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1

Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes  

E-Print Network (OSTI)

Design considerations for a laser-plasma linear collider,"E.Esarey, and W.P.Leemans, "Free-electron laser driven bythe LBNL laser-plasma accelerator," in Proc. Adv. Acc. Con.

Geddes, C.G.R.

2011-01-01T23:59:59.000Z

2

Laser Wakefield Particle Accelerators Project at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Particle Acceleration Laser Wakefield Particle Acceleration Vorpal.jpg Key Challenges: Design of multiple-staged, 10-GeV laser-wakefield plasma accelerated next-generation hardware...

3

Characteristics of a tapered capillary plasma waveguide for laser wakefield acceleration  

SciTech Connect

We developed a gas-filled capillary with a tapered density for laser wakefield acceleration, of which the tapering was realized by employing gas feed-lines with different cross-sections. Plasma diagnostics show that the capillary plasma has a significant longitudinal density tapering and a transverse parabolic profile. By using the tapered capillary plasma, high transmission (over 90%) of laser beams, meaning good optical guiding, was observed. These results demonstrate the potential of the tapered plasma source for high-energy laser wakefield acceleration, where the dephasing problem is minimized.

Kim, M. S.; Jang, D. G.; Lee, T. H.; Nam, I. H. [Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)] [Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Lee, I. W.; Suk, H. [Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of) [Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); APRI, Gwangju Institute of Science and Technology (GIST), Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

2013-05-20T23:59:59.000Z

4

Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration | U.S.  

Office of Science (SC) Website

Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration High Energy Physics (HEP) HEP Home About Research Facilities Science Highlights Benefits of HEP Funding Opportunities Advisory Committees News & Resources Contact Information High Energy Physics U.S. Department of Energy SC-25/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3624 F: (301) 903-2597 E: sc.hep@science.doe.gov More Information » July 2013 Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration Scientists at University of Texas, Austin, accelerate electrons to 2 GeV in table top apparatus. Print Text Size: A A A Subscribe FeedbackShare Page Click to enlarge photo. Enlarge Photo Image courtesy of Neil Fazel The inside of the University of Texas, Austin, vacuum chamber where

5

Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC  

SciTech Connect

We present 2-D particle-in-cell simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approximately} 10{sup 16} W/cm{sup 2}) and high ({approximately} 10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling electron-neutral collisions in a particle-in-cell code.

Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

2000-06-01T23:59:59.000Z

6

Laser guiding at relativistic intensities and wakefield particle accleration in plasma channels  

E-Print Network (OSTI)

Laser Guiding at Relativistic Intensities and Wakefieldfirst time in a high gradient laser wakefield accelerator byguiding the drive laser pulse. Channels formed by

2004-01-01T23:59:59.000Z

7

Plasma Wakefield Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

rpwa rpwa Sign In Launch the Developer Dashboard SLAC National Accelerator Laboratory DOE | Stanford | SLAC | SSRL | LCLS | AD | PPA | Photon Science | PULSE | SIMES FACET User Facility : FACET An Office of Science User Facility Search this site... Search Help (new window) Top Link Bar FACET User Facility FACET Home About FACET FACET Experimental Facilities FACET Users Research at FACET SAREC Expand SAREC FACET FAQs FACET User Facility Quick Launch FACET Users Home FACET Division ARD Home About FACET FACET News FACET Users FACET Experimental Facilities FACET Research Expand FACET Research FACET Images Expand FACET Images SAREC Expand SAREC FACET Project Site (restricted) FACET FAQs FACET Site TOC All Site Content Department of Energy Page Content Plasma Wakefield Acceleration

8

Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration in Plasma Channels  

E-Print Network (OSTI)

pulsed, THz radiation from laser accelerated relativisticGuiding of Relativistic Laser Pulses by Plasma Channels,"Wake Fields by Colliding Laser Pulses,"Phys. Rev. Lett.

2005-01-01T23:59:59.000Z

9

Laser Wakefield Acceleration Experiments Using HERCULES Laser  

Science Conference Proceedings (OSTI)

Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing laser power and plasma electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 6.1x10{sup 19} W/cm{sup 2} at laser power of 80 TW to be delivered to the gas-jet using F/10 focusing optics. We found that electron beam charge was increased significantly with an increase of laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. We also studied the influence of laser focusing conditions by changing the f-number of the optics to F/15 and found an increase in density threshold for electron production compared to the F/10 configuration. The analysis of different phenomena such as betatron motion of electrons, side scattering of the laser pulse for different focusing conditions, the influence of plasma density down ramp on LWFA are shown.

Matsuoka, T.; McGuffey, C.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science and FOCUS Center, University of Michigan, Ann Arbor, MI 48109 (United States); Horovitz, Y. [Center for Ultrafast Optical Science and FOCUS Center, University of Michigan, Ann Arbor, MI 48109 (United States); Dynamical Experiments Group, Propulsion Division, Soreq NRC, Yavnee 81800 (Israel)

2009-07-25T23:59:59.000Z

10

Design of 10 GeV laser wakefield accelerator stages with shaped laser modes  

E-Print Network (OSTI)

DESIGN OF 10 GEV LASER WAKEFIELD ACCELERATORSTAGES WITH SHAPED LASER MODES ? E. Cormier-Michel, E.PAL framework, of 10 GeV laser plasma wake?eld ac- celerator

Cormier-Michel, Estelle

2010-01-01T23:59:59.000Z

11

Laser Wakefield diagnostic using holographic longitudinal interferometry  

DOE Green Energy (OSTI)

We propose a diagnostic technique for wakefield measurement in plasma channels. A new technique for plasma channel creation, the Ignitor Heater scheme was proposed and experimentally tested in hydrogen and nitrogen previously. It makes use of two laser pulses. The Ignitor, an ultrashort (sub 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used to heat the existing spark via in-verse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. Laser pulses injected into such plasma channels produce a plasma wake that has a phase velocity close to the speed of light. A discussion of plasma wake measurements, using a Longitudinal Interferometry Wakefield Diagnostic Based on Time Domain Rayleigh Refractometry with Holographic Inversion, will be presented.

Volfbeyn, P.; Esarey, E.; Leemans, W.P.

1999-03-26T23:59:59.000Z

12

Stimulated Raman Side Scattering in Laser Wakefield Acceleration  

Science Conference Proceedings (OSTI)

Stimulated Raman side scattering of an ultrashort high power laser pulse is studied in experiments on laser wakefield acceleration. Experiments and simulations reveal that stimulated Raman side scattering occurs at the beginning of the interaction, that it contributes to the evolution of the pulse prior to wakefield formation, and also that it affects the quality of electron beams generated. The relativistic shift of the plasma frequency is measured.

Matsuoka, T.; McGuffey, C.; Cummings, P. G.; Horovitz, Y.; Dollar, F.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Bulanov, S. S.; Thomas, A. G. R.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science and FOCUS Center, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-07-16T23:59:59.000Z

13

Resonant Excitation of Plasma Wakefields  

SciTech Connect

We describe characteristics of the bunch train and plasma source used in a resonant plasma wakefield experiment at the Brookhaven National Laboratory Accelerator Test Facility. The bunch train has the proper correlated spread to unambiguously observe the expected energy gain by the witness bunch at resonance. The plasma density in the capillary discharge is sufficiently high to reach the resonance with the typical bunch train spacing of this experiment. It is also uniform over more than 3/4 of the 2 cm-long capillary.

Muggli, P.; Allen, B. [University of Southern California, Los Angeles, CA 90089 (United States); Yakimenko, V.; Fedurin, M.; Kusche, K.; Babzien, M. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

2010-11-04T23:59:59.000Z

14

Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling Laser Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame VayBoost.gif An image showing the "boosted frame," in which the observer moves at near light speed. The laser pulse is represented in blue and red; the wakefields are colored pale blue and yellow. In this frame, the plasma (yellow box) has contracted and the wavefronts are fewer and farther apart, resulting in far fewer calculations and faster results. Why it Matters: Laser driven plasma waves can produce accelerating gradients orders of magnitude greater than standard accelerating structures. High quality electron beams of energy up to 1 GeV have been produced in just a few centimeters and 10-GeV stages being planned as

15

Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Wakefield Accelerators in a Lorentz Boosted Frame Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame VayBoost.gif An image showing the "boosted frame," in which...

16

Energy Measurement in a Plasma Wakefield Accelerator  

SciTech Connect

In the E-167 plasma wakefield acceleration experiment, electrons with an initial energy of 42GeV are accelerated in a meter-scale lithium plasma. Particles are leaving plasma with a large energy spread. To determine the spectrum of the accelerated particles, a two-plane spectrometer has been set up.

Ischebeck, R

2007-07-06T23:59:59.000Z

17

Effect of pulse profile and chirp on a laser wakefield generation  

SciTech Connect

A laser wakefield driven by an asymmetric laser pulse with/without chirp is investigated analytically and through two-dimensional particle-in-cell simulations. For a laser pulse with an appropriate pulse length compared with the plasma wavelength, the wakefield amplitude can be enhanced by using an asymmetric un-chirped laser pulse with a fast rise time; however, the growth is small. On the other hand, the wakefield can be greatly enhanced for both positively chirped laser pulse having a fast rise time and negatively chirped laser pulse having a slow rise time. Simulations show that at the early laser-plasma interaction stage, due to the influence of the fast rise time the wakefield driven by the positively chirped laser pulse is more intense than that driven by the negatively chirped laser pulse, which is in good agreement with analytical results. At a later time, since the laser pulse with positive chirp exhibits opposite evolution to the one with negative chirp when propagating in plasma, the wakefield in the latter case grows more intensely. These effects should be useful in laser wakefield acceleration experiments operating at low plasma densities.

