental in the rapid development of circular and linear charged particle accelerators in the second half of the twentieth century. We had harnessed the powerful microwave radio-frequency sources from few tens of MHz to up to 90 GHz spanning L-band to W-band frequencies. Simultaneously in the second half of the twentieth century, lasers began to offer very first opportunities of controlling charged particles at smaller resolutions on the scale of wavelengths of visible light. We also witnessed in this period the emergence of the photon and neutron sciences driven by accelerators built-by-design producing tailored and ultra-bright pulses of bright photons and neutrons to probe structure and function of matter from aggregate to individual molecular and atomic scales in unexplored territories in material and life sciences. As we enter the twenty first century, the race for ever higher energies, brightness and luminosity to probe atto-metric and atto-second domains of the ultra-small structures and ultra-fast processes continues. These developments depend crucially on yet further advancements in the production and control of high power and high frequency microwaves and light sources, often intricately coupled in their operation to the high energy beams themselves. We give a glimpse of the recent developments and innovations in the electromagnetic production and control of charged particle beams in the service of science and society. (author)

  10. Particle Acceleration by a Short-Intense Elliptically Polarized Electromagnetic

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Particle Acceleration by a Short-Intense Elliptically Polarized Electromagnetic Pulse Propagating to plasma physics and particle accelerators. The interaction physics of fields with particles has also been, Colchester CO4 3SQ, U.K. Abstract. The motion of a charged particle driven by an electromagnetic pulse

  11. TOPICS IN THE PHYSICS OF PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    their whole lives to accelerator physics. As high energysome appreciation of accelerator physics. We cannot, nor dolectures on basic accelerator physics; then you will hear

  12. PRODUCTION AND APPLICATIONS OF NEUTRONS USING PARTICLE ACCELERATORS

    SciTech Connect (OSTI)

    David L. Chichester

    2009-11-01T23:59:59.000Z

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  13. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre and astroparticle physics as well as accelerator physics. The theoretical astroparticle physics group at DESY has processes Requirements · Ph.D. in physics or astronomy · Experience with modeling of particle acceleration

  14. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre as accelerator physics. DESY develops, runs and uses accelerators and detectors for the investigati of the Helmholtz Association PARTICLE PHYSICS· DESY has openings for: DESY-Fellowships (f/m) DESY DESY is one

  15. Laser wakefield simulations towards development of compact particle accelerators

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Laser wakefield simulations towards development of compact particle accelerators C.G.R. Geddes1, D understanding of accelerator physics to advance beam performance and stability, and particle simulations model, France; 9 Oxford University, UK E-mail: cgrgeddes@lbl.gov Abstract. Laser driven wakefield accelerators

  16. Model-independent particle accelerator tuning

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Scheinker, Alexander; Pang, Xiaoying; Rybarcyk, Larry

    2013-10-01T23:59:59.000Z

    We present a new model-independent dynamic feedback technique, rotation rate tuning, for automatically and simultaneously tuning coupled components of uncertain, complex systems. The main advantages of the method are: 1) It has the ability to handle unknown, time-varying systems, 2) It gives known bounds on parameter update rates, 3) We give an analytic proof of its convergence and its stability, and 4) It has a simple digital implementation through a control system such as the Experimental Physics and Industrial Control System (EPICS). Because this technique is model independent it may be useful as a real-time, in-hardware, feedback-based optimization scheme formore »uncertain and time-varying systems. In particular, it is robust enough to handle uncertainty due to coupling, thermal cycling, misalignments, and manufacturing imperfections. As a result, it may be used as a fine-tuning supplement for existing accelerator tuning/control schemes. We present multi-particle simulation results demonstrating the scheme’s ability to simultaneously adaptively adjust the set points of twenty two quadrupole magnets and two RF buncher cavities in the Los Alamos Neutron Science Center (LANSCE) Linear Accelerator’s transport region, while the beam properties and RF phase shift are continuously varying. The tuning is based only on beam current readings, without knowledge of particle dynamics. We also present an outline of how to implement this general scheme in software for optimization, and in hardware for feedback-based control/tuning, for a wide range of systems.« less

  17. Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

    E-Print Network [OSTI]

    Barnard, J.J.

    2008-01-01T23:59:59.000Z

    Wiedermann, Particle Accelerator Physics, Springer-Verlag (invariants applied to accelerator physics. Remains one ofWiedemann, Particle Accelerator Physics II: Nonlinear and

  18. Surfatron acceleration of a relativistic particle by electromagnetic plane wave

    E-Print Network [OSTI]

    A. I. Neishtadt; A. A. Vasiliev; A. V. Artemyev

    2010-11-09T23:59:59.000Z

    We study motion of a relativistic charged particle in a plane slow electromagnetic wave and background uniform magnetic field. The wave propagates normally to the background field. Under certain conditions, the resonance between the wave and the Larmor motion of the particle is possible. Capture into this resonance results in acceleration of the particle along the wave front (surfatron acceleration). We analyse the phenomenon of capture and show that a captured particle never leaves the resonance and its energy infinitely grows. Scattering on the resonance is also studied. We find that this scattering results in diffusive growth of the particle energy. Finally, we estimate energy losses due to radiation by an accelerated particle.

  19. Turbulent Particle Acceleration in the Diffuse Cluster Plasma

    E-Print Network [OSTI]

    J. A. Eilek; J. C. Weatherall

    1999-06-30T23:59:59.000Z

    In situ particle acceleration is probably occuring in cluster radio haloes. This is suggested by the uniformity and extent of the haloes, given that spatial diffusion is slow and that radiative losses limit particle lifetimes. Stochastic acceleration by plasma turbulence is the most likely mechanism. Alfven wave turbulence has been suggested as the means of acceleration, but it is too slow to be important in the cluster environment. We propose, instead, that acceleration occurs via strong lower-hybrid wave turbulence. We find that particle acceleration will be effective in clusters if only a small fraction of the cluster energy density is in this form.

  20. Accelerating universes driven by bulk particles

    SciTech Connect (OSTI)

    Brito, F.A. [Departamento de Fisica, Universidade Federal de Campina Grande, 58109-970 Campina Grande, Paraiba (Brazil); Cruz, F.F.; Oliveira, J.F.N. [Departamento de Matematica, Universidade Regional do Cariri, 63040-000 Juazeiro do Norte, Ceara (Brazil)

    2005-04-15T23:59:59.000Z

    We consider our universe as a 3d domain wall embedded in a 5d dimensional Minkowski space-time. We address the problem of inflation and late time acceleration driven by bulk particles colliding with the 3d domain wall. The expansion of our universe is mainly related to these bulk particles. Since our universe tends to be permeated by a large number of isolated structures, as temperature diminishes with the expansion, we model our universe with a 3d domain wall with increasing internal structures. These structures could be unstable 2d domain walls evolving to fermi-balls which are candidates to cold dark matter. The momentum transfer of bulk particles colliding with the 3d domain wall is related to the reflection coefficient. We show a nontrivial dependence of the reflection coefficient with the number of internal dark matter structures inside the 3d domain wall. As the population of such structures increases the velocity of the domain wall expansion also increases. The expansion is exponential at early times and polynomial at late times. We connect this picture with string/M-theory by considering BPS 3d domain walls with structures which can appear through the bosonic sector of a five-dimensional supergravity theory.

  1. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre of the Helmholtz Association ACCELERATOR PHYSICS· DESY, Hamburg location, is seeking: Scientist (f/m) (tenure and astroparticle physics as well as accelerator physics. DESY operates the world's brightest storage-ring-based X

  2. Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration in Plasma Channels C for the first time in a high gradient laser wakefield accelerator by guiding the drive laser pulse. Channels formed by hydrodynamic shock were used to guide acceleration relevant laser intensities of at least 1E18

  3. Particle Acceleration in Rotating Modified Hayward and Bardeen Black Holes

    E-Print Network [OSTI]

    Behnam Pourhassan; Ujjal Debnath

    2015-06-10T23:59:59.000Z

    In this paper we consider rotating modified Hayward and Bardeen black holes as particle accelerators. We investigate the the center of mass energy of two colliding neutral particles with same rest masses falling from rest at infinity to near the horizons of the mentioned black holes. We also investigate the range of the particle's angular momentum and the orbit of the particle.

  4. Particle Acceleration in Rotating Modified Hayward and Bardeen Black Holes

    E-Print Network [OSTI]

    Pourhassan, Behnam

    2015-01-01T23:59:59.000Z

    In this paper we consider rotating modified Hayward and Bardeen black holes as particle accelerators. We investigate the the center of mass energy of two colliding neutral particles with same rest masses falling from rest at infinity to near the horizons of the mentioned black holes. We also investigate the range of the particle's angular momentum and the orbit of the particle.

  5. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre/m) Accelerator Research DESY DESY is one of the world's leading research centres for photon science, particle with universities. The DESY focus is on conventional and plasma-based accele- rators with applications in photon

  6. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre develops, builds and operates large accelerator facilities for photon science and particle physics of the Helmholtz Association ASTROPARTICLE PHYSICS· DESY, Zeuthen location, is seeking: Scientist (f/m) DESY DESY

  7. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research CentreD-Students (f/m) DESY DESY is one of the world's leading research centres for photon science, particle and astroparticle physics as well as accelerator physics. The Photo Injector Test Facility PITZ in Zeuthen (near

  8. Acceleration of low energy charged particles by gravitational waves

    E-Print Network [OSTI]

    G. Voyatzis; L. Vlahos; S. Ichtiaroglou; D. Papadopoulos

    2005-12-07T23:59:59.000Z

    The acceleration of charged particles in the presence of a magnetic field and gravitational waves is under consideration. It is shown that the weak gravitational waves can cause the acceleration of low energy particles under appropriate conditions. Such conditions may be satisfied close to the source of the gravitational waves if the magnetized plasma is in a turbulent state.

  9. Applications of pyroelectric particle accelerators Jeffrey A. Geuther, Yaron Danon *

    E-Print Network [OSTI]

    Danon, Yaron

    Applications of pyroelectric particle accelerators Jeffrey A. Geuther, Yaron Danon * Rensselaer mounted to the crystal. By using the combined fields of two polarized crystals, the acceleration potential can be doubled, with one crystal acting as a particle emitter and the other crys- tal serving

  10. Iron Speciation and Mixing in Single Aerosol Particles from the Asian Continental Outflow

    SciTech Connect (OSTI)

    Moffet, Ryan C.; Furutani, Hiroshi; Rodel, Tobias; Henn, Tobias R.; Sprau, Peter; Laskin, Alexander; Uematsu, Mitsuo; Gilles, Marry K.

    2012-04-04T23:59:59.000Z

    Bioavailable iron from atmospheric aerosol is an essential nutrient that can control oceanic productivity, thereby impacting the global carbon budget and climate. Particles collected on Okinawa Island during an atmospheric pollution transport event from China were analyzed using complementary single particle techniques to determine the iron source and speciation. Comparing the spatial distribution of iron within ambient particles and standard Asian mineral dust, it was determined that field-collected atmospheric Fe-containing particles have numerous sources, including anthropogenic sources such as coal combustion. Fe-containing particles were found to be internally mixed with secondary species such as sulfate, soot, and organic carbon. The mass weighted average Fe(II) fraction (defined as Fe(II)/[Fe(II)+Fe(III)]) was determined to be 0.33 {+-} 0.08. Within the experimental uncertainty, this value lies close to the range of 0.26-0.30 determined for representative Asian mineral dust. Previous studies have indicated that the solubility of iron from combustion is much higher than that from mineral dust. Therefore, chemical and/or physical differences other than oxidation state may help explain the higher solubility of iron in atmospheric particles.

  11. A particle accelerator employing transient space charge potentials

    DOE Patents [OSTI]

    Post, R.F.

    1988-02-25T23:59:59.000Z

    The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles. 3 figs.

  12. Kinetic approaches to particle acceleration at cosmic ray modified shocks

    E-Print Network [OSTI]

    Elena Amato; Pasquale Blasi; Stefano Gabici

    2008-01-09T23:59:59.000Z

    Kinetic approaches provide an effective description of the process of particle acceleration at shock fronts and allow to take into account the dynamical reaction of the accelerated particles as well as the amplification of the turbulent magnetic field as due to streaming instability. The latter does in turn affect the maximum achievable momentum and thereby the acceleration process itself, in a chain of causality which is typical of non-linear systems. Here we provide a technical description of two of these kinetic approaches and show that they basically lead to the same conclusions. In particular we discuss the effects of shock modification on the spectral shape of the accelerated particles, on the maximum momentum, on the thermodynamic properties of the background fluid and on the escaping and advected fluxes of accelerated particles.

  13. Particle acceleration in superluminal strong waves

    E-Print Network [OSTI]

    Teraki, Yuto; Nagataki, Shigehiro

    2015-01-01T23:59:59.000Z

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them by using numerical methods in the context of the termination shock of the pulsar wind nebulae. We pursue the electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of primary SLSW and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave felt by the electrons moving nearly along the wavevector changes very slowly compared to the oscillation of the wave, which is called "phase locked", and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in the pre-acceleration for the shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. How...

  14. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre of the Helmholtz Association PARTICLE PHYSICS· DESY has openings for: DESY-Fellowships (f/m) DESY DESY is one of the world's leading research centres for photon science, particle and astroparticle physics as well

  15. Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

    E-Print Network [OSTI]

    Barnard, J.J.

    2008-01-01T23:59:59.000Z

    of. the 1991 Particle Accelerator Conference (Ref. [3]), p.of the l J J3 Particle Accelerator Conference, Washington,Beam Physics, US Particle Accelerator School Notes, http://

  16. 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.

  17. Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics

    E-Print Network [OSTI]

    Zisman, Michael S.

    2008-01-01T23:59:59.000Z

    on a synergy between accelerator physics and acceleratorthe dreams of the accelerator physics community into thelike to thank my accelerator physics and particle physics

  18. Seventy Five Years of Particle Accelerators (LBNL Summer Lecture Series)

    ScienceCinema (OSTI)

    Sessler, Andy

    2011-04-28T23:59:59.000Z

    Summer Lecture Series 2006: Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe.

  19. A GPU Accelerated Smoothed Particle Hydrodynamics Capability For Houdini

    E-Print Network [OSTI]

    Sanford, Mathew

    2012-10-19T23:59:59.000Z

    on the desired result. One common fluid simulation technique is the Smoothed Particle Hydrodynamics (SPH) method. This method is highly parellelizable. I have implemented a method to integrate a Graphics Processor Unit (GPU) accelerated SPH capability into the 3D...

  20. CO2 LASER TECHNOLOGY FOR ADVANCED PARTICLE ACCELERATORS

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

    Actually, in this case, we talk about evanescent EM fields vanishing within a l -thick layer above the surface. In the third group of methods, particles are accelerated not by EM...

  1. Black holes as particle accelerators: a brief review

    E-Print Network [OSTI]

    Tomohiro Harada; Masashi Kimura

    2014-11-18T23:59:59.000Z

    Rapidly rotating Kerr black holes can accelerate particles to arbitrarily high energy if the angular momentum of the particle is fine-tuned to some critical value. This phenomenon is robust as it is founded on the basic properties of geodesic orbits around a near-extremal Kerr black hole. On the other hand, the maximum energy of the acceleration is subjected to several physical effects. There is convincing evidence that the particle acceleration to arbitrarily high energy is one of the universal properties of general near-extremal black holes. We also discuss gravitational particle acceleration in more general context. This article is intended to provide a pedagogical introduction to and a brief overview of this topic for non-specialists.

  2. Particle Acceleration in Gamma-Ray Burst Jets

    E-Print Network [OSTI]

    Frank M. Rieger; Peter Duffy

    2005-11-02T23:59:59.000Z

    Gradual shear acceleration of energetic particles in gamma-ray burst (GRB) jets is considered. Special emphasis is given to the analysis of universal structured jets, and characteristic acceleration timescales are determined for a power-law and a Gaussian evolution of the bulk flow Lorentz factor $\\gamma_b$ with angle $\\phi$ from the jet axis. The results suggest that local power-law particle distributions may be generated and that higher energy particles are generally concentrated closer to the jet axis. Taking several constraints into account we show that efficient electron acceleration in gradual shear flows, with maximum particle energy successively decreasing with time, may be possible on scales larger than $r \\sim 10^{15}$ cm, provided the jet magnetic field becomes sufficiently weak and/or decreases rapidly enough with distance, while efficient acceleration of protons to ultra-high energies $> 10^{20}$ eV may be possible under a wide range of conditions.

  3. Particle Acceleration Around 5-dimensional Kerr Black Hole

    E-Print Network [OSTI]

    Ahmadjon Abdujabbarov; Naresh Dadhich; Bobomurat Ahmedov; Husan Eshkuvatov

    2013-12-11T23:59:59.000Z

    On the lines of the 4-dimensional Kerr black hole we consider the particle acceleration near a 5-dimensional Kerr black hole which has the two rotation parameters. It turns out that the center of mass energy of the two equal mass colliding particles as expected diverges for the extremal black hole and there is a symmetry in the results for $\\theta = 0, \\pi/2$. Because of the two rotation parameters, $r=0$ can be a horizon without being a curvature singularity. It is shown that the acceleration of particles to high energies near the 5-D extreme rotating black hole avoids fine-tuning of the angular momentum of particles.

  4. Particle Acceleration in three dimensional Reconnection Regions: A New Test Particle Approach

    E-Print Network [OSTI]

    Rudiger Schopper; Guido T. Birk; Harald Lesch

    2001-06-29T23:59:59.000Z

    Magnetic Reconnection is an efficient and fast acceleration mechanism by means of direct electric field acceleration parallel to the magnetic field. Thus, acceleration of particles in reconnection regions is a very important topic in plasma astrophysics. This paper shows that the conventional analytical models and numerical test particle investigations can be misleading concerning the energy distribution of the accelerated particles, since they oversimplify the electric field structure by the assumption that the field is homogeneous. These investigations of the acceleration of charged test particles are extended by considering three-dimensional field configurations characterized by localized field-aligned electric fields. Moreover, effects of radiative losses are discussed. The comparison between homogeneous and inhomogeneous electric field acceleration in reconnection regions shows dramatic differences concerning both, the maximum particle energy and the form of the energy distribution.

  5. Relativistic Particle Acceleration in a Folded Current Sheet

    E-Print Network [OSTI]

    S. Zenitani; M. Hoshino

    2005-05-24T23:59:59.000Z

    Two-dimensional particle simulations of a relativistic Harris current sheet of pair plasmashave demonstrated that the system is unstable to the relativistic drift kink instability (RDKI) and that a new kind of acceleration process takes place in the deformed current sheet. This process contributes to the generation of non-thermal particles and contributes to the fast magnetic dissipation in the current sheet structure. The acceleration mechanism and a brief comparison with relativistic magnetic reconnection are presented.

  6. Particle Acceleration in (by) Accretion Discs

    E-Print Network [OSTI]

    J. I. Katz

    1992-05-04T23:59:59.000Z

    I present a model for acceleration of protons by the second-order Fermi process acting on randomly scrambled magnetic flux arches above an accretion disc. The accelerated protons collide with thermal protons in the disc, producing degraded energetic protons, charged and neutral pions, and neutrons. The pions produce gamma-rays by spontaneous decay of $\\pi^0$ and by bremsstrahlung and Compton processes following the decay of $\\pi^\\pm$ to $e^\\pm$.

  7. Fermilab | Science | Particle Accelerators | LHC and Future Accelerators

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

    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 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator Complex

  8. Particle Acceleration in an Evolving Network of Unstable Current Sheets

    E-Print Network [OSTI]

    L. Vlahos; H. Isliker; F. Lepreti

    2004-02-26T23:59:59.000Z

    We study the acceleration of electrons and protons interacting with localized, multiple, small-scale dissipation regions inside an evolving, turbulent active region. The dissipation regions are Unstable Current Sheets (UCS), and in their ensemble they form a complex, fractal, evolving network of acceleration centers. Acceleration and energy dissipation are thus assumed to be fragmented. A large-scale magnetic topology provides the connectivity between the UCS and determines in this way the degree of possible multiple acceleration. The particles travel along the magnetic field freely without loosing or gaining energy, till they reach a UCS. In a UCS, a variety of acceleration mechanisms are active, with the end-result that the particles depart with a new momentum. The stochastic acceleration process is represented in the form of Continuous Time Random Walk (CTRW), which allows to estimate the evolution of the energy distribution of the particles. It is found that under certain conditions electrons are heated and accelerated to energies above 1 MeV in much less than a second. Hard X-ray (HXR) and microwave spectra are calculated from the electrons' energy distributions, and they are found to be compatible with the observations. Ions (protons) are also heated and accelerated, reaching energies up to 10 MeV almost simultaneously with the electrons. The diffusion of the particles inside the active region is extremely fast (anomalous super-diffusion). Although our approach does not provide insight into the details of the specific acceleration mechanisms involved, its benefits are that it relates acceleration to the energy release, and it well describes the stochastic nature of the acceleration process.

  9. Particle trajectories and acceleration during 3D fan reconnection

    E-Print Network [OSTI]

    S. Dalla; P. K. Browning

    2008-11-07T23:59:59.000Z

    Context. The primary energy release in solar flares is almost certainly due to magnetic reconnection, making this a strong candidate as a mechanism for particle acceleration. While particle acceleration in 2D geometries has been widely studied, investigations in 3D are a recent development. Two main classes of reconnection regimes at a 3D magnetic null point have been identified: fan and spine reconnection Aims. Here we investigate particle trajectories and acceleration during reconnection at a 3D null point, using a test particle numerical code, and compare the efficiency of the fan and spine regimes in generating an energetic particle population. Methods. We calculated the time evolution of the energy spectra. We discuss the geometry of particle escape from the two configurations and characterise the trapped and escaped populations. Results. We find that fan reconnection is less efficent than spine reconnection in providing seed particles to the region of strong electric field where acceleration is possible. The establishment of a steady-state spectrum requires approximately double the time in fan reconnection. The steady-state energy spectrum at intermediate energies (protons 1 keV to 0.1 MeV) is comparable in the fan and spine regimes. While in spine reconnection particle escape takes place in two symmetric jets along the spine, in fan reconnection no jets are produced and particles escape in the fan plane, in a ribbon-like structure.

  10. Thermal Particle Injection in Nonlinear Diffusive Shock Acceleration

    E-Print Network [OSTI]

    Donald C. Ellison; Pasquale Blasi; Stefano Gabici

    2005-07-05T23:59:59.000Z

    Particle acceleration in collisionless astrophysical shocks, i.e., diffusive shock acceleration (DSA), is the most likely mechanism for producing cosmic rays, at least below 10^{15} eV. Despite the success of this theory, several key elements, including the injection of thermal particles, remains poorly understood. We investigate injection in strongly nonlinear shocks by comparing a semi-analytic model of DSA with a Monte Carlo model. These two models treat injection quite differently and we show, for a particular set of parameters, how these differences influence the overall acceleration efficiency and the shape of the broad-band distribution function.

  11. Hydrodynamic Simulation of Supernova Remnants Including Efficient Particle Acceleration

    E-Print Network [OSTI]

    Donald C. Ellison; Anne Decourchelle; Jean Ballet

    2003-08-19T23:59:59.000Z

    A number of supernova remnants (SNRs) show nonthermal X-rays assumed to be synchrotron emission from shock accelerated TeV electrons. The existence of these TeV electrons strongly suggests that the shocks in SNRs are sources of galactic cosmic rays (CRs). In addition, there is convincing evidence from broad-band studies of individual SNRs and elsewhere that the particle acceleration process in SNRs can be efficient and nonlinear. If SNR shocks are efficient particle accelerators, the production of CRs impacts the thermal properties of the shock heated, X-ray emitting gas and the SNR evolution. We report on a technique that couples nonlinear diffusive shock acceleration, including the backreaction of the accelerated particles on the structure of the forward and reverse shocks, with a hydrodynamic simulation of SNR evolution. Compared to models which ignore CRs, the most important hydrodynamical effects of placing a significant fraction of shock energy into CRs are larger shock compression ratios and lower temperatures in the shocked gas. We compare our results, which use an approximate description of the acceleration process, with a more complete model where the full CR transport equations are solved (i.e., Berezhko et al., 2002), and find excellent agreement for the CR spectrum summed over the SNR lifetime and the evolving shock compression ratio. The importance of the coupling between particle acceleration and SNR dynamics for the interpretation of broad-band continuum and thermal X-ray observations is discussed.

  12. Particle Acceleration in Relativistic Jets due to Weibel Instability

    E-Print Network [OSTI]

    K. -I. Nishikawa; P. Hardee; G. Richardson; R. Preece; H. Sol; G. J. Fishman

    2003-06-04T23:59:59.000Z

    Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. While some Fermi acceleration may occur at the jet front, the majority of electron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which contribute to the electron's transverse deflection behind the jet head. The ``jitter'' radiation (Medvedev 2000) from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  13. 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.

  14. uge particle accelerators have been at the vanguard of research in particle

    E-Print Network [OSTI]

    Valero-Cuevas, Francisco

    under construc- tion at CERN in Geneva,will attempt to find the Higgs boson, a particle associatedH uge particle accelerators have been at the vanguard of research in particle physics for more than half a century; through high-energy collisions of accelera- ted particles, the fundamental building

  15. Particle acceleration from reconnection in the geomagnetic tail

    SciTech Connect (OSTI)

    Birn, J.; Borovsky, J.E.; Thomsen, M.F.; McComas, D.J.; Reeves, G.D.; Belian, R.D. [Los Alamos National Lab., NM (United States); Hesse, M. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Schindler, K. [Ruhr-Univ., Bochum (Germany)

    1997-08-01T23:59:59.000Z

    Acceleration of charged particles in the near geomagnetic tail, associated with a dynamic magnetic reconnection process, was investigated by a combined effort of data analysis, using Los Alamos data from geosynchronous orbit, MHD modeling of the dynamic evolution of the magnetotail, and test particle tracing in the electric and magnetic fields obtained from the MHD simulation.

  16. Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron

    E-Print Network [OSTI]

    Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron A Research Centre DESY DESY is one of the world's leading research centres for photon science, particle and astroparticle with universities. The DESY focus is on conventional and plasma-based accele- rators with applications in photon

  17. 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

  18. Covariant Quantum Green's Function for an Accelerated Particle

    E-Print Network [OSTI]

    T. Garavaglia

    2001-04-03T23:59:59.000Z

    Covariant relativistic quantum theory is used to study the covariant Green's function, which can be used to determine the proper time evolved wave functions that are solutions to the covariant Schr\\"odinger type equation for a massive spin zero particle. The concept of covariant action is used to obtain the Green's function for an accelerated relativistic particle.

  19. Detecting the ambient neutralino dark matter particles at accelerator

    E-Print Network [OSTI]

    Tai-Fu Feng; Xue-Qian Li; Wen-Gan Ma; Jian-Xiong Wang; Gong-Bo Zhao

    2006-10-30T23:59:59.000Z

    In this work, we present a new strategy to investigate the possibility of direct detection of the ambient neutralino matter at accelerator. We calculate the cross sections for both elastic and inelastic scattering processes of the dark matter particles with the beam particles at $e^+e^-$ and hadron colliders.

  20. Particle acceleration by ultra-relativistic shocks: theory and simulations

    E-Print Network [OSTI]

    Abraham Achterberg; Yves A. Gallant; John G. Kirk; Axel W. Guthmann

    2001-07-27T23:59:59.000Z

    We consider the acceleration of charged particles near ultra-relativistic shocks, with Lorentz factor Gamma_s >> 1. We present simulations of the acceleration process and compare these with results from semi-analytical calculations. We show that the spectrum that results from acceleration near ultra-relativistic shocks is a power law, N(E) \\propto E^{-s}, with a nearly universal value s \\approx 2.2 - 2.3 for the slope of this power law. We confirm that the ultra-relativistic equivalent of Fermi acceleration at a shock differs from its non-relativistic counterpart by the occurence of large anisotropies in the distribution of the accelerated particles near the shock. In the rest frame of the upstream fluid, particles can only outrun the shock when their direction of motion lies within a small loss cone of opening angle theta_c \\approx 1/Gamma_s around the shock normal. We also show that all physically plausible deflection or scattering mechanisms can change the upstream flight direction of relativistic particles originating from downstream by only a small amount: Delta theta ~ 1/Gamma_s. This limits the energy change per shock crossing cycle to Delta E ~ E, except for the first cycle where particles originate upstream. In that case the upstream energy is boosted by a factor ~ Gamma_s^2 for those particles that are scattered back across the shock into the upstream region.

  1. Collisionless Shocks -- Magnetic Field Generation and Particle Acceleration

    E-Print Network [OSTI]

    J. Trier Frederiksen; C. B. Hededal; T. Haugboelle; A. Nordlund

    2003-03-16T23:59:59.000Z

    We present numerical results from plasma particle simulations of collisionless shocks and ultra-relativistic counter-streaming plasmas. We demonstrate how the field-particle interactions lead to particle acceleration behind the shock-front. Further, we demonstrate how ultra relativistic counter-streaming plasmas create large scale patchy magnetic field structures and that these field structures propagate down-stream of the shock front. These results may help explain the origin of the magnetic fields and accelerated electrons responsible for afterglow synchrotron radiation from gamma ray bursts.

  2. In-situ Particle Acceleration in Collisionless Shocks

    E-Print Network [OSTI]

    C. B. Hededal; T. Haugboelle; J. T. Frederiksen; Å. Nordlund

    2005-02-18T23:59:59.000Z

    The outflows from gamma ray bursts, active galactic nuclei and relativistic jets in general interact with the surrounding media through collisionless shocks. With three dimensional relativistic particle-in-cell simulations we investigate such shocks. The results from these experiments show that small--scale magnetic filaments with strengths of up to percents of equipartition are generated and that electrons are accelerated to power law distributions N(E)~E^{-p} in the vicinity of the filaments through a new acceleration mechanism. The acceleration is locally confined, instantaneous and differs from recursive acceleration processes such as Fermi acceleration. We find that the proposed acceleration mechanism competes with thermalization and becomes important at high Lorentz factors.

  3. Spacetime noncommutative effect on black hole as particle accelerators

    E-Print Network [OSTI]

    Chikun Ding; Changqing Liu; Qian Guo

    2013-01-08T23:59:59.000Z

    We study the spacetime noncommutative effect on black hole as particle accelerators and, find that particle falling from infinity with zero velocity cannot collide with unbound energy when the noncommutative Kerr black hole is exactly extremal. Our results also show that the bigger of the spinning black hole's mass is, the higher of center of mass energy that the particles obtain. For small and medium noncommutative Schwarzschild black hole, the collision energy depends on the black holes' mass.

  4. Constraints on Particle Acceleration from the Diffuse Isotropic Gamma-Ray Background

    E-Print Network [OSTI]

    Karl Mannheim

    2000-05-26T23:59:59.000Z

    Gamma rays trace accelerated particles, and the observed flux of extragalactic gamma rays therefore constrains the global efficiency for particle acceleration. Extragalactic jets in active galactic nuclei can account for the gamma ray background if their particle acceleration efficiency considerably exceeds ~ 18 per cent which would imply that particle acceleration is an essential part of the thermodynamics in these sources.

  5. Particle acceleration in the driven relativistic reconnection

    E-Print Network [OSTI]

    Yuri Lyubarsky; Michael Liverts

    2008-05-07T23:59:59.000Z

    We study the compression driven magnetic reconnection in the relativistic electron-positron plasma. Making use of a 2.5D particle-in-cell code, we simulated compression of a magnetized plasma layer containing a current sheet within it. We found that the particle spectrum within the reconnecting sheet becomes non-thermal; it could be approximated by a power-law distribution with an index of -1 and an exponential cutoff.

  6. Particle acceleration in three-dimensional tearing configurations

    E-Print Network [OSTI]

    Christoph Nodes; Guido T. Birk; Harald Lesch; R. Schopper

    2003-01-17T23:59:59.000Z

    In three-dimensional electromagnetic configurations that result from unstable resistive tearing modes particles can efficiently be accelerated to relativistic energies. To prove this resistive magnetohydrodynamic simulations are used as input configurations for successive test particle simulations. The simulations show the capability of three-dimensional non-linearly evolved tearing modes to accelerate particles perpendicular to the plane of the reconnecting magnetic field components. The simulations differ considerably from analytical approaches by involving a realistic three-dimensional electric field with a non-homogenous component parallel to the current direction. The resulting particle spectra exhibit strong pitch-angle anisotropies. Typically, about 5-8 % of an initially Maxwellian distribution is accelerated to the maximum energy levels given by the macroscopic generalized electric potential structure. Results are shown for both, non-relativistic particle acceleration that is of interest, e.g., in the context of auroral arcs and solar flares, and relativistic particle energization that is relevant, e.g., in the context of active galactic nuclei.

  7. Computer-based training for particle accelerator personnel

    SciTech Connect (OSTI)

    Silbar, Richard R. [WhistleSoft, Inc., 168 Dos Brazos, Los Alamos, New Mexico 87544 (United States)

    1999-06-10T23:59:59.000Z

    A continuing problem at many laboratories is the training of new operators in the arcane technology of particle accelerators. Presently most of this training occurs 'on the job,' under a mentor. Such training is expensive, and while it provides operational experience, it is frequently lax in providing the physics background needed to truly understand accelerator systems. Using computers in a self-paced, interactive environment can be more effective in meeting this training need.

  8. Particle acceleration in rotating and shearing jets from AGN

    E-Print Network [OSTI]

    F. M. Rieger; K. Mannheim

    2002-10-14T23:59:59.000Z

    We model the acceleration of energetic particles due to shear and centrifugal effects in rotating astrophysical jets. The appropriate equation describing the diffusive transport of energetic particles in a collisionless, rotating background flow is derived and analytical steady state solutions are discussed. In particular, by considering velocity profiles from rigid, over flat to Keplerian rotation, the effects of centrifugal and shear acceleration of particles scattered by magnetic inhomogeneities are distinguished. In the case where shear acceleration dominates, it is confirmed that power law particle momentum solutions $f(p) \\propto p^{-(3+\\alpha)}$ exist, if the mean scattering time $\\tau_c \\propto p^{\\alpha}$ is an increasing function of momentum. We show that for a more complex interplay between shear and centrifugal acceleration, the recovered power law momentum spectra might be significantly steeper but flatten with increasing azimuthal velocity due to the increasing centrifugal effects. The possible relevance of shear and centrifugal acceleration for the observed extended emission in AGN is demonstrated for the case of the jet in the quasar 3C273.

  9. Accelerator Cavities as a Probe of Millicharged Particles

    E-Print Network [OSTI]

    H. Gies; J. Jaeckel; A. Ringwald

    2006-08-21T23:59:59.000Z

    We investigate Schwinger pair production of millicharged fermions in the strong electric field of cavities used for particle accelerators. Even without a direct detection mechanism at hand, millicharged particles, if they exist, contribute to the energy loss of the cavity and thus leave an imprint on the cavity's quality factor. Already conservative estimates substantially constrain the electric charge of these hypothetical particles; the resulting bounds are competitive with the currently best laboratory bounds which arise from experiments based on polarized laser light propagating in a magnetic field. We propose an experimental setup for measuring the electric current comprised of the millicharged particles produced in the cavity.

  10. Particle acceleration in thick parallel shocks with high compression ratio

    E-Print Network [OSTI]

    Joni J. P. Virtanen; Rami Vainio

    2005-06-06T23:59:59.000Z

    We report studies on first-order Fermi acceleration in parallel modified shock waves with a large scattering center compression ratio expected from turbulence transmission models. Using a Monte Carlo technique we have modeled particle acceleration in shocks with a velocity ranging from nonrelativistic to ultrarelativistic and a thickness extending from nearly steplike to very wide structures exceeding the particle diffusion length by orders of magnitude. The nonrelativistic diffusion approximation is found to be surprisingly accurate in predicting the spectral index of a thick shock with large compression ratio even in the cases involving relativistic shock speeds.

  11. Charged spinning black holes as particle accelerators

    SciTech Connect (OSTI)

    Wei Shaowen; Liu Yuxiao; Guo Heng; Fu Chune [Institute of Theoretical Physics, Lanzhou University, Lanzhou 730000 (China)

    2010-11-15T23:59:59.000Z

    It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin a but also on the charge Q of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin a of the extremal black hole satisfies (1/{radical}(3)){<=}(a/M){<=}1, where M is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge Q.

  12. Outline Layout Ion Sources Acceleration Accumulation Collision Detectors References Brief Overview of Particle

    E-Print Network [OSTI]

    Budker, Dmitry

    of Particle Accelerators Eugene S. Evans1 February 17, 2010 1 University of California, Berkeley Eugene S. Evans Brief Overview of Particle Accelerators #12;Outline Layout Ion Sources Acceleration Accumulation Collider at CERN Eugene S. Evans Brief Overview of Particle Accelerators #12;Outline Layout Ion Sources

  13. Particle acceleration at oblique shocks and discon tinuities of the density profile

    E-Print Network [OSTI]

    Gieseler, Udo D. J.

    Particle acceleration at oblique shocks and discon­ tinuities of the density profile U. D. J acceleration, the phase space spectral index s of accelerated particles depends solely on the compression ratio, the density profile of accelerated test particles is a continuous function of position (e.g., Kirk 1994, page

  14. Shock Acceleration of the Energetic Particle Background in the Solar Wind David T. Sodaitis

    E-Print Network [OSTI]

    Shock Acceleration of the Energetic Particle Background in the Solar Wind David T. Sodaitis Physics background via the mechanism of second order Fermi acceleration. In this acceleration method, the particle- eration by interplanetary shocks that joins wave excitation with particle acceleration by using the cold

  15. How Particle Accelerators Work | Department of Energy

    Energy Savers [EERE]

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov.Energy02.pdf7 OPAM Flash2011-37Energy HighlightsCarbon CaptureShadeParticle

  16. Particle acceleration in relativistic collisionless shocks: Fermi process at last?

    E-Print Network [OSTI]

    Anatoly Spitkovsky

    2008-02-24T23:59:59.000Z

    We present evidence that relativistic shocks propagating in unmagnetized plasmas can self-consistently accelerate particles. We use long-term two-dimensional particle-in-cell simulations to study the well-developed shock structure in unmagnetized pair plasma. The particle spectrum downstream of such a shock consists of two components: a relativistic Maxwellian, with characteristic temperature set by the upstream kinetic energy of the flow, and a high-energy tail, extending to energies >100 times that of the thermal peak. This tail is best fitted as a power law in energy with index -2.4+-0.1, modified by an exponential cutoff. The cutoff moves to higher energies with time of the simulation, leaving a larger power law range. The number of particles in the tail is ~1% of the downstream population, and they carry ~10% of the kinetic energy in the downstream. Upon investigation of the trajectories of particles in the tail, we find that the energy gains occur as particles bounce between the upstream and downstream regions in the magnetic fields generated by the Weibel instability. We compare this mechanism to the first order Fermi acceleration, and set a lower limit on the efficiency of shock acceleration process.

  17. Relativistic parsec-scale jets: I. Particle acceleration

    E-Print Network [OSTI]

    A. R. Beresnyak; Ya. N. Istomin; V. I. Pariev

    2003-03-05T23:59:59.000Z

    We develop a theory of particle acceleration inside relativistic rotating electron-positron force-free jets with spiral magnetic fields. We considered perturbation of the stationary magnetic field structure and found that acceleration takes place in the regions where the Alfven resonant condition with the eigenmodes in the jet is fulfilled, i.e. where the local Alfven speed is equal to the phase speed of an eigenmode. The acceleration mechanism is regular acceleration by the electric field of the electromagnetic wave, which is the eigenmode of the force-free cylindrical jet: particles drift out of the region of the large wave amplitude near the Alfven resonant surface and gain energy. Acceleration in the strong electric field near the Alfven resonance and synchrotron losses combine to form a power-law energy spectrum of ultra-relativistic electrons and positrons with index between 2 and 3 depending upon the initial energy of the injected particles. The power law distribution ranges from 10 MeV to 1000 MeV.

  18. Accurate and efficient spin integration for particle accelerators

    E-Print Network [OSTI]

    Abell, Dan T; Ranjbar, Vahid H; Barber, Desmond P

    2015-01-01T23:59:59.000Z

    Accurate spin tracking is a valuable tool for understanding spin dynamics in particle accelerators and can help improve the performance of an accelerator. In this paper, we present a detailed discussion of the integrators in the spin tracking code gpuSpinTrack. We have implemented orbital integrators based on drift-kick, bend-kick, and matrix-kick splits. On top of the orbital integrators, we have implemented various integrators for the spin motion. These integrators use quaternions and Romberg quadratures to accelerate both the computation and the convergence of spin rotations. We evaluate their performance and accuracy in quantitative detail for individual elements as well as for the entire RHIC lattice. We exploit the inherently data-parallel nature of spin tracking to accelerate our algorithms on graphics processing units.

  19. Acceleration of particles by black holes: kinematic explanation

    E-Print Network [OSTI]

    O. B. Zaslavskii

    2011-06-21T23:59:59.000Z

    A new simple and general explanation of the effect of acceleration of particles by black holes to infinite energies in the centre of mass frame is suggested. It is based on kinematics of particles moving near the horizon. This effect arises when particles of two kinds collide near the horizon. For massive particles, the first kind represents a particle with the generic energy and angular momentum (I call them "usual"). Near the horizon, such a particle has a velocity almost equal to that of light in the frame that corotates with a black hole (the frame is static if a black hole is static). The second kind (called "critical") consists of particles with the velocity vvelocity approaches the speed of light c, the Lorentz factor grows unbound. This explanation applies both to generic rotating black holes and charged ones (even for radial motion of particles). If one of colliding particles is massless (photon), the critical particle is distinguished by the fact that its frequency is finite near the horizon. The existence (or absence) of the effect is determined depending on competition of two factors - gravitational blue shift for a photon propagating towards a black hole and the Doppler effect due to transformation from the locally nonrotating frame to a comoving one. Classification of all possible types of collisions is suggested depending on whether massive or massless particle is critical or usual.

  20. PARTICLE ACCELERATION IN A THREE-DIMENSIONAL MODEL OF RECONNECTING CORONAL MAGNETIC FIELDS

    E-Print Network [OSTI]

    Isliker, Heinz

    PARTICLE ACCELERATION IN A THREE-DIMENSIONAL MODEL OF RECONNECTING CORONAL MAGNETIC FIELDS PETER J in final form 18 October 2005) Abstract. Particle acceleration in large-scale turbulent coronal magnetic to be addressed, such as feedback between particle acceleration and MHD, are discussed. Keywords: particle

  1. PARTICLE ACCELERATION IN RELATIVISTIC JETS DUE TO WEIBEL INSTABILITY K.-I. Nishikawa1

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    PARTICLE ACCELERATION IN RELATIVISTIC JETS DUE TO WEIBEL INSTABILITY K.-I. Nishikawa1 National are responsible for particle (electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle code, we have investigated particle acceleration associated with a relativ- istic jet

  2. PARTICLE ACCELERATION ASYMMETRY IN A RECONNECTING NONNEUTRAL CURRENT SHEET Valentina V. Zharkova and Mykola Gordovskyy

    E-Print Network [OSTI]

    Zharkova, Valentina V.

    PARTICLE ACCELERATION ASYMMETRY IN A RECONNECTING NONNEUTRAL CURRENT SHEET Valentina V. Zharkova is found to accelerate particles to coherent energy spectra in a range of 10­100 keV for electrons and 100 of particles -- Sun: flares -- Sun: magnetic fields 1. INTRODUCTION Particle acceleration in solar flares

  3. PARTICLE ACCELERATION AND MAGNETIC FIELD GENERATION IN ELECTRON-POSITRON RELATIVISTIC SHOCKS

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    PARTICLE ACCELERATION AND MAGNETIC FIELD GENERATION IN ELECTRON-POSITRON RELATIVISTIC SHOCKS K are responsible for particle (electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic

  4. Non-extremal Kerr black holes as particle accelerators

    E-Print Network [OSTI]

    Sijie Gao; Changchun Zhong

    2011-08-03T23:59:59.000Z

    It has been shown that extremal Kerr black holes can be used as particle accelerators and arbitrarily high energy may be obtained near the event horizon. We study particle collisions near the event horizon (outer horizon) and Cauchy horizon (inner horizon) of a non-extremal Kerr black hole. Firstly, we provide a general proof showing that particles cannot collide with arbitrarily high energies at the outter horizon. Secondly, we show that ultraenergetic collisions can occur near the inner horizon of a Kerr black hole with any spin parameter $a$.

  5. Acceleration of particles in Einstein-Maxwell-Dilaton black hole

    E-Print Network [OSTI]

    Pu-Jian Mao; Ran Li; Lin-Yu Jia; Ji-Rong Ren

    2011-03-08T23:59:59.000Z

    It has been recently pointed out that, under certain conditions, the energy of particles accelerated by black holes in the center-of-mass frame can become arbitrarily high. In this Letter, we study the collision of two particles around the four-dimensional Kaluza-Klein black hole in Einstein-Maxwell-Dilaton theory. We find that the center-of-mass energy for a pair of colliding particles is unlimited at the horizon of charged nonrotating and extremal rotating Kaluza-Klein black hole.

  6. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    SciTech Connect (OSTI)

    Rubel, Oliver; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Wu, Kesheng; Prabhat,; Weber, Gunther H.; Ushizima, Daniela M.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2009-10-19T23:59:59.000Z

    Numerical simulations of laser wakefield particle accelerators play a key role in the understanding of the complex acceleration process and in the design of expensive experimental facilities. As the size and complexity of simulation output grows, an increasingly acute challenge is the practical need for computational techniques that aid in scientific knowledge discovery. To that end, we present a set of data-understanding algorithms that work in concert in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration in very large simulation datasets. These techniques work cooperatively by first identifying features of interest in individual timesteps, then integrating features across timesteps, and based on the information derived perform analysis of temporally dynamic features. This combination of techniques supports accurate detection of particle beams enabling a deeper level of scientific understanding of physical phenomena than hasbeen possible before. By combining efficient data analysis algorithms and state-of-the-art data management we enable high-performance analysis of extremely large particle datasets in 3D. We demonstrate the usefulness of our methods for a variety of 2D and 3D datasets and discuss the performance of our analysis pipeline.

  7. String Black Holes as Particle Accelerators to Arbitrarily High Energy

    E-Print Network [OSTI]

    Parthapratim Pradhan

    2014-03-25T23:59:59.000Z

    We show that an extremal Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole may act as a particle accelerator with arbitrarily high energy when two uncharged particles falling freely from rest to infinity on the near horizon. We show that the center of mass energy of collision independent of the extreme fine tuning of the angular momentum of the colliding particles. We further show that the center of mass energy of collisions of particles at the ISCO ($r_{ISCO}$) or at the photon orbit ($r_{ph}$) or at the marginally bound circular orbit ($r_{mb}$) i.e. at $r \\equiv r_{ISCO}=r_{ph}=r_{mb}=2M$ could be arbitrarily large for the aforementioned spacetimes, which is different from Schwarzschild and Reissner-Nordstr{\\o}m spcetimes. For non-extremal GMGHS spacetimes the CM energy is finite and depends upon the asymptotic value of the dilation field ($\\phi_{0}$).

  8. Single particles accelerate final stages of capillary break up

    E-Print Network [OSTI]

    Lindner, Anke; Wagner, Christian

    2015-01-01T23:59:59.000Z

    Droplet formation of suspensions is present in many industrial and technological processes such as coating and food engineering. Whilst the finite time singularity of the minimum neck diameter in capillary break-up of simple liquids can be described by well known self-similarity solutions, the pinching of non-Brownian suspension depends in a complex way on the particle dynamics in the thinning thread. Here we focus on the very dilute regime where the filament contains only isolated beads to identify the physical mechanisms leading to the pronounced acceleration of the filament thinning observed. This accelerated regime is characterized by an asymmetric shape of the filament with an enhanced curvature that depends on the size and the spatial distribution of the particles within the capillary thread.

  9. Linear particle accelerator with seal structure between electrodes and insulators

    DOE Patents [OSTI]

    Broadhurst, John H. (Golden Valley, MN)

    1989-01-01T23:59:59.000Z

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  10. Single particles accelerate final stages of capillary break up

    E-Print Network [OSTI]

    Anke Lindner; Jorge Eduardo Fiscina; Christian Wagner

    2015-06-12T23:59:59.000Z

    Droplet formation of suspensions is present in many industrial and technological processes such as coating and food engineering. Whilst the finite time singularity of the minimum neck diameter in capillary break-up of simple liquids can be described by well known self-similarity solutions, the pinching of non-Brownian suspension depends in a complex way on the particle dynamics in the thinning thread. Here we focus on the very dilute regime where the filament contains only isolated beads to identify the physical mechanisms leading to the pronounced acceleration of the filament thinning observed. This accelerated regime is characterized by an asymmetric shape of the filament with an enhanced curvature that depends on the size and the spatial distribution of the particles within the capillary thread.

  11. Particle acceleration at supernova shocks in young stellar clusters

    E-Print Network [OSTI]

    Bykov, A M; Osipov, S M

    2011-01-01T23:59:59.000Z

    We briefly discuss models of energetic particle acceleration by supernova shock in active starforming regions at different stages of their evolution. Strong shocks may strongly amplify magnetic fields due to cosmic ray driven instabilities. We discuss the magnetic field amplification emphasizing the role of the long-wavelength instabilities. Supernova shock propagating in the vicinity of a powerful stellar wind in a young stellar cluster is argued to increase the maximal CR energies at a given evolution stage of supernova remnant (SNR) and can convert a sizeable fraction of the kinetic energy release into energetic particles.

  12. Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications

    SciTech Connect (OSTI)

    Brown, Michael R.

    2006-11-16T23:59:59.000Z

    Project Title: Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications PI: Michael R. Brown, Swarthmore College The purpose of the project was to provide theoretical and modeling support to the Swarthmore Spheromak Experiment (SSX). Accordingly, the theoretical effort was tightly integrated into the SSX experimental effort. During the grant period, Michael Brown and his experimental collaborators at Swarthmore, with assistance from W. Matthaeus as appropriate, made substantial progress in understanding the physics SSX plasmas.

  13. 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

  14. ensl-00167302,version1-18Aug2007 Measurement of particle and bubble accelerations in turbulence

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ensl-00167302,version1-18Aug2007 Measurement of particle and bubble accelerations in turbulence R motion are resolved and the particle acceleration is measured. For neutrally buoyant par- ticles, our 1.4) and to air bubbles. We observe that the acceleration variance strongly depends on the particle

  15. To be submitted to ApJ Letters Particle acceleration in stressed coronal magnetic fields

    E-Print Network [OSTI]

    Vlahos, Loukas

    To be submitted to ApJ Letters Particle acceleration in stressed coronal magnetic fields R an analysis of particle acceleration in a model of the complex magnetic field environment in the flaring solar a relativistic test particle code. It is shown that both ions and electrons are accelerated readily

  16. Accurate Modeling of Laser-Plasma Accelerators with Particle-In-Cell Codes

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Accurate Modeling of Laser-Plasma Accelerators with Particle-In-Cell Codes Estelle Michel , B. A-plasma accelerators. Here we investigate the numerical heating and macro-particle trajectory errors in 2D PIC wake and be accelerated to high energies [4]. In a particle-grid approach such as PIC, finite

  17. PARTICLE ACCELERATION BY THE SUN ''Physics Department & Space Sciences Laboratory, University of California, Berkeley, CA

    E-Print Network [OSTI]

    California at Berkeley, University of

    PARTICLE ACCELERATION BY THE SUN R. P. Lin" ''Physics Department & Space Sciences Laboratory. INTRODUCTION The Sun is the most energetic particle accelerator in the solar system. In large solar flares energetic particle (SEP) events observed near 1 AU, but they, however, appear to be accelerated by shock

  18. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams C. B. Schroeder, E of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator-charge force of a charged particle beam. Laser-driven plasma accelerators (LPAs) were first proposed in 1979

  19. FPI4 5:00 ROBUST CONTROL OF PARTICLE ACCELERATORS* W. Joel D. Johnson

    E-Print Network [OSTI]

    FPI4 5:00 ROBUST CONTROL OF PARTICLE ACCELERATORS* W. Joel D. Johnson Los Alamos National of an electron particle accelerator. This new scheme has greater stability and performance robustness than was previously achieved. 1. Introduction One application of an electron particle accelerator is to drive a Free

  20. Feature-based Analysis of Plasma-based Particle Acceleration Data

    E-Print Network [OSTI]

    Feature-based Analysis of Plasma-based Particle Acceleration Data Oliver Rübel 1 , Cameron G;1 Feature-based Analysis of Plasma-based Particle Acceleration Data Oliver R¨ubel, Cameron G.R. Geddes, Min Chen, Estelle Cormier-Michel, and E. Wes Bethel Abstract Plasma-based particle accelerators can produce

  1. Particle acceleration and radiation in Pulsar Wind Nebulae

    E-Print Network [OSTI]

    Amato, Elena

    2015-01-01T23:59:59.000Z

    Pulsar Wind Nebulae are the astrophysical sources that host the most relativistic shocks in Nature and the only Galactic sources in which we have direct evidence of PeV particles. These facts make them very interesting from the point of view of particle acceleration physics, and their proximity and brightness make them a place where fundamental processes common to different classes of relativistic sources have a better chance to be understood. I will discuss how well we understand the physics of Pulsar Wind Nebulae, describing recent progress and highlighting the main open questions. I will be mostly concerned with the subject of particle acceleration, but, as we will see, in order to clarify the physics of this process, it is important to determine the conditions of the plasma in the nebula. These in turn can only be constrained through detailed modelling of the PWN dynamics and radiation. The shock in the Crab Nebula is probably the most efficient accelerator known, both in terms of conversion of the flow e...

  2. Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism

    E-Print Network [OSTI]

    A. Tawfik; A. Saleh; M. T. Ghoneim; A. A. Hady

    2010-10-14T23:59:59.000Z

    The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and stochastic Fermi mechanisms. It is apparent that the latter are not depending on the particle's charge, quantitatively. Based on this model, a considerable portion of the dynamics, that derives a charged particle parallel to a magnetic field $\\mathbf{B}$ and under the influence of a force $\\mathbf{F}$, is assumed to be composed of an acceleration by a non-magnetic force $\\mathbf{F}_{\\parallel}$ and a gyromotion along $\\mathbf{B}$ direction, plus drifts in the direction of $\\mathbf{F}_{\\perp}$. The model and its formalism are introduced. Various examples for drift motions and accelerating forces are suggested. The formalism is given in a non-relativistic version. Obviously, the translation into the relativistic version is standard. In a forthcoming work, a quantitative estimation of the energy gained by charged cosmic rays in various astrophysical objects will be evaluated.

  3. The Particle Accelerator Simulation Code PyORBIT

    SciTech Connect (OSTI)

    Gorlov, Timofey V [ORNL; Holmes, Jeffrey A [ORNL; Cousineau, Sarah M [ORNL; Shishlo, Andrei P [ORNL

    2015-01-01T23:59:59.000Z

    The particle accelerator simulation code PyORBIT is presented. The structure, implementation, history, parallel and simulation capabilities, and future development of the code are discussed. The PyORBIT code is a new implementation and extension of algorithms of the original ORBIT code that was developed for the Spallation Neutron Source accelerator at the Oak Ridge National Laboratory. The PyORBIT code has a two level structure. The upper level uses the Python programming language to control the flow of intensive calculations performed by the lower level code implemented in the C++ language. The parallel capabilities are based on MPI communications. The PyORBIT is an open source code accessible to the public through the Google Open Source Projects Hosting service.

  4. Rotating Hayward's regular black hole as particle accelerator

    E-Print Network [OSTI]

    Muhammed Amir; Sushant G. Ghosh

    2015-06-10T23:59:59.000Z

    Recently, Ban\\~{a}dos, Silk and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy ($E_{CM}$) when the collision takes place near the horizon. The rotating Hayward's regular black hole, apart from Mass ($M$) and angular momentum ($a$), has a new parameter $g$ ($g>0$ is a constant) that provides a deviation from the Kerr black hole. We demonstrate that for each $g$, with $M=1$, there exist critical $a_{E}$ and $r_{H}^{E}$, which corresponds to a regular extremal black hole with degenerate horizon, and $a_{E}$ decreases and $r_{H}^{E}$ increases with increase in $g$. While $aparticle accelerator and thus in turn may provide a suitable framework for Plank-scale physics. For a non-extremal case, there always exist a finite upper bound of $E_{CM}$, which increases with deviation parameter $g$.

  5. Proceedings of the 22nd Particle Accelerator Conference (PAC'07)

    SciTech Connect (OSTI)

    N /A

    2007-08-01T23:59:59.000Z

    The twenty-second Particle Accelerator Conference, PAC'07, took place at the Albuquerque Convention Centre in Albuquerque, the largest city in New Mexico, from Monday to Friday, 2007 June 25 to 29. It was attended by over 1350 delegates from 25 different countries (63% North America, 24% Europe, 11% Asia and 2% Other), and was held under the auspices of the two professional societies that oversee and make holding this series of conferences possible, the Division of Physics of Beams within APS, and the Nuclear and Plasma Sciences Society within IEEE. As host of the conference, Los Alamos National Laboratory (LANL) is especially thanked for their many contributions and assistance both prior to and during the conference. The Convention Center was an ideal location for information sharing and discussions between the interdisciplinary aspects of the accelerator community, as well as for related meetings and ad-hoc 'rump' sessions.

  6. DIFFUSIVE ACCELERATION OF PARTICLES AT OBLIQUE, RELATIVISTIC, MAGNETOHYDRODYNAMIC SHOCKS

    SciTech Connect (OSTI)

    Summerlin, Errol J. [Heliospheric Physics Laboratory, Code 672, NASA's Goddard Space Flight Center, Greenbelt, MD 20770 (United States); Baring, Matthew G., E-mail: errol.summerlin@nasa.gov, E-mail: baring@rice.edu [Department of Physics and Astronomy, MS 108, Rice University, Houston, TX 77251 (United States)

    2012-01-20T23:59:59.000Z

    Diffusive shock acceleration (DSA) at relativistic shocks is expected to be an important acceleration mechanism in a variety of astrophysical objects including extragalactic jets in active galactic nuclei and gamma-ray bursts. These sources remain good candidate sites for the generation of ultrahigh energy cosmic rays. In this paper, key predictions of DSA at relativistic shocks that are germane to the production of relativistic electrons and ions are outlined. The technique employed to identify these characteristics is a Monte Carlo simulation of such diffusive acceleration in test-particle, relativistic, oblique, magnetohydrodynamic (MHD) shocks. Using a compact prescription for diffusion of charges in MHD turbulence, this approach generates particle angular and momentum distributions at any position upstream or downstream of the shock. Simulation output is presented for both small angle and large angle scattering scenarios, and a variety of shock obliquities including superluminal regimes when the de Hoffmann-Teller frame does not exist. The distribution function power-law indices compare favorably with results from other techniques. They are found to depend sensitively on the mean magnetic field orientation in the shock, and the nature of MHD turbulence that propagates along fields in shock environs. An interesting regime of flat-spectrum generation is addressed; we provide evidence for it being due to shock drift acceleration, a phenomenon well known in heliospheric shock studies. The impact of these theoretical results on blazar science is outlined. Specifically, Fermi Large Area Telescope gamma-ray observations of these relativistic jet sources are providing significant constraints on important environmental quantities for relativistic shocks, namely, the field obliquity, the frequency of scattering, and the level of field turbulence.

  7. Waveguides in three-dimensional photonic bandgap materials for particle-accelerator on a

    E-Print Network [OSTI]

    Byer, Robert L.

    Waveguides in three-dimensional photonic bandgap materials for particle-accelerator on a chip@physics.anu.edu.au Abstract: The quest for less costly and more compact high-energy particle accelerators of suggested concepts, the photonic accelerator design by B. M. Cowan [Phys. Rev. ST Accel. Beams 11, 011301

  8. GPU accelerated simulations of bluff body flows using vortex particle methods

    E-Print Network [OSTI]

    Cottet, Georges-Henri

    GPU accelerated simulations of bluff body flows using vortex particle methods Diego Rossinelli in press as: D. Rossinelli et al., GPU accelerated simulations of bluff body flows using vortex particle Penalization Bluff body flows a b s t r a c t We present a GPU accelerated solver for simulations of bluff body

  9. Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasmaa)

    E-Print Network [OSTI]

    Ji, Hantao

    Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasmaa January 2014; accepted 20 February 2014; published online 7 May 2014) Bulk ion acceleration and particle-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential

  10. Charged particle acceleration in dense plasma channels I. Y. Dodin and N. J. Fisch

    E-Print Network [OSTI]

    Charged particle acceleration in dense plasma channels I. Y. Dodin and N. J. Fisch Department amplitude and the energy of a charged particle accelerated in a plasma channel. The maximum energy gain accelerators can operate at much higher magnitudes as they utilize electrostatic fields due to charge

  11. Time Dependence of Particle Creation from Accelerating Mirrors

    E-Print Network [OSTI]

    Michael R. R. Good; Paul R. Anderson; Charles R. Evans

    2013-03-27T23:59:59.000Z

    Particle production due to a quantized, massless, minimally coupled scalar field in two-dimensional flat spacetime with an accelerating mirror is investigated, with a focus on the time dependence of the process. We analyze first the classes of trajectories previously investigated by Carlitz and Willey and by Walker and Davies. We then analyze four new classes of trajectories, all of which can be expressed analytically and for which several ancillary properties can be derived analytically. The time dependence is investigated through the use of wave packets for the modes of the quantized field that are in the out vacuum state. It is shown for most of the trajectories studied that good time resolution of the particle production process can be obtained.