Zhang Xiaomei; Shen Baifei; Ji Liangliang; Wang Wenpeng; Xu Jiancai; Yu Yahong; Yi Longqing; Wang Xiaofeng [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Hafz, Nasr A. M. [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Kulagin, V. [Sternberg Astronomical Institute of Moscow State University, Moscow 119992 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, 141700 (Russian Federation)

2012-05-15T23:59:59.000Z

18

Numerical methods for instability mitigation in the modeling of laser wakefield accelerators in a Lorentz-boosted frame  

Science Conference Proceedings (OSTI)

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [1] has been shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups required mitigation of a high-frequency instability ... Keywords: Boosted frame, Laser wakefield acceleration, Numerical instability, Particle-in-cell, Plasma simulation, Special relativity

J. -L. Vay; C. G. R. Geddes; E. Cormier-Michel; D. P. Grote

2011-07-01T23:59:59.000Z

19

Results from Plasma Wakefield Experiments at FACET  

SciTech Connect

We report initial results of the Plasma Wakefield Acceleration (PWFA) Experiments performed at FACET - Facility for Advanced aCcelertor Experimental Tests at SLAC National Accelerator Laboratory. At FACET a 23 GeV electron beam with 1.8 x 10{sup 10} electrons is compressed to 20 {mu}m longitudinally and focused down to 10 {mu}m x 10 {mu}m transverse spot size for user driven experiments. Construction of the FACET facility completed in May 2011 with a first run of user assisted commissioning throughout the summer. The first PWFA experiments will use single electron bunches combined with a high density lithium plasma to produce accelerating gradients > 10 GeV/m benchmarking the FACET beam and the newly installed experimental hardware. Future plans for further study of plasma wakefield acceleration will be reviewed. The experimental hardware and operation of the plasma heat-pipe oven have been successfully commissioned. Plasma wakefield acceleration was not observed because the electron bunch density was insufficient to ionize the lithium vapor. The remaining commissioning time in summer 2011 will be dedicated to delivering the FACET design parameters for the experimental programs which will begin in early 2012. PWFA experiments require the shorter bunches and smaller transverse sizes to create the plasma and drive large amplitude wakefields. Low emittance and high energy will minimize head erosion which was found to be a limiting factor in acceleration distance and energy gain. We will run the PWFA experiments with the design single bunch conditions in early 2012. Future PWFA experiments at FACET are discussed in [5][6] and include drive and witness bunch production for high energy beam manipulation, ramped bunch to optimize tranformer ratio, field-ionized cesium plasma, preionized plasmas, positron acceleration, etc.. We will install a notch collimator for two-bunch operation as well as new beam diagnostics such as the X-band TCAV [7] to resolve the two bunches. With these new instruments and desired beam parameters in place next year, we will be able to complete the studies of plasma wakefield acceleration in the next few years.

Li, S.Z.; Clarke, C.I.; England, R.J.; Frederico, J.; Gessner, S.J.; Hogan, M.J.; Jobe, R.K.; Litos, M.D.; Walz, D.R.; /SLAC; Muggli, P.; /Munich, Max Planck Inst.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Adli, E.; /U. Oslo

2011-12-13T23:59:59.000Z

20

Electron bunch injection at an angle into a laser wakefield  

E-Print Network (OSTI)

External injection of electron bunches longer than the plasma wavelength in a laser wakefield accelerator can lead to the generation of femtosecond ultrarelativistic bunches with a couple of percent energy spread. Extensive study has been done on external electron bunch (e.g. one generated by a photo-cathode rf linac) injection in a laser wakefield for different configurations. In this paper we investigate a new way of external injection where the electron bunch is injected at a small angle into the wakefield. This way one can avoid the ponderomotive scattering as well as the vacuum-plasma transition region, which tend to destroy the injected bunch. In our simulations, the effect of the laser pulse dynamics is also taken into account. It is shown that injection at an angle can provide compressed and accelerated electron bunches with less than 2% energy spread. Another advantage of this scheme is that it has less stringent requirements in terms of the size of the injected bunch and there is the potential to tr...

Luttikhof, M J H; Van Goor, F A; Boller, K -J

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

X-ray phase contrast imaging of biological specimens with femtosecond pulses of betatron radiation from a compact laser plasma wakefield accelerator  

Science Conference Proceedings (OSTI)

We show that x-rays from a recently demonstrated table top source of bright, ultrafast, coherent synchrotron radiation [Kneip et al., Nat. Phys. 6, 980 (2010)] can be applied to phase contrast imaging of biological specimens. Our scheme is based on focusing a high power short pulse laser in a tenuous gas jet, setting up a plasma wakefield accelerator that accelerates and wiggles electrons analogously to a conventional synchrotron, but on the centimeter rather than tens of meter scale. We use the scheme to record absorption and phase contrast images of a tetra fish, damselfly and yellow jacket, in particular highlighting the contrast enhancement achievable with the simple propagation technique of phase contrast imaging. Coherence and ultrafast pulse duration will allow for the study of various aspects of biomechanics.

Kneip, S. [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science, University of Michigan, Ann Arbor 48109 (United States); McGuffey, C.; Dollar, F.; Chvykov, V.; Kalintchenko, G.; Krushelnick, K.; Maksimchuk, A.; Mangles, S. P. D.; Matsuoka, T.; Schumaker, W.; Thomas, A. G. R.; Yanovsky, V. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor 48109 (United States); Bloom, M. S.; Najmudin, Z.; Palmer, C. A. J.; Schreiber, J. [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

2011-08-29T23:59:59.000Z

22

Group velocity dispersion and relativistic effects on the wakefield induced by chirped laser pulse in parabolic plasma channel  

SciTech Connect

The excitation of wake field plasma waves by a short laser pulse propagating through a parabolic plasma channel is studied. The laser pulse is assumed to be initially chirped. In this regard, the effects of initial and induced chirp on the plasma wake field as well as the laser pulse parameters are investigated. The group velocity dispersion and nonlinear relativistic effects were taken into account to evaluate the excited wake field in two dimension using source dependent expansion method. Positive, negative, and un-chirped laser pulses were employed in numerical code to evaluate the effectiveness of the initial chirp on 2-D wake field excitation. Numerical results showed that for laser irradiances exceeding 10{sup 18}W/cm{sup 2}, an intense laser pulse with initial positive chirp generates larger wake field compared to negatively and un-chirped pulses.

Sohbatzadeh, F. [Department of Atomic and Molecular Physics, Science Faculty, University of Mazandaran, Babolsar (Iran, Islamic Republic of); Akou, H. [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167 (Iran, Islamic Republic of)

2013-04-15T23:59:59.000Z

23

Preformed transient gas channels for laser wakefield particle acceleration  

SciTech Connect

Acceleration of electrons by laser-driven plasma wake fields is limited by the range over which a laser pulse can maintain its intensity. This distance is typically given by the Rayleigh range for the focused laser beam, usually on the order of 0.1 mm to 1 mm. For practical particle acceleration, interaction distances on the order of centimeters are required. Therefore, some means of guiding high intensity laser pulses is necessary. Light intensities on the order of a few times 10{sup 17} W/cm{sup 2} are required for laser wakefield acceleration schemes using near IR radiation. Gas densities on the order of or greater than 10{sup 17} cm{sup {minus}3} are also needed. Laser-atom interaction studies in this density and intensity regime are generally limited by the concomitant problems in beam propagation introduced by the creation of a plasma. In addition to the interaction distance limit imposed by the Rayleigh range, defocusing of the high intensity laser pulse further limits the peak intensity which can be achieved. To solve the problem of beam propagation limitations in laser-plasma wakefield experiments, two potential methods for creating transient propagation channels in gaseous targets are investigated. The first involves creation of a charge-neutral channel in a gas by an initial laser pulse, which then is ionized by a second, ultrashort, high-intensity pulse to create a waveguide. The second method involves the ionization of a gas column by an ultrashort pulse; a transient waveguide is formed by the subsequent expansion of the heated plasma into the neutral gas.

Wood, W.M.

1994-11-01T23:59:59.000Z

24

Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration  

Science Conference Proceedings (OSTI)

An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed 'Trojan Horse' acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment 'E-210: Trojan Horse Plasma Wakefield Acceleration' has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.

Hidding, B.; Rosenzweig, J. B.; Xi, Y.; O'Shea, B.; Andonian, G.; Schiller, D.; Barber, S.; Williams, O.; Pretzler, G.; Koenigstein, T.; Kleeschulte, F.; Hogan, M. J.; Litos, M.; Corde, S.; White, W. W.; Muggli, P.; Bruhwiler, D. L.; Lotov, K. [Institut fuer Laser- und Plasmaphysik, Heinrich-Heine-Universitaet Duesseldorf 40225 Duesseldorf (Germany) and Particle Beam Physics Laboratory, Department for Physics and Astronomy, UCLA (United States); Particle Beam Physics Laboratory, Department for Physics and Astronomy, UCLA (United States); Institut fuer Laser- und Plasmaphysik, Heinrich-Heine-Universitaet Duesseldorf 40225 Duesseldorf (Germany); Stanford Linear Accelerator Center (United States); Max-Planck-Institut fuer Physik, Muenchen (Germany); Tech-X Corporation, Boulder, Colorado (United States) and 1348 Redwood Ave., Boulder, Colorado 80304 (United States); Budker Institute of Nuclear Physics SB RAS, 630090, Novosibirsk (Russian Federation) and Novosibirsk State University, 630090, Novosibirsk (Russian Federation)

2012-12-21T23:59:59.000Z

25

Experimental laser wakefield acceleration scalings exceeding 100 TW  

Science Conference Proceedings (OSTI)

Understanding the scaling of laser wakefield acceleration (LWFA) is crucial to the design of potential future systems. A number of computational and theoretical studies have predicted scalings with laser power for various parameters, but experimental studies have typically been limited to small parameter ranges. Here, we detail extensive measurements of LWFA experiments conducted over a considerable range in power from 20 to 110 TW, which allows for a greater plasma density range and for a large number of data points. These measurements include scalings of the electron beam charge and maximum energy as functions of density as well as injection threshold density, beam charge, and total beam energy as functions of laser power. The observed scalings are consistent with theoretical understandings of operation in the bubble regime.

McGuffey, C.; Matsuoka, T.; Schumaker, W.; Dollar, F.; Zulick, C.; Chvykov, V.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Thomas, A. G. R.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Kneip, S.; Najmudin, Z. [Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom)

2012-06-15T23:59:59.000Z

26

Analysis of Laser Wakefield Particle Acceleration Data at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Analysis of Laser Wakefield Particle Acceleration Data LWFAIllustrationSmall.png In collaboration with researchers of the LOASIS program (LBNL) and the SciDAC SDM center (LBNL) we...

27

Plasma Focusing & Dielectric Wakefield Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

pf pf Sign In Launch the Developer Dashboard SLAC National Accelerator Laboratory DOE | Stanford | SLAC | SSRL | LCLS | AD | PPA | Photon Science | PULSE | SIMES FACET User Facility : FACET An Office of Science User Facility Search this site... Search Help (new window) Top Link Bar FACET User Facility FACET Home About FACET FACET Experimental Facilities FACET Users Research at FACET SAREC Expand SAREC FACET FAQs FACET User Facility Quick Launch FACET Users Home FACET Division ARD Home About FACET FACET News FACET Users FACET Experimental Facilities FACET Research Expand FACET Research FACET Images Expand FACET Images SAREC Expand SAREC FACET Project Site (restricted) FACET FAQs FACET Site TOC All Site Content Department of Energy Page Content Plasma Focusing & Dielectric Wakefield Acceleration

28

Wakefield Simulations for the Laser Acceleration Experiment at SLAC  

SciTech Connect

Laser-driven acceleration in dielectric photonic band gap structures can provide gradients on the order of GeV/m. The small transverse dimension of the structure, on the order of the laser wavelength, presents interesting wakefield-related issues. Higher order modes can seriously degrade beam quality, and a detailed understanding is needed to mitigate such effects. On the other hand, wakefields also provide a direct way to probe the interaction of a relativistic bunch with the synchronous modes supported by the structure. Simulation studies have been carried out as part of the effort to understand the impact on beam dynamics, and to compare with data from beam experiments designed to characterize candidate structures. In this paper, we present simulation results of wakefields excited by a sub-wavelength bunch in optical photonic band gap structures.

Ng, Johnny

2012-04-18T23:59:59.000Z

29

Modeling laser wakefield accelerator experiments with ultrafast particle-in-cell simulations in boosted frames  

Science Conference Proceedings (OSTI)

The development of new laser systems at the 10 Petawatt range will push laser wakefield accelerators to novel regimes, for which theoretical scalings predict the possibility to accelerate electron bunches up to tens of GeVs in meter-scale plasmas. Numerical simulations will play a crucial role in testing, probing, and optimizing the physical parameters and the setup of future experiments. Fully kinetic simulations are computationally very demanding, pushing the limits of today's supercomputers. In this paper, the recent developments in the OSIRIS framework [R. A. Fonseca et al., Lect. Notes Comput. Sci. 2331, 342 (2002)] are described, in particular the boosted frame scheme, which leads to a dramatic change in the computational resources required to model laser wakefield accelerators. Results from one-to-one modeling of the next generation of laser systems are discussed, including the confirmation of electron bunch acceleration to the energy frontier.

Martins, S. F.; Fonseca, R. A.; Vieira, J.; Silva, L. O. [GoLP/Instituto de Plasmas e Fusao Nuclear-Laboratorio Associado, Instituto Superior Tecnico, Lisbon (Portugal); Lu, W.; Mori, W. B. [University of California Los Angeles, Los Angeles, California 90095 (United States)

2010-05-15T23:59:59.000Z

30

Effects of Ionization in a Laser Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Experimental results are presented from studies of the ionization injection process in laser wakefield acceleration using the Hercules laser with laser power up to 100 TW. Gas jet targets consisting of gas mixtures reduced the density threshold required for electron injection and increased the maximum beam charge. Gas mixture targets produced smooth beams even at densities which would produce severe beam breakup in pure He targets and the divergence was found to increase with gas mixture pressure.

McGuffey, C.; Schumaker, W.; Matsuoka, T.; Dollar, F. J.; Chvykov, V.; Kalintchenko, G.; Yanovsky, V.; Thomas, A. G. R.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI (United States); Kneip, S. [Imperial College London, SW 7 2AZ (United Kingdom); Bychenkov, V. Yu. [P. N. Lebedev Physics Institute, Leninskij prospekt, 53, Moscow (Russian Federation); Glazyrin, I. V.; Karpeev, A. V. [Russian Federal Nuclear Centre All-Russian Institute of Technical Physics, 456770, Snezhinsk, Chelyabinsk Region (Russian Federation)

2010-11-04T23:59:59.000Z

31

Preparation For Laser Wakefield Experiments Driven by the Texas Petawatt Laser System  

Science Conference Proceedings (OSTI)

Laboratories around the world are planning petawatt laser driven experiments. The Texas petawatt laser offers the ability to demonstrate laser wake field acceleration (LWFA) in a unique regime with pulse duration ({approx}160 fs) shorter than other petawatt scale systems currently in operation or under development. By focusing the 1.25 PW, 200 J, 160 fs pulses to peak intensity {approx}10{sup 19} W/cm{sup 2}, multi-GeV electron bunches can be produced from a low density He gas jet. The rarefied plasma density (5x10{sup 16}-10{sup 17} cm{sup -3}) required for near-resonant LWFA minimizes plasma lensing and offers long dephasing length for electron acceleration over distances ({approx}10 cm) exceeding the Rayleigh range. Because of the high power, the laser can be focused to a spot (r{sub 0}{approx}100 microns) greater than the plasma wavelength (r{sub 0}>{lambda}{sub p}), thus minimizing radial propagation effects. Together these properties enable the laser pulse to self-guide without the use of a preformed channel lending simplicity and stability to the overall acceleration process. Particle-in-cell (PIC) simulations show the laser experiences self-focusing which, because of ultrashort pulse duration, does not lead to a collapse of the wakefield and can generate over 3 GeV electron energy. The presented material will include details of initial measurements of the Texas petawatt laser system, simulations of laser wakefield acceleration for the given laser parameters and the experimental setup currently under construction.

Reed, S. A.; Kalmykov, S.; Gaul, E.; Martinez, M.; Henderson, W.; Dong, P.; Gao, X.; Sanders, J. C.; Wang, X.; Shvets, G.; Ditmire, T.; Downer, M. [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

2009-01-22T23:59:59.000Z

32

Modeling laser wakefield accelerators in a Lorentz boosted frame  

Science Conference Proceedings (OSTI)

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high-frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing the frame of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.

Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grotec, D. P.

2010-06-15T23:59:59.000Z

33

Modeling laser wakefield accelerators in a Lorentz boosted frame  

Science Conference Proceedings (OSTI)

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [1] is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing theframe of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.

Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grote, D.P.

2010-09-15T23:59:59.000Z

34

Laser wakefield acceleration experiments at the University of Michigan  

Science Conference Proceedings (OSTI)

Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing the laser power and electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 8x10{sup 19} W/cm{sup 2} at laser power of 100 TW to be delivered to the gas-jet using f/10 focusing optics. We found that electron beam charge was increased significantly with an increase of the laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. Betatron motion of electrons was also observed depending on laser power and electron density.

Matsuoka, T.; McGuffey, C.; Horovitz, Y.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Reed, S.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science and FOCUS Center, University of Michigan, Ann Arbor, MI 48109 (United States); Huntington, C. M.; Drake, R. P. [Atmospheric Oceanic and Space Sciences, Space Physics Research Lab., University of Michigan, Ann Arbor, MI 48109 (United States); Levin, M.; Zigler, A. [Hebrew University, Jerusalem (Israel)

2009-01-22T23:59:59.000Z

35

Summary Report of Working Group 4: Plasma Wakefield Acceleration  

Science Conference Proceedings (OSTI)

This report gives a guide to the discussions of Working Group 4 of the 2010 Advanced Accelerator Concepts Workshop, which was devoted to theory, simulation and experimental issues associated with plasma wakefield acceleration (PWFA). Sessions were organized thematically in this group, concentrating on broad issues of: exploitation of future facilities such as FACET; pushing the accelerating gradient beyond the current frontier, to over a TeV/m; use of positively charged beams to drive plasma wakes; resonant excitation of the PWFA with pulse trains; beam-plasma instabilities; and injection and capture of electron beams into PWFA systems.