  12. Black Holes are neither Particle Accelerators nor Dark Matter Probes

    E-Print Network [OSTI]

    Sean T. McWilliams

    2012-12-06T23:59:59.000Z

    It has been suggested that maximally spinning black holes can serve as particle accelerators, reaching arbitrarily high center-of-mass energies. Despite several objections regarding the practical achievability of such high energies, and demonstrations past and present that such large energies could never reach a distant observer, interest in this problem has remained substantial. We show that, unfortunately, a maximally spinning black hole can never serve as a probe of high energy collisions, even in principle and despite the correctness of the original diverging energy calculation. Black holes can indeed facilitate dark matter annihilation, but the most energetic photons can carry little more than the rest energy of the dark matter particles to a distant observer, and those photons are actually generated relatively far from the black hole where relativistic effects are negligible. Therefore, any strong gravitational potential could probe dark matter equally well, and an appeal to black holes for facilitating such collisions is unnecessary.

  13. Feature-based Analysis of Plasma-based Particle Acceleration Data

    SciTech Connect (OSTI)

    Ruebel, Oliver; Geddes, Cameron G.R.; Chen, Min; Cormier-Michel, Estelle; Bethel, E. Wes

    2013-07-05T23:59:59.000Z

    Plasma-based particle accelerators can produce and sustain thousands of times stronger acceleration fields than conventional particle accelerators, providing a potential solution to the problem of the growing size and cost of conventional particle accelerators. To facilitate scientific knowledge discovery from the ever growing collections of accelerator simulation data generated by accelerator physicists to investigate next-generation plasma-based particle accelerator designs, we describe a novel approach for automatic detection and classification of particle beams and beam substructures due to temporal differences in the acceleration process, here called acceleration features. The automatic feature detection in combination with a novel visualization tool for fast, intuitive, query-based exploration of acceleration features enables an effective top-down data exploration process, starting from a high-level, feature-based view down to the level of individual particles. We describe the application of our analysis in practice to analyze simulations of single pulse and dual and triple colliding pulse accelerator designs, and to study the formation and evolution of particle beams, to compare substructures of a beam and to investigate transverse particle loss.

  14. A threshold for laser-driven linear particle acceleration in unbounded vacuum

    E-Print Network [OSTI]

    Wong, Liang Jie

    2011-01-01T23:59:59.000Z

    We hypothesize that a charged particle in unbounded vacuum can be substantially accelerated by a force linear in the electric field of a propagating electromagnetic wave only if the accelerating field is capable of bringing ...

  15. Particle Beam Stability in the Hollow Plasma Channel Wake Field Accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Particle Beam Stability in the Hollow Plasma Channel Wake Field Accelerator Carl B. Schroeder1 structure is the transverse instability of the particle beam. INTRODUCTION Plasma-based accelerators have. The electromagnetic wake field response of a hollow plasma channel to a driver (laser or charged particle beam

  16. Randomly accelerated particle in a box: Mean absorption time for partially absorbing and inelastic boundaries

    E-Print Network [OSTI]

    Randomly accelerated particle in a box: Mean absorption time for partially absorbing and inelastic accelerated particle which moves on the half line x 0 with an absorbing boundary at x=0. The motion, Philadelphia, Pennsylvania 19122, USA Received 11 February 2005; published 13 April 2005 Consider a particle

  17. Accelerating Particle Filter using Randomized Multiscale and Fast Multipole Type Methods

    E-Print Network [OSTI]

    Averbuch, Amir

    1 Accelerating Particle Filter using Randomized Multiscale and Fast Multipole Type Methods Gil that accelerates the computation of particle filters. Unlike the conventional way, which calculates weights over Shabat, Yaniv Shmueli, Amit Bermanis and Amir Averbuch Abstract--Particle filter is a powerful method

  18. Theory of nonlinear particle acceleration at shocks and self-generation of the magnetic field

    E-Print Network [OSTI]

    Pasquale Blasi; Elena Amato

    2007-06-12T23:59:59.000Z

    We present some recent developments in the theory of particle acceleration at shock fronts in the presence of dynamical reaction of the accelerated particles and self-generation of magnetic field due to streaming instability. The spectra of accelerated particles, the velocity, magnetic field and temperature profiles can be calculated in this approach anywhere in the precursor and in the downstream region. The implications for the origin of cosmic rays and for the phenomenology of supernova remnants will be discussed.

  19. Acceleration of inertial particles in wall bounded flows: DNS and LES with stochastic modelling of the subgrid acceleration

    E-Print Network [OSTI]

    Boyer, Edmond

    environmental systems, from sediment transport to atmospheric dispersion of pollutants or solid depositionAcceleration of inertial particles in wall bounded flows: DNS and LES with stochastic modelling and LES with stochastic modelling of the subgrid acceleration R´emi Zamansky, Ivana Vinkovic, Mikhael

  20. Photo of the Week: What Does a Particle Accelerator Have in Common...

    Energy Savers [EERE]

    could be widely used in medicine and industry -- particle accelerators are used for cancer research, processing computer chips, and even producing the shrink wrap used to keep...

  1. Particle acceleration, magnetic field generation, and emission in relativistic pair jets

    E-Print Network [OSTI]

    K. -I. Nishikawa; P. Hardee; C. B. Hededal; G. Richardson; H. Sol; R. Preece; G. J. Fishman

    2005-02-16T23:59:59.000Z

    Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating into an ambient plasma. We find that the growth times of Weibel instability are proportional to the Lorentz factors of jets. Simulations show that the Weibel instability created in the collisionless shock front accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction.

  2. The Mysterious Universe - Exploring Our World with Particle Accelerators

    ScienceCinema (OSTI)

    Brau, James E [University of Oregon

    2014-06-25T23:59:59.000Z

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  3. Fundamentals of Non-relativistic Collisionless Shock Physics: V. Acceleration of Charged Particles

    E-Print Network [OSTI]

    R. A. Treumann; C. H. Jaroschek

    2008-06-25T23:59:59.000Z

    A comprehensive review is given of the various processes proposed for accelerating particles by shocks to high energies. These energies are limited by several bounds: the non-relativistic nature of the heliospheric collisionless shocks to which this review restricts, the finite size of these shocks, the finite width of the downstream region, and to the nature of turbulence. In general, collisionless shocks in the heliosphere cannot accelerate particles to very high energies. As a fundamental problem of the acceleration mechanism the injection of see particles is identified. Some mecchanisms for production of seed particles are invoked. Acceleration of electrons begins to uncover its nature. The following problems are covered in this chapter: 1. Introduction -- first and second order Fermi acceleration, 2. Accelerating ions when they are already fast, diffusive acceleration, convection diffusion equation, Lee's self-consistent quasilinear shock acceleration model, 3. Observations, 4. The injection problem, ion surfing, test particle simulations, self-consistent shock acceleration simulations, downstream leakage, trapped particle acceleration, 5. Accelerating electrons, Sonnerup-Wu mechanism, Hoshino's electron shock surfing on quasi-perpendicular shocks, quasiparallel shock surfing.

  4. A general solution to non-linear particle acceleration at non-relativistic shock waves

    E-Print Network [OSTI]

    Elena Amato; Pasquale Blasi

    2005-09-22T23:59:59.000Z

    Diffusive acceleration at collisionless shock waves remains one of the most promising acceleration mechanisms for the description of the origin of cosmic rays at all energies. A crucial ingredient to be taken into account is the reaction of accelerated particles on the shock, which in turn determines the efficiency of the process. Here we propose a semi-analytical kinetic method that allows us to calculate the shock modification induced by accelerated particles together with the efficiency for particle acceleration and the spectra of accelerated particles. The shock modification is calculated for arbitrary environment parameters (Mach number, maximum momentum, density) and for arbitrary diffusion properties of the medium. Several dependences of the diffusion coefficient on particle momentum and location are considered to assess the goodness of the method.

  5. Automated detection and analysis of particle beams in laser-plasma accelerator simulations 367 Automated detection and analysis

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Automated detection and analysis of particle beams in laser-plasma accelerator simulations 367 0 Automated detection and analysis of particle beams in laser-plasma accelerator simulations Daniela M (particle) accelerators [Geddes et al. (2009); Tajima & Dawson (1979)] model the acceleration of electrons

  6. Diagnostic resonant cavity for a charged particle accelerator

    DOE Patents [OSTI]

    Barov, Nikolai (San Diego, CA)

    2007-10-02T23:59:59.000Z

    Disclosed is a diagnostic resonant cavity for determining characteristics of a charged particle beam, such as an electron beam, produced in a charged particle accelerator. The cavity is based on resonant quadrupole-mode and higher order cavities. Enhanced shunt impedance in such cavities is obtained by the incorporation of a set of four or more electrically conductive rods extending inwardly from either one or both of the end walls of the cavity, so as to form capacitive gaps near the outer radius of the beam tube. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained. In alternative embodiments the cavity may include either four or more opposing pairs of rods which extend coaxially toward one another from the opposite end walls of the cavity and are spaced from one another to form capacitative gaps; or the cavity may include a single set of individual rods that extend from one end wall to a point adjacent the opposing end wall.

  7. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    DOE Patents [OSTI]

    Danby, Gordon T. (Wading River, NY); Jackson, John W. (Shoreham, NY)

    1991-01-01T23:59:59.000Z

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

  8. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    DOE Patents [OSTI]

    Danby, G.T.; Jackson, J.W.

    1990-03-19T23:59:59.000Z

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

  9. Acceleration statistics of solid particles in turbulent channel flow R. Zamansky, I. Vinkovic, and M. Gorokhovski

    E-Print Network [OSTI]

    Boyer, Edmond

    ) suggesting that when particle inertia increases, particle acceler- ation variance decreases due to bothAcceleration statistics of solid particles in turbulent channel flow R. Zamansky, I. Vinkovic in near-wall turbulence Phys. Fluids 24, 035110 (2012) Smoothed particle hydrodynamics simulations

  10. Cavitation Inception on Microparticles: A Self-Propelled Particle Accelerator Manish Arora,1

    E-Print Network [OSTI]

    Ohl, Claus-Dieter

    Cavitation Inception on Microparticles: A Self-Propelled Particle Accelerator Manish Arora,1 Claus) Corrugated, hydrophilic particles with diameters between 30 and 150 m are found to cause cavitation inception of the particle and the displaced liquid. The analysis suggests that all particles which cause cavitation

  11. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration, time- varying laser wakefield particle accelerator simulation data. We ex- tend histogramBit, a state-of-the-art index/query technology, to acceler- ate data mining and multi-dimensional histogram

  12. EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION

    E-Print Network [OSTI]

    Herbordt, Martin

    EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION Matt Chiu ABSTRACT The acceleration of molecular dynamics (MD) simulations using high performance reconfigurable: determining the short-range force between particle pairs. In particular, we present the first FPGA study

  13. DC-like Phase Space Manipulation and Particle Acceleration Using Chirped AC Fields

    SciTech Connect (OSTI)

    P.F. Schmit and N.J. Fisch

    2009-06-17T23:59:59.000Z

    Waves in plasmas can accelerate particles that are resonant with the wave. A DC electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. We investigate the effect on a Hamiltonian distribution of an accelerating potential waveform, which could, for example, represent the average ponderomotive effect of two counterpropagating electromagnetic waves. In particular, we examine the apparent DC-like time-asymptotic response of the distribution in regimes where the potential structure is accelerated adiabatically. A highly resonant population within the distribution is always present, and we characterize its nonadiabatic response during wave-particle resonance using an integral method in the noninertial reference frame moving with the wave. Finally, we show that in the limit of infinitely slow acceleration of the wave, these highly resonant particles disappear and the response

  14. On the efficiency of particle acceleration by rotating magnetospheres in AGN

    E-Print Network [OSTI]

    Zaza Osmanov; Andria D. Rogava; Gianluigi Bodo

    2007-03-16T23:59:59.000Z

    To investigate the efficiency of centrifugal acceleration of particles as a possible mechanism for the generation of ultra-high $\\gamma$-ray nonthermal emission from TeV blazars, we study the centrifugal acceleration of electrons by rotating magnetic field lines, for an extended range of inclination angles and determine the maximum Lorentz factors $\\gamma_{max}$ attainable by the electrons via this process. {Two principal limiting mechanisms for the particle acceleration, inverse Compton scattering and breakdown of the bead-on-the-wire approximation, are examined. Particles may be centrifugally accelerated up to $\\gamma_{max} \\simeq 10^8$ and the main limiting mechanism for the $\\gamma_{max}$ is the inverse Compton scattering. The energy of centrifugally accelerated particles can be amply sufficient for the generation (via inverse Compton scattering) of the ultra-high energy (up to $20TeV$) gamma emission in TeV blazars.

  15. Particle Acceleration at Ultra-Relativistic Shocks and the Spectra of Relativistic Fireballs

    E-Print Network [OSTI]

    Yves A. Gallant; Abraham Achterberg; John G. Kirk; Axel W. Guthmann

    2000-01-28T23:59:59.000Z

    We examine Fermi-type acceleration at relativistic shocks, and distinguish between the initial boost of the first shock crossing cycle, where the energy gain per particle can be very large, and the Fermi process proper with repeated shock crossings, in which the typical energy gain is of order unity. We calculate by means of numerical simulations the spectrum and angular distribution of particles accelerated by this Fermi process, in particular in the case where particle dynamics can be approximated as small-angle scattering. We show that synchrotron emission from electrons or positrons accelerated by this process can account remarkably well for the observed power-law spectra of GRB afterglows and Crab-like supernova remnants. In the context of a decelerating relativistic fireball, we calculate the maximum particle energy attainable by acceleration at the external blast wave, and discuss the minimum energy for this acceleration process and its consequences for the observed spectrum.

  16. Energetic particle acceleration in a 3D magnetic field reconnection model: a role of MHD turbulence

    E-Print Network [OSTI]

    Tomasz Kobak; Michal Ostrowski

    2000-06-07T23:59:59.000Z

    The role of MHD turbulence in the cosmic ray acceleration process in a volume with a reconnecting magnetic field is studied by means of Monte Carlo simulations. We performed modelling of proton acceleration with the 3D analytic model of stationary reconnection of Craig et al. (1995) providing the unperturbed background conditions. Perturbations of particle trajectories due to a turbulent magnetic field component were simulated using small-amplitude pitch-angle momentum scattering, enabling modelling of both small and large amplitude turbulence in a wide wave vector range. Within the approach, no second-order Fermi acceleration process is allowed. Comparison of the acceleration process in models involving particle trajectory perturbations to the unperturbed one reveals that the turbulence can substantially increase the acceleration efficiency, enabling much higher final particle energies and flat particle spectra.

  17. Particle Acceleration through Multiple Conversions from Charged into Neutral State and Back

    E-Print Network [OSTI]

    E. V. Derishev; F. A. Aharonian; V. V. Kocharovsky; Vl. V. Kocharovsky

    2003-06-09T23:59:59.000Z

    We propose a new way of quick and very efficient acceleration of protons and/or electrons in relativistic bulk flows. The new mechanism takes advantage of conversion of particles from the charged state (protons or electrons/positrons) into neutral state (neutrons or photons) and back. In most cases, the conversion is photon-induced and requires presence of intense radiation fields, but the converter acceleration mechanism may also operate via inelastic nucleon-nucleon collisions. Like in the traditional model -- ``stochastic'' (or diffusive) acceleration, -- the acceleration cycle in our scenario consists of escape of particles from the relativistic flow followed by their return back after deflection from the ambient magnetic field. The difference is that the charge-changing reactions, which occur during the cycle, allow accelerated particles to increase their energies in each cycle by a factor roughly equal to the bulk Lorentz factor squared. The emerging spectra of accelerated particles can be very hard and their cut-off energy in some cases is larger than in the standard mechanism. This drastically reduces the required energy budget of the sources of the highest-energy particles observed in cosmic rays. Also, the proposed acceleration mechanism may serve as an efficient means of transferring the energy of bulk motion to gamma-radiation and, if the accelerated particles are nucleons, routinely produces high-energy neutrinos at $\\sim 50 %$ relative efficiency.

  18. Effect of polarization and focusing on laser pulse driven auto-resonant particle acceleration

    SciTech Connect (OSTI)

    Sagar, Vikram; Sengupta, Sudip; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)

    2014-04-15T23:59:59.000Z

    The effect of laser polarization and focusing is theoretically studied on the final energy gain of a particle in the Auto-resonant acceleration scheme using a finite duration laser pulse with Gaussian shaped temporal envelope. The exact expressions for dynamical variables viz. position, momentum, and energy are obtained by analytically solving the relativistic equation of motion describing particle dynamics in the combined field of an elliptically polarized finite duration pulse and homogeneous static axial magnetic field. From the solutions, it is shown that for a given set of laser parameters viz. intensity and pulse length along with static magnetic field, the energy gain by a positively charged particle is maximum for a right circularly polarized laser pulse. Further, a new scheme is proposed for particle acceleration by subjecting it to the combined field of a focused finite duration laser pulse and static axial magnetic field. In this scheme, the particle is initially accelerated by the focused laser field, which drives the non-resonant particle to second stage of acceleration by cyclotron Auto-resonance. The new scheme is found to be efficient over two individual schemes, i.e., auto-resonant acceleration and direct acceleration by focused laser field, as significant particle acceleration can be achieved at one order lesser values of static axial magnetic field and laser intensity.

  19. Plasmonic Meta-Surface for Efficient Ultra-Short Pulse Laser-Driven Particle Acceleration

    E-Print Network [OSTI]

    Bar-Lev, Doron

    2014-01-01T23:59:59.000Z

    A laser-driven particle accelerator based on plasmonic nano-antennas is proposed and analyzed. The concept utilizes the enhancement and localization of the electric field by nano-antennas to maximize the acceleration gradient and to overcome potential metallic losses. The structure is optimized for accelerating relativistic particles using a femto-second laser source operating at 800nm, and is shown to support the bandwidth of ultra-short laser pulses (up to 16fsec) while providing a high acceleration gradient potentially reaching 11.6GV/m.

  20. Accelerated Expansion of the universe based on Particle Creation-Destruction Processes in FRW universes

    E-Print Network [OSTI]

    Alberto C. Balfagon

    2015-03-16T23:59:59.000Z

    Particle creation has been considered as a possible justification for the accelerated expansion of the universe obeying the second law of thermodynamics. This paper introduces the possibility that the destruction of baryonic and/or dark matter particles also verifies the second law of thermodynamics thanks to a particle exchange with dark energy. General equations for the variation of the number of particles in accelerated universes have been obtained. Finally, a new model of the universe has been developed which predicts dark energy properties as well as particle exchange processes between dark energy and baryonic and/or dark matter.

  1. Non linear particle acceleration at non-relativistic shock waves in the presence of self-generated turbulence

    E-Print Network [OSTI]

    Elena Amato; Pasquale Blasi

    2006-06-23T23:59:59.000Z

    Particle acceleration at astrophysical shocks may be very efficient if magnetic scattering is self-generated by the same particles. This nonlinear process adds to the nonlinear modification of the shock due to the dynamical reaction of the accelerated particles on the shock. Building on a previous general solution of the problem of particle acceleration with arbitrary diffusion coefficients (Amato & Blasi, 2005), we present here the first semi-analytical calculation of particle acceleration with both effects taken into account at the same time: charged particles are accelerated in the background of Alfven waves that they generate due to the streaming instability, and modify the dynamics of the plasma in the shock vicinity.

  2. Non-linear model of particle acceleration at colliding shock flows

    E-Print Network [OSTI]

    Bykov, A M; Osipov, S M

    2012-01-01T23:59:59.000Z

    Powerful stellar winds and supernova explosions with intense energy release in the form of strong shock waves can convert a sizeable part of the kinetic energy release into energetic particles. The starforming regions are argued as a favorable site of energetic particle acceleration and could be efficient sources of nonthermal emission. We present here a non-linear time-dependent model of particle acceleration in the vicinity of two closely approaching fast magnetohydrodynamic (MHD) shocks. Such MHD flows are expected to occur in rich young stellar cluster where a supernova is exploding in the vicinity of a strong stellar wind of a nearby massive star. We find that the spectrum of the high energy particles accelerated at the stage of two closely approaching shocks can be harder than that formed at a forward shock of an isolated supernova remnant. The presented method can be applied to model particle acceleration in a variety of systems with colliding MHD flows.

  3. Particle Accelerators, 1990, Vol. 32, pp. 241-247 Reprints available directly from the publisher

    E-Print Network [OSTI]

    Morrison, Philip J.,

    profile is importa.nt for the study of laser acceler- ation of particles. For a specific relation betweenParticle Accelerators, 1990, Vol. 32, pp. 241-247 Reprints available directly from the publisher in plasma. Carrying out numerical particle simulation runs in which a deviation from this relation

  4. IPAC15 Jefferson Lab - International Particle Accelerator Conference...

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

    D07 High Intensity Circular Machines - Space Charge, Halos D08 High Intensity in Linear Accelerators - Space Charge, Halos D09 Emittance manipulation, Bunch Compression...

  5. IPAC15 Jefferson Lab - International Particle Accelerator Conference...

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

    National Accelerator Facility United States of America Gupta Lalit Institute for Plasma Research India Gupta Lipi Cornell University CLASSE Cornell Laboratory for...

  6. Equilibrium of a confined, randomly accelerated, inelastic particle: Is there inelastic collapse? Theodore W. Burkhardt and Stanislav N. Kotsev

    E-Print Network [OSTI]

    Equilibrium of a confined, randomly accelerated, inelastic particle: Is there inelastic collapse-dimensional motion of a particle randomly accelerated by Gaussian white noise on the line segment 0 x 1. INTRODUCTION Consider a particle randomly accelerated on the line seg- ment 0 x 1 according to d2 x dt2

  7. PARTICLE ACCELERATION IN AN EVOLVING NETWORK OF UNSTABLE CURRENT SHEETS Loukas Vlahos, Heinz Isliker, and Fabio Lepreti

    E-Print Network [OSTI]

    Isliker, Heinz

    PARTICLE ACCELERATION IN AN EVOLVING NETWORK OF UNSTABLE CURRENT SHEETS Loukas Vlahos, Heinz the UCSs and in this way determines the degree of possible multiple acceleration. The particles travel, a variety of acceleration mechanisms are active, with the end result that the particles depart with a new

  8. Proposed few-optical cycle laser-driven particle accelerator structure T. Plettner, P. P. Lu, and R. L. Byer

    E-Print Network [OSTI]

    Byer, Robert L.

    Proposed few-optical cycle laser-driven particle accelerator structure T. Plettner, P. P. Lu, and R importance for future laser-driven particle accelerators. Application of such short pulses for laser-driven particle accelerators appears especially appealing from a gradient and an efficiency point of view

  9. 8. Particle Diffusion and Acceleration Proceedings of the Workshop: ``Diffuse Thermal and Relativistic Plasma in Galaxy Clusters''

    E-Print Network [OSTI]

    Boehringer, Hans

    8. Particle Diffusion and Acceleration #12; #12; Proceedings of the Workshop: ``Diffuse Thermal. Feretti & P. Schuecker, MPE Report 271, pp. 249­253 Turbulent Particle Acceleration in the Diffuse Cluster Abstract. In situ particle acceleration is probably occur­ ing in cluster radio haloes. This is suggested

  10. Charged-particle acceleration and energy loss in laser-produced plasmas D. G. Hicks,a)

    E-Print Network [OSTI]

    Charged-particle acceleration and energy loss in laser-produced plasmas D. G. Hicks,a) C. K. Li, F, particle energy shifts were dominated by acceleration effects. Using a simple model for the accelerating T. R. Boehly et al., Opt. Commun. 133, 495 1997 . Comparing the energy shifts of four particle types

  11. Particle Acceleration at shocks: some modern aspects of an old problem

    E-Print Network [OSTI]

    Pasquale Blasi

    2004-11-02T23:59:59.000Z

    The acceleration of charged particles at astrophysical collisionless shock waves is one of the best studied processes for the energization of particles to ultrarelativistic energies, required by multifrequency observations in a variety of astrophysical situations. In this paper we discuss some work aimed at describing one of the main progresses made in the theory of shock acceleration, namely the introduction of the non-linear backreaction of the accelerated particles onto the shocked fluid. The implications for the investigation of the origin of ultra high energy cosmic rays will be discussed.

  12. Electromagnetic field-computation for particle accelerators, today and tomorrow

    SciTech Connect (OSTI)

    Turner, L.R.; Kettunen, L.

    1991-01-01T23:59:59.000Z

    In this paper, we first review the magnets needed in accelerators, then discuss computations for accelerator magnets performed with present codes, and finally describe a new volume integral code which shows promise, and should be suitable for parallel computation. 9 refs., 10 figs.

  13. DNS AND LES WITH STOCHASTIC MODELLING OF SUBGRID ACCELERATION APPLIED TO SOLID PARTICLES IN A HIGH

    E-Print Network [OSTI]

    Boyer, Edmond

    implications for many environmental systems, from sediment transport to at- mospheric dispersion of pollutantsDNS AND LES WITH STOCHASTIC MODELLING OF SUBGRID ACCELERATION APPLIED TO SOLID PARTICLES IN A HIGH Stochastic Acceleration Model), in which an approximation to the instantaneous non-filtered velocity field

  14. A Phenomenological Cost Model for High Energy Particle Accelerators

    E-Print Network [OSTI]

    Vladimir Shiltsev

    2014-04-15T23:59:59.000Z

    Accelerator-based high-energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the colliders has progressed immensely, while the beam energy, luminosity, facility size, and cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. In this paper we derive a simple scaling model for the cost of large accelerators and colliding beam facilities based on costs of 17 big facilities which have been either built or carefully estimated. Although this approach cannot replace an actual cost estimate based on an engineering design, this parameterization is to indicate a somewhat realistic cost range for consideration of what future frontier accelerator facilities might be fiscally realizable.

  15. Acceleration of heavy and light particles in turbulence: comparison between experiments and direct numerical simulations

    E-Print Network [OSTI]

    R. Volk; E. Calzavarini; G. Verhille; D. Lohse; N. Mordant; J. -F. Pinton; F. Toschi

    2007-10-17T23:59:59.000Z

    We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation timescale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.

  16. High-energy particle acceleration in the shell of a supernova remnant

    E-Print Network [OSTI]

    H. E. S. S. Collaboration; :; F. Aharonian

    2004-11-18T23:59:59.000Z

    A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7-3946 (G347.3-0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy \\gamma-rays of TeV energies (1 TeV=10^{12} eV). We present a TeV \\gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

  17. SINGLE CRYSTAL NIOBIUM TUBES FOR PARTICLE COLLIDERS ACCELERATOR CAVITIES

    SciTech Connect (OSTI)

    MURPHY, JAMES E [University of Nevada, Reno] [University of Nevada, Reno

    2013-02-28T23:59:59.000Z

    The objective of this research project is to produce single crystal niobium (Nb) tubes for use as particle accelerator cavities for the Fermi laboratory’s International Linear Collider project. Single crystal Nb tubes may have superior performance compared to a polycrystalline tubes because the absence of grain boundaries may permit the use of higher accelerating voltages. In addition, Nb tubes that are subjected to the high temperature, high vacuum crystallization process are very pure and well annealed. Any impurity with a significantly higher vapor pressure than Nb should be decreased by the relatively long exposure at high temperature to the high vacuum environment. After application of the single crystal process, the surfaces of the Nb tubes are bright and shiny, and the tube resembles an electro polished Nb tube. For these reasons, there is interest in single crystal Nb tubes and in a process that will produce single crystal tubes. To convert a polycrystalline niobium tube into a single crystal, the tube is heated to within a few hundred ?C of the melting temperature of niobium, which is 2477 ?C. RF heating is used to rapidly heat the tube in a narrow zone and after reaching the operating temperature, the hot zone is slowly passed along the length of the tube. For crystallization tests with Nb tubes, the traverse rate was in the range of 1-10 cm per hour. All the crystallization tests in this study were performed in a water-cooled, stainless steel chamber under a vacuum of 5 x10-6 torr or better. In earliest tests of the single crystal growth process, the Nb tubes had an OD of 1.9 cm and a wall thickness of 0.15 mm. With these relatively small Nb tubes, the single crystal process was always successful in producing single crystal tubes. In these early tests, the operating temperature was normally maintained at 2200 ?C, and the traverse rate was 5 cm per hour. In the next test series, the Nb tube size was increased to 3.8 cm OD and the wall thickness was increased 0.18 mm and eventually to 0.21 mm. Again, with these larger tubes, single crystal tubes were usually produced by the crystallization process. The power supply was generally operated at full output during these tests, and the traverse rate was 5 cm per hour. In a few tests, the traverse rate was increased to 10 cm per hour, and at the faster traverse rate, single crystal growth was not achieved. In these tests with a faster traverse rate, it was thought that the tube was not heated to a high enough temperature to achieve single crystal growth. In the next series of tests, the tube OD was unchanged at 3.8 cm and the wall thickness was increased to 0.30 mm. The increased wall thickness made it difficult to reach an operating temperature above 2,000 ?C, and although the single crystal process caused a large increase in the crystal grains, no single crystal tubes were produced. It was assumed that the operating temperature in these tests was not high enough to achieve single crystal growth. In FY 2012, a larger power supply was purchased and installed. With the new power supply, temperatures above the melting point of Nb were easily obtained regardless of the tube thickness. A series of crystallization tests was initiated to determine if indeed the operating temperature of the previous tests was too low to achieve single crystal growth. For these tests, the Nb tube OD remained at 3.8 cm and the wall thickness was 0.30 mm. The first test had an operating temperature of 2,000 ?C. and the operating temperature was increased by 50 ?C increments for each successive test. The final test was very near the Nb melting temperature, and indeed, the Nb tube eventually melted in the center of the tube. These tests showed that higher temperatures did yield larger grain sizes if the traverse rate was held constant at 5 cm per hour, but no single crystal tubes were produced even at the highest operating temperature. In addition, slowing the traverse rate to as low as 1 cm per hour did not yield a single crystal tube regardless of operating temperature. At this time, it

  18. Energetic Electrons Accelerated in Solar Particle Events Space Sciences Laboratory, University of Berkeley, CA 94720

    E-Print Network [OSTI]

    California at Berkeley, University of

    , University of Berkeley, CA 94720 Abstract. New measurements of energetic solar electrons from the WIND and ACE/WIND should provide new insights into the origins of energetic solar particles. INTRODUCTIONEnergetic Electrons Accelerated in Solar Particle Events R. P. Lin Space Sciences Laboratory

  19. Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

  20. Math Bite: Constructing Efficient Particle Accelerators is as Easy as 1+1=2 (Thanks to Vladimir Visnjic)

    E-Print Network [OSTI]

    Zeilberger, Doron

    Math Bite: Constructing Efficient Particle Accelerators is as Easy as 1+1=2 (Thanks's ingenious constr* *uction of two local waves on the particle beam in an accelerator that promises to save to the accelerator) of which we only need to know that * *it is nonnegative and has zeros. The number of sources

  1. Math Bite: Constructing Ecient Particle Accelerators is as Easy as 1+1=2 (Thanks to Vladimir Visnjic)

    E-Print Network [OSTI]

    Zeilberger, Doron

    Math Bite: Constructing EÆcient Particle Accelerators is as Easy as 1+1=2 (Thanks to Vladimir of two local waves on the particle beam in an accelerator that promises to save the American taxpayer to the accelerator) of which we only need to know that it is nonnegative and has zeros. The number of sources

  2. 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.