Rosenzweig, J.B.; /UCLA; Seryi, A.; /SLAC

2012-06-11T23:59:59.000Z

36

DEVELOPMENT OF ONE METER-LONG LITHIUM PLASMA SOURCE AND EXCIMER MODE REDUCTION FOR PLASMA WAKEFIELD  

E-Print Network (OSTI)

DEVELOPMENT OF ONE METER-LONG LITHIUM PLASMA SOURCE AND EXCIMER MODE REDUCTION FOR PLASMA WAKEFIELD 94720 K. Marsh, P. Muggli, S. Wang, and C. Joshi, UCLA, Los Angeles, CA 90024 Abstract A one meter long reduction. 1 INTRODUCTION A one-meter long plasma source has been constructed which will permit

37

Simulations of laser-wakefield acceleration with external electron-bunch injection for REGAE experiments at DESY  

Science Conference Proceedings (OSTI)

We present particle-in-cell simulations for future laser-plasma wakefield experiments with external bunch injection at the REGAE accelerator facility at DESY, Hamburg, Germany. Two effects have been studied in detail: emittance evolution of electron bunches externally injected into a wake, and longitudinal bunch compression inside the wakefield. Results show significant transverse emittance growth during the injection process, if the electron bunch is not matched to its intrinsic betatron motion inside the wakefield. This might introduce the necessity to include beam-matching sections upstream of each plasma-accelerator section with fundamental implications on the design of staged laser wakefield accelerators. When externally injected at the zero-field crossing of the laser-driven wake, the electron bunch may undergo significant compression in longitudinal direction and be accelerated simultaneously due to the gradient in the acting force. The mechanism would allow for production of single high-energy, ultra-short (on the order of one femtosecond) bunches at REGAE. The optimal conditions for maximal bunch compression are discussed in the presented studies.

Grebenyuk, Julia; Mehrling, Timon; Tsung, Frank S.; Floettman, Klaus; Osterhoff, Jens [Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg (Germany); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany); University of California, Los Angeles, CA 90095 (United States); Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg (Germany); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany)

2012-12-21T23:59:59.000Z

38

Ionization Induced Trapping in a Laser Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Experimental studies of electrons produced in a laser wakefield accelerator indicate trapping initiated by ionization of target gas atoms. Targets composed of helium and controlled amounts of various gases were found to increase the beam charge by as much as an order of magnitude compared to pure helium at the same electron density and decrease the beam divergence from 5.1+-1.0 to 2.9+-0.8 mrad. The measurements are supported by particle-in-cell modeling including ionization. This mechanism should allow generation of electron beams with lower emittance and higher charge than in preionized gas.

McGuffey, C.; Thomas, A. G. R.; Schumaker, W.; Matsuoka, T.; Chvykov, V.; Dollar, F. J.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Bychenkov, V. Yu.; Glazyrin, I. V.; Karpeev, A. V. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53, Moscow 119991 (Russian Federation); RFNC-VNIITF, Snezhinsk 456770, Chelyabinsk region (Russian Federation)

2010-01-15T23:59:59.000Z

39

Physics of Laser-driven plasma-based acceleration  

SciTech Connect

The physics of plasma-based accelerators driven by short-pulse lasers is reviewed. This includes the laser wake-field accelerator, the plasma beat wave accelerator, the self-modulated laser wake-field accelerator, and plasma waves driven by multiple laser pulses. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse direction, electron dephasing, laser pulse energy depletion, as well as beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and plasmas with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Recent experimental results are summarized.

Esarey, Eric; Schroeder, Carl B.

2003-06-30T23:59:59.000Z

40

Trans-Debye Scale Plasma Modeling & Stochastic GRB Wakefield Plasma Processes  

E-Print Network (OSTI)

Modeling plasma physical processes in astrophysical context demands for both detailed kinetics and large scale development of the electromagnetic field densities. We present a new framework for modeling plasma physics of hot tenuous plasmas by a two-split scheme, in which the large scale fields are modeled by means of a particle-in-cell (PIC) code, and in which binary collision processes and single-particle processes are modeled through a Monte-Carlo approach. Our novel simulation tool -- the PhotonPlasma code -- is a unique hybrid model; it combines a highly parallelized (Vlasov) particle-in-cell approach with continuous weighting of particles and a sub-Debye Monte-Carlo binary particle interaction framework. As an illustration of the capabilities we present results from a numerical study of Gamma-Ray Burst - Circumburst Medium interaction and plasma preconditioning via Compton scattering. We argue that important microphysical processes can only viably be investigated by means of hybrid codes such as the PhotonPlasma code. Our first results from 3D simulations with this new simulation tool suggest that magnetic fields and plasma filaments are created in the wakefield of prompt gamma-ray bursts. Furthermore, the photon flux density gradient impacts on particle acceleration in the burst head and wakefield. We discuss some possible implications of the circumburst medium being preconditioned for a trailing afterglow shock front. We also discuss important improvements for future studies of GRB wakefields processes, using the PhotonPlasma code.

J. Trier Frederiksen; T. Haugboelle; A. Nordlund

2008-08-06T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
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41

Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.

Kirby, Neil; /SLAC

2009-10-30T23:59:59.000Z

42

Characteristics of an envelope model for laser-plasma accelerator simulation  

Science Conference Proceedings (OSTI)

Simulation of laser-plasma accelerator (LPA) experiments is computationally intensive due to the disparate length scales involved. Current experiments extend hundreds of laser wavelengths transversely and many thousands in the propagation direction, ... Keywords: Envelope model, Laser wakefield acceleration, Laser-plasma acceleration, PIC, Plasma accelerator

Benjamin M. Cowan; David L. Bruhwiler; Estelle Cormier-Michel; Eric Esarey; Cameron G. R. Geddes; Peter Messmer; Kevin M. Paul

2011-01-01T23:59:59.000Z

43

Studies of laser wakefield structures and electron acceleration in underdense plasmasa...  

E-Print Network (OSTI)

a0 1 can be estimated as E eEwfLdph, where Ewf ne cm-3 V/cm is the plasma wave amplitude, providing energy observed in the experi- ment. The corresponding wakefield amplitudes are Ewf=0.32 GV/cm and Ewf=0 amplitude dependence Ewf ne and hence electron energy gain on plasma density and for the dephasing lengths

Shvets, Gennady

44

Scaling of Energy Gain with Plasma Parameters in a Plasma Wakefield Accelerator  

SciTech Connect

We have recently demonstrating the doubling of the energy of particles of the ultra-short, ultra-relativistic electron bunches of the Stanford Linear Accelerator Center [1]. This energy doubling occurred in a plasma only 85 cm-long with a density of {approx} 2.6 x 10{sup 17} e{sup -}/cm{sup -3}. This milestone is the result of systematic measurements that show the scaling of the energy gain with plasma length and density, and show the reproducibility and the stability of the acceleration process. We show that the energy gain increases linearly with plasma length from 13 to 31 cm. These are key steps toward the application of beam-driven plasma accelerators or plasma wakefield accelerators (PWFA) to doubling the energy of a future linear collider without doubling its length.

Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

2008-01-28T23:59:59.000Z

45

Scaling of the Longitudinal Electric Field and Transformer Ratio in a Nonlinear Plasma Wakefield Accelerator  

Science Conference Proceedings (OSTI)

The scaling of the two important figures of merit, the transformer ratio T and the longitudinal electric field E{sub z}, with the peak drive-bunch current I{sub p}, in a nonlinear plasma wakefield accelerator is presented for the first time. The longitudinal field scales as I{sub P}{sup 0.623{+-}0.007}, in good agreement with nonlinear wakefield theory ({approx}I{sub P}{sup 0.5}), while the unloaded transformer ratio is shown to be greater than unity and scales weakly with the bunch current. The effect of bunch head erosion on both parameters is also discussed.

Blumenfeld, I.; /SLAC; Clayton, C.E.; /UCLA; Decker, F.J.; Hogan, M.J.; /SLAC; Huang, C.; /UCLA; Ischebeck, R.; Iverson, R.H.; /SLAC; Joshi, C.; /UCLA; Katsouleas, T.; /Southern California U.; Kirby, N.; /SLAC; Lu, W.; Marsh, K.A.; Mori, W.B.; /UCLA; Muggli, P.; Oz, E.; /Southern California U.; Siemann, R.H.; Walz, D.R.; /SLAC; Zhou, M.; /UCLA

2012-06-12T23:59:59.000Z

46

GeV Wakefield acceleration of low energy electron bunches using Petawatt lasers  

Science Conference Proceedings (OSTI)

The possibility of accelerating electrons to the GeV level using a Petawatt laser focused in a uniform plasma is investigated. The proposed scheme relies on the wakefield acceleration of an electron bunch from a state-of-the-art radio-frequency accelerator. Using an analytical model as well as numerical simulations performed with WAKE [P. Mora and T. M. Antonsen, Phys. Plasmas 4, 217 (1997)], a systematical study of the injector parameters is carried out. In particular, it is found that the quality of the accelerated electron bunch--in terms of bunch length and energy spread--depends crucially on the injection energy. Injection energies of a few MeV lead to a GeV electron beam with sub-100 fs bunches and 10% energy spreads. Most of the features of the acceleration process can be explained within the linear response framework, including both the reduction of energy spread and bunch length at low injection energies. The role of nonlinear effects is discussed.