  3. Computer codes used in particle accelerator design: First edition

    SciTech Connect (OSTI)

    Not Available

    1987-01-01T23:59:59.000Z

    This paper contains a listing of more than 150 programs that have been used in the design and analysis of accelerators. Given on each citation are person to contact, classification of the computer code, publications describing the code, computer and language runned on, and a short description of the code. Codes are indexed by subject, person to contact, and code acronym. (LEW)

  4. FPGA-based Particle Recognition in the HADES Abstract--Modern FPGA technologies are often employed in nuclear and particle physics experimental facilities to accelerate

    E-Print Network [OSTI]

    Jantsch, Axel

    are often employed in nuclear and particle physics experimental facilities to accelerate application the emission direction, the en- ergy, and the mass of the produced particles when the accelerated beam hits1 FPGA-based Particle Recognition in the HADES Experiment Abstract--Modern FPGA technologies

  5. Acceleration of particles in an isotropic random force field

    E-Print Network [OSTI]

    Hector Javier Durand-Manterola

    2012-04-18T23:59:59.000Z

    If we have a particle immersed in a field of random forces, each interaction of the particle with the field can enlarge or diminish its kinetic energy. In this work is shown that in general, for any field of random force with uniform distribution of directions, the probability to gain kinetic energy is larger that the probability to lose it. Therefore, if the particle is submitted to a great number of interactions with the force stochastic field, the final result will be that the particle will gain energy. The probability to gain energy in each interaction is Pg=1/2 (1+T/(2Po)), where T is the impulse given by the field and Po is the momentum of the particle before the interaction. The probability to lose energy in each interaction is Pl=1/2 (1-T/(2Po)).

  6. Detecting chaos in particle accelerators through the frequency map analysis method

    E-Print Network [OSTI]

    Yannis Papaphilippou

    2014-06-05T23:59:59.000Z

    The motion of beams in particle accelerators is dominated by a plethora of non-linear effects which can enhance chaotic motion and limit their performance. The application of advanced non-linear dynamics methods for detecting and correcting these effects and thereby increasing the region of beam stability plays an essential role during the accelerator design phase but also their operation. After describing the nature of non-linear effects and their impact on performance parameters of different particle accelerator categories, the theory of non-linear particle motion is outlined. The recent developments on the methods employed for the analysis of chaotic beam motion are detailed. In particular, the ability of the frequency map analysis method to detect chaotic motion and guide the correction of non-linear effects is demonstrated in particle tracking simulations but also experimental data.

  7. String black hole: Can it be a particle accelerator ?

    E-Print Network [OSTI]

    Sharmanthie Fernando

    2014-08-21T23:59:59.000Z

    In this paper we have studied the possibility of the center-of-mass energy of two particles colliding near the horizon of a static charged black hole in string theory. Various cases corresponding to the electric charge and the angular momentum of the particles were considered. The studies were done for the general black hole as well as for the extreme black hole. There were two scenarios where the center-of-mass energy reach very large values if the appropriate properties of the particles are chosen.

  8. Stochastic models of Lagrangian acceleration of fluid particle in developed turbulence

    E-Print Network [OSTI]

    A. K. Aringazin; M. I. Mazhitov

    2005-07-27T23:59:59.000Z

    Modeling statistical properties of motion of a Lagrangian particle advected by a high-Reynolds-number flow is of much practical interest and complement traditional studies of turbulence made in Eulerian framework. The strong and nonlocal character of Lagrangian particle coupling due to pressure effects makes the main obstacle to derive turbulence statistics from the three-dimensional Navier-Stokes equation; motion of a single fluid-particle is strongly correlated to that of the other particles. Recent breakthrough Lagrangian experiments with high resolution of Kolmogorov scale have motivated growing interest to acceleration of a fluid particle. Experimental stationary statistics of Lagrangian acceleration conditioned on Lagrangian velocity reveals essential dependence of the acceleration variance upon the velocity. This is confirmed by direct numerical simulations. Lagrangian intermittency is considerably stronger than the Eulerian one. Statistics of Lagrangian acceleration depends on Reynolds number. In this review we present description of new simple models of Lagrangian acceleration that enable data analysis and some advance in phenomenological study of the Lagrangian single-particle dynamics. Simple Lagrangian stochastic modeling by Langevin-type dynamical equations is one the widely used tools. The models are aimed particularly to describe the observed highly non-Gaussian conditional and unconditional acceleration distributions. Stochastic one-dimensional toy models capture main features of the observed stationary statistics of acceleration. We review various models and focus in a more detail on the model which has some deductive support from the Navier-Stokes equation. Comparative analysis on the basis of the experimental data and direct numerical simulations is made.

  9. Acceleration of particles near the inner black hole horizon

    E-Print Network [OSTI]

    O. B. Zaslavskii

    2011-12-16T23:59:59.000Z

    We study the possibility of obtaining unbound energy E_{c.m.} in the centre of mass frame when two particles collide near the inner black hole horizon. We consider two different cases - when both particles move (i) in the same direction or (ii) in the opposite ones. We also discuss two different versions of the effect - whether an infinite energy can be released in the collision (strong version) or the energy E_{c.m.} is finite but can be made as large as one likes (weak version). We demonstrate that the strong version of the effect is impossible in both cases (i) and (ii). In case (i) this is due to the fact that in the situation when E_{c.m.} formally diverges on the horizon, one of particles passes through the bifurcation point where two horizons meet while the second particle does not, so collision does not occur. In case (ii), both particles hit different branches of the horizon. The weak version is possible in both cases, provided at least one of particles starts its motion inside the horizon along the direction of spatial symmetry from infinity.

  10. Constraints on particle acceleration sites in the Crab Nebula from relativistic MHD simulations

    E-Print Network [OSTI]

    Olmi, Barbara; Amato, Elena; Bucciantini, Niccolò

    2015-01-01T23:59:59.000Z

    The Crab Nebula is one of the most efficient accelerators in the Galaxy and the only galactic source showing direct evidence of PeV particles. In spite of this, the physical process behind such effective acceleration is still a deep mystery. While particle acceleration, at least at the highest energies, is commonly thought to occur at the pulsar wind termination shock, the properties of the upstream flow are thought to be non-uniform along the shock surface, and important constraints on the mechanism at work come from exact knowledge of where along this surface particles are being accelerated. Here we use axisymmetric relativistic MHD simulations to obtain constraints on the acceleration site(s) of particles of different energies in the Crab Nebula. Various scenarios are considered for the injection of particles responsible for synchrotron radiation in the different frequency bands, radio, optical and X-rays. The resulting emission properties are compared with available data on the multi wavelength time varia...

  11. Automated detection and analysis of particle beams in laser-plasma accelerator simulations

    SciTech Connect (OSTI)

    Ushizima, Daniela Mayumi; Geddes, C.G.; Cormier-Michel, E.; Bethel, E. Wes; Jacobsen, J.; Prabhat, ,; R.ubel, O.; Weber, G,; Hamann, B.

    2010-05-21T23:59:59.000Z

    Numerical simulations of laser-plasma wakefield (particle) accelerators model the acceleration of electrons trapped in plasma oscillations (wakes) left behind when an intense laser pulse propagates through the plasma. The goal of these simulations is to better understand the process involved in plasma wake generation and how electrons are trapped and accelerated by the wake. Understanding of such accelerators, and their development, offer high accelerating gradients, potentially reducing size and cost of new accelerators. One operating regime of interest is where a trapped subset of electrons loads the wake and forms an isolated group of accelerated particles with low spread in momentum and position, desirable characteristics for many applications. The electrons trapped in the wake may be accelerated to high energies, the plasma gradient in the wake reaching up to a gigaelectronvolt per centimeter. High-energy electron accelerators power intense X-ray radiation to terahertz sources, and are used in many applications including medical radiotherapy and imaging. To extract information from the simulation about the quality of the beam, a typical approach is to examine plots of the entire dataset, visually determining the adequate parameters necessary to select a subset of particles, which is then further analyzed. This procedure requires laborious examination of massive data sets over many time steps using several plots, a routine that is unfeasible for large data collections. Demand for automated analysis is growing along with the volume and size of simulations. Current 2D LWFA simulation datasets are typically between 1GB and 100GB in size, but simulations in 3D are of the order of TBs. The increase in the number of datasets and dataset sizes leads to a need for automatic routines to recognize particle patterns as particle bunches (beam of electrons) for subsequent analysis. Because of the growth in dataset size, the application of machine learning techniques for scientific data mining is increasingly considered. In plasma simulations, Bagherjeiran et al. presented a comprehensive report on applying graph-based techniques for orbit classification. They used the KAM classifier to label points and components in single and multiple orbits. Love et al. conducted an image space analysis of coherent structures in plasma simulations. They used a number of segmentation and region-growing techniques to isolate regions of interest in orbit plots. Both approaches analyzed particle accelerator data, targeting the system dynamics in terms of particle orbits. However, they did not address particle dynamics as a function of time or inspected the behavior of bunches of particles. Ruebel et al. addressed the visual analysis of massive laser wakefield acceleration (LWFA) simulation data using interactive procedures to query the data. Sophisticated visualization tools were provided to inspect the data manually. Ruebel et al. have integrated these tools to the visualization and analysis system VisIt, in addition to utilizing efficient data management based on HDF5, H5Part, and the index/query tool FastBit. In Ruebel et al. proposed automatic beam path analysis using a suite of methods to classify particles in simulation data and to analyze their temporal evolution. To enable researchers to accurately define particle beams, the method computes a set of measures based on the path of particles relative to the distance of the particles to a beam. To achieve good performance, this framework uses an analysis pipeline designed to quickly reduce the amount of data that needs to be considered in the actual path distance computation. As part of this process, region-growing methods are utilized to detect particle bunches at single time steps. Efficient data reduction is essential to enable automated analysis of large data sets as described in the next section, where data reduction methods are steered to the particular requirements of our clustering analysis. Previously, we have described the application of a set of algorithms to automate the data analys

  12. The Black Hole Particle Accelerator as a Machine to make Baby Universes

    E-Print Network [OSTI]

    A. J. S. Hamilton

    2013-05-20T23:59:59.000Z

    General relativity predicts that the inner horizon of an astronomically realistic rotating black hole is subject to the mass inflation instability. The inflationary instability acts like a gravity-powered particle accelerator of extraordinary power, accelerating accreted streams of particles along the principal outgoing and ingoing null directions at the inner horizon to collision energies that would, if nothing intervened, typically exceed exponentially the Planck energy. The inflationary instability is fueled by ongoing accretion, and is occurring inevitably in essentially every black hole in our Universe. This extravagant machine, the Black Hole Particle Accelerator, has the hallmarks of a device to make baby universes. Since collisions are most numerous inside supermassive black holes, reproductive efficiency requires our Universe to make supermassive black holes efficiently, as is observed.

  13. MONTE CARLO SIMULATIONS OF NONLINEAR PARTICLE ACCELERATION IN PARALLEL TRANS-RELATIVISTIC SHOCKS

    SciTech Connect (OSTI)

    Ellison, Donald C.; Warren, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States); Bykov, Andrei M., E-mail: don_ellison@ncsu.edu, E-mail: ambykov@yahoo.com [Ioffe Institute for Physics and Technology, 194021 St. Petersburg (Russian Federation)

    2013-10-10T23:59:59.000Z

    We present results from a Monte Carlo simulation of a parallel collisionless shock undergoing particle acceleration. Our simulation, which contains parameterized scattering and a particular thermal leakage injection model, calculates the feedback between accelerated particles ahead of the shock, which influence the shock precursor and 'smooth' the shock, and thermal particle injection. We show that there is a transition between nonrelativistic shocks, where the acceleration efficiency can be extremely high and the nonlinear compression ratio can be substantially greater than the Rankine-Hugoniot value, and fully relativistic shocks, where diffusive shock acceleration is less efficient and the compression ratio remains at the Rankine-Hugoniot value. This transition occurs in the trans-relativistic regime and, for the particular parameters we use, occurs around a shock Lorentz factor ?{sub 0} = 1.5. We also find that nonlinear shock smoothing dramatically reduces the acceleration efficiency presumed to occur with large-angle scattering in ultra-relativistic shocks. Our ability to seamlessly treat the transition from ultra-relativistic to trans-relativistic to nonrelativistic shocks may be important for evolving relativistic systems, such as gamma-ray bursts and Type Ibc supernovae. We expect a substantial evolution of shock accelerated spectra during this transition from soft early on to much harder when the blast-wave shock becomes nonrelativistic.

  14. Charged Particles' Acceleration through Reconnecting Current Sheets in Solar Flares

    E-Print Network [OSTI]

    Anastasiadis, Anastasios

    . We set B0=100 Gauss as a reference value of the main magnetic field component. A particle (c4 + 1 2 y2 )2 + 1 2 (I2 - z + y)2 - z (3) where py, and c4 = z-y2 /2 are the canonical momenta

  15. Test particle simulation of direct laser acceleration in a density-modulated plasma waveguide

    SciTech Connect (OSTI)

    Lin, M.-W.; Jovanovic, I. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2012-11-15T23:59:59.000Z

    Direct laser acceleration (DLA) of electrons by the use of the intense axial electric field of an ultrafast radially polarized laser pulse is a promising technique for future compact accelerators. Density-modulated plasma waveguides can be implemented for guiding the propagation of the laser pulse to extend the acceleration distance and for the quasi-phase-matching between the accelerated electrons and the laser pulse. A test particle model is developed to study the optimal axial density modulation structure of plasma waveguides for laser pulses to efficiently accelerate co-propagating electrons. A simple analytical approach is also presented, which can be used to estimate the energy gain in DLA. The analytical model is validated by the test particle simulation. The effect of injection phase and acceleration of electrons injected at various radial positions are studied. The results indicate that a positively chirped density modulation of the waveguide structure is required to accelerate electron with low initial energies, and can be effectively optimized. A wider tolerance on the injection phase and radial distance from the waveguide axis exists for electrons injected with a higher initial energy.

  16. 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.

  17. Particle acceleration in sub-cycle optical cells

    E-Print Network [OSTI]

    F. Terranova

    2014-07-07T23:59:59.000Z

    A single laser pulse with spot size smaller than half its wavelength ($w_0 particles. In this paper, we discuss the properties of an optical cell consisting of $N$ sub-cycle pulses that propagate in the direction perpendicular to the electron motion. We show that the energy gain produced by the cell is proportional to $N$ and it is sizable even for $\\mathcal{O}(1\\mathrm{~TW})$ pulses.

  18. A STEADY-STATE FEL: PARTICLE DYNAMICS IN THE FEL PORTION OF A TWO-BEAM ACCELERATOR

    E-Print Network [OSTI]

    Sternbach, E.

    2008-01-01T23:59:59.000Z

    September 8-13, 1985 A STEADY-STATE FEL: PARTICLE DYNAMICSIN THE FEL PORTION OF A TWO-BEAM ACCELERATOR E. SternbachLBL-19939 A STEADY-STATE FEL: PARTICLE DYNAMICS IN THE FEL

  19. Stochastic particle acceleration and synchrotron self--Compton radiation in TeV blazars

    E-Print Network [OSTI]

    K. Katarzynski; G. Ghisellini; A. Mastichiadis; F. Tavecchio; L. Maraschi

    2006-03-14T23:59:59.000Z

    We analyse the influence of the stochastic particle acceleration for the evolution of the electron spectrum. We assume that all investigated spectra are generated inside a spherical, homogeneous source and also analyse the synchrotron and inverse Compton emission generated by such an object. The stochastic acceleration is treated as the diffusion of the particle momentum and is described by the momentum-diffusion equation. We investigate the stationary and time dependent solutions of the equation for several different evolutionary scenarios. The scenarios are divided into two general classes. First, we analyse a few cases without injection or escape of the particles during the evolution. Then we investigate the scenarios where we assume continuous injection and simultaneous escape of the particles. In the case of no injection and escape the acceleration process, competing with the radiative cooling, only modifies the initial particle spectrum. The competition leads to a thermal or quasi-thermal distribution of the particle energy. In the case of the injection and simultaneous escape the resulting spectra depend mostly on the energy distribution of the injected particles. In the simplest case, where the particles are injected at the lowest possible energies, the competition between the acceleration and the escape forms a power-law energy distribution. We apply our modeling to the high energy activity of the blazar Mrk 501 observed in April 1997. Calculating the evolution of the electron spectrum self-consistently we can reproduce the observed spectra well with a number of free parameters that is comparable to or less than in the "classic stationary" one--zone synchrotron self-Compton scenario.

  20. Rotating charged hairy black hole in (2+1) dimensions and particle acceleration

    E-Print Network [OSTI]

    J. Sadeghi; B. Pourhassan; H. Farahani

    2013-10-26T23:59:59.000Z

    In this paper we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.

  1. Rotating charged cylindrical black holes as particle accelerators

    SciTech Connect (OSTI)

    Said, Jackson Levi [Physics Department, University of Malta, Msida MSD 2080 (Malta); Adami, Kristian Zarb [Physics Department, University of Malta, Msida MSD 2080 (Malta); Physics Department, University of Oxford, Oxford, OX1 3RH (United Kingdom)

    2011-05-15T23:59:59.000Z

    It has recently been pointed out that arbitrary center-of-mass energies may be obtained for particle collisions near the horizon of an extremal Kerr black hole. We investigate this mechanism in cylindrical topology. In particular we consider the center-of-mass energies of a cylindrical black hole with an extremal rotation and charge parameter. The geodesics are first derived with a rotating charged cylindrical black hole producing the background gravitational field. Finally the center-of-mass is determined for this background and its extremal limit is taken.

  2. Extragalactic circuits, transmission lines, and CR particle acceleration

    E-Print Network [OSTI]

    Kronberg, Philipp P

    2014-01-01T23:59:59.000Z

    A non-negligible fraction of a Supermassive Black Hole's (SMBH) rest mass energy gets transported into extragalactic space by a remarkable process in jets which are incompletely understood. What are the physical processes which transport this energy? It is likely that the energy flows electromagnetically, rather than via a particle beam flux. The deduced electromagnetic fields may produce particles of energy as high as $\\sim 10^{20}$ eV. The energetics of SMBH accretion disk models and the electromagnetic energy transfer imply that a SMBH should generate a $10^{18} - 10^{19}$ Amp\\`eres current close to the black hole and its accretion disk. We describe the so far best observation-based estimate of the magnitude of the current flow along the axis of the jet extending from the nucleus of the active galaxy in 3C303. The current is measured to be $I \\sim 10^{18}$ Amp\\`eres at $\\sim 40$ kpc away from the AGN. This indicates that organized current flow remains intact over multi-kpc distances. The electric current $...

  3. Particle Acceleration and Radiation associated with Magnetic Field Generation from Relativistic Collisionless Shocks

    E-Print Network [OSTI]

    K. -I. Nishikawa; P. Hardee; G. Richardson; R. Preece; H. Sol; G. J. Fishman

    2003-12-03T23:59:59.000Z

    Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which contribute to the electron's transverse deflection behind the jet head. The ``jitter'' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  4. A Chandra study of particle acceleration in the multiple hotspots of nearby radio galaxies

    E-Print Network [OSTI]

    M. J. Hardcastle; J. H. Croston; R. P. Kraft

    2007-07-19T23:59:59.000Z

    We present Chandra observations of a small sample of nearby classical double radio galaxies which have more than one radio hotspot in at least one of their lobes. The X-ray emission from the hotspots of these comparatively low-power objects is expected to be synchrotron in origin, and therefore to provide information about the locations of high-energy particle acceleration. In some models of the relationship between the jet and hotspot the hotspots that are not the current jet termination point should be detached from the energy supply from the active nucleus and therefore not capable of accelerating particles to high energies. We find that in fact some secondary hotspots are X-ray sources, and thus probably locations for high-energy particle acceleration after the initial jet termination shock. In detail, though, we show that the spatial structures seen in X-ray are not consistent with naive expectations from a simple shock model: the current locations of the acceleration of the highest-energy observable particles in powerful radio galaxies need not be coincident with the peaks of radio or even optical emission.

  5. Query-driven Analysis of Plasma-based Particle Acceleration Data Oliver Rubel

    E-Print Network [OSTI]

    Query-driven Analysis of Plasma-based Particle Acceleration Data Oliver R¨ubel LBNL Cameron G. R. Geddes LBNL Min Chen LBNL Estelle Cormier-Michel Tech-X Corp. E. W. Bethel LBNL x(x106 ) 2000 4000

  6. Particle-In-Cell Modeling of Plasma-Based Accelerators in Two and Three Dimensions

    E-Print Network [OSTI]

    Hemker, Roy G

    2015-01-01T23:59:59.000Z

    In this dissertation, a fully object-oriented, fully relativistic, multi-dimensional Particle-In-Cell code was developed and applied to answer key questions in plasma-based accelerator research. The simulations increase the understanding of the processes in laser plasma and beam-plasma interaction, allow for comparison with experiments, and motivate the development of theoretical models. The simulations support the idea that the injection of electrons in a plasma wave by using a transversely propagating laser pulse is possible. The beam parameters of the injected electrons found in the simulations compare reasonably with beams produced by conventional methods and therefore laser injection is an interesting concept for future plasma-based accelerators. Simulations of the optical guiding of a laser wakefield driver in a parabolic plasma channel support the idea that electrons can be accelerated over distances much longer than the Rayleigh length in a channel. Simulations of plasma wakefield acceleration in the ...

  7. Particle Acceleration Zones Above Pulsar Polar Caps: Electron and Positron Pair Formation Fronts

    E-Print Network [OSTI]

    Alice K. Harding; Alexander G. Muslimov

    1998-05-11T23:59:59.000Z

    We investigate self-consistent particle acceleration near a pulsar polar cap (PC) by the electrostatic field due to the effect of inertial frame dragging. Test particles gain energy from the electric field parallel to the open magnetic field lines and lose energy by both curvature radiation (CR) and resonant and non-resonant inverse Compton scattering (ICS) with soft thermal X-rays from the neutron star (NS) surface. Gamma-rays radiated by electrons accelerated from the stellar surface produce pairs in the strong magnetic field, which screen the electric field beyond a pair formation front (PFF). Some of the created positrons can be accelerated back toward the surface and produce gamma-rays and pairs that create another PFF above the surface. We find that ICS photons control PFF formation near the surface, but due to the different angles at which the electron and positron scatter the soft photons, positron initiated cascades develop above the surface and screen the accelerating electric field. Stable acceleration from the NS surface is therefore not possible in the presence of dominant ICS energy losses. However, we find that stable acceleration zones may occur at some distance above the surface, where CR dominates the electron and positron energy losses, and there is up-down symmetry between the electron and positron PFFs. We examine the dependence of CR-controlled acceleration zone voltage, width and height above the surface on parameters of the pulsar and its soft X-ray emission. For most pulsars, we find that acceleration will start at a height of 0.5 - 1 stellar radii above the NS surface.

  8. COMBINING PARTICLE ACCELERATION AND CORONAL HEATING VIA DATA-CONSTRAINED CALCULATIONS OF NANOFLARES IN CORONAL LOOPS

    SciTech Connect (OSTI)

    Gontikakis, C.; Efthymiopoulos, C.; Georgoulis, M. K. [Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou 4, 11528 Athens (Greece); Patsourakos, S. [Section of Astro-Geophysics, Department of Physics, University of Ioannina, 45110 Ioannina (Greece); Anastasiadis, A., E-mail: cgontik@academyofathens.gr [National Observatory of Athens, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, GR-15236, Palaia Penteli (Greece)

    2013-07-10T23:59:59.000Z

    We model nanoflare heating of extrapolated active-region coronal loops via the acceleration of electrons and protons in Harris-type current sheets. The kinetic energy of the accelerated particles is estimated using semi-analytical and test-particle-tracing approaches. Vector magnetograms and photospheric Doppler velocity maps of NOAA active region 09114, recorded by the Imaging Vector Magnetograph, were used for this analysis. A current-free field extrapolation of the active-region corona was first constructed. The corresponding Poynting fluxes at the footpoints of 5000 extrapolated coronal loops were then calculated. Assuming that reconnecting current sheets develop along these loops, we utilized previous results to estimate the kinetic energy gain of the accelerated particles. We related this energy to nanoflare heating and macroscopic loop characteristics. Kinetic energies of 0.1-8 keV (for electrons) and 0.3-470 keV (for protons) were found to cause heating rates ranging from 10{sup -6} to 1 erg s{sup -1} cm{sup -3}. Hydrodynamic simulations show that such heating rates can sustain plasma in coronal conditions inside the loops and generate plasma thermal distributions that are consistent with active-region observations. We concluded the analysis by computing the form of X-ray spectra generated by the accelerated electrons using the thick-target approach. These spectra were found to be in agreement with observed X-ray spectra, thus supporting the plausibility of our nanoflare-heating scenario.

  9. Particle-In-Cell Simulation of Electron Acceleration in Solar Coronal Jets

    E-Print Network [OSTI]

    Baumann, G

    2012-01-01T23:59:59.000Z

    We investigate electron acceleration resulting from 3D magnetic reconnection between an emerging, twisted magnetic flux rope and a pre-existing weak, open magnetic field. We first follow the rise of an unstable, twisted flux tube with a resistive MHD simulation where the numerical resolution is enhanced by using fixed mesh refinement. As in previous MHD investigations of similar situations the rise of the flux tube into the pre-existing inclined coronal magnetic field results in the formation of a solar coronal jet. A snapshot of the MHD model is then used as an initial and boundary condition for a particle-in-cell simulation, using up to half a billion cells and over 20 billion charged particle. Particle acceleration occurs mainly in the reconnection current sheet, with accelerated electrons displaying a power law dN/dE distribution with an index of about -1.65. The main acceleration mechanism is a systematic electric field, striving to maintaining the electric current in the current sheet against losses cau...

  10. A new expression for the transition rate of an accelerated particle detector

    E-Print Network [OSTI]

    J. Louko; A. Satz

    2006-11-22T23:59:59.000Z

    We analyse the instantaneous transition rate of an accelerated Unruh-DeWitt particle detector whose coupling to a quantum field on Minkowski space is regularised by a finite spatial profile. We show, under mild technical assumptions, that the zero size limit of the detector response is well defined, independent of the choice of the profile function, and given by a manifestly finite integral formula that no longer involves epsilon-regulators or limits. Applications to specific trajectories are discussed, recovering in particular the thermal result for uniform acceleration. Extensions of the model to de Sitter space are also considered.

  11. Non-perturbative aspects of particle acceleration in non-linear electrodynamics

    E-Print Network [OSTI]

    David A. Burton; Stephen P. Flood; Haibao Wen

    2015-04-20T23:59:59.000Z

    We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can `surf' a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.

  12. KINETIC MODELING OF PARTICLE ACCELERATION IN A SOLAR NULL-POINT RECONNECTION REGION

    SciTech Connect (OSTI)

    Baumann, G.; Haugbolle, T.; Nordlund, A., E-mail: gbaumann@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2013-07-10T23:59:59.000Z

    The primary focus of this paper is on the particle acceleration mechanism in solar coronal three-dimensional reconnection null-point regions. Starting from a potential field extrapolation of a Solar and Heliospheric Observatory (SOHO) magnetogram taken on 2002 November 16, we first performed magnetohydrodynamics (MHD) simulations with horizontal motions observed by SOHO applied to the photospheric boundary of the computational box. After a build-up of electric current in the fan plane of the null point, a sub-section of the evolved MHD data was used as initial and boundary conditions for a kinetic particle-in-cell model of the plasma. We find that sub-relativistic electron acceleration is mainly driven by a systematic electric field in the current sheet. A non-thermal population of electrons with a power-law distribution in energy forms in the simulated pre-flare phase, featuring a power-law index of about -1.78. This work provides a first step toward bridging the gap between macroscopic scales on the order of hundreds of Mm and kinetic scales on the order of centimeter in the solar corona, and explains how to achieve such a cross-scale coupling by utilizing either physical modifications or (equivalent) modifications of the constants of nature. With their exceptionally high resolution-up to 135 billion particles and 3.5 billion grid cells of size 17.5 km-these simulations offer a new opportunity to study particle acceleration in solar-like settings.

  13. Particle Acceleration and Plasma Dynamics during Magnetic Reconnection in the Magnetically-dominated Regime

    E-Print Network [OSTI]

    Guo, Fan; Daughton, William; Li, Hui

    2015-01-01T23:59:59.000Z

    Magnetic reconnection is thought to be the driver for many explosive phenomena in the universe. The energy release and particle acceleration during reconnection have been proposed as a mechanism for producing high-energy emissions and cosmic rays. We carry out two- and three-dimensional kinetic simulations to investigate relativistic magnetic reconnection and the associated particle acceleration. The simulations focus on electron-positron plasmas starting with a magnetically dominated, force-free current sheet ($\\sigma \\equiv B^2/(4\\pi n_e m_e c^2) \\gg 1$). For this limit, we demonstrate that relativistic reconnection is highly efficient at accelerating particles through a first-order Fermi process accomplished by the curvature drift of particles along the electric field induced by the relativistic flows. This mechanism gives rise to the formation of hard power-law spectra $f \\propto (\\gamma-1)^{-p}$ and approaches $p = 1$ for sufficiently large $\\sigma$ and system size. Eventually most of the available magne...

  14. Status of materials handbooks for particle accelerator and nuclear reactor applications

    SciTech Connect (OSTI)

    Maloy, Stuart [Los Alamos National Laboratory (LANL); Rogers, Berylene [Los Alamos National Laboratory (LANL); Ren, Weiju [ORNL; Philip, Rittenhouse [Consultant

    2008-01-01T23:59:59.000Z

    In support of research and development for accelerator applications, a materials handbook was developed in August of 1998 funded by the Accelerator Production of Tritium Project. This handbook, presently called Advanced Fuel Cycle Initiative (AFCI) Materials Handbook, Materials Data for Particle Accelerator Applications, has just issued Revision 5 and contains detailed information showing the effects of irradiation on many properties for a wide variety of materials. Development of a web-accessible materials database for Generation IV Reactor Programs has been ongoing for about three years. This handbook provides a single authoritative source for qualified materials data applicable to all Generation IV reactor concepts. A beta version of this Gen IV Materials Handbook has been completed and is presently under evaluation.

  15. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    SciTech Connect (OSTI)

    Rubel, Oliver; Prabhat, Mr.; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2008-08-28T23:59:59.000Z

    Our work combines and extends techniques from high-performance scientific data management and visualization to enable scientific researchers to gain insight from extremely large, complex, time-varying laser wakefield particle accelerator simulation data. We extend histogram-based parallel coordinates for use in visual information display as well as an interface for guiding and performing data mining operations, which are based upon multi-dimensional and temporal thresholding and data subsetting operations. To achieve very high performance on parallel computing platforms, we leverage FastBit, a state-of-the-art index/query technology, to accelerate data mining and multi-dimensional histogram computation. We show how these techniques are used in practice by scientific researchers to identify, visualize and analyze a particle beam in a large, time-varying dataset.

  16. Preferential Heating and Acceleration of {alpha} Particles by Alfven-Cyclotron Waves

    SciTech Connect (OSTI)

    Araneda, J. A.; Maneva, Y.; Marsch, E. [Departamento de Fisica, Universidad de Concepcion, Concepcion 4070386 (Chile); Max-Planck Institut fuer Sonnensystemforschung, Katlenburg-Lindau 37191 (Germany)

    2009-05-01T23:59:59.000Z

    Preferential heating and acceleration of heavy ions in the solar wind and corona represent a long-standing theoretical problem in space physics, and are distinct experimental signatures of kinetic processes occurring in collisionless plasmas. We show that fast and slow ion-acoustic waves (IAW) and transverse waves, driven by Alfven-cyclotron wave parametric instabilities can selectively destroy the coherent fluid motion of different ion species and, in this way lead to their differential heating and acceleration. Trapping of the more abundant protons by the fast IAW generates a proton beam with drift speed of about the Alfven speed. Because of their larger mass, {alpha} particles do not become significantly trapped and start, by conservation of total ion momentum, drifting relative to the receding bulk protons. Thus the resulting core protons and the {alpha} particles are differentially heated via pitch-angle scattering.

  17. A 2D Particle in Cell model for ion extraction and focusing in electrostatic accelerators

    SciTech Connect (OSTI)

    Veltri, P., E-mail: pierluigi.veltri@igi.cnr.it; Serianni, G. [Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy)] [Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, Viale dell’ Università 2, 35020 Legnaro (PD) (Italy)] [INFN-LNL, Viale dell’ Università 2, 35020 Legnaro (PD) (Italy)

    2014-02-15T23:59:59.000Z

    Negative ions are fundamental to produce intense and high energy neutral beams used to heat the plasma in fusion devices. The processes regulating the ion extraction involve the formation of a sheath on a scale comparable to the Debye length of the plasma. On the other hand, the ion acceleration as a beam is obtained on distances greater than ?{sub D}. The paper presents a model for both the phases of ion extraction and acceleration of the ions and its implementation in a numerical code. The space charge of particles is deposited following usual Particle in Cell codes technique, while the field is solved with finite element methods. Some hypotheses on the beam plasma transition are described, allowing to model both regions at the same time. The code was tested with the geometry of the NIO1 negative ions source, and the results are compared with existing ray tracing codes and discussed.

  18. Compressible Turbulence in Galaxy Clusters: Physics and Stochastic Particle Re-acceleration

    E-Print Network [OSTI]

    G. Brunetti; A. Lazarian

    2007-03-22T23:59:59.000Z

    We attempt to explain the non-thermal emission arising from galaxy clusters as a result of the re-acceleration of electrons by compressible turbulence induced by cluster mergers. In our model intracluster medium (ICM) is represented by a high beta plasma in which turbulent motions are driven at large scales. The corresponding injection velocities are higher than the Alfven velocity. As a result, the turbulence is approximately isotropic up to the scale at which the turbulent velocity gets comparable with the Alfven velocity. Under the hypothesis that turbulence in the ICM is highly super- Alfvenic the magnetic field is passively advected and the field lines are bended on scales smaller than that of the classical, unmagnetized, ion-ion mean free path. This affects ion diffusion and the strength of the effective viscosity. Under these conditions the bulk of turbulence in hot (5-10 keV temperature) galaxy clusters is likely to be dissipated at collisionless scales via resonant coupling with thermal and fast particles. We use collisionless physics to derive the amplitude of the different components of the energy of the compressible modes, and review and extend the treatment of plasma damping in the ICM. We calculate the acceleration of both protons and electrons taking into account both TTD acceleration and non-resonant acceleration by large scale compressions. We find that relativistic electrons can be re-accelerated in the ICM up to energies of several GeV provided that the rms velocity of the compressible turbulent-eddies is (V_L/c_s)^2~0.15-0.3. We find that under typical conditions ~ 2-5 % of the energy flux of the cascading of compressible motions injected at large scales goes into the acceleration of fast particles and that this may explain the observed non-thermal emission from merging galaxy clusters.

  19. Improving beam stability in particle accelerator models by using Hamiltonian control

    E-Print Network [OSTI]

    J. Boreux; T. Carletti; Ch. Skokos; M. Vittot

    2011-09-21T23:59:59.000Z

    We derive a Hamiltonian control theory which can be applied to a 4D symplectic map that models a ring particle accelerator composed of elements with sextupole nonlinearity. The controlled system is designed to exhibit a more regular orbital behavior than the uncontrolled one. Using the Smaller Alignement Index (SALI) chaos indicator, we are able to show that the controlled system has a dynamical aperture up to 1.7 times larger than the original mode

  20. gEMpicker: A Highly Parallel GPU-Accelerated Particle Picking Tool for Cryo-Electron Microscopy

    E-Print Network [OSTI]

    Boyer, Edmond

    gEMpicker: A Highly Parallel GPU-Accelerated Particle Picking Tool for Cryo-Electron Microscopy Abstract Background: Picking images of particles in cryo-electron micrographs is an important step particle images. Thus, a computational bottleneck in reaching high resolution is the accurate and automatic

  1. Mon. Not. R. Astron. Soc. 000, 116 (2012) Printed 29 November 2012 (MN LATEX style file v2.2) Stochastic Particle Acceleration by Helical Turbulence

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    .2) Stochastic Particle Acceleration by Helical Turbulence in Solar Flares Gregory D. Fleishman1,2,3 and Igor N, a nonzero turbulence helicity has a potentially strong effect on the particle acceleration because- rectly accelerating the charged particles in addition to the commonly considered stochastic turbulent

  2. Novel Methods in the Particle-In-Cell Accelerator Code-Framework Warp

    SciTech Connect (OSTI)

    Vay, J. -L.; Grote, D. P.; Cohen, R. H.; Friedman, A.; Grote, D. P.; Cohen, R. H.; Friedman, A.

    2011-09-01T23:59:59.000Z

    The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This paper presents an overview of Warp’s capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including Particle-In-Cell with Adaptive Mesh Refinement, a large-timestep “drift-Lorentz” mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride20 based digital filtering), with great emphasis on the description of the mesh refinement capability. Selected examples of applications of the methods to the abovementioned fields are given.

  3. Gamma-ray novae as probes of relativistic particle acceleration at non-relativistic shocks

    E-Print Network [OSTI]

    Metzger, Brian D; Vurm, Indrek; Hascoet, Romain; Beloborodov, Andrei M; Chomiuk, Laura

    2015-01-01T23:59:59.000Z

    The Fermi LAT discovery that classical novae produce >100 MeV gamma-rays establishes that shocks and relativistic particle acceleration are key features of these events. These shocks are likely to be radiative due to the high densities of the nova ejecta at early times coincident with the gamma-ray emission. Thermal X-rays radiated behind the shock are absorbed by neutral gas and reprocessed into optical emission, similar to Type IIn (interacting) supernovae. The ratio of gamma-ray and optical luminosities, L_gam/L_opt, thus sets a lower limit on the fraction of the shock power used to accelerate relativistic particles, e_nth. The measured values of L_gam/L_opt for two classical novae, V1324 Sco and V339 Del, constrains e_nth > 1e-2 and > 1e-3, respectively. Inverse Compton models for the gamma-ray emission are disfavored given the low electron acceleration efficiency, e_nth ~ 1e-4-1e-3, inferred from observations of Galactic cosmic rays and particle-in-cell (PIC) numerical simulations. Recent hybrid PIC simu...

  4. Settlement in an Amereican landscape : a place of work amidst a particle accelerator's transformation of the Texas prarie

    E-Print Network [OSTI]

    Falliers, Christopher B. (Christopher Basil)

    1991-01-01T23:59:59.000Z

    This thesis considers the design of the research facility accompanying the Superconducting Super Collider, a large particle accelerator planned for central Texas. It will focus on this Pl'Qject as a form of human settlement ...

  5. C. R. Physique 10 (2009) 188196 Laser acceleration of particles in plasmas / Acclration laser de particules dans les plasmas

    E-Print Network [OSTI]

    Strathclyde, University of

    2009-01-01T23:59:59.000Z

    the properties of beams of protons accelerated in ultra-intense laser irradiation of planar foil targets accélérés par l'interaction d'une impulsion laser ultra intense avec une cible solide est discuté. PlusC. R. Physique 10 (2009) 188­196 Laser acceleration of particles in plasmas / Accélération laser de

  6. Review of Heavy-ion Induced Desorption Studies for Particle Accelerators

    E-Print Network [OSTI]

    Mahner, E

    2008-01-01T23:59:59.000Z

    During high-intensity heavy-ion operation of several particle accelerators worldwide, large dynamic pressure rises of orders of magnitude were caused by lost beam ions that impacted under grazing angle onto the vacuum chamber walls. This ion-induced desorption, observed, for example, at CERN, GSI, and BNL, can seriously limit the ion intensity, luminosity, and beam lifetime of the accelerator. For the heavyion program at CERN's Large Hadron Collider collisions between beams of fully stripped lead (208Pb82+) ions with a beam energy of 2.76 TeV/u and a nominal luminosity of 10**27 cm**-2 s**-1 are foreseen. The GSI future project FAIR (Facility for Antiproton and Ion Research) aims at a beam intensity of 10**12 uranium (238U28+) ions per second to be extracted from the synchrotron SIS18. Over the past years an experimental effort has been made to study the observed dynamic vacuum degradations, which are important to understand and overcome for present and future particle accelerators. The paper reviews the resu...

  7. DNS of vertical plane channel flow with finite-size particles: Voronoi analysis, acceleration statistics and particle-conditioned averaging

    E-Print Network [OSTI]

    Garcia-Villalba, Manuel; Uhlmann, Markus

    2012-01-01T23:59:59.000Z

    We have performed a direct numerical simulation of dilute turbulent particulate flow in a vertical plane channel, fully resolving the phase interfaces. The flow conditions are the same as those in the main case of "Uhlmann, M., Phys. Fluids, vol. 20, 2008, 053305", with the exception of the computational domain length which has been doubled in the present study. The statistics of flow and particle motion are not significantly altered by the elongation of the domain. The large-scale columnar-like structures which had previously been identified do persist and they are still only marginally decorrelated in the prolonged domain. Voronoi analysis of the spatial particle distribution shows that the state of the dispersed phase can be characterized as slightly more ordered than random tending towards a homogeneous spatial distribution. It is also found that the p.d.f.'s of Lagrangian particle accelerations for wall-normal and spanwise directions follow a lognormal distribution as observed in previous experiments of ...

  8. Magnetospheric Eternally Collapsing Objects (MECOs): Likely New Class of Source of Cosmic Particle Acceleration

    E-Print Network [OSTI]

    Abhas Mitra

    2005-07-29T23:59:59.000Z

    It is known that spinning pulsars could be source of VHE-UHE cosmic particle acceleration. It is also conjectured that (fictitious) spinning Black Holes (BH) could be sites of cosmic particle acceleration. However, it has been shown by Mitra and Leiter and Robertson that General Relativity (GR) actually does not allow the existence or formation of finite mass BHs. It was predicted that the BH Candiadates (BHCs) have strong intrinsic magnetic fields (like pulsars) instead of Event Horizons. And this prediction has tentatively been verified in a series of papers by Robertson & Leiter. Thus all observed BH Candidates are actually not BHs, and, they are expected to be MECOs. Stellar mass MECOs are GR analogs of conventionally known isolated pulsars. While pulsars are/have (i) COLD, i.e., not supported by radiation pressure, MECOs are HOT, i.e., supported primarily by trapped radiation pressure, (ii) upper mass limit of 3-4 Msolar MECOs, being HOT, have no Upper Mass Limit, (iii) surface gravitational red shift, z ~ 0.1 -0.2, MECOs have z >> 1 so that photons can remain almost permanently trapped inside them, (iv) magnetic field B > 10^{13} G. It may be recalled that isolated (non- accreting) uncharged BHs are cold and dead objects without any physical activity. On the other hand, isolated spinning MECOs are like extreme GR pulsars.

  9. Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasma

    SciTech Connect (OSTI)

    Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E. [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-05-15T23:59:59.000Z

    Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a “well” structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3–4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the electron diffusion region. Unlike ions, electrons acquire energy mostly from the reconnection electric field, and the energy gain is localized near the X-point. However, the increase in the electron bulk flow energy remains negligible. These observations support the assertion that efficient electron heating mechanisms exist around the electron diffusion region and that the heat generated there is quickly transported along the magnetic field due to the high parallel thermal conductivity of electrons. Classical Ohmic dissipation based on the perpendicular Spitzer resistivity is too small to balance the measured heat flux, indicating the presence of anomalous electron heating.

  10. Solid particle acceleration in a high Reynolds number channel flow: DNS and LES with stochastic modelling of subgrid acceleration

    E-Print Network [OSTI]

    Boyer, Edmond

    sediment transport to atmospheric dispersion of pollutants or solid deposition in marine flows. Previous modelling of subgrid acceleration This article has been downloaded from IOPscience. Please scroll down in a high Reynolds number channel flow: DNS and LES with stochastic modelling of subgrid acceleration R

  11. Using X-ray observations to identify the particle acceleration mechanisms in VHE SNRs and "dark" VHE sources

    E-Print Network [OSTI]

    G. Pühlhofer

    2007-10-17T23:59:59.000Z

    Very high energy (VHE) gamma-ray observations have proven to be very successful in localizing Galactic acceleration sites of VHE particles. Observations of shell-type supernova remnants have confirmed that particles are accelerated to VHE energies in supernova blast waves; the interpretation of the gamma-ray data in terms of hadronic or leptonic particle components in these objects relies nevertheless strongly on input from X-ray observations. The largest identified Galactic VHE source class consists of pulsar wind nebulae, as detected in X-rays. Many of the remaining VHE sources remain however unidentified until now. With X-ray observations of these enigmatic "dark" objects one hopes to solve the following questions: What is the astrophysical nature of these sources? Are they predominantly electron or hadron accelerators? And what is their contribution to the overall cosmic ray energy budget? The paper aims to provide an overview over the identification status of the Galactic VHE source population.

  12. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    E-Print Network [OSTI]

    Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia, G

    2014-01-01T23:59:59.000Z

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  13. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    E-Print Network [OSTI]

    Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia G , G

    2014-01-01T23:59:59.000Z

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN { the AWAKE experiment { has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  14. A charged particle in a homogeneous magnetic field accelerated by a time periodic Aharonov-Bohm flux

    E-Print Network [OSTI]

    T. Kalvoda; P. Stovicek

    2011-07-14T23:59:59.000Z

    We consider a nonrelativistic quantum charged particle moving on a plane under the influence of a uniform magnetic field and driven by a periodically time-dependent Aharonov-Bohm flux. We observe an acceleration effect in the case when the Aharonov-Bohm flux depends on time as a sinusoidal function whose frequency is in resonance with the cyclotron frequency. In particular, the energy of the particle increases linearly for large times. An explicit formula for the acceleration rate is derived with the aid of the quantum averaging method, and then it is checked against a numerical solution with a very good agreement.

  15. Particle acceleration at shock waves moving at arbitrary speed: the case of large scale magnetic field and anisotropic scattering

    E-Print Network [OSTI]

    G. Morlino; P. Blasi; M. Vietri

    2007-01-08T23:59:59.000Z

    A mathematical approach to investigate particle acceleration at shock waves moving at arbitrary speed in a medium with arbitrary scattering properties was first discussed in (Vietri 2003) and (Blasi & Vietri 2005}. We use this method and somewhat extend it in order to include the effect of a large scale magnetic field in the upstream plasma, with arbitrary orientation with respect to the direction of motion of the shock. We also use this approach to investigate the effects of anisotropic scattering on spectra and anisotropies of the distribution function of the accelerated particles.

  16. Application of Atmospheric Plasma-Sprayed Ferrite Layers for Particle Accelerators

    E-Print Network [OSTI]

    Caspers, F; Federmann, S; Taborelli, M; Schulz, C; Bobzin, K; Wu, J

    2013-01-01T23:59:59.000Z

    A common problem in all kinds of cavity-like structures in particle accelerators is the occurrence of RF-resonances. Typically, ferrite plates attached to the walls of such structures as diagnostic devices, kickers or collimators, are used to dampen those undesired modes. However, the heat transfer rate from these plates to the walls is rather limited. Brazing ferrite plates to the walls is not possible in most cases due to the different thermal expansion coefficients. To overcome those limitations, atmospheric plasma spraying techniques have been investigated. Ferrite layers with a thickness from 50 ?m to about 300 ?m can be deposited on metallic surfaces like stainless steel exhibiting good thermal contact and still reasonable absorption properties. In this paper the technological aspects of plasma deposition are discussed and results of specifically developed RF loss measurement procedures for such thin magnetically lossy layers on metal are presented.

  17. Insights into the particle acceleration of a peculiar gamma -ray radio galaxy IC 310

    E-Print Network [OSTI]

    Sitarek, J; Mannheim, K; Colin, P; Kadler, M; Schultz, R; Krauß, F; Ros, E; Bach, U; Wilms, J

    2015-01-01T23:59:59.000Z

    IC 310 has recently been identified as a gamma-ray emitter based on observations at GeV energies with Fermi-LAT and at very high energies (VHE, E > 100 GeV) with the MAGIC telescopes. Despite IC 310 having been classified as a radio galaxy with the jet observed at an angle > 10 degrees, it exhibits a mixture of multiwavelength properties of a radio galaxy and a blazar, possibly making it a transitional object. On the night of 12/13th of November 2012 the MAGIC telescopes observed a series of violent outbursts from the direction of IC 310 with flux-doubling time scales faster than 5 min and a peculiar spectrum spreading over 2 orders of magnitude. Such fast variability constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole, challenging the shock acceleration models, commonly used in explanation of gamma-ray radiation from active galaxies. Here we will show that this emission can be associated with pulsar-like particle acceleration by the electric...

  18. Production of .sup.64 Cu and other radionuclides using a charged-particle accelerator

    DOE Patents [OSTI]

    Welch, Michael J. (Creve Couer, MO); McCarthy, Deborah W. (Maryland Heights, MO); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

    2000-01-01T23:59:59.000Z

    Radionuclides are produced according to the present invention at commercially significant yields and at specific activities which are suitable for use in radiodiagnostic agents such as PET imaging agents and radiotherapeutic agents and/or compositions. In the method and system of the present invention, a solid target having an isotopically enriched target layer electroplated on an inert substrate is positioned in a specially designed target holder and irradiated with a charged-particle beam. The beam is preferably generated using an accelerator such as a biomedical cyclotron at energies ranging from about 5 MeV to about 25 MeV. The target is preferably directly irradiated, without an intervening attenuating foil, and with the charged particle beam impinging an area which substantially matches the target area. The irradiated target is remotely and automatically transferred from the target holder, preferably without transferring any target holder subassemblies, to a conveyance system which is preferably a pneumatic or hydraulic conveyance system, and then further transferred to an automated separation system. The system is effective for processing a single target or a plurality of targets. After separation, the unreacted target material can be recycled for preparation of other targets. In a preferred application of the invention, a biomedical cyclotron has been used to produce over 500 mCi of .sup.64 Cu having a specific activity of over 300 mCi/.mu.g Cu according to the reaction .sup.64 Ni(p,n).sup.64 Cu. These results indicate that accelerator-produced .sup.64 Cu is suitable for radiopharmaceutical diagnostic and therapeutic applications.

  19. 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.

  20. GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method

    SciTech Connect (OSTI)

    Gong Chunye, E-mail: gongchunye@gmail.com [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Liu Jie, E-mail: liujie@nudt.edu.cn [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Chi Lihua [School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Huang Haowei [Institut fuer Informatik, Technische Universitaet Muenchen, D-85748 Garching, Munich (Germany); Fang Jingyue [School of Physics and Mathematics, National University of Defense Technology, Changsha 410073 (China); Gong Zhenghu [School of Computer Science, National University of Defense Technology, Changsha 410073 (China)

    2011-07-01T23:59:59.000Z

    Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates (S{sub n}) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.

  1. The X-ray Jet in Centaurus A: Clues on the Jet Structure and Particle Acceleration

    E-Print Network [OSTI]

    Jun Kataoka; Lukasz Stawarz; Felix Aharonian; Fumio Takahara; Michal Ostrowski; Philip G. Edwards

    2005-12-10T23:59:59.000Z

    We report detailed studies of the X-ray emission from the kpc scale jet in the nearest active galaxy, Cen A. 41 compact sources were found within the jet, 13 of which were newly identified. We construct the luminosity function for the detected jet-knots and argue that the remaining emission is most likely to be truly diffuse, rather than resulting from the pile-up of unresolved faint knots. The transverse jet profile reveals that the extended emission has the intensity peak at the jet boundaries. We note that limb-brightened jet morphologies have been observed previously at radio frequencies in some jet sources, but never so clearly at higher photon energies. Our result therefore supports a stratified jet model, consisting of a relativistic outflow including a boundary layer with a velocity shear. In addition, we found that the X-ray spectrum of the diffuse component is almost uniform across and along the jet. We discuss this spectral behavior within a framework of shock and stochastic particle acceleration processes. We note some evidence for a possible spectral hardening at the outer sheath of the jet. Due to the limited photon statistics of the present data, further deep observations of Cen A are required to determine the reality of this finding, however we note that the existence of the hard X-ray features at outer jet boundaries would provide an important challenge to theories for the evolution of ultra-relativistic particles within the jets.

  2. On the continuum radio-spectrum of Cas A: possible evidence of the non-linear particle acceleration

    E-Print Network [OSTI]

    Oni?, D

    2015-01-01T23:59:59.000Z

    Integrated radio-spectrum of Cas A in continuum was analyzed with special emphasis on possible high frequency spectral curvature. We conclude that the most probable scenario is that Planck's new data reveal the imprint of non-linear particle acceleration in the case of this young Galactic supernova remnant (SNR).

  3. A complete cosmic scenario from inflation to late time acceleration: Non-equilibrium thermodynamics in the context of particle creation

    E-Print Network [OSTI]

    Subenoy Chakraborty; Subhajit Saha

    2015-07-06T23:59:59.000Z

    The paper deals with the mechanism of particle creation in the framework of irreversible thermodynamics. The second order non-equilibrium thermodynamical prescription of Israel and Stewart has been presented with particle creation rate, treated as the dissipative effect. In the background of a flat FRW model, we assume the non-equilibrium thermodynamical process to be isentropic so that the entropy per particle does not change and consequently the dissipative pressure can be expressed linearly in terms of the particle creation rate. Here the dissipative pressure behaves as a dynamical variable having a non-linear inhomogeneous evolution equation and the entropy flow vector satisfies the second law of thermodynamics. Further, using the Friedmann equations and by proper choice of the particle creation rate as a function of the Hubble parameter, it is possible to show (separately) a transition from the inflationary phase to the radiation era and also from matter dominated era to late time acceleration. Also, in analogy to analytic continuation, it is possible to show a continuous cosmic evolution from inflation to late time acceleration by adjusting the parameters. It is found that in the de Sitter phase, the comoving entropy increases exponentially with time, keeping entropy per particle unchanged. Subsequently, the above cosmological scenarios has been described from field theoretic point of view by introducing a scalar field having self interacting potential. Finally, we make an attempt to show the cosmological phenomenon of particle creation as Hawking radiation, particularly during the inflationary era.

  4. Vacuum effects of ultra-low mass particle account for Recent Acceleration of Universe

    E-Print Network [OSTI]

    Leonard Parker; Alpan Raval

    1999-08-04T23:59:59.000Z

    In recent work, we showed that non-perturbative vacuum effects of a very low mass particle could induce, at a redshift of order 1, a transition from a matter-dominated to an accelerating universe. In that work, we used the simplification of a sudden transition out of the matter-dominated stage and were able to fit the Type Ia supernovae (SNe-Ia) data points with a spatially-open universe. In the present work, we find a more accurate, smooth {\\it spatially-flat} analytic solution to the quantum-corrected Einstein equations. This solution gives a good fit to the SNe-Ia data with a particle mass parameter $m_h$ in the range $6.40 \\times 10^{-33}$ eV to $7.25 \\times 10^{-33}$ eV. It follows that the ratio of total matter density (including dark matter) to critical density, $\\O_0$, is in the range 0.58 to 0.15, and the age $t_0$ of the universe is in the range $8.10 h^{-1}$ Gyr to $12.2 h^{-1}$ Gyr, where $h$ is the present value of the Hubble constant, measured as a fraction of the value 100 km/(s Mpc). This spatially-flat model agrees with estimates of the position of the first acoustic peak in the small angular scale fluctuations of the cosmic background radiation, and with light-element abundances of standard big-bang nucleosynthesis. Our model has only a single free parameter, $m_h$, and does not require that we live at a special time in the evolution of the universe.

  5. Electron acceleration with improved Stochastic Differential Equation method: cutoff shape of electron distribution in test-particle limit

    E-Print Network [OSTI]

    Yamazaki, Ryo; Tsuchihashi, Yuka; Nakajima, Ryosuke; Ohira, Yutaka; Yanagita, Shohei

    2015-01-01T23:59:59.000Z

    We develop a method of stochastic differential equation to simulate electron acceleration at astrophysical shocks. Our method is based on It\\^{o}'s stochastic differential equations coupled with a particle splitting, employing a skew Brownian motion where an asymmetric shock crossing probability is considered. Using this code, we perform simulations of electron acceleration at stationary plane parallel shock with various parameter sets, and studied how the cutoff shape, which is characterized by cutoff shape parameter $a$, changes with the momentum dependence of the diffusion coefficient $\\beta$. In the age-limited cases, we reproduce previous results of other authors, $a\\approx2\\beta$. In the cooling-limited cases, the analytical expectation $a\\approx\\beta+1$ is roughly reproduced although we recognize deviations to some extent. In the case of escape-limited acceleration, numerical result fits analytical stationary solution well, but deviates from the previous asymptotic analytical formula $a\\approx\\beta$.

  6. Particle acceleration and high-frequency (X-ray and $?$-ray) emission in the jets of active galactic nuclei

    E-Print Network [OSTI]

    V. V. Usov; M. V. Smolsky

    1998-10-26T23:59:59.000Z

    It is suggested that the outflowing plasma in the jets of active galactic nuclei (AGNs) is inhomogeneous and consists of separate clouds. These clouds are strongly magnetized and move away from the central engine at relativistic speeds. The clouds interact with an ambient medium which is assumed to be at rest. In the process of this interaction, particles of the ambient medium are accelerated to high energies at the cloud front and flow ahead of the front. It is shown that the radiation of the accelerated particles may be responsible for the X-ray and $\\gamma$-ray emission from AGN jets. TeV $\\gamma$-ray emission is generated in the inner parts of AGN jets where the Lorentz factor of the cloud fronts is $\\Gamma_0\\geq 30$, while GeV $\\gamma$-ray emission emanates from the outer parts of AGN jets where $\\Gamma_0$ is $\\sim 10$.

  7. Self-interaction in the Bopp–Podolsky electrodynamics: Can the observable mass of a charged particle depend on its acceleration?

    SciTech Connect (OSTI)

    Zayats, Alexei E., E-mail: Alexei.Zayats@kpfu.ru

    2014-03-15T23:59:59.000Z

    In this paper we obtain the expression for the self-force in the model with the Lagrangian containing additional terms, quadratic in Maxwell tensor derivatives (so-called Bopp–Podolsky electrodynamics). Features of this force are analyzed for various limiting cases. When a charged particle moves along straight line with a uniform acceleration, an explicit formula is found. In the framework of the considered model, an observable renormalized particle mass is shown to depend on its acceleration. This dependence allows, in principle, to extract experimentally a value of the particle bare mass. -- Highlights: •An expression for the self-force in the Bopp–Podolsky electrodynamics is given. •For a uniformly accelerated charged particle an explicit formula for the self-force is obtained. •Dependence between the observable mass of a charged particle and its acceleration is found.

  8. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    SciTech Connect (OSTI)

    Byer, Robert L.

    2013-11-07T23:59:59.000Z

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  9. Efficient Modeling of Plasma Wake Field Acceleration Experiments Using Particle-In-Cell Methods

    E-Print Network [OSTI]

    An, Weiming

    2013-01-01T23:59:59.000Z

    bubble) and (c) the beam particles (plotted as colored dots:bubble) and (c) the beam particles (plotted as colored dots:

  10. Physics 227 Winter, 1998 Problem Set 6 Due date: Monday, February 16 6.1 uniform acceleration It is possible to expose a particle to a constant force, as seen

    E-Print Network [OSTI]

    Witten, Thomas A.

    , the particle experiences uniform acceleration: its speed changes by a constant amount for each (small) unit of proper time. In the particle's frame, the acceleration is always a, while its own speed is always 0. Now suppose the particle starts from rest in the lab frame and starts "falling" under uniform acceleration

  11. A Framework for a General Purpose Intelligent Control System for Particle Accelerators. Phase II Final Report

    SciTech Connect (OSTI)

    Dr. Robert Westervelt; Dr. William Klein; Dr. Michael Kroupa; Eric Olsson; Rick Rothrock

    1999-06-28T23:59:59.000Z

    Vista Control Systems, Inc. has developed a portable system for intelligent accelerator control. The design is general in scope and is thus configurable to a wide range of accelerator facilities and control problems. The control system employs a multi-layer organization in which knowledge-based decision making is used to dynamically configure lower level optimization and control algorithms.