Lifschitz, A.F.; Faure, J.; Malka, V.; Mora, P. [Laboratoire d'Optique Appliquee, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau (France); Laboratoire de Physique Theorique, Ecole Polytechnique, CNRS, UMR 7644, 91128 Palaiseau (France)

2005-09-15T23:59:59.000Z

47

Two-Pulse Ionization Injection into Quasi-Linear Laser Wakefields  

E-Print Network (OSTI)

We describe a scheme for controlling electron injection into the quasi-linear wakefield driven by a guided drive pulse via ionization of a dopant species by a collinear injection laser pulse with a short Rayleigh range. The scheme is analyzed by particle in cell simulations which show controlled injection and acceleration of electrons to an energy of 370 MeV, a relative energy spread of 2%, and a normalized transverse emittance of 3.0 {\\mu}m.

Bourgeois, Nicolas; Hooker, Simon M

2013-01-01T23:59:59.000Z

48

Controlling the betatron oscillations of a wakefield-accelerated electron beam by temporally asymmetric laser pulses  

Science Conference Proceedings (OSTI)

Based on two-dimensional particle-in-cell simulations, we investigated the electron beam's transverse oscillations by temporally asymmetric laser pulses in laser wakefield acceleration. Of particular interest in this article are the effects of ultrashort laser pulses having sharp rising and slow falling time scales. In this situation, the accelerated electron beam interacts directly with the laser field and undergoes transverse oscillations due to a phase-slip with the laser field. This oscillation can be matched with the betatron oscillation due to the focusing force of the ions, which can lead to a large transverse oscillation amplitude due to the resonance between them. Furthermore, in this case, the electron beam can be microbunched at the laser wavelength, which may provide the possibility for generation of a coherent synchrotron radiation.

Nam, Inhyuk [Graduate Program of Photonics and Applied Physics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hur, Min Sup [School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Uhm, Han Sup [Electrophysics Department, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hafz, Nasr A. M.; Suk, Hyyong [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of)

2011-04-15T23:59:59.000Z

49

Benchmarking the codes VORPAL, OSIRIS, and QuickPIC with Laser Wakefield Acceleration Simulations  

DOE Green Energy (OSTI)

Three-dimensional laser wakefield acceleration (LWFA) simulations have recently been performed to benchmark the commonly used particle-in-cell (PIC) codes VORPAL, OSIRIS, and QuickPIC. The simulations were run in parallel on over 100 processors, using parameters relevant to LWFA with ultra-short Ti-Sapphire laser pulses propagating in hydrogen gas. Both first-order and second-order particle shapes were employed. We present the results of this benchmarking exercise, and show that accelerating gradients from full PIC agree for all values of a0 and that full and reduced PIC agree well for values of a0 approaching 4.

Paul, Kevin; Huang, C.; Bruhwiler, D.L.; Mori, W.B.; Tsung, F.S.; Cormier-Michel, E.; Geddes, C.G.R.; Cowan, B.; Cary, J.R.; Esarey, E.; Fonseca, R.A.; Martins, S.F.; Silva, L.O.

2008-09-08T23:59:59.000Z

50

Generation of tunable, 100-800 MeV quasi-monoenergetic electron beams from a laser-wakefield accelerator in the blowout regime  

Science Conference Proceedings (OSTI)

In this paper, we present results on a scalable high-energy electron source based on laser wakefield acceleration. The electron accelerator using 30-80 TW, 30 fs laser pulses, operates in the blowout regime, and produces high-quality, quasi-monoenergetic electron beams in the range 100-800 MeV. These beams have angular divergence of 1-4 mrad, and 5%-25% energy spread, with a resulting brightness 10{sup 11} electrons mm{sup -2} MeV{sup -1} mrad{sup -2}. The beam parameters can be tuned by varying the laser and plasma conditions. The use of a high-quality laser pulse and appropriate target conditions enables optimization of beam quality, concentrating a significant fraction of the accelerated charge into the quasi-monoenergetic component.

Banerjee, S.; Powers, N. D.; Ramanathan, V.; Ghebregziabher, I.; Brown, K. J.; Maharjan, C. M.; Chen, S.; Umstadter, D. P. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299 (United States); Beck, A.; Lefebvre, E.; Kalmykov, S. Y.; Shadwick, B. A. [CEA, DAM, DIF, 91297 Arpajon Cedex (France)

2012-05-15T23:59:59.000Z

51

Analytic model of electron self-injection in a plasma wakefield accelerator in the strongly nonlinear bubble regime  

Science Conference Proceedings (OSTI)

Self-injection of background electrons in plasma wakefield accelerators in the highly nonlinear bubble regime is analyzed using particle-in-cell and semi-analytic modeling. It is shown that the return current in the bubble sheath layer is crucial for accurate determination of the trapped particle trajectories.

Yi, S. A.; Khudik, V.; Siemon, C.; Shvets, G. [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, One University Station C1500, Austin, Texas (United States)

2012-12-21T23:59:59.000Z

52

Plasma wakefields in the quasi-nonlinear regime: Experiments at ATF  

Science Conference Proceedings (OSTI)

In this work we present details of planned experiments to investigate certain aspects of the quasi non linear regime (QNL) of plasma wakefield acceleration (PWFA). In the QNL regime it is, in principal, possible to combine the benefits of both nonlinear and linear PWFA. That is, beams of high quality can be maintained through acceleration due to the complete ejection of plasma electrons from beam occupied region, while large energy gains can be achieved through use of transformer ratio increasing schemes, such as ramped bunch trains. With the addition of an short focal length PMQ triplet capable of focusing beams to the few micron scale and the ability to generate tunable bunch trains, the Accelerator Test Facility (ATF) at Brookhaven National Lab offers the unique capabilities to probe these characteristics of the QNL regime.

Rosenzweig, J. B.; Andonian, G.; Barber, S.; Ferrario, M.; Muggli, P.; O'Shea, B.; Sakai, Y.; Valloni, A.; Williams, O.; Xi, Y.; Yakimenko, V. [UCLA Dept. of Physics and Astronomy, 405 Hilgard Ave. Los Angeles, CA, 90095 (United States); Accelerator Division, Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati , Via E. Fermi 40, Frascati (RM) 00044 (Italy); Max Planck Institute for Physics, Munich (Germany); UCLA Dept. of Physics and Astronomy, 405 Hilgard Ave. Los Angeles, CA, 90095 (United States); Brookhaven National Laboratory, Upton, NY, 11973 (United States)

2012-12-21T23:59:59.000Z

53

Exploiting multi-scale parallelism for large scale numerical modelling of laser wakefield accelerators  

E-Print Network (OSTI)

A new generation of laser wakefield accelerators, supported by the extreme accelerating fields generated in the interaction of PW-Class lasers and underdense targets, promises the production of high quality electron beams in short distances for multiple applications. Achieving this goal will rely heavily on numerical modeling for further understanding of the underlying physics and identification of optimal regimes, but large scale modeling of these scenarios is computationally heavy and requires efficient use of state-of-the-art Petascale supercomputing systems. We discuss the main difficulties involved in running these simulations and the new developments implemented in the OSIRIS framework to address these issues, ranging from multi-dimensional dynamic load balancing and hybrid distributed / shared memory parallelism to the vectorization of the PIC algorithm. We present the results of the OASCR Joule Metric program on the issue of large scale modeling of LWFA, demonstrating speedups of over 1 order of magni...

Fonseca, Ricardo A; Fiúza, Frederico; Davidson, Asher; Tsung, Frank S; Mori, Warren B; Silva, Luís O

2013-01-01T23:59:59.000Z

54

Laser triggered injection of electrons in a laser wakefield accelerator with the colliding pulse method  

E-Print Network (OSTI)

Laser Triggered Injection ofElectrons in a Laser Wake?eld Accelerator with the CollidingAn injection scheme for a laser wake?eld accelerator that

2004-01-01T23:59:59.000Z

55

Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic  

Science Conference Proceedings (OSTI)

The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

Bakeman, M.S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T.; Lin, C.; Robinson, K.E.; Schroeder, C.B.; Toth, Cs.; Weingartner, R.; Gruner, F.; Esarey, E.; Leemans, W.P.