  12. Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration

    SciTech Connect (OSTI)

    Tang, V; Adams, M L; Rusnak, B

    2009-07-24T23:59:59.000Z

    The final Z-pinch stage of a Dense Plasma Focus (DPF) could be used as a simple, compact, and potentially rugged plasma-based high-gradient accelerator with fields at the 100 MV/m level. In this paper we review previously published experimental beam data that indicate the feasibility of such an DPF-based accelerator, qualitatively discuss the physical acceleration processes in terms of the induced voltages, and as a starting point examine the DPF acceleration potential by numerically applying a self-consistent DPF system model that includes the induced voltage from both macroscopic and instability driven plasma dynamics. Applications to the remote detection of high explosives and a multi-staged acceleration concept are briefly discussed.

  13. Charged particle driver for ICF using an accelerated, focused compact torus

    SciTech Connect (OSTI)

    Meeker, D.J.; Hammer, J.H.; Hartman, C.W.

    1986-06-01T23:59:59.000Z

    We report the status of evaluating an accelerated and focused compact torus as a driver for ICF. We are studying the acceleration and focusing aspects experimentally in the RACE facility, a recently completed ring generator coupled to a 260 kJ acceleration bank. Compact torus and ICF target interaction is being investigated with PIC codes and LASNEX, a 2D magneto-hydrodynamics code. Final conditions required of the CT are discussed as well as coupling issues such as superthermal electron production. We conclude with an economic evaluation of a few 100 MW reactor driven by a compact torus. 9 refs., 5 figs., 1 tab.

  14. Multiorbit induction accelerators

    SciTech Connect (OSTI)

    Zvontsov, A.A.; Kas'yanov, V.A.; Chakhlov, V.L.

    1985-09-01T23:59:59.000Z

    Large numbers of particles accelerated per cycle are made possible by accelerating simultaneously in several equilibrium orbits in a single betatron structure. (AIP)

  15. Selected topics in particle accelerators: Proceedings of the CAP meetings. Volume 4

    SciTech Connect (OSTI)

    Parsa, Z. [ed.] [comp.

    1995-10-01T23:59:59.000Z

    This Report includes copies of transparencies and notes from the presentations made at the Center for Accelerator Physics at Brookhaven National Laboratory. Editing and changes to the authors` contributions in this Report were made only to fulfill the publication requirements. This volume includes notes and transparencies on eight presentations: ``Application of Accelerator-Driven Spallation Targets - Including Tritium Production and Nuclear Waste Transmutation``, ``BNL 5 MW Pulsed Spallation Neutron Source Study``, ``Designing and Understanding of Magnets with the Help of Conformal Mapping``, ``Laser - Electron Beam Scattering Coherent Compton X-Ray Sources``, ``The LHC Project``, ``Optimization of the Photocathode-Linac Separation for the ATF [Accelerator Test Facility] Injection System``, ``On CEBAF Commissioning: First Results``, and ``The Proposed Booster Application Facility at BNL``. An Appendix lists dates, topics, and speakers from October 1989 to December 1994.

  16. Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection*

    E-Print Network [OSTI]

    Wurtele, Jonathan

    particle injection* W. P. Leemans,,a) P. Volfbeyn, K. Z. Guo, and S. Chattopadhyay Ernest Orlando Lawrence-based injection of particles into a plasma wake, are presented. Details of the experimental program at Lawrence for the accel- erating fields as well as guiding for the laser, and a suitable laser driver. The most

  17. Lagrangian Measurements of Inertial Particle Accelerations in Grid Generated Wind Tunnel Turbulence

    E-Print Network [OSTI]

    Gylfason, Ármann

    (where the particle-fluid density ratio is order 1000), or fuel drops in combustors, respond exponential tails that are narrower than those of a fluid particles (St 0) and there is a decrease selectively sample the fluid field and are less likely to experience regions of the fluid undergoing

  18. Small-scale magnetic islands in the solar wind and their role in particle acceleration. Part 1: Dynamics of magnetic islands near the heliospheric current sheet

    E-Print Network [OSTI]

    Khabarova, O; Li, G; Roux, J A le; Webb, G M; Dosch, A; Malandraki, O E

    2015-01-01T23:59:59.000Z

    Increases of ion fluxes in the keV-MeV range are sometimes observed near the heliospheric current sheet (HCS) during periods when other sources are absent. These resemble solar energetic particle (SEP) events, but the events are weaker and apparently local. Conventional explanations based on either shock acceleration of charged particles or particle acceleration due to magnetic reconnection at interplanetary current sheets are not persuasive. We suggest instead that recurrent magnetic reconnection occurs at the HCS and smaller current sheets in the solar wind (Zharkova & Khabarova 2012), of which a consequence is particle energization by the dynamically evolving secondary current sheets and magnetic islands (Zank et al. 2014; Drake et al. 2006a). The effectiveness of the trapping and acceleration process associated with magnetic islands depends in part on the topology of the HCS. We show that the HCS possesses ripples superimposed on the large-scale flat or wavy structure. We conjecture that the ripples c...

  19. User's manual for ONEDANT: a code package for one-dimensional, diffusion-accelerated, neutral-particle transport

    SciTech Connect (OSTI)

    O'Dell, R.D.; Brinkley, F.W. Jr.; Marr, D.R.

    1982-02-01T23:59:59.000Z

    ONEDANT is designed for the CDC-7600, but the program has been implemented and run on the IBM-370/190 and CRAY-I computers. ONEDANT solves the one-dimensional multigroup transport equation in plane, cylindrical, spherical, and two-angle plane geometries. Both regular and adjoint, inhomogeneous and homogeneous (k/sub eff/ and eigenvalue search) problems subject to vacuum, reflective, periodic, white, albedo, or inhomogeneous boundary flux conditions are solved. General anisotropic scattering is allowed and anisotropic inhomogeneous sources are permitted. ONEDANT numerically solves the one-dimensional, multigroup form of the neutral-particle, steady-state form of the Boltzmann transport equation. The discrete-ordinates approximation is used for treating the angular variation of the particle distribution and the diamond-difference scheme is used for phase space discretization. Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm. A standard inner (within-group) iteration, outer (energy-group-dependent source) iteration technique is used. Both inner and outer iterations are accelerated using the diffusion synthetic acceleration method. (WHK)

  20. Particle Acceleration and Gamma-ray emission due to magnetic reconnection in the core region of radio galaxies

    E-Print Network [OSTI]

    Khiali, Behrouz; Sol, Hélène

    2015-01-01T23:59:59.000Z

    The current detectors of gamma-ray emission have too poor resolution to determine whether this emission is produced in the jet or in the core, specially of low luminous, non-blazar AGNs (as radio galaxies). In recent works it has been found that the power released by events of turbulent fast magnetic reconnection in the core region of these sources is more than sufficient to reproduce the observed gamma-ray luminosities. Besides, 3D MHD simulations with test particles have demonstrated that a first-order Fermi process within reconnection sites with embedded turbulence results very efficient particle acceleration rates. Employing this acceleration mechanism and the model above, and considering the relevant leptonic and hadronic loss processes in the core region, we computed the spectral energy distribution (SED) of radio galaxies for which very high energy (VHE) emission has been detected (namely, M87, Cen A, Per A, and IC 310). We found that these match very well specially with the VHE observations, therefore...

  1. Particle acceleration and radiation friction effects in the filamentation instability of pair plasmas

    E-Print Network [OSTI]

    D'Angelo, M; Sgattoni, A; Pegoraro, F; Macchi, A

    2015-01-01T23:59:59.000Z

    The evolution of the filamentation instability produced by two counter-streaming pair plasmas is studied with particle-in-cell (PIC) simulations in both one (1D) and two (2D) spatial dimensions. Radiation friction effects on particles are taken into account. After an exponential growth of both the magnetic field and the current density, a nonlinear quasi-stationary phase sets up characterized by filaments of opposite currents. During the nonlinear stage, a strong broadening of the particle energy spectrum occurs accompanied by the formation of a peak at twice their initial energy. A simple theory of the peak formation is presented. The presence of radiative losses does not change the dynamics of the instability but affects the structure of the particle spectra.

  2. Particle acceleration close to the supermassive black hole horizon: the case of M87

    E-Print Network [OSTI]

    F. M. Rieger; F. A. Aharonian

    2008-05-27T23:59:59.000Z

    The radio galaxy M87 has recently been found to be a rapidly variable TeV emitting source. We analyze the implications of the observed TeV characteristics and show that it proves challenging to account for them within conventional acceleration and emission models. We discuss a new pulsar-type scenario for the origin of variable, very high energy (VHE) emission close to the central supermassive black hole and show that magneto-centrifugally accelerated electrons could efficiently Compton upscatter sub-mm ADAF disk photons to the TeV regime, leading to VHE characteristics close to the observed ones. This suggests, conversely, that VHE observations of highly under-luminous AGNs could provide an important diagnostic tool for probing the conditions prevalent in the inner accretion disk of these sources.

  3. Particle accelerator control and data acquisition in the context of VAX/VMS

    SciTech Connect (OSTI)

    Schaller, S.C.; Corley, J.K.

    1983-01-01T23:59:59.000Z

    The Los Alamos Meson Physics Facility (LAMPF) Control System monitors and controls a linear accelerator through more than 10,000 widely disparate I/O devices. The heart of the Control System software is the Data System, which provides a uniform application program interface based on symbolic device names. In many ways the Data System parallels the VAX/VMS Record Management Services (RMS) in its needs for asynchronous operations, protection, and locks for multiprocess interactions. Since the accelerator control hardware is continually changing, it is important that privileged code be kept to a minimum or be testable in a non-privileged environment. This paper describes the LAMPF Data System design including the use of VAX/VMS user written system services (both kernel and supervisor mode), a user supplied image rundown routine, the VAX/VMS lock manager, and a large (3.5 Mbyte) protected global section.

  4. High rate resistive plate chambers: An inexpensive, fast, large area detector of energetic charged particles for accelerator and non-accelerator applications

    SciTech Connect (OSTI)

    Wuest, C.R.; Ables, E.; Bionta, R.M.; Clamp, O.; Haro, M.; Mauger, G.J.; Miller, K.; Olson, H.; Ramsey, P.

    1993-05-01T23:59:59.000Z

    Resistive Plate Chambers, or RPCs, have been used until recently as large detectors of cosmic ray muons. They are now finding use as fast large-area trigger and muon detection systems for different high energy physics detectors such the L3 Detector at LEP and future detectors to be built at the Superconducting Super Collider (SSC) and at the Large Hadron Collider (LHC) at CERN. RPC systems at these accelerators must operate with high efficiency, providing nanosecond timing resolution in particle fluences up to a few tens of kHz/cm{sup 2} -- with thousands of square meters of active area. RPCs are simple and cheap to construct. The authors report here recent work on RPCs using new materials that exhibit a combination of desirable RPC features such as low bulk resistivity, high dielectric strength, low mass, and low cost. These new materials were originally developed for use in electronics assembly areas and other applications, where static electric charge buildup can damage sensitive electrical systems.

  5. 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.

  6. A Novel Scheme to Search for Fractional Charge Particles in Low Energy Accelerator Experiments

    E-Print Network [OSTI]

    Jianguo Bian; Jiahui Wang

    2010-06-15T23:59:59.000Z

    In the Standard Model of particle physics, the quarks and anti-quarks have fractional charge equal to $\\pm1/3$ or $\\pm2/3$ of the electron's charge. There has been a large number of experiments searching for fractional charge, isolatable, elementary particles using a variety of methods, including $e^+e^-$ collisions using dE/dx ionization energy loss measurements, but no evidence has been found to confirm existence of free fractional charge particles, which leads to the quark confinement theory. In this paper, a proposal to search for this kind particles is presented, which is based on the conservation law of four-momentum. Thanks to the CLEOc and BESIII detectors' large coverage, good particle identification, precision measurements of tracks' momenta and their large recorded data samples, these features make the scheme feasible in practice. The advantage of the scheme is independent of any theoretical models and sensitive for a small fraction of the quarks transitioning to the unconfinement phase from the confinement phase.

  7. Accelerating Dissipative Particle Dynamics Simulations on GPUs: Algorithms, Numerics and Applications

    E-Print Network [OSTI]

    Tang, Yu-Hang

    2013-01-01T23:59:59.000Z

    We present a scalable dissipative particle dynamics simulation code, fully implemented on the Graphics Processing Units (GPUs) using a hybrid CUDA/MPI programming model, which achieves 10-30 times speedup on a single GPU over 16 CPU cores and almost linear weak scaling across a thousand nodes. A unified framework is developed within which the efficient generation of the neighbor list and maintaining particle data locality are addressed. Our algorithm generates strictly ordered neighbor lists in parallel, while the construction is deterministic and makes no use of atomic operations or sorting. Such neighbor list leads to optimal data loading efficiency when combined with a two-level particle reordering scheme. A faster in situ generation scheme for Gaussian random numbers is proposed using precomputed binary signatures. We designed custom transcendental functions that are fast and accurate for evaluating the pairwise interaction. The correctness and accuracy of the code is verified through a set of test cases ...

  8. Condensed Surfaces of Magnetic Neutron Stars, Thermal Surface Emission, and Particle Acceleration Above Pulsar Polar Caps

    E-Print Network [OSTI]

    Zach Medin; Dong Lai

    2008-01-18T23:59:59.000Z

    For sufficiently strong magnetic fields and/or low temperatures, the neutron star surface may be in a condensed state with little gas or plasma above it. Such surface condensation can significantly affect the thermal emission from isolated neutron stars, and may lead to the formation of a charge-depleted acceleration zone ("vacuum gap") in the magnetosphere above the stellar polar cap. Using the latest results on the cohesive property of magnetic condensed matter, we quantitatively determine the conditions for surface condensation and vacuum gap formation in magnetic neutron stars. We find that condensation can occur if the thermal energy kT of the neutron star surface is less than about 8% of its cohesive energy Q_s, and that a vacuum gap can form if the neutron star's rotation axis and magnetic moment point in opposite directions and kT is less than about 4% of Q_s. Thus, vacuum gap accelerators may exist for some neutron stars. Motivated by this result, we also study the physics of pair cascades in the vacuum gap model for photon emission by accelerating electrons and positrons due to both curvature radiation and resonant/nonresonant inverse Compton scattering. Our calculations of the condition of cascade-induced vacuum breakdown and the related pulsar death line/boundary generalize previous works to the superstrong field regime. We find that inverse Compton scatterings do not produce a sufficient number of high energy photons in the gap and thus do not lead to pair cascades for most neutron star parameters. We discuss the implications of our results for the recent observations of neutron star thermal radiation as well as for the detection/non-detection of radio emission from high-B pulsars and magnetars.

  9. Review of Particle Physics

    E-Print Network [OSTI]

    Nakamura, Kenzo

    2010-01-01T23:59:59.000Z

    for non-accelerator physics . . . . . . . . . 328 ParticleColliders, accelerator physics of Coupling between matterdetectors for non-accelerator physics (Figure 29.5) . . .

  10. Means for the focusing and acceleration of parallel beams of charged particles. [Patent application

    DOE Patents [OSTI]

    Maschke, A.W.

    1980-09-23T23:59:59.000Z

    Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

  11. Acceleration of Energetic Particles Through Self-Generated Waves in a Decelerating Coronal Shock

    E-Print Network [OSTI]

    Sanahuja, Blai

    , Finland Department of Physics, University of Helsinki, Finland Abstract. We have developed a simulation- ered the primary source of large solar energetic parti- cle (SEP) intensities. Injected particles repeatedly cross the shock front, scattering from the plasma waves, and gain energy on each crossing

  12. Radiation Heat Transfer in Particle-Laden Gaseous Flame: Flame Acceleration and Triggering Detonation

    E-Print Network [OSTI]

    Liberman, M A; Kiverin, A D

    2015-01-01T23:59:59.000Z

    In this study we examine influence of the radiation heat transfer on the combustion regimes in the mixture, formed by suspension of fine inert particles in hydrogen gas. The gaseous phase is assumed to be transparent for the thermal radiation, while the radiant heat absorbed by the particles is then lost by conduction to the surrounding gas. The particles and gas ahead of the flame is assumed to be heated by radiation from the original flame. It is shown that the maximum temperature increase due to the radiation preheating becomes larger for a flame with lower velocity. For a flame with small enough velocity temperature of the radiation preheating may exceed the crossover temperature, so that the radiation heat transfer may become a dominant mechanism of the flame propagation. In the case of non-uniform distribution of particles, the temperature gradient formed due to the radiation preheating can initiate either deflagration or detonation ahead of the original flame via the Zel'dovich's gradient mechanism. Th...

  13. Real-time particle-detection probabilities in accelerated macroscopic detectors

    E-Print Network [OSTI]

    Charis Anastopoulos; Ntina Savvidou

    2014-03-04T23:59:59.000Z

    We construct the detection rate for particle detectors moving along non-inertial trajectories and interacting with quantum fields. The detectors described here are characterized by the presence of records of observation throughout their history, so that the detection rate corresponds to directly measurable quantities. This is in contrast to past treatments of detectors, which actually refer to probes, i.e., microscopic systems from which we extract information only after their interaction has been completed. Our treatment incorporates the irreversibility due to the creation of macroscopic records of observation. The key result is a real-time description of particle detection and a rigorously defined time-local probability density function (PDF). The PDF depends on the scale $\\sigma$ of the temporal coarse-graining that is necessary for the formation of a macroscopic record. The evaluation of the PDF for Unruh-DeWitt detectors along different types of trajectory shows that only paths with at least one characteristic time-scale much smaller than $\\sigma$ lead to appreciable particle detection. Our approach allows for averaging over fast motions and thus predicts a constant detection rate for all fast periodic motions.

  14. Berkeley Lab Compact Accelerator Sets World Record

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

    Berkeley Lab Particle Accelerator Sets World Record Berkeley Lab Particle Accelerator Sets World Record Simulations at NERSC Help Validate Experimental Laser-Plasma Design December...

  15. Licensing East Asian Resources

    E-Print Network [OSTI]

    Chu, Victoria; Eggleston, Holly

    2008-01-01T23:59:59.000Z

    our licensing of East Asian Resources here at UCSD. y It isthe history of electronic resources and the use of licensesclick through, or even use a resource with posted terms on a

  16. The Asian war bow

    E-Print Network [OSTI]

    Nieminen, Timo A

    2011-01-01T23:59:59.000Z

    The bow is one of the earliest complex machines, a prime example of the storage and transfer of energy. The physics of the bow illuminates compromises and design choices made in Asian military archery.

  17. Asian American women entrepreneurs

    E-Print Network [OSTI]

    Suh, Clara J

    2014-01-01T23:59:59.000Z

    There are an estimated 620,300 firms owned by Asian American women nationwide, and they contribute $105 billion to the U.S. economy. They are also active in Greater Boston's innovation and entrepreneurship communities. ...

  18. Three-dimensional particle-in-cell simulation of electron acceleration by Langmuir waves in an inhomogeneous plasma

    SciTech Connect (OSTI)

    Pechhacker, R.; Tsiklauri, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)] [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-01-15T23:59:59.000Z

    A possible solution to the unexplained high intensity hard x-ray emission observable during solar flares was investigated via 3D fully relativistic, electromagnetic particle-in-cell simulations with realistic ion to electron mass ratio. A beam of accelerated electrons was injected into a magnetised, Maxwellian, homogeneous, and inhomogeneous background plasma. The electron distribution function was unstable to the beam-plasma instability and was shown to generate Langmuir waves, while relaxing to plateau formation. In order to estimate the role of the background density gradient on an unbound (infinite spatial extent) beam, three different scenarios were investigated: (a) a uniform density background; (b) a weak density gradient, n{sub e,R}/n{sub e,L}?=?3; (c) a strong gradient case, n{sub e,R}/n{sub e,L}?=?10, where n{sub e,R} and n{sub e,L} denote background electron densities on the left and right edges of the simulation box, respectively. The strong gradient case produced the largest fraction of electrons beyond 15v{sub th}. Furthermore, two cases (uniform and strong gradient background) with spatially localized beam injections were performed aiming to show drifts of the generated Langmuir wave wavenumbers, as suggested in previous studies. For the strong gradient case, the Langmuir wave power is shown to drift to smaller wavenumbers, as found in previous quasi-linear simulations.

  19. East Asian Security in 2025

    E-Print Network [OSTI]

    Heavin, Reagan; Hudson, Adam; Krueger, Brandon; O'Neil, Sean; Rozell, Griffin; Suma, Matt

    2008-01-01T23:59:59.000Z

    East Asian Security in 2025 Who We Are • Reagan Heavin – Energy • Adam Hudson – State Capacity • Brandon Krueger – Military • Sean O’Neil – Demographics • Griffin Rozell – Balance of Power • Matt Suma – Economy East Asian Security in 2025 China...: Competition, Cooperation, Plateau? Reagan Heavin Adam Hudson Brandon Krueger Sean O’Neil Griffin Rozell Matt Suma 24 April 2008 East Asian Security in 2025 Agenda • Conclusions • Projections • Drivers • Four Outcomes • Questions East Asian Security in 2025...

  20. Fermilab | Science | Particle Accelerators

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

    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 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A This photophotoReleasesfeature

  1. Accelerator Concepts Workshop

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

    Colliders to Synchrotron Radiation Sources. The wide scope of the workshop includes new methods of particle acceleration to high energies, techniques for production of...

  2. Accelerator R&D

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

    Superconducting RF Module with a PBG Coupler Cell, 2013 North American Particle Accelerator Conference, Pasadena, CA, September 29 - October 4th, 2013. Evgenya I. Simakov,...

  3. Plasma accelerator

    DOE Patents [OSTI]

    Wang, Zhehui (Los Alamos, NM); Barnes, Cris W. (Santa Fe, NM)

    2002-01-01T23:59:59.000Z

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  4. The design and performance of a water cooling system for a prototype coupled cavity linear particle accelerator for the spallation neutron source

    SciTech Connect (OSTI)

    Bernardin, J. D. (John D.); Ammerman, C. N. (Curtt N.); Hopkins, S. M. (Steve M.)

    2002-01-01T23:59:59.000Z

    The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. The SNS will generate and employ neutrons as a research tool in a variety of disciplines including biology, material science, superconductivity, chemistry, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of, in part, a multi-cell copper structure termed a coupled cavity linac (CCL). The CCL is responsible for accelerating the protons from an energy of 87 MeV, to 185 MeV. Acceleration of the charged protons is achieved by the use of large electrical field gradients established within specially designed contoured cavities of the CCL. While a large amount of the electrical energy is used to accelerate the protons, approximately 60-80% of this electrical energy is dissipated in the CCL's copper structure. To maintain an acceptable operating temperature, as well as minimize thermal stresses and maintain desired contours of the accelerator cavities, the electrical waste heat must be removed from the CCL structure. This is done using specially designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by a complex water cooling and temperature control system. This paper discusses the design, analysis, and testing of a water cooling system for a prototype CCL. First, the design concept and method of water temperature control is discussed. Second, the layout of the prototype water cooling system, including the selection of plumbing components, instrumentation, as well as controller hardware and software is presented. Next, the development of a numerical network model used to size the pump, heat exchanger, and plumbing equipment, is discussed. Finally, empirical pressure, flow rate, and temperature data from the prototype CCL water cooling tests are used to assess water cooling system performance and numerical modeling accuracy.

  5. Safety training and safe operating procedures written for PBFA (Particle Beam Fusion Accelerator) II and applicable to other pulsed power facilities

    SciTech Connect (OSTI)

    Donovan, G.L.; Goldstein, S.A.

    1986-12-01T23:59:59.000Z

    To ensure that work in advancing pulsed power technology is performed with an acceptably low risk, pulsed power research facilities at Sandia National Laboratories must satisfy general safety guidelines established by the Department of Energy, policies and formats of the Environment, Safety, and Health (ES and H) Department, and detailed procedures formulated by the Pulsed Power Sciences Directorate. The approach to safety training and to writing safe operating procedures, and the procedures presented here are specific to the Particle Beam Fusion Accelerator II (PBFA II) Facility but are applicable as guidelines to other research and development facilities which have similar hazards.

  6. Accelerated Quantum Dynamics

    E-Print Network [OSTI]

    Lynch, Morgan H

    2015-01-01T23:59:59.000Z

    In this paper we establish a formalism for the computation of observables due to acceleration-induced particle physics processes. General expressions for the transition rate, multiplicity, power, spectra, and displacement law of particles undergoing time-dependent acceleration and transitioning into a final state of arbitrary particle number are obtained. The transition rate, power, and spectra are characterised by unique polynomials of multiplicity and thermal distributions of both bosonic and fermionic statistics. The acceleration dependent multiplicity is computed in terms of the branching fractions of the associated inertial processes. The displacement law of the spectra predicts the energy of the emitted particles are directly proportional to the accelerated temperature. These results extend our understanding of particle physics into the high acceleration sector.

  7. Proposal for the Award of Two Contracts for the Technical Services for Work on Components of CERN Particle Accelerators and High Energy Physics Experiments

    E-Print Network [OSTI]

    2003-01-01T23:59:59.000Z

    This document concerns the award of two contracts for the technical services for work on components of CERN particle accelerators and high energy physics experiments. Following a market survey carried out among 73 firms in fourteen Member States, a call for tenders (IT-3156/SPL) was sent on 4 November 2002 to three consortia in four Member States. By the closing date, CERN had received tenders from the three consortia. The Finance Committee is invited to agree to the negotiation of two contracts with: 1) the consortium SERCO FACILITIES MANAGEMENT (NL) - GERARD PERRIER INDUSTRIE (FR) - INEO ALPES (FR), the lowest bidder, for approximately 55% of the technical services for work on components of CERN particle accelerators and high energy physics experiments, for an initial period of five years and for a total amount not exceeding 37 435 270 euros (54 902 500 Swiss francs), subject to revision for inflation from 1 January 2005. The contract will include options for two one-year extensions beyond the initial five-...

  8. 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...

  9. Asian Perspectives on Sustainable Development

    E-Print Network [OSTI]

    Hall, Sharon J.

    Asian Perspectives on Sustainable Development Thursday, March 28, 2013 9:00 ­ 10:30 a.m. Wrigley society can help spur a more sustainable growth. Pamela Mar's work focuses on Asian development, corporate and social development. Asia needs to rethink how it grows to ensure that social progress and environmental

  10. A novel adaptive time stepping variant of the Boris-Buneman integrator for the simulation of particle accelerators with space charge

    E-Print Network [OSTI]

    Matthias Toggweiler; Andreas Adelmann; Peter Arbenz; Jianjun J. Yang

    2012-11-15T23:59:59.000Z

    We show that adaptive time stepping in particle accelerator simulation is an enhancement for certain problems. The new algorithm has been implemented in the OPAL (Object Oriented Parallel Accelerator Library) framework, and is compared to the existing code. The idea is to adjust the frequency of costly self field calculations, which are needed to model Coulomb interaction (space charge) effects. In analogy to a Kepler orbit simulation that requires a higher time step resolution at the close encounter, we propose to choose the time step based on the magnitude of the space charge forces. Inspired by geometric integration techniques, our algorithm chooses the time step proportional to a function of the current phase space state instead of calculating a local error estimate like a conventional adaptive procedure. In this paper we build up on first observations made in recent work. A more profound argument is given on how exactly the time step should be chosen. An intermediate algorithm, initially built to allow a clearer analysis by introducing separate time steps for external field and self field integration, turned out to be useful in itself already for a large class of problems.

  11. Imaginaries of the Asian modern

    E-Print Network [OSTI]

    Lé, Lan Xuân

    2009-01-01T23:59:59.000Z

    In an age of globalization, texts increasingly migrate not only out of their native medium, but their native countries as well. Within the East Asian region, a booming television program trade circulates television texts, ...

  12. Leaky Fermi accelerators

    E-Print Network [OSTI]

    Shah, Kushal; Rom-Kedar, Vered; Turaev, Dmitry

    2015-01-01T23:59:59.000Z

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  13. THE DIELECTRIC WALL ACCELERATOR

    SciTech Connect (OSTI)

    Caporaso, G J; Chen, Y; Sampayan, S E

    2009-08-17T23:59:59.000Z

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  14. Compact accelerator for medical therapy

    DOE Patents [OSTI]

    Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

    2010-05-04T23:59:59.000Z

    A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

  15. Lab Breakthrough: Fermilab Accelerator Technology

    Broader source: Energy.gov [DOE]

    Fermilab scientists developed techniques to retrofit some of the 30,000 particle accelerators in use around the world to make them more efficient and powerful.

  16. Accelerator on a Chip

    ScienceCinema (OSTI)

    England, Joel

    2014-07-16T23:59:59.000Z

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  17. BNL | Accelerator Test Facility

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

    and new approaches to particle acceleration and x-ray generation. A next-generation ultra-fast CO2 laser based on chirped pulse amplification in isotopic gas mixtures is...

  18. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema (OSTI)

    None

    2014-08-12T23:59:59.000Z

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  19. Assessment of the mixing state and cloud nucleating efficiency of Asian aerosols using aircraft-based measurements of hygroscopicity

    E-Print Network [OSTI]

    Thomas, Timothy William

    2006-08-16T23:59:59.000Z

    particles that act as cloud condensation nuclei. This study employs Tandem Differential Mobility Analyzer (TDMA) data collected in the vicinity of Japan during the Asian Aerosol Characterization Experiment (ACE-Asia) to investigate the influence of aerosol...

  20. 8, 20612084, 2008 Estimation of Asian

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 2061­2084, 2008 Estimation of Asian dust effect on cloud radiation forcing J. Su et al Chemistry and Physics Discussions Estimation of Asian dust aerosol effect on cloud radiation forcing using of Asian dust effect on cloud radiation forcing J. Su et al. Title Page Abstract Introduction Conclusions

  1. ACCELERATOR R&D S U M M A R Y

    E-Print Network [OSTI]

    &D] #12;2 · Accelerators remain an essential component in Elementary Particle Physics Research of accelerator science and technology by the elementary particle physics program. Particle accelerators continue accelerator technologies is vital to the future of accelerator based elementary particle physics as well

  2. The role of plasma in advanced accelerators* Jonathan S. Wurtele+

    E-Print Network [OSTI]

    Wurtele, Jonathan

    concentrated on using plasma to accelerate charged particles, photon accel- eration is another area of active generation of particle accelerators. The develop- ment and status of advanced accelerator concepts, plasma beam, and is known as the particle beam wake field accelerator.6~67 While most studies have

  3. Long-term XMM-Newton investigation of two particle-accelerating colliding-wind binaries in NGC6604: HD168112 and HD167971

    E-Print Network [OSTI]

    De Becker, M

    2015-01-01T23:59:59.000Z

    The long-term (over more than one decade) X-ray emission from two massive stellar systems known to be particle accelerators is investigated using XMM-Newton. Their X-ray properties are interpreted taking into account recent information about their multiplicity and orbital parameters. The two targets, HD168112 and HD167971 appear to be overluminous in X-rays, lending additional support to the idea that a significant contribution of the X-ray emission comes from colliding-wind regions. The variability of the X-ray flux from HD168112 is interpreted in terms of varying separation expected to follow the 1/D rule for adiabatic shocked winds. For HD167971, marginal decrease of the X-ray flux in September 2002 could tentatively be explained by a partial wind eclipse in the close pair. No long-term variability could be demonstrated despite the significant difference of separation between 2002 and 2014. This suggests the colliding-wind region in the wide orbit does not contribute a lot to the total X-ray emission, with...

  4. Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC

    E-Print Network [OSTI]

    Wechsler, Risa H.

    #12;Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC is continually improving accelerators, both here and at other laboratories, and paving the way for a new generation of particle acceleration technology. SLAC's famous linear accelerator

  5. The Asian Wood Pellet Markets

    E-Print Network [OSTI]

    The Asian Wood Pellet Markets Joseph A. Roos and Allen M. Brackley United States Department Wood Pellet plant in North Pole, Alaska. Clockwise from upper left: pelleting machine; pellets bagged for home use; a Superior Pellet Fuels bag; inventory of product ready for shipment to retailers. Upper

  6. Particle acceleration at interplanetary shocks

    E-Print Network [OSTI]

    Zank, G. P.; Li, Gang; Verkhoglyadova, Olga

    2007-01-01T23:59:59.000Z

    i the shock compression ratio] is the spectral index of theindex is unchanged although the distribution experiences compression).

  7. Accelerators and the Accelerator Community

    E-Print Network [OSTI]

    Malamud, Ernest

    2009-01-01T23:59:59.000Z

    for a PhD in accelerator physics was by E.O. Lawrence.of Beams) organizes accelerator physics sessions at APSstudents specializing in accelerator physics are not being “

  8. Recent Advances in Plasma Acceleration

    SciTech Connect (OSTI)

    Hogan, Mark

    2007-03-19T23:59:59.000Z

    The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

  9. Accelerator on a Chip: How It Works

    SciTech Connect (OSTI)

    None

    2014-06-30T23:59:59.000Z

    In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

  10. Asian American Pacific Islander Heritage Month

    Broader source: Energy.gov [DOE]

    Generations of Asian Americans and Pacific Islanders (AAPIs) have helped make America what it is today. Their histories recall bitter hardships and proud accomplishments -- from the laborers who...

  11. ACCELERATORS: ENGINES FOR TRAVERSING A LARGE AND OFTEN DIFFICULT LANDSCAPE

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2014-01-01T23:59:59.000Z

    California. ACCELERATORS: ENGINES FOR TRAVERSING A LARGE ANDthat go with them, are from: “Engines of Discovery: Particle

  12. asian port cities: Topics by E-print Network

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

    Heritage Month with community festivals, government 64 Remarks on Asian Option Pricing Asian option pricing is an active research area. Computer Technologies and...

  13. THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY The Radiological Research Accelerator Facility

    E-Print Network [OSTI]

    THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY 71 The Radiological Research Accelerator Facility the irradiated cells. Both the microbeam and the track segment facilities continue to be utilized in various investigations of this phenomenon. The single- particle microbeam facility provides precise control of the number

  14. THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY The Radiological Research Accelerator Facility

    E-Print Network [OSTI]

    THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY 1 The Radiological Research Accelerator Facility for Radiological Research (CRR). Using the mi- crobeam facility, 10% of the cells were irradiated through particle beam as well as the first fo- cused microbeam in the new microbeam facility. · Another significant

  15. 6, 1261112670, 2006 Asian pollution over

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 6, 12611­12670, 2006 Asian pollution over Europe A. Stohl et al. Title Page Abstract Discussions Aircraft measurements over Europe of an air pollution plume from Southeast Asia ­ aerosol Asian pollution over Europe A. Stohl et al. Title Page Abstract Introduction Conclusions References

  16. Asian Clinical Tropical Medicine Bangkok, Thailand

    E-Print Network [OSTI]

    Minnesota, University of

    Asian Clinical Tropical Medicine Bangkok, Thailand July 21 ­ August 3, 2012 Join the Faculty, and the University of Minnesota as they co-host the fourth Asian Clinical Tropical Medical Course in beautiful Bangkok, Thailand. Healthcare providers with experience and/or a special interest in clinical tropical

  17. Laser acceleration of ion beams

    E-Print Network [OSTI]

    I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan

    2007-02-01T23:59:59.000Z

    We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

  18. Sequentially pulsed traveling wave accelerator

    DOE Patents [OSTI]

    Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

    2009-08-18T23:59:59.000Z

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  19. Sensitivity studies on the impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate

    SciTech Connect (OSTI)

    Qian, Yun; Flanner, M. G.; Leung, Lai-Yung R.; Wang, Weiguo

    2011-03-02T23:59:59.000Z

    The Tibetan Plateau (TP), the highest and largest plateau in the world, has long been identified to be critical in regulating the Asian monsoon climate and hydrological cycle. The snowpack and glaciers over the TP provide fresh water to billions of people in Asian countries, but the TP glaciers have been retreating extensively at a speed faster than any other part of the world. In this study a series of experiments with a global climate model are designed to simulate black carbon (BC) and dust in snow and their radiative forcing and to assess the relative impacts of anthropogenic CO2 and carbonaceous particles in the atmosphere and snow, respectively, on the snowpack over the TP, as well as their subsequent impacts on the Asian monsoon climate and hydrological cycle. Results show a large BC content in snow over the TP, especially the southern slope, with concentration larger than 100 µk/kg. Because of the high aerosol content in snow and large incident solar radiation in the low latitude and high elevation, the TP exhibits the largest surface radiative forcing induced by aerosols (e.g. BC, Dust) in snow compared to other snow-covered regions in the world. The aerosol-induced snow albedo perturbations generate surface radiative forcing of 5-25 W m-2 during spring, with a maximum in April or May. BC-in-snow increases the surface air temperature by around 1.0oC averaged over the TP and reduces snowpack over the TP more than that induced by pre-industrial to present CO2 increase and carbonaceous particles in the atmosphere during spring. As a result, runoff increases during late winter and early spring but decreases during late spring and early summer (i.e. a trend toward earlier melt dates). The snowmelt efficacy, defined as the snowpack reduction per unit degree of warming induced by the forcing agent, is 1-4 times larger for BC-in-snow than CO2 increase during April-July, indicating that BC-in-snow more efficiently accelerates snowmelt because the increased net solar radiation induced by reduced albedo melts the snow more efficiently than snow melt due to warming in the air. The TP also influences the South (SAM) and East (EAM) Asian monsoon through its dynamical and thermal forcing. During boreal spring, aerosols are transported by the southwesterly and reach the higher altitude and/or deposited in the snowpack over the TP. While BC and OM in the atmosphere directly absorb sunlight and warm the air, the darkened snow surface polluted by BC absorbs more solar radiation and increases the skin temperature, which warms the air above by the increased sensible heat flux over the TP. Both effects enhance the upward motion of air and spur deep convection along the TP during pre-monsoon season, resulting in earlier onset of the SAM and increase of moisture, cloudiness and convective precipitation over northern India. BC-in-snow has a more significant impact on the EAM in July than CO2 increase and carbonaceous particles in the atmosphere. Contributed by the significant increase of both sensible heat flux associated with the warm skin temperature and latent heat flux associated with increased soil moisture with long memory, the role of the TP as a heat pump is elevated from spring through summer as the land-sea thermal contrast increases to strengthen the EAM. As a result, both southern China and northern China become wetter, but central China (i.e. Yangtze River Basin) becomes drier - a near zonal anomaly pattern that is consistent with the dominant mode of precipitation variability in East Asia. ?

  20. Method and apparatus for varying accelerator beam output energy

    DOE Patents [OSTI]

    Young, Lloyd M. (Los Alamos, NM)

    1998-01-01T23:59:59.000Z

    A coupled cavity accelerator (CCA) accelerates a charged particle beam with rf energy from a rf source. An input accelerating cavity receives the charged particle beam and an output accelerating cavity outputs the charged particle beam at an increased energy. Intermediate accelerating cavities connect the input and the output accelerating cavities to accelerate the charged particle beam. A plurality of tunable coupling cavities are arranged so that each one of the tunable coupling cavities respectively connect an adjacent pair of the input, output, and intermediate accelerating cavities to transfer the rf energy along the accelerating cavities. An output tunable coupling cavity can be detuned to variably change the phase of the rf energy reflected from the output coupling cavity so that regions of the accelerator can be selectively turned off when one of the intermediate tunable coupling cavities is also detuned.

  1. The Laboratory SLAC National Accelerator Laboratory is home to a two-mile

    E-Print Network [OSTI]

    Wechsler, Risa H.

    -program laboratory for photon science, astrophysics, and accelerator and particle physics research. Six scientists promises to be just as extraordinary. #12;Accelerator Physics Particle accelerators are the working engines#12;The Laboratory SLAC National Accelerator Laboratory is home to a two-mile linear accelerator

  2. Visualizing Particle-in-Cell Simulation of Laser Wakefield Particle...

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

    of times greater than those obtained in conventional particle accelerators. LWFAs use the electric field of a plasma wave - the wakefield - driven by the radiation pressure of an...

  3. Development of PUNDA (Parametric Universal Nonlinear Dynamics Approximator) Models for Self-Validating Knowledge-Guided Modelling of Nonlinear Processes in Particle Accelerators \\& Industry

    SciTech Connect (OSTI)

    Sayyar-Rodsari, Bijan; Schweiger, Carl; Hartman, Eric

    2007-10-07T23:59:59.000Z

    The difficult problems being tackled in the accelerator community are those that are nonlinear, substantially unmodeled, and vary over time. Such problems are ideal candidates for model-based optimization and control if representative models of the problem can be developed that capture the necessary mathematical relations and remain valid throughout the operation region of the system, and through variations in system dynamics. The goal of this proposal is to develop the methodology and the algorithms for building high-fidelity mathematical representations of complex nonlinear systems via constrained training of combined first-principles and neural network models.

  4. Buffered Electropolishing – A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators

    SciTech Connect (OSTI)

    Hui Tian, Charles Reece, Michael Kelley

    2009-05-01T23:59:59.000Z

    Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nano-smoothness. Electropolishing (EP) is the technique of choice to be developed for high-field superconducting radio frequency (SRF) cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulphuric and hydrofluoric acid electrolyte controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are guiding a systematic characterization to form the basis for cavities process optimization.

  5. A Novel Approach to Non linear Shock Acceleration

    E-Print Network [OSTI]

    Pasquale Blasi

    2001-11-28T23:59:59.000Z

    First order Fermi acceleration at astrophysical shocks is often invoked as a mechanism for the generation of non-thermal particles. This mechanism is especially simple in the approximation that the accelerated particles behave like test particles, not affecting the shocked fluid. Many complications enter the calculations when the accelerated particles have a backreaction on the fluid, in which case we may enter the non linear regime of shock acceleration. In this paper we summarize the main features of a semi-analytical approach to the study of the non linearity in shock acceleration, and compare some of the results with previous attempts and with the output of numerical simulations.

  6. Injection and acceleration of H at Earth's bow shock

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Injection and acceleration of H and He2 at Earth's bow shock M. Scholer1 , H. Kucharek1 , K the injection and subsequent acceleration of part of the solar wind ions at the Earth's bow shock. The shocks particles does not contribute to ion injection. Acceleration models that permit thermal particles to scatter

  7. Accelerate Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Accelerate Energy Productivity 2030 Over the next year, the U.S. Department of Energy, the Council on Competitiveness and the Alliance to Save Energy will join forces to undertake...

  8. Final Report: Measurements of Core Conditions, Implosion Symmetry, and Anomaloes Acceleration Mechanisms on Omega through Charged Particle Spectroscopy, November 1, 1997 - December 31, 1998

    SciTech Connect (OSTI)

    Petrasso, R.; Li, C.K.

    1999-10-19T23:59:59.000Z

    This work concerns the first spectroscopic measurements of energetic charged particles on Omega. Individual line profiles include D-3He protons (14.7 MeV) and alphas (3.6 MeV), D-T alphas (3.5 MeV), D-D protons (3.0 MeV), and D-D tutons (1.0 MeV)

  9. Asian American and African American masculinities : race, citizenship, and culture in post-civil rights

    E-Print Network [OSTI]

    Chon-Smith, Chong

    2006-01-01T23:59:59.000Z

    Eroticized Asian in Gay Male Porn,” in Q&A: Queer in AsianEroticized Asian in Gay Male Porn. ” In Q&A: Queer in AsianEroticized Asian in Gay Male Porn,” in Q&A: Queer in Asian

  10. Asian American and Pacific Islander Heritage Month Program

    Broader source: Energy.gov [DOE]

    Asian Pacific American Heritage Month is a celebration of the culture, traditions, and history of Asian Americans and Pacific Islanders in the United States. Join the Energy Department for the...

  11. asian dust particles: Topics by E-print Network

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

    and meteorological parameters in the Gobi region indicated that invasion of polar cold air played an important role climate indices that are appropriate for the scale of...

  12. Japan-Asian Studies Program Academic Year 2011-2012

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    Japan-Asian Studies Program Academic Year 2011-2012 Eligibility All University of Tokyo students by University of Tokyo #12;01 IntroductionIntroduction Japan-Asian Studies Program 2011 The Japan-Asian Studies approach to Asia, including Japan, that transcends departments and fields. It can be participated

  13. Muon acceleration in cosmic-ray sources

    SciTech Connect (OSTI)

    Klein, Spencer R.; Mikkelsen, Rune E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Becker Tjus, Julia [Fakultät für Physik and Astronomie, Theoretische Physik I, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2013-12-20T23:59:59.000Z

    Many models of ultra-high energy cosmic-ray production involve acceleration in linear accelerators located in gamma-ray bursts, magnetars, or other sources. These transient sources have short lifetimes, which necessitate very high accelerating gradients, up to 10{sup 13} keV cm{sup –1}. At gradients above 1.6 keV cm{sup –1}, muons produced by hadronic interactions undergo significant acceleration before they decay. This muon acceleration hardens the neutrino energy spectrum and greatly increases the high-energy neutrino flux. Using the IceCube high-energy diffuse neutrino flux limits, we set two-dimensional limits on the source opacity and matter density, as a function of accelerating gradient. These limits put strong constraints on different models of particle acceleration, particularly those based on plasma wake-field acceleration, and limit models for sources like gamma-ray bursts and magnetars.

  14. Accelerator Technology Division progress report, FY 1992

    SciTech Connect (OSTI)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01T23:59:59.000Z

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  15. Gamma-Ray and Hard X-Ray Emission from Pulsar-Aided Supernovae as a Probe of Particle Acceleration in Embryonic Pulsar Wind Nebulae

    E-Print Network [OSTI]

    Murase, Kohta; Kiuchi, Kenta; Bartos, Imre

    2014-01-01T23:59:59.000Z

    It has been suggested that some classes of luminous supernovae (SNe) and gamma-ray bursts (GRBs) are driven by newborn magnetars. Fast-rotating proto-neutron stars have also been of interest as potential sources of gravitational waves (GWs). We show that for a range of rotation periods and magnetic fields, hard X rays and GeV gamma rays provide us with a promising probe of pulsar-aided SNe. It is observationally known that young pulsar wind nebulae (PWNe) in the Milky Way are very efficient lepton accelerators. We argue that, if embryonic PWNe satisfy similar conditions at early stages of SNe (in ~1-10 months after the explosion), external inverse-Compton emission via upscatterings of SN photons is naturally expected in the GeV range as well as broadband synchrotron emission. To fully take into account the Klein-Nishina effect and two-photon annihilation process that are important at early times, we perform detailed calculations including electromagnetic cascades. Our results suggest that hard X-ray telescope...

  16. Acceleration Fund

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

    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 for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In theACME - AcceleratedAccelerating

  17. U.S. Department of Energy and India Partner to Advance Accelerator...

    Energy Savers [EERE]

    specifically aims to expand research collaborations in superconducting radiofrequency accelerator technology, heavy ion physics, and particle detector development at DOE's...

  18. Cosmic Ray Acceleration at Relativistic Shocks

    E-Print Network [OSTI]

    Michal Ostrowski

    2003-10-29T23:59:59.000Z

    Theoretical studies of cosmic ray particle acceleration in the first-order Fermi process at relativistic shocks are reviewed. At the beginning we discuss the acceleration processes acting at mildly relativistic shock waves. An essential role of oblique field configurations and field perturbations in forming the particle energy spectrum and changing the acceleration time scale is discussed. Then, we report on attempts to consider particle acceleration at ultra-relativistic shocks, often yielding an asymptotic spectral index sigma = 2.2 at large shock Lorentz factors. We explain why this result is limited to the cases of highly turbulent conditions near shocks. We conclude that our present knowledge of the acceleration processes acting at relativistic shocks is insufficient to allow for realistic modelling of the real shocks. The present review is a modified, extended and updated version of Ostrowski (1999).

  19. FFAG ACCELERATOR PROTON DRIVER FOR NEUTRINO FACTORY.

    SciTech Connect (OSTI)

    RUGGIERO, A.

    2005-06-21T23:59:59.000Z

    This paper is the summary of a conceptual study of a Proton Driver for Neutrino Factory based on the use of a Fixed-Field Alternating-Gradient (FFAG) Accelerator. The required proton energy range for an optimum neutrino production is 5 to 12 GeV. This can be accomplished with a group of three concentric rings each with 807 m circumference [1]. FFAG Accelerators [2] have the capability to accelerate charged particles over a large momentum range ({+-}30-50%) and the feature of constant bending and focusing fields. Particles can be accelerated very fast at the rate given by the accelerating field of RF cavities placed in proper locations between magnets. The performance of FFAG accelerators is to be placed between that of Super-Conducting Linear Accelerators (SCL), with which they share the fast acceleration rate, and Rapid-Cycling Synchrotrons (RCS), as they allow the beam to re-circulate over fewer revolutions. Brookhaven National Laboratory is involved in the study of feasibility of FFAG Accelerators to accelerate intense beams of protons in the GeV energy range for a variety of applications the most important of which is the Upgrade of the Alternating Gradient Synchrotron (AGS) with a new FFAG injector [3] accelerating from 400 MeV to 1.5 GeV. The ring would be housed in the AGS tunnel and has henceforth a circumference of 807 m.

  20. Improvement of classical accelerators by lasers

    E-Print Network [OSTI]

    Hora, Heinrich

    1991-01-01T23:59:59.000Z

    Of the unconventional accelerator techniques those including lasers are reported. After explaining the advances by lasers for classical accelerator techniques, as FELs and other methods for 100 GHz generation of GW pulses, a survey is given of far field and near field laser acceleration. Problems of the beat-wave accelerator are discussed and schemes for particle interaction in vacuum without plasma are elaborated. One scheme is the Boreham experiment and another is the acceleration of "standing" wave fields where charged particles are trapped in the intensity minima. Another scheme uses the relativistic acceleration by half waves where the now available petawatt-picosecond laser pulses should produce GeV electron pulses of high luminosity. Increase of these electron enrgies would need very large lasers in the future.

  1. Aviation Sustainable Biofuels: An Asian Airline Perspective

    E-Print Network [OSTI]

    Aviation Sustainable Biofuels: An Asian Airline Perspective Dr Mark Watson Head of Environmental Affairs, Cathay Pacific Airways Ltd, Hong Kong Aviation Biofuels Session World Biofuels Markets, Rotterdam 24 March 2011 #12;Aviation Biofuels in Asia: Current Status · Focus on "2nd generation" sustainable

  2. accelerated electron beams: Topics by E-print Network

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

    of the various flavors of Particle Accelerator Conferences 23 contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series 24 contains one...

  3. accelerator electron beam: Topics by E-print Network

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

    of the various flavors of Particle Accelerator Conferences 23 contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series 24 contains one...

  4. accelerated carbon ion: Topics by E-print Network

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

    as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the...

  5. Diffusive Shock Acceleration: the Fermi Mechanism

    E-Print Network [OSTI]

    Matthew G. Baring

    1997-11-16T23:59:59.000Z

    The mechanism of diffusive Fermi acceleration at collisionless plasma shock waves is widely invoked in astrophysics to explain the appearance of non-thermal particle populations in a variety of environments, including sites of cosmic ray production, and is observed to operate at several sites in the heliosphere. This review outlines the principal results from the theory of diffusive shock acceleration, focusing first on how it produces power-law distributions in test-particle regimes, where the shock dynamics are dominated by the thermal populations that provide the seed particles for the acceleration process. Then the importance of non-linear modifications to the shock hydrodynamics by the accelerated particles is addressed, emphasizing how these subsequently influence non-thermal spectral formation.

  6. Desired Improvements in Laser-Plasma Accelerators

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

    surface polaritons in thin SiC films to sub-wavelength lithography and compact particle acceleration Gennady Shvets, University of Texas at Austin Alan Feinerman (UIC) Chris Zorman...

  7. Double Coronal Hard and Soft X-ray Source Observed by RHESSI: Evidence for Magnetic Reconnection and Particle Acceleration in Solar Flares

    E-Print Network [OSTI]

    Wei Liu; Vahe' Petrosian; Brian R. Dennis; Yan Wei Jiang

    2007-12-18T23:59:59.000Z

    We present data analysis and interpretation of an M1.4-class flare observed with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) on April 30, 2002. This event, with its footpoints occulted by the solar limb, exhibits a rarely observed, but theoretically expected, double-source structure in the corona. The two coronal sources, observed over the 6-30 keV range, appear at different altitudes and show energy-dependent structures with the higher-energy emission being closer together. Spectral analysis implies that the emission at higher energies in the inner region between the two sources is mainly nonthermal, while the emission at lower energies in the outer region is primarily thermal. The two sources are both visible for about 12 minutes and have similar light curves and power-law spectra above about 20 keV. These observations suggest that the magnetic reconnection site lies between the two sources. Bi-directional outflows of the released energy in the form of turbulence and/or particles from the reconnection site can be the source of the observed radiation. The spatially resolved thermal emission below about 15 keV, on the other hand, indicates that the lower source has a larger emission measure but a lower temperature than the upper source. This is likely the result of the differences in the magnetic field and plasma density of the two sources.

  8. Accelerators for Intensity Frontier Research

    SciTech Connect (OSTI)

    Derwent, Paul; /Fermilab

    2012-05-11T23:59:59.000Z

    In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

  9. Stochastic Acceleration in Relativistic Parallel Shocks

    E-Print Network [OSTI]

    Joni J. P. Virtanen; Rami Vainio

    2004-11-08T23:59:59.000Z

    (abridged) We present results of test-particle simulations on both the first and the second order Fermi acceleration at relativistic parallel shock waves. We consider two scenarios for particle injection: (i) particles injected at the shock front, then accelerated at the shock by the first order mechanism and subsequently by the stochastic process in the downstream region; and (ii) particles injected uniformly throughout the downstream region to the stochastic process. We show that regardless of the injection scenario, depending on the magnetic field strength, plasma composition, and the employed turbulence model, the stochastic mechanism can have considerable effects on the particle spectrum on temporal and spatial scales too short to be resolved in extragalactic jets. Stochastic acceleration is shown to be able to produce spectra that are significantly flatter than the limiting case of particle energy spectral index -1 of the first order mechanism. Our study also reveals a possibility of re-acceleration of the stochastically accelerated spectrum at the shock, as particles at high energies become more and more mobile as their mean free path increases with energy. Our findings suggest that the role of the second order mechanism in the turbulent downstream of a relativistic shock with respect to the first order mechanism at the shock front has been underestimated in the past, and that the second order mechanism may have significant effects on the form of the particle spectra and its evolution.

  10. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect (OSTI)

    Cowan, B.; /SLAC

    2005-09-19T23:59:59.000Z

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We demonstrate guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode. We also discuss particle beam dynamics in the structure, presenting a novel method for focusing the beam. In addition we describe some potential coupling methods for the structure.

  11. Accelerator target

    DOE Patents [OSTI]

    Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

    1999-06-29T23:59:59.000Z

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

  12. Accelerator target

    DOE Patents [OSTI]

    Schlyer, David J. (Bellport, NY); Ferrieri, Richard A. (Patchogue, NY); Koehler, Conrad (Miller Place, NY)

    1999-01-01T23:59:59.000Z

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  13. MUON ACCELERATION

    SciTech Connect (OSTI)

    BERG,S.J.

    2003-11-18T23:59:59.000Z

    One of the major motivations driving recent interest in FFAGs is their use for the cost-effective acceleration of muons. This paper summarizes the progress in this area that was achieved leading up to and at the FFAG workshop at KEK from July 7-12, 2003. Much of the relevant background and references are also given here, to give a context to the progress we have made.

  14. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, P.; /Fermilab; Cary, J.; /Tech-X, Boulder; McInnes, L.C.; /Argonne; Mori, W.; /UCLA; Ng, C.; /SLAC; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14T23:59:59.000Z

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization for software development and applications accounts for the natural domain areas (beam dynamics, electromagnetics, and advanced acceleration), and all areas depend on the enabling technologies activities, such as solvers and component technology, to deliver the desired performance and integrated simulation environment. The ComPASS applications focus on computationally challenging problems important for design or performance optimization to all major HEP, NP, and BES accelerator facilities. With the cost and complexity of particle accelerators rising, the use of computation to optimize their designs and find improved operating regimes becomes essential, potentially leading to significant cost savings with modest investment.

  15. Accelerators and the Accelerator Community

    SciTech Connect (OSTI)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01T23:59:59.000Z

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  16. ACCELERATORS FOR PHYSICS EXPERIMENTS: FROM DIAGNOSTICS AND CONTROL TO DESIGN

    E-Print Network [OSTI]

    Haviland, David

    ACCELERATORS FOR PHYSICS EXPERIMENTS: FROM DIAGNOSTICS AND CONTROL TO DESIGN Elena Wildner high-energy physics laboratory in the world. Here, a number of particle accelerators are connected;Abstract This thesis develops techniques of control-methods, optimization, and diagnostics of accelerator

  17. Commnity Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2008-07-01T23:59:59.000Z

    The design and performance optimization of particle accelerators is essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC1 Accelerator Science and Technology project, the SciDAC2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modeling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multi-physics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  18. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2011-10-21T23:59:59.000Z

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  19. Peculiar acceleration

    E-Print Network [OSTI]

    Luca Amendola; Claudia Quercellini; Amedeo Balbi

    2007-08-08T23:59:59.000Z

    It has been proposed recently to observe the change in cosmological redshift of distant galaxies or quasars with the next generation of large telescope and ultra-stable spectrographs (the so-called Sandage-Loeb test). Here we investigate the possibility of observing the change in peculiar velocity in nearby clusters and galaxies. This ``peculiar acceleration'' could help reconstructing the gravitational potential without assuming virialization. We show that the expected effect is of the same order of magnitude of the cosmological velocity shift. Finally, we discuss how to convert the theoretical predictions into quantities directly related to observations.

  20. ACCELERATE ENERGY

    Broader source: Energy.gov (indexed) [DOE]

    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 742Energy China 2015ofDepartmentDepartment of Energy ThisThistheSummaryACCELERATE ENERGY

  1. Linear Accelerator

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

    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 for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatestCenter (LMI-EFRC) -Choices toLeeLinear Accelerator

  2. Efficient control of accelerator maps

    E-Print Network [OSTI]

    Jehan Boreux; Timoteo Carletti; Charalampos Skokos; Yannis Papaphilippou; Michel Vittot

    2011-09-21T23:59:59.000Z

    Recently, the Hamiltonian Control Theory was used in [Boreux et al.] to increase the dynamic aperture of a ring particle accelerator having a localized thin sextupole magnet. In this letter, these results are extended by proving that a simplified version of the obtained general control term leads to significant improvements of the dynamic aperture of the uncontrolled model. In addition, the dynamics of flat beams based on the same accelerator model can be significantly improved by a reduced controlled term applied in only 1 degree of freedom.

  3. Electron Cloud Effects in Accelerators

    SciTech Connect (OSTI)

    Furman, M.A.

    2012-11-30T23:59:59.000Z

    Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  4. LASER ACCELERATION IN VACUUM J.L. Hsu, T. Katsouleas

    E-Print Network [OSTI]

    Wurtele, Jonathan

    LASER ACCELERATION IN VACUUM J.L. Hsu, T. Katsouleas University of Southern California, Los Angeles electric fields of high-brightness lasers (e.g., up to order TV/cm) to accelerate particles. Unfortunately, as is well known, it is difficult to couple the vacuum field of the laser to particles so as to achieve a net

  5. asian tropical rain: Topics by E-print Network

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

    J. 37 Ocean-atmosphere-land feedbacks on the western North Pacific-East Asian summer climate Environmental Sciences and Ecology Websites Summary: limiting poleward extent of...

  6. asian pacific neural: Topics by E-print Network

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

    of 27 Ocean-atmosphere-land feedbacks on the western North Pacific-East Asian summer climate Environmental Sciences and Ecology Websites Summary: limiting poleward extent of...

  7. asian winter monsoon: Topics by E-print Network

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

    J. 74 Ocean-atmosphere-land feedbacks on the western North Pacific-East Asian summer climate Environmental Sciences and Ecology Websites Summary: limiting poleward extent of...

  8. asian pacific association: Topics by E-print Network

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

    of 30 Ocean-atmosphere-land feedbacks on the western North Pacific-East Asian summer climate Environmental Sciences and Ecology Websites Summary: limiting poleward extent of...

  9. asian summer monsoon: Topics by E-print Network

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

    30 Ocean-atmosphere-land feedbacks on the western North Pacific-East Asian summer climate Environmental Sciences and Ecology Websites Summary: limiting poleward extent of...

  10. asian life scientists: Topics by E-print Network

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

    east-asian-languages Vertes, Akos 32 William Dampier, seaman, scientist University of Kansas - KU ScholarWorks Summary: <* Iflands near Cambodia China, Formofi, Luconia, Ce...

  11. asian corn borer: Topics by E-print Network

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

    activity. In this talk, Pamela Mar will highlight society can help spur a more sustainable growth. Pamela Mar's work focuses on Asian development, corporate Hall, Sharon J....

  12. asian populations levels: Topics by E-print Network

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

    asymptomatic condition, that is widespread in Southeast Asian populations of Malasia, Indonesia, Papua New Guinea (more) Ziervogel, Cheryl Anne 2008-01-01 2 Population Total...

  13. asian population predictors: Topics by E-print Network

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

    asymptomatic condition, that is widespread in Southeast Asian populations of Malasia, Indonesia, Papua New Guinea (more) Ziervogel, Cheryl Anne 2008-01-01 2 Population Total...

  14. asian population modified: Topics by E-print Network

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

    asymptomatic condition, that is widespread in Southeast Asian populations of Malasia, Indonesia, Papua New Guinea (more) Ziervogel, Cheryl Anne 2008-01-01 2 Population Total...