2010-06-01T23:59:59.000Z

56

PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. Plasma wake excitation driven by lasers or particle beams is examined, and the implications of the different physical excitation mechanisms for accelerator design are discussed. Plasma-based accelerators have attracted considerable attention owing to the ultrahigh field gradients sustainable in a plasma wave, enabling compact accelerators. These relativistic plasma waves are excited by displacing electrons in a neutral plasma. Two basic mechanisms for excitation of plasma waves are actively being researched: (i) excitation by the nonlinear ponderomotive force (radiation pressure) of an intense laser or (ii) excitation by the space-charge force of a dense charged particle beam. There has been significant recent experimental success using lasers and particle beam drivers for plasma acceleration. In particular, for laser-plasma accelerators (LPAs), the demonstration at LBNL in 2006 of high-quality, 1 GeV electron beams produced in approximately 3 cm plasma using a 40 TW laser. In 2007, for beam-driven plasma accelerators, or plasma-wakefield accelerators (PWFAs), the energy doubling over a meter to 42 GeV of a fraction of beam electrons on the tail of an electron beam by the plasma wave excited by the head was demonstrated at SLAC. These experimental successes have resulted in further interest in the development of plasma-based acceleration as a basis for a linear collider, and preliminary collider designs using laser drivers and beam drivers are being developed. The different physical mechanisms of plasma wave excitation, as well as the typical characteristics of the drivers, have implications for accelerator design. In the following, we identify the similarities and differences between wave excitation by lasers and particle beams. The field structure of the plasma wave driven by lasers or particle beams is discussed, as well as the regimes of operation (linear and nonlinear wave). Limitations owing to driver emittance are also discussed.

Schroeder, Carl B.; Esarey, Eric; Benedetti, Carlo; Toth, Csaba; Geddes, Cameron; Leemans, Wim

2011-04-01T23:59:59.000Z

57

Excitation of Accelerating Plasma Waves by Counter-propagating Laser Beams  

SciTech Connect

Generation of accelerating plasma waves using two counter-propagating laser beams is considered. Colliding-beam accelerator requires two laser pulses: the long pump and the short timing beam. We emphasize the similarities and differences between the conventional laser wakefield accelerator and the colliding-beam accelerator (CBA). The highly nonlinear nature of the wake excitation is explained using both nonlinear optics and plasma physics concepts. Two regimes of CBA are considered: (i) the short-pulse regime, where the timing beam is shorter than the plasma period, and (ii) the parametric excitation regime, where the timing beam is longer than the plasma period. Possible future experiments are also outlined.

Gennady Shvets; Nathaniel J. Fisch; and Alexander Pukhov

2001-08-30T23:59:59.000Z

58

LASER WAKEFIELD ACCELERATION BEYOND 1 GeV USING IONIZATION INDUCED INJECTION*  

Science Conference Proceedings (OSTI)

A series of laser wake field accelerator experiments leading to electron energy exceeding 1 GeV are described. Theoretical concepts and experimental methods developed while conducting experiments using the 10 TW Ti:Sapphire laser at UCLA were implemented and transferred successfully to the 100 TW Callisto Laser System at the Jupiter Laser Facility at LLNL. To reach electron energies greater than 1 GeV with current laser systems, it is necessary to inject and trap electrons into the wake and to guide the laser for more than 1 cm of plasma. Using the 10 TW laser, the physics of self-guiding and the limitations in regards to pump depletion over cm-scale plasmas were demonstrated. Furthermore, a novel injection mechanism was explored which allows injection by ionization at conditions necessary for generating electron energies greater than a GeV. The 10 TW results were followed by self-guiding at the 100 TW scale over cm plasma lengths. The energy of the self-injected electrons, at 3 x 10{sup 18} cm{sup -3} plasma density, was limited by dephasing to 720 MeV. Implementation of ionization injection allowed extending the acceleration well beyond a centimeter and 1.4 GeV electrons were measured.

Marsh, K A; Clayton, C E; Joshi, C; Lu, W; Mori, W B; Pak, A; silva, L O; Lemos, N; Fonseca, R A; de Freitas, S; Albert, F; Doeppner, T; Filip, C; Froula, D; Glenzer, S H; Price, D; Ralph, J; Pollock, B B

2011-03-22T23:59:59.000Z

59

Nonlinear laser energy depletion in laser-plasma accelerators  

E-Print Network (OSTI)

Nonlinear laser energydepletion in laser-plasma accelerators ? B. A. Shadwick,of intense, short-pulse lasers via excitation of plasma

Shadwick, B.A.

2009-01-01T23:59:59.000Z

60

Observation of Synchrotron Radiation from Electrons Accelerated in a Petawatt-Laser-Generated Plasma Cavity  

Science Conference Proceedings (OSTI)

The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured synchrotron spectrum is found to scale as the Maxwellian temperature of the simultaneously measured electron spectra. At low laser intensity transverse oscillations are negligible as the electrons are predominantly accelerated axially by the laser generated wakefield. At high laser intensity, electrons are directly accelerated by the laser and enter a highly radiative regime with up to 5% of their energy converted into x rays.

Kneip, S.; Nagel, S. R.; Bellei, C.; Dangor, A. E.; Mangles, S. P. D.; Nilson, P. M.; Willingale, L.; Najmudin, Z. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Bourgeois, N.; Marques, J. R. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau (France); Gopal, A. [Department of Electronics, Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Heathcote, R. [Central Laser Facility, Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom); Maksimchuk, A.; Reed, S. [Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States); Phuoc, K. Ta; Rousse, A. [Laboratoire d'Optique Applique, ENSTA, Ecole Polytechnique, 91761 Palaiseau (France); Tzoufras, M.; Tsung, F. S.; Mori, W. B. [Department of Physics and Astronomy and Department of Electrical Engineering, UCLA, Los Angeles, California 90095 (United States); Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States)

2008-03-14T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Laser wakefield simulation using a speed-of-light frame envelope model  

E-Print Network (OSTI)

Laser wake?eld simulation using a speed-of-light frameAbstract. Simulation of laser wake?eld accelerator (LWFA)extend hundreds of laser wave- lengths transversely and many

Cowan, B.

2010-01-01T23:59:59.000Z

62

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network (OSTI)

LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

Schroeder, C. B.

2010-01-01T23:59:59.000Z

63

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

E-Print Network (OSTI)

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

Geddes, Cameron G.R.

2010-01-01T23:59:59.000Z

64

Staging laser plasma accelerators for increased beam energy  

E-Print Network (OSTI)

Staging Laser Plasma Accelerators for Increased Beam Energy94720, USA Abstract. Staging laser plasma accelerators is anefficient way of mitigating laser pump depletion in laser

Panasenko, Dmitriy

2010-01-01T23:59:59.000Z

65

Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator  

SciTech Connect

The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become strongly radially self-modulated over centimeter distances, leading to wake excitation in the blowout regime with accelerating fields in excess of 20 GV/m. We show that particles energy variations exceeding 10 GeV can occur in meter-long plasmas. We find that the self-modulation of positively and negatively charged bunches differs when the blowout is reached. Seeding the self-modulation instability mitigates the effect of the competing hosing instability. This work reveals that a proof-of-principle experiment to test the physics of bunch self-modulation can be performed with available lepton bunches and with existing experimental apparatus and diagnostics.

Vieira, J.; Silva, L. O. [GoLP/Instituto de Plasmas e Fusao Nuclear, Laboratorio Associado Instituto Superior Tecnico, Technical University of Lisbon, Lisboa (Portugal); Fang, Y. [University of Southern California, Los Angeles, California 90089 (United States); Mori, W. B. [University of California, Los Angeles, California 90095 (United States); Muggli, P. [University of Southern California, Los Angeles, California 90089 (United States); Max Planck Institute for Physics, Munich (Germany)

2012-06-15T23:59:59.000Z

66

Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources  

E-Print Network (OSTI)

of high- gradient, laser plasma particle accelerators.particle accelerators, plasmas can sustain acceleratingthat use laser-driven plasma waves. These plasma- based

Geddes, Cameron G.R.

2010-01-01T23:59:59.000Z

67

Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV  

E-Print Network (OSTI)

Gearhart,“Construction of a Cerenkov light source,” Rev.Plasma density from Cerenkov radiation, betatroncal considerations in the use of Cerenkov radiation as an

2001-01-01T23:59:59.000Z

68

Trapping and dark current in plasma-based accelerators  

SciTech Connect

The trapping of thermal electrons in a nonlinear plasma wave of arbitrary phase velocity is investigated. The threshold plasma wave amplitude for trapping plasma electrons is calculated, thereby determining the fraction trapped and the expected dark current in a plasma-based accelerator. It is shown that the presence of a laser field (e.g., trapping in the self-modulated regime of the laser wakefield accelerator) increases the trapping threshold. Implications for experimental and numerical laser-plasma studies are discussed.

Schroder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.

2004-06-01T23:59:59.000Z

69

Study on the effects of ion motion on laser-induced plasma wakes  

Science Conference Proceedings (OSTI)

A 2D analytical model is presented for the generation of plasma wakes (or bubbles) with an ultra-intense laser pulse by taking into account the response of plasma ions. It is shown that the effect of ion motion becomes significant at the laser intensity exceeding 10{sup 21} W/cm{sup 2} and plasma background density below 10{sup 19} cm{sup -3}. In this regime, ion motion tends to suppress the electrostatic field induced by charge separation and makes the electron acceleration less effective. As a result, the assumption of immobile ions overestimates the efficiency of laser wake-field acceleration of electrons. Based on the analytical model, the dynamics of plasma ions in laser-induced wake field is investigated. It is found that only one bubble appears as the plasmas background density exceeds the resonant density and the deposited laser energy is concentrated into the bubble, resulting in the generation of an ion bunch with extremely high energy density.