  15. asian population lessons: Topics by E-print Network

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

    asymptomatic condition, that is widespread in Southeast Asian populations of Malasia, Indonesia, Papua New Guinea (more) Ziervogel, Cheryl Anne 2008-01-01 2 Population Total...

  16. asian populations identifies: Topics by E-print Network

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

    asymptomatic condition, that is widespread in Southeast Asian populations of Malasia, Indonesia, Papua New Guinea (more) Ziervogel, Cheryl Anne 2008-01-01 2 Population Total...

  17. asian mathematical conference: Topics by E-print Network

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

    and Mathematical ... Committee Special History reading course for 4 English exchange students C) ... 113 BBBOOOGGGAAAZZZIIIIIIMAASMAAS M.A. in Asian Engineering Websites...

  18. asian international college: Topics by E-print Network

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

    Open Access Theses and Dissertations Summary: ?? Because Asian American college students are commonly perceived to be highly achieving and functioning, psychosocial...

  19. POPULATION ECOLOGY Phenology of Asian Citrus Psyllid (Hemiptera: Liviidae) and

    E-Print Network [OSTI]

    Hoddle, Mark S.

    POPULATION ECOLOGY Phenology of Asian Citrus Psyllid (Hemiptera: Liviidae) and Associated citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), initiates economic losses in citrus due

  20. Asian Development Bank Technical Assistance Report on Building...

    Open Energy Info (EERE)

    of the Sustainable Energy Authority in Sri Lanka Jump to: navigation, search Name Asian Development Bank Technical Assistance Report on Building the Capacity of the Sustainable...

  1. Electrostatic wire stabilizing a charged particle beam

    DOE Patents [OSTI]

    Prono, D.S.; Caporaso, G.J.; Briggs, R.J.

    1983-03-21T23:59:59.000Z

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  2. Final Report: Particle Physics Research Program

    SciTech Connect (OSTI)

    Karchin, Paul E.

    2011-09-01T23:59:59.000Z

    We describe recent progress in accelerator-based experiments in high-energy particle physics and progress in theoretical investigations in particle physics. We also describe future plans in these areas.

  3. Application to Particle Accelerator Beam Stabilization Glenn...

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

    in a 10 MHz frequency band," what he is referring to, whether he knows it or not, is the partial sum of k values in Eq. (13) corre- sponding to the frequency range of interest....

  4. Fermilab | Science | Particle Accelerators | Advanced Superconducting Test

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

    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 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A This

  5. How Particle Accelerators Work | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    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 742Energy ChinaofSchaefer To:Department ofOral Testimony of Secretary SamuelAs youBriefing

  6. Laser Wakefield Particle Accelerators Project at NERSC

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

    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 for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home asLCLSLaboratoryRowlandRevolutionizingLaser

  7. Asian Institute of Technology | Open Energy Information

    Open Energy Info (EERE)

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-fTriWildcatAntrimArkansasAshford, Alabama:AshworthsandTechnology Name Asian

  8. Asian Age Enterprise Ltd | Open Energy Information

    Open Energy Info (EERE)

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof EnergyInnovation in Carbon Capture andsoftwareAsian Age Enterprise Ltd Place:

  9. Asian Development Bank Institute | Open Energy Information

    Open Energy Info (EERE)

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof EnergyInnovation in Carbon Capture andsoftwareAsian Age Enterprise LtdBank

  10. Asian longhorn beetle www.forestry.gov.uk/planthealth

    E-Print Network [OSTI]

    Asian longhorn beetle www.forestry.gov.uk/planthealth Pest Alert The threat to trees in Britain infested areas is subject to statutory controls. March 2013 The Asian longhorn beetle, a native to China: plant.health@forestry.gsi.gov.uk · Fera Plant Health and Seeds Inspectorate T: 01904 462000; E

  11. Diffusive Acceleration of Ions at Interplanetary Shocks

    E-Print Network [OSTI]

    Matthew G. Baring; Errol J. Summerlin

    2005-06-08T23:59:59.000Z

    Heliospheric shocks are excellent systems for testing theories of particle acceleration in their environs. These generally fall into two classes: (1) interplanetary shocks that are linear in their ion acceleration characteristics, with the non-thermal ions serving as test particles, and (2) non-linear systems such as the Earth's bow shock and the solar wind termination shock, where the accelerated ions strongly influence the magnetohydrodynamic structure of the shock. This paper explores the modelling of diffusive acceleration at a particular interplanetary shock, with an emphasis on explaining in situ measurements of ion distribution functions. The observational data for this event was acquired on day 292 of 1991 by the Ulysses mission. The modeling is performed using a well-known kinetic Monte Carlo simulation, which has yielded good agreement with observations at several heliospheric shocks, as have other theoretical techniques, namely hybrid plasma simulations, and numerical solution of the diffusion-convection equation. In this theory/data comparison, it is demonstrated that diffusive acceleration theory can, to first order, successfully account for both the proton distribution data near the shock, and the observation of energetic protons farther upstream of this interplanetary shock than lower energy pick-up protons, using a single turbulence parameter. The principal conclusion is that diffusive acceleration of inflowing upstream ions can model this pick-up ion-rich event without the invoking any seed pre-acceleration mechanism, though this investigation does not rule out the action of such pre-acceleration.

  12. for sequence accelerators

    E-Print Network [OSTI]

    Zakharov, Vladimir

    Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona April 17, 2012 #12;Wynn's -algorithm for sequence accelerators using high

  13. Compensation Techniques in Accelerator Physics

    SciTech Connect (OSTI)

    Hisham Kamal Sayed

    2011-05-31T23:59:59.000Z

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  14. ACCELERATOR TEST FACILITY

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

    LABORATORY PHYSICS DEPARTMENT Effective: 04012004 Page 1 of 2 Subject: Accelerator Test Facility - Linear Accelerator General Systems Guide Prepared by: Michael Zarcone...

  15. Muon Collider Progress: Accelerators

    E-Print Network [OSTI]

    Michael S. Zisman

    2011-09-14T23:59:59.000Z

    A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 \\times 10^34 cm^-2s^-1. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance ("cooling"). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

  16. Radio frequency focused interdigital linear accelerator

    DOE Patents [OSTI]

    Swenson, Donald A.; Starling, W. Joel

    2006-08-29T23:59:59.000Z

    An interdigital (Wideroe) linear accelerator employing drift tubes, and associated support stems that couple to both the longitudinal and support stem electromagnetic fields of the linac, creating rf quadrupole fields along the axis of the linac to provide transverse focusing for the particle beam. Each drift tube comprises two separate electrodes operating at different electrical potentials as determined by cavity rf fields. Each electrode supports two fingers, pointing towards the opposite end of the drift tube, forming a four-finger geometry that produces an rf quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to one half of the particle wavelength .beta..lamda., where .beta. is the particle velocity in units of the velocity of light and .lamda. is the free space wavelength of the rf. Particles are accelerated in the gaps between drift tubes. The particle beam is focused in regions inside the drift tubes.

  17. Radio frequency quadrupole resonator for linear accelerator

    DOE Patents [OSTI]

    Moretti, Alfred (Downers Grove, IL)

    1985-01-01T23:59:59.000Z

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  18. SLAC National Accelerator Laboratory Accelerator Physics Faculty Search

    E-Print Network [OSTI]

    Ford, James

    SLAC National Accelerator Laboratory Accelerator Physics Faculty Search The SLAC National Accelerator Laboratory invites applications for a faculty appointment in Accelerator Physics (LCLS), LCLS-II, SPEAR-3, NLC Test Accelerator (NLCTA), Cathode Test Facility (CTF), the proposed

  19. USPAS Achievement in Accelerator Physics Award to Kwang-Je Kim...

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

    Kim of ASD October 22, 2013 Bookmark and Share Kwang-Je Kim The 2013 U.S. Particle Accelerator School (USPAS) Prize for Achievement in Accelerator Physics and Technology has...

  20. Superconducting Radiofrequency (SRF) Accelerator Cavities

    ScienceCinema (OSTI)

    Reece, Charlie

    2014-05-22T23:59:59.000Z

    Charlie Reece, an accelerator technology scientist, explains how superconducting radiofrequency accelerator cavities work.

  1. Focusing particle concentrator with application to ultrafine particles

    DOE Patents [OSTI]

    Hering, Susanne; Lewis, Gregory; Spielman, Steven R.

    2013-06-11T23:59:59.000Z

    Technology is presented for the high efficiency concentration of fine and ultrafine airborne particles into a small fraction of the sampled airflow by condensational enlargement, aerodynamic focusing and flow separation. A nozzle concentrator structure including an acceleration nozzle with a flow extraction structure may be coupled to a containment vessel. The containment vessel may include a water condensation growth tube to facilitate the concentration of ultrafine particles. The containment vessel may further include a separate carrier flow introduced at the center of the sampled flow, upstream of the acceleration nozzle of the nozzle concentrator to facilitate the separation of particle and vapor constituents.

  2. Development of a Charged Particle Microbeam for Targeted and Single Particle Subcellular Irradiation

    SciTech Connect (OSTI)

    Yanch, Jacquelyn C.

    2004-03-12T23:59:59.000Z

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube.

  3. asian monsoon intensity: Topics by E-print Network

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

    the result of changes Asian Monsoon; MgCa; oxygen isotopes; millennial-scale climate change. G 3 G 3Geochemistry Geophysics Linsley, Braddock K. 19 Accepted for publication, The...

  4. asian helicobacter pylori: Topics by E-print Network

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

    asian helicobacter pylori 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 ??? ??? Helicobacter...

  5. Our Commitment to Asian American and Pacific Islanders at the...

    Energy Savers [EERE]

    Heritage Month Family Day at the Smithsonian This year it will be at the National Museum of American History on Saturday, May 4, 2013. More details to come. 2013 Asian...

  6. Celebrating Asian American Pacific Islander Heritage Month at...

    Broader source: Energy.gov (indexed) [DOE]

    Heritage Month Family Day at the Smithsonian This year it will be at the National Museum of American History on Saturday, May 4, 2013. More details to come. 2013 Asian...

  7. The British Asian Option K. Glover, G. Peskir & F. Samee

    E-Print Network [OSTI]

    Sidorov, Nikita

    The British Asian Option K. Glover, G. Peskir & F. Samee Sequential Anal. Vol. 29, No. 3, 2010 Option K. Glover, G. Peskir & F. Samee Sequential Anal. Vol. 29, No. 3, 2010, (311­327) Research Report

  8. Closing Event- Asian American and Pacific Islander Heritage Month

    Broader source: Energy.gov [DOE]

    Invited speakers from Congress, the federal government, and DOE will speak about Asian American and Pacific Islander programs and policy at the Department, and their contributions to the DOE...

  9. asian countries current: Topics by E-print Network

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

    the Views of Teachers and Students Texas A&M University - TxSpace Summary: related to reform mathematics were not more likely to be deemphasized in each East Asian country. Also,...

  10. asian tiger mosquito: Topics by E-print Network

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

    11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Climate Change and Range Expansion of the Asian Tiger Mosquito (Aedes albopictus) in Northeastern USA...

  11. Thomas Jefferson National Accelerator Facility

    SciTech Connect (OSTI)

    Joseph Grames, Douglas Higinbotham, Hugh Montgomery

    2010-09-01T23:59:59.000Z

    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. The technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.

  12. Acceleration Rates and Injection Efficiencies in Oblique Shocks

    E-Print Network [OSTI]

    D. C. Ellison; M. G. Baring; F. C. Jones

    1995-06-12T23:59:59.000Z

    The rate at which particles are accelerated by the first-order Fermi mechanism in shocks depends on the angle, \\teq{\\Tbone}, that the upstream magnetic field makes with the shock normal. The greater the obliquity the greater the rate, and in quasi-perpendicular shocks rates can be hundreds of times higher than those seen in parallel shocks. In many circumstances pertaining to evolving shocks (\\eg, supernova blast waves and interplanetary traveling shocks), high acceleration rates imply high maximum particle energies and obliquity effects may have important astrophysical consequences. However, as is demonstrated here, the efficiency for injecting thermal particles into the acceleration mechanism also depends strongly on obliquity and, in general, varies inversely with \\teq{\\Tbone}. The degree of turbulence and the resulting cross-field diffusion strongly influences both injection efficiency and acceleration rates. The test particle \\mc simulation of shock acceleration used here assumes large-angle scattering, computes particle orbits exactly in shocked, laminar, non-relativistic flows, and calculates the injection efficiency as a function of obliquity, Mach number, and degree of turbulence. We find that turbulence must be quite strong for high Mach number, highly oblique shocks to inject significant numbers of thermal particles and that only modest gains in acceleration rates can be expected for strong oblique shocks over parallel ones if the only source of seed particles is the thermal background.

  13. Direct laser acceleration of electrons in free-space

    E-Print Network [OSTI]

    Carbajo, Sergio; Wong, Liang Jie; Miller, R J Dwayne; Kärtner, Franz X

    2015-01-01T23:59:59.000Z

    Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle accelerati...

  14. E-Print Network 3.0 - athens tandem accelerator Sample Search...

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

    results for: athens tandem accelerator Page: << < 1 2 3 4 5 > >> 1 Workshop on Thermonuclear Reaction Rates for Astrophysics Applications Summary: , particle physics, neutrino...

  15. Use of dielectric material in muon accelerator RF cavities

    E-Print Network [OSTI]

    French, Katheryn Decker

    2011-01-01T23:59:59.000Z

    The building of a muon collider is motivated by the desire to collide point-like particles while reducing the limitations imposed by synchrotron radiation. The many challenges unique to muon accelerators are derived from ...

  16. Jefferson Lab Fall Lecture: Exploring Our World With Particle...

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

    with Particle Accelerators." The universe is dark and mysterious, more so than even Einstein imagined, Brau says. While modern science has established an understanding of...

  17. Some Frontiers of Accelerator Physics

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2008-01-01T23:59:59.000Z

    Some Frontiers of Accelerator Physics A.M. Sessler OctoberSOME FRONTIERS OF ACCELERATOR PHYSICS* Andrew M. Sessleris Some Frontiers of Accelerator Physics and it is most

  18. Experimental Particle Physics

    SciTech Connect (OSTI)

    Rosenfeld, Carl [Univ of South Carolina; Mishra, Sanjib R. [Univ of South Carolina; Petti, Roberto [Univ of South Carolina; Purohit, Milind V. [Univ of South Carolina

    2014-08-31T23:59:59.000Z

    The high energy physics group at the University of South Carolina, under the leadership of Profs. S.R. Mishra, R. Petti, M.V. Purohit, J.R. Wilson (co-PI's), and C. Rosenfeld (PI), engaged in studies in "Experimental Particle Physics." The group collaborated with similar groups at other universities and at national laboratories to conduct experimental studies of elementary particle properties. We utilized the particle accelerators at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, the Stanford Linear Accelerator Center (SLAC) in California, and the European Center for Nuclear Research (CERN) in Switzerland. Mishra, Rosenfeld, and Petti worked predominantly on neutrino experiments. Experiments conducted in the last fifteen years that used cosmic rays and the core of the sun as a source of neutrinos showed conclusively that, contrary to the former conventional wisdom, the "flavor" of a neutrino is not immutable. A neutrino of flavor "e," "mu," or "tau," as determined from its provenance, may swap its identity with one of the other flavors -- in our jargon, they "oscillate." The oscillation phenomenon is extraordinarily difficult to study because neutrino interactions with our instruments are exceedingly rare -- they travel through the earth mostly unimpeded -- and because they must travel great distances before a substantial proportion have made the identity swap. Three of the experiments that we worked on, MINOS, NOvA, and LBNE utilize a beam of neutrinos from an accelerator at Fermilab to determine the parameters governing the oscillation. Two other experiments that we worked on, NOMAD and MIPP, provide measurements supportive of the oscillation experiments. Good measurements of the neutrino oscillation parameters may constitute a "low energy window" on related phenomena that are otherwise unobservable because they would occur only at energies way above the reach of conceivable accelerators. Purohit and Wilson participated in the BaBar experiment, which collected data at SLAC until 2008. They continued to analyze the voluminous BaBar data with an emphasis on precision tests of Quantum Chromodynamics and on properties of the "eta_B," a bottom quark paired in a meson with a strange quark. The ATLAS experiment became the principal research focus for Purohit. One of the world's largest pieces of scientific equipment, ATLAS observes particle collisions at the highest-energy particle accelerator ever built, the Large Hadron Collider (LHC) at CERN. Our efforts on ATLAS included participation in the commissioning, calibration, and installation of components called "CSCs". The unprecedented energy of 14 TeV enabled the ATLAS and CMS collaborations to declare discovery of the famous Higgs particle in 2012.

  19. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect (OSTI)

    Cowan, Benjamin M.

    2007-08-22T23:59:59.000Z

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  20. Electrostatic wire for stabilizing a charged particle beam

    DOE Patents [OSTI]

    Prono, Daniel S. (Livermore, CA); Caporaso, George J. (Livermore, CA); Briggs, Richard J. (Livermore, CA)

    1985-01-01T23:59:59.000Z

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  1. High brightness electron accelerator

    DOE Patents [OSTI]

    Sheffield, Richard L. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM); Young, Lloyd M. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  2. REVIEW OF PARTICLE PHYSICS

    E-Print Network [OSTI]

    Beringer, Juerg

    2013-01-01T23:59:59.000Z

    387 Colliders, accelerator physics of Coverage Color octet50, 974 Accelerator physics offor non-accelerator physics . . . . . . . . . 368 Number

  3. Analytical tools in accelerator physics

    SciTech Connect (OSTI)

    Litvinenko, V.N.

    2010-09-01T23:59:59.000Z

    This paper is a sub-set of my lectures presented in the Accelerator Physics course (USPAS, Santa Rosa, California, January 14-25, 2008). It is based on my notes I wrote during period from 1976 to 1979 in Novosibirsk. Only few copies (in Russian) were distributed to my colleagues in Novosibirsk Institute of Nuclear Physics. The goal of these notes is a complete description starting from the arbitrary reference orbit, explicit expressions for 4-potential and accelerator Hamiltonian and finishing with parameterization with action and angle variables. To a large degree follow logic developed in Theory of Cyclic Particle Accelerators by A.A.Kolmensky and A.N.Lebedev [Kolomensky], but going beyond the book in a number of directions. One of unusual feature is these notes use of matrix function and Sylvester formula for calculating matrices of arbitrary elements. Teaching the USPAS course motivated me to translate significant part of my notes into the English. I also included some introductory materials following Classical Theory of Fields by L.D. Landau and E.M. Liftsitz [Landau]. A large number of short notes covering various techniques are placed in the Appendices.

  4. On the Move: Transnational South Asian Dancers and the 'Flexible' Dancing Body

    E-Print Network [OSTI]

    KEDHAR, ANUSHA LAKSHMI

    2011-01-01T23:59:59.000Z

    11 June 2009. Ong, Aiwha. Flexible Citizenship: The CulturalAsian Dancers and the ‘Flexible’ Dancing Body A DissertationAsian Dancers and the ‘Flexible’ Dancing Body by Anusha

  5. Proton linear accelerators: A theoretical and historical introduction

    SciTech Connect (OSTI)

    Lapostolle, P.M.

    1989-07-01T23:59:59.000Z

    From the beginning, the development of linear accelerators has followed a number of different directions. This report surveys the basic ideas and general principles of such machines, pointing out the problems that have led to the various improvements, with the hope that it may also aid further progress. After a brief historical survey, the principal aspects of accelerator theory are covered in some detail: phase stability, focusing, radio-frequency accelerating structures, the detailed calculation of particle dynamics, and space-charge effects at high intensities. These developments apply essentially to proton and ion accelerators, and only the last chapter deals with a few aspects relative to electrons. 134 refs.

  6. Plasma Wakefield Acceleration for Ultrahigh Energy Cosmic Rays

    E-Print Network [OSTI]

    Pisin Chen; Toshiki Tajima; Yoshiyuki Takahashi

    2002-05-21T23:59:59.000Z

    A cosmic acceleration mechanism is introduced which is based on the wakefields excited by the Alfven shocks in a relativistically flowing plasma, where the energy gain per distance of a test particle is Lorentz invariant. We show that there exists a threshold condition for transparency below which the accelerating particle is collision-free and suffers little energy loss in the plasma medium. The stochastic encounters of the random accelerating-decelerating phases results in a power-law energy spectrum: f(e) 1/e^2. The environment suitable for such plasma wakefield acceleration can be cosmically abundant. As an example, we discuss the possible production of super-GZK ultra high energy cosmic rays (UHECR) through this mechanism in the atmosphere of gamma ray bursts. We show that the acceleration gradient can be as high as G ~ 10^16 eV/cm. The estimated event rate in our model agrees with that from UHECR observations.

  7. Acculturation and Its Effects on Help-Seeking Attitudes among Asian Indians

    E-Print Network [OSTI]

    Mohan, Sarita

    2012-02-14T23:59:59.000Z

    There is a lack of research in the mental health field and on help-seeking regarding the Asian Indian population. Asian Indians are the third largest Asian subgroup in the United States; thus, it is important to understand their culture...

  8. Ion Acceleration by Short Chirped Laser Pulses

    E-Print Network [OSTI]

    Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán

    2015-01-01T23:59:59.000Z

    Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

  9. The grating as an accelerating structure

    SciTech Connect (OSTI)

    Fernow, R.C.

    1991-02-01T23:59:59.000Z

    This report considers the use of a diffraction grating as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of a grating. Calculations are made of the strength of the accelerating modes for structures with {pi} and 2{pi} phase advance per period and for incident waves polarized with either the E or H vector along the grooves of the grating. We consider examples of using gratings in a laser linac and in a grating lens. We also briefly examine previous results published about this subject. 36 refs.

  10. Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator C. B. Schroeder,1

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    by resonant excitation [1]. In conventional accelerators, the size of these accel- erating fields is limited particle beam. For the laser wakefield accelerator one of the most se- vere limitations is the weakening- neous plasma. These properties make it well suited as a structure for both particle beam wakefield

  11. Under consideration for publication in J. Plasma Phys. 1 Plasma acceleration by the interaction of

    E-Print Network [OSTI]

    Boyer, Edmond

    efficiency. This work is based on particle-in-cell (PIC) numerical simulations and on analytical non electromagnetic fields consistent with the theory, and they show that the particle acceleration result in plasma Acceler- ation by Parallel Alfv´en Waves Interactions (APAWI). Most of the known Alfv´enic acceleration

  12. Physics 309, The University of Chicago, Winter 2003 INTRODUCTION TO ACCELERATOR PHYSICS

    E-Print Network [OSTI]

    Physics 309, The University of Chicago, Winter 2003 INTRODUCTION TO ACCELERATOR PHYSICS Instructor: Kwang-Je Kim (kwangje@aps.anl.gov) Particle accelerators are becoming larger and more complex to satisfy in high-energy colliders for elementary particle physics and in synchrotron radiation facilities

  13. GeV electron beams from a centimetre-scale accelerator

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    V) electron accelerators are essential to synchrotron radiation facilities and free-electron lasers, and as modules for high-energy particle physics. Radiofrequency-based accelerators are limited to relatively low needed to drive radiation sources, and many kilometres to generate particle energies of interest to high

  14. Proof-of-principle experiments of laser Wakefield acceleration

    SciTech Connect (OSTI)

    Nakajima, K.; Kawakubo, T.; Nakanishi, H. [National Lab. for Higher Energy Physics, Ibaraki (Japan)] [and others

    1994-04-01T23:59:59.000Z

    Recently there has been a great interest in laser-plasma accelerators as possible next-generation particle accelerators because of their potential for ultra high accelerating gradients and compact size compared with conventional accelerators. It is known that the laser pulse is capable of exciting a plasma wave propagating at a phase velocity close to the velocity of light by means of beating two-frequency lasers or an ultra short laser pulse. These schemes came to be known as the Beat Wave Accelerator (BWA) for beating lasers or as the Laser Wakefield Accelerator (LWFA) for a short pulse laser. In this paper, the principle of laser wakefield particle acceleration has been tested by the Nd:glass laser system providing a short pulse with a power of 10 TW and a duration of 1 ps. Electrons accelerated up to 18 MeV/c have been observed by injecting 1 MeV/c electrons emitted from a solid target by an intense laser impact. The accelerating field gradient of 30 GeV/m is inferred.

  15. Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

    SciTech Connect (OSTI)

    Allwine, K Jerry; Flaherty, Julia E.

    2007-08-01T23:59:59.000Z

    This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

  16. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20T23:59:59.000Z

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  17. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

    1987-01-01T23:59:59.000Z

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  18. Variable energy constant current accelerator structure

    DOE Patents [OSTI]

    Anderson, Oscar A. (Berkeley, CA)

    1990-01-01T23:59:59.000Z

    A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90.degree. intervals with opposing electrodes maintained at the same potential. Adjacent cylinder electrodes of the quadrupole structure are maintained at different potentials to thereby reshape the cross section of the charged particle beam to an ellipse in cross section at the mid point along each quadrupole electrode unit in the accelerator modules. The beam is maintained in focus by alternating the major axis of the ellipse along the x and y axis respectively at adjacent quadrupoles. In another embodiment, electrostatic ring electrodes may be utilized instead of the quadrupole electrodes.

  19. Advanced Accelerator Concepts Workshop

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

    on high energy ion generation Levi Schachter Active Media Accelerators Benjamin Bowes Ultrafast 2-D radiative transport in a micron-scale aluminum plasma excited at...

  20. Accelerator Test Facility

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

    Test Facility Vitaly Yakimenko October 6-7, 2010 ATF User meeting DOE HE, S. Vigdor, ALD - (Contact) T. Ludlam Chair, Physics Department V. Yakimenko Director ATF, Accelerator...

  1. Market Acceleration (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2010-09-01T23:59:59.000Z

    The fact sheet summarizes the goals and activities of the DOE Solar Energy Technologies Program efforts within its market acceleration subprogram.

  2. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect (OSTI)

    Shin, Young-Min [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    2014-09-12T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 Ap to 0.6 .Ap in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  3. Beam-driven acceleration in ultra-dense plasma media

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shin, Young-Min [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  4. Beam-driven acceleration in ultra-dense plasma media

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shin, Young-Min

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r)more »from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.« less

  5. Computation of Normal Shocks Running into a Cloud of Particles using a High-Order Particle-Source-in-Cell

    E-Print Network [OSTI]

    Jacobs, Gustaaf "Guus"

    Computation of Normal Shocks Running into a Cloud of Particles using a High-Order Particle are studied with bronze particle cloud in the accelerated flow behind a running shock. The forty thousands particle clouds are arranged initially in a rectangular, triangular and circular shape. The flows

  6. GeV electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

    E-Print Network [OSTI]

    P. E. Masson-Laborde; M. Z. Mo; A. Ali; S. Fourmaux; P. Lassonde; J. C. Kieffer; W. Rozmus; D. Teychenne; R. Fedosejevs

    2014-08-06T23:59:59.000Z

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its own wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional (3D) particle-in-cell (PIC) simulations support this analysis, and confirm the scenario.

  7. Community petascale project for accelerator science and simulation: Advancing computational science for future accelerators and accelerator technologies

    E-Print Network [OSTI]

    Spentzouris, Panagiotis

    2008-01-01T23:59:59.000Z

    program for computational accelerator physics development isof computational accelerator physics applications, withof computational accelerator physics. Under ComPASS, the

  8. Western Bushido: The American Invention of Asian Martial Arts 

    E-Print Network [OSTI]

    Miracle, Jared Tyler

    2014-12-03T23:59:59.000Z

    Prior to the Second World War, very few Americans were aware that martial arts existed outside of the Olympic institutions (e.g. boxing and wrestling) and it wasn’t until the 1960s and 1970s that Asian martial culture became mainstream...

  9. Evidence for a Mu llerian mimetic radiation in Asian pitvipers

    E-Print Network [OSTI]

    Thorpe, Roger Stephen

    Evidence for a Mu¨ llerian mimetic radiation in Asian pitvipers K. L. Sanders, A. Malhotra* and R¨llerian mimicry, in which toxic species gain mutual protection from shared warning signals, is poorly understood knowledge, this represents the first evidence of a Mu¨llerian mimetic radiation in vipers. The putative

  10. Sustainability principles of the Asian Development Bank's (ADB's) energy

    E-Print Network [OSTI]

    Chaudhuri, Sanjay

    Sustainability principles of the Asian Development Bank's (ADB's) energy policy: An opportunity Development Bank (ADB) energy projects to determine how they address the energy sector challenges facing) improving energy efficiency; (2) promoting renewable energy; (3) reducing energy poverty; and (4) enhancing

  11. GEOSYNTHETICS ASIA 2012 Asian Regional Conference on Geosynthetics

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    regarding the behavior of geosynthetic clay liners (GCLs) as part of a composite liner, focused on the GM side in contact with the GCL. Keywords: Geosynthetics, composite liners, geosynthetic clay linerGEOSYNTHETICS ASIA 2012 5th Asian Regional Conference on Geosynthetics 10 to 15 December 2012

  12. asian semantic web: Topics by E-print Network

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

    asian semantic web 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 Semantic Web CiteSeer Summary:...

  13. Neutrino physics at accelerators

    E-Print Network [OSTI]

    Enrique Fernandez

    2006-07-16T23:59:59.000Z

    Present and future neutrino experiments at accelerators are mainly concerned with understanding the neutrino oscillation phenomenon and its implications. Here a brief account of neutrino oscillations is given together with a description of the supporting data. Some current and planned accelerator neutrino experiments are also explained.

  14. Microscale acceleration history discriminators

    DOE Patents [OSTI]

    Polosky, Marc A. (Albuquerque, NM); Plummer, David W. (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  15. Accelerators (4/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  16. Accelerators (5/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  17. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2004-07-23T23:59:59.000Z

    To establish accelerator-specific safety requirements which, when supplemented by other applicable safety and health requirements, will serve to prevent injuries and illnesses associated with Department of Energy (DOE) or National Nuclear Security Administration (NNSA) accelerator operations. Cancels DOE O 420.2A. Certified 5-13-08. Canceled by DOE O 420.2C.

  18. Accelerators (3/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  19. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2011-07-21T23:59:59.000Z

    The order defines accelerators and establishes accelerator specific safety requirements and approval authorities which, when supplemented by other applicable safety and health requirements, promote safe operations to ensure protection of workers, the public, and the environment. Cancels DOE O 420.2B.

  20. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2001-01-08T23:59:59.000Z

    To establish accelerator-specific safety requirements which, when supplemented by other applicable safety and health requirements, will serve to prevent injuries and illnesses associated with Department of Energy (DOE) or National Nuclear Security Administration (NNSA) accelerator operations. Cancels DOE O 420.2. Canceled by DOE O 420.2B.