Zhou Suyun [Institute of Modern Optical Technologies, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); School of Materials Sciences and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Yuan Xiao [Institute of Modern Optical Technologies, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Xu Han [National Laboratory for Parallel and Distributed Processing, School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Cao, L. H.; Cai, H. B.; Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2012-09-15T23:59:59.000Z

70

Formation of electrostatic structures by wakefield acceleration in ultrarelativistic plasma flows: Electron acceleration to cosmic ray energies  

SciTech Connect

The ever increasing performance of supercomputers is now enabling kinetic simulations of extreme astrophysical and laser produced plasmas. Three-dimensional particle-in-cell (PIC) simulations of relativistic shocks have revealed highly filamented spatial structures and their ability to accelerate particles to ultrarelativistic speeds. However, these PIC simulations have not yet revealed mechanisms that could produce particles with tera-electron volt energies and beyond. In this work, PIC simulations in one dimension (1D) of the foreshock region of an internal shock in a gamma ray burst are performed to address this issue. The large spatiotemporal range accessible to a 1D simulation enables the self-consistent evolution of proton phase space structures that can accelerate particles to giga-electron volt energies in the jet frame of reference, and to tens of tera-electron volt in the Earth's frame of reference. One potential source of ultrahigh energy cosmic rays may thus be the thermalization of relativistically moving plasma.

Dieckmann, M.E.; Shukla, P.K.; Eliasson, B. [Institute of Theoretical Physics IV, Ruhr-University Bochum, D-44780 Bochum (Germany)

2006-06-15T23:59:59.000Z

71

CUSHMAN & WAKEFIELD, Inc  

NLE Websites -- All DOE Office Websites (Extended Search)

& Wakefield Launches Environmental Challenge Corporate initiative underway to increase energy and water efficiency and reduce waste NEW YORK - October 20, 2009 - In the spirit of...

72

Surface plasma wave excitation via laser irradiated overdense plasma foil  

SciTech Connect

A laser irradiated overdense plasma foil is seen to be susceptible to parametric excitation of surface plasma wave (SPW) and ion acoustic wave (IAW) on the ion plasma period time scale. The SPW is localised near the front surface of the foil while IAW extends upto the rear. The evanescent laser field and the SPW exert a ponderomotive force on electrons driving the IAW. The density perturbation associated with the latter beats with the laser induced oscillatory electron velocity to drive the SPW. At relativistic laser intensity, the growth rate is of the order of ion plasma frequency.

Kumar, Pawan; Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)

2012-04-09T23:59:59.000Z

73

Free-electron laser driven by the LBNL laser-plasma accelerator  

E-Print Network (OSTI)

OF AN XUV FEL DRIVEN BY THE LASER-PLASMA ACCELERATOR AT THEFree-electron laser driven bythe LBNL laser-plasma accelerator C. B. Schroeder ? , W. M.

Schroeder, C. B.

2010-01-01T23:59:59.000Z

74

Operational plasma density and laser parameters for future colliders based on laser-plasma accelerators  

SciTech Connect

The operational plasma density and laser parameters for future colliders based on laser-plasma accelerators are discussed. Beamstrahlung limits the charge per bunch at low plasma densities. Reduced laser intensity is examined to improve accelerator efficiency in the beamstrahlung-limited regime.

Schroeder, C. B.; Esarey, E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2012-12-21T23:59:59.000Z

75

Free-electron laser driven by the LBNL laser-plasma accelerator  

E-Print Network (OSTI)

Free-electron laser driven by the LBNL laser-plasmaA design of a compact free-electron laser (FEL), generatingare considered. Keywords: Free-electron laser, laser-plasma

Schroeder, C. B.

2010-01-01T23:59:59.000Z

76

Plasma heating effects during laser welding  

SciTech Connect

Laser welding is a relatively low heat input process used in joining precisely machined components with minimum distortion and heat affects to surrounding material. The CO/sub 2/ (10.6 ..mu..m) and Nd-YAG (1.06 ..mu..m) lasers are the primary lasers used for welding in industry today. Average powers range up to 20 kW for CO/sub 2/ and 400 W for Nd-YAG with pulse lengths of milliseconds to continuous wave. Control of the process depends on an understanding of the laser-plasma-material interaction and characterization of the laser beam being used. Inherent plasma formation above the material surface and subsequent modulation of the incident laser radiation directly affect the energy transfer to the target material. The temporal and spatial characteristics of the laser beam affect the available power density incident on the target, which is important in achieving repeatability in the process. Other factors such as surface texture, surface contaminants, surface chemistry, and welding environment affect plasma formation which determines the weld penetration. This work involves studies of the laser-plasma-material interaction process and particularly the effect of the plasma on the coupling of laser energy to a material during welding. A pulsed Nd-YAG laser was used with maximum average power of 400 W.

Lewis, G.K.; Dixon, R.D.

1985-01-01T23:59:59.000Z

77

Spectroscopic characterization of laser-induced tin plasma  

E-Print Network (OSTI)

H. R. Griem, Principles of Plasma Spectroscopy ?Cambridge,Beke?, Principles of Laser Plasmas ?Wiley-Interscience, NewIn the early stage of plasma evolution, the electron

Harilal, S S; O'Shay, B; Tillack, M S; Mathew, M V

2005-01-01T23:59:59.000Z

78

Relativistic Laser Plasma Research for Fast Ignition Laser Fusion  

E-Print Network (OSTI)

Reviewed are the present status and future prospects of the laser fusion research at the ILE (Institute of Laser Engineering) Osaka. The Gekko XII and Peta Watt laser system have been operated for investigating the fast ignition, the relativistic laser plasma interactions and so on. In particular, the fast ignition experiments with cone shell target have been in progress as the UK and US-Japan collaboration programs. In the experiments, the imploded high density plasmas are heated by irradiating 500 J level peta watt laser pulse. The thermal neutron yield is found to increase by three orders of magnitude by injecting the peta watt laser into the cone shell target. Transport of relativistic high density electron is the critical issue as the basic physics for understanding the dense plasma heating process. By the theory, simulation and experiment, the collective phenomena in the interactions of intense relativistic electron current with dense plasmas has been investigated to find the formation of self organized flow as the result of filamentation (Weibel) instability. Through the present understanding, the new project, FIREX-I has started recently to prove the principle of the fast ignition scheme. Keywords: fast ignition, peta watt laser, relativistic electron, weibel instability

Mima Kunioki; Tanaka Kazuo. A; Kodama Ryosuke; Johzaki Tomohiro; Nagatomo Hideo; Shiraga Hiroyuki; Miyanaga Noriaki; Azechi Hiroshi; Nakai Mitsuo; Norimatsu Takayoshi; Nagai Keiji; Sunahara Atsushi; Nishihara Katsunobu; Taguchi Toshihiro; Sakagami Hitoshi; Sentoku Yasuhiko; Ruhl Hartmut

2003-01-01T23:59:59.000Z

79

Spectroscopic characterization of laser ablation brass plasma  

Science Conference Proceedings (OSTI)

We present optical emission studies of the laser ablation brass plasma generated by the fundamental, second, and third harmonics of a neodymium doped yttrium aluminum garnet laser. The spectra predominantly reveal the spectral lines of the neutral and singly ionized copper and zinc. The excitation temperatures are determined by the Boltzmann plot method, whereas the electron number densities have been extracted from the Stark broadened line profiles. The spatial variations in the spectral line intensities and the plasma parameters at 1000, 500, and 100 mbar air pressures have been evaluated. Besides, the effect of the ambient gases (He, Ne, and Ar), the laser irradiance, and the laser wavelengths on the plasma parameters have been investigated.

Shaikh, Nek M. [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Institute of Physics, University of Sindh, 76080 Jamshoro (Pakistan); Hafeez, Sarwat; Kalyar, M. A.; Ali, R.; Baig, M. A. [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

2008-11-15T23:59:59.000Z

80

Enhanced laser beam coupling to a plasma  

DOE Patents (OSTI)

Density perturbations are induced in a heated plasma by means of a pair of oppositely directed, polarized laser beams of the same frequency. The wavelength of the density perturbations is equal to one half the wavelength of the laser beams. A third laser beam is linearly polarized and directed at the perturbed plasma along a line that is perpendicular to the direction of the two opposed beams. The electric field of the third beam is oriented to lie in the plane containing the three beams. The frequency of the third beam is chosen to cause it to interact resonantly with the plasma density perturbations, thereby efficiently coupling the energy of the third beam to the plasma.

Steiger, Arno D. (Pleasanton, CA); Woods, Cornelius H. (Livermore, CA)

1976-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Laser-plasma interactions for fast ignition  

E-Print Network (OSTI)

In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser plasma interactions (LPI) relevant to fast ignition. Increases in computational and modeling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multi-dimensional particle-in-cell (PIC) simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity are considered, as well as the dependence on plasma parameters. Different numerical modeling approaches and configurations are addressed, providing an overview of the modeling capabilities and limitations. In addition, we discuss the compa...

Kemp, A J; Debayle, A; Johzaki, T; Mori, W B; Patel, P K; Sentoku, Y; Silva, L O

2013-01-01T23:59:59.000Z

82

The BErkeley Lab Laser Accelerator (BELLA): A 10 GeV Laser Plasma Accelerator  

E-Print Network (OSTI)

The BErkeley Lab Laser Accelerator (BELLA):A 10 GeV Laser Plasma Accelerator W.P. Leemans ' , R.of the design of a 10 GeV laser plasma accelerator (LPA)

Leemans, W.P.

2011-01-01T23:59:59.000Z

83

Adventures in Laser Produced Plasma Research  

SciTech Connect

In the UK the study of laser produced plasmas and their applications began in the universities and evolved to a current system where the research is mainly carried out at the Rutherford Appleton Laboratory Central Laser Facility ( CLF) which is provided to support the universities. My own research work has been closely tied to this evolution and in this review I describe the history with particular reference to my participation in it.

Key, M

2006-01-13T23:59:59.000Z

84

Modeling of 10 GeV-1 TeV laser-plasma accelerators using Lorentz booster simulations  

SciTech Connect

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [J.-L. Vay, Phys. Rev. Lett. 98 130405 (2007)] allows direct and e#14;fficient full-scale modeling of deeply depleted and beam loaded laser-plasma stages of 10 GeV-1 TeV (parameters not computationally accessible otherwise). This verifies the scaling of plasma accelerators to very high energies and accurately models the laser evolution and the accelerated electron beam transverse dynamics and energy spread. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively. Agreement at the percentage level is demonstrated between simulations using different frames of reference for a 0.1 GeV class stage. Obtaining these speedups and levels of accuracy was permitted by solutions for handling data input (in particular particle and laser beams injection) and output in a relativistically boosted frame of reference, as well as mitigation of a high-frequency instability that otherwise limits effectiveness.

Vay, J.-L.; Geddes, C.G.R.; Esarey, E.; Esarey, E.; Leemans, W.P.; Cormier-Michel, E.; Grote, D.P.

2011-12-01T23:59:59.000Z

85

Particle-in-cell simulations of plasma accelerators and electron-neutral collisions  

Science Conference Proceedings (OSTI)

We present 2-D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approx}10{sup 16} W/cm{sup 2}) and high ({approx}10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications of XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.

Bruhwiler, David L.; Giacone, Rodolfo E.; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, W.P.; Shadwick, B.A.

2001-10-01T23:59:59.000Z

86

Design considerations for a laser-plasma linear collider  

SciTech Connect

Design considerations for a next-generation electron-positron linear collider based on laser-plasma-accelerators are discussed. Several of the advantages and challenges of laser-plasma based accelerator technology are addressed. An example of the parameters for a 1 TeV laser-plasma based collider is presented.

Schroeder, C. B.; Esarey, E.; Geddes, C. G. R.; Toth, Cs.; Leemans, W. P.

2008-08-01T23:59:59.000Z

87

High-charge energetic electron bunch generated by intersecting laser pulses  

SciTech Connect

The interaction of two energetic electron bunches generated in the wakefields of two intense intersecting laser pulses in rarefied plasmas is investigated using particle-in-cell simulations. It is found that, with suitable intersection angle between the two laser pulses, the initially independent wakefield accelerated electron bunches can merged into a single one with high charge, energy, and narrow energy spread. The dynamics of the laser-pulse intersection and wake-bubble merging process is also investigated, and the crucial roles of the intersection angle are pointed out and analyzed.

Yang Lei; Deng Zhigang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wang, Xingang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062 (China)

2013-03-15T23:59:59.000Z

88

PRECISE CHARGE MEASUREMENT FOR LASER PLASMA ACCELERATORS  

SciTech Connect

Cross-calibrations of charge diagnostics are conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). Employed diagnostics are a scintillating screen, activation based measurement, and integrating current transformer. The diagnostics agreed within {+-}8 %, showing that they can provide accurate charge measurements for LPAs provided they are used properly.

Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Sokollik, Thomas; Shiraishi, Satomi; Tilborg, Jeroen van; Osterhoff, Jens; Donahue, Rich; Rodgers, David; Smith, Alan; Byrne, Warren; Leemans, Wim

2011-07-19T23:59:59.000Z

89

Control of Laser Plasma Based Accelerators up to 1 GeV  

E-Print Network (OSTI)

2 1.2 LOASIS Laser Plasma Based94 Laser Energy Loss vs.Laser Pointintg (310 µm) . . . . . . . . . . . . . . . 95

Nakamura, Kei

2008-01-01T23:59:59.000Z

90

Measurements of Radiation Near An Atomic Spectral Line From the Interaction of a 30-GeV Electron Beam And a Long Plasma  

Science Conference Proceedings (OSTI)

Emissions produced or initiated by a 30 GeV electron beam propagating through a {approx}1 m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma; estimates of plasma and neutral density have been extracted. Increases in visible background radiation consistent with increased plasma recombination emissions due to dissipation of wakefields were simultaneously measured.

Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; /LBL, Berkeley; Assmann, R.; Decker, F.J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; /SLAC; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.A.; Mori, W.B.; Wang, S.; /UCLA; Katsouleas, T.; Lee, S.; Muggli, P.; /Southern California U.

2005-09-12T23:59:59.000Z

91

Control of Laser Plasma Based Accelerators up to 1 GeV  

Science Conference Proceedings (OSTI)

This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and output laser properties as well as a large angular acceptance (> {+-} 10 mrad) were realized by employing a slitless scheme. A scintillating screen (LANEX Fast back, LANEX-FB)--camera system allowed faster than 1 Hz operation and evaluation of the spatial properties of e-beams. The design provided sufficient resolution for the whole range of the ESM (below 5% for beams with 2 mrad divergence). The calibration between light yield from LANEX-FB and total charge, and a study on the electron energy dependence (0.071 to 1.23 GeV) of LANEX-FB were performed at the Advanced light source (ALS), Lawrence Berkeley National Laboratory (LBNL). Using this calibration data, the developed ESM provided a charge measurement as well. The production of high quality electron beams up to 1 GeV from a centimeter-scale accelerator was demonstrated. The experiment used a 310 {micro}m diameter gas-filled capillary discharge waveguide that channeled relativistically-intense laser pulses (42 TW, 4.5 x 10{sup 18} W/cm{sup 2}) over 3.3 centimeters of sufficiently low density ({approx_equal} 4.3 x 10{sup 18}/cm{sup 3}) plasma. Also demonstrated was stable self-injection and acceleration at a beam energy of {approx_equal} 0.5 GeV by using a 225 {micro}m diameter capillary. Relativistically-intense laser pulses (12 TW, 1.3 x 10{sup 18}W/cm{sup 2}) were guided over 3.3 centimeters of low density ({approx_equal} 3.5 x 10{sup 18}/cm{sup 3}) plasma in this experiment. A statistical analysis of the CDG-LWFAs performance was carried out. By taking advantage of the high repetition rate experimental system, several thousands of shots were taken in a broad range of the laser and plasma parameters. An analysis program was developed to sort and select the data by specified parameters, and then to evaluate performance statistically. The analysis suggested that the generation of GeV-level beams comes from a highly unstable and regime. By having the plasma density slightly above the threshold density for self injection, (1) the longest dephasing length possible was provided, which led to the generation of high energy e-beams, and (2) the number of electrons injected into the wakefield was kept small, which led to the generation of high quality (low energy spread) e-beams by minimizing the beam loading effect on the wake. The analysis of the stable half-GeV beam regime showed the requirements for stable self injection and acceleration. A small change of discharge delay t{sub dsc}, and input energy E{sub in}, significantly affected performance. The statistical analysis provided information for future optimization, and suggested possible schemes for improvement of the stability and higher quality beam generation. A CDG-LWFA is envisioned as a construction block for the next generation accelerator, enabling significant cost and size reductions.

Nakamura, Kei

2007-12-03T23:59:59.000Z

92

Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators  

SciTech Connect

Tapered plasma channels are considered for controlling dephasing of a beam with respect to a plasma wave driven by a weakly-relativistic, short-pulse laser. Tapering allows for enhanced energy gain in a single laser plasma accelerator stage. Expressions are derived for the taper, or longitudinal plasma density variation, required to maintain a beam at a constant phase in the longitudinal and/or transverse fields of the plasma wave. In a plasma channel, the phase velocities of the longitudinal and transverse fields differ, and, hence, the required tapering differs. The length over which the tapered plasma density becomes singular is calculated. Linear plasma tapering as well as discontinuous plasma tapering, which moves beams to adjacent plasma wave buckets, are also considered. The energy gain of an accelerated electron in a tapered laser-plasma accelerator is calculated and the laser pulse length to optimize the energy gain is determined.

Rittershofer, W.; Schroeder, C.B.; Esarey, E.; Gruner, F.J.; Leemans, W.P.

2010-05-17T23:59:59.000Z

93

Tailoring the air plasma with a double laser pulse  

SciTech Connect

We present a comprehensive model of plasma dynamics that enables a detailed understanding of the ways the air plasma induced in the atmosphere in the wake of a laser-induced filament can be controlled by an additional laser pulse. Our model self-consistently integrates plasma-kinetic, Navier-Stokes, electron heat conduction, and electron-vibration energy transfer equations, serving to reveal laser-plasma interaction regimes where the plasma lifetime can be substantially increased through an efficient control over plasma temperature, as well as suppression of attachment and recombination processes. The model is used to quantify the limitations on the length of uniform laser-filament heating due to the self-defocusing of laser radiation by the radial profile of electron density. The envisaged applications include sustaining plasma guides for long-distance transmission of microwaves, standoff detection of impurities and potentially hazardous agents, as well as lightning control and protection.

Shneider, M. N.; Miles, R. B. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States); Zheltikov, A. M. [Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843-4242 (United States)

2011-06-15T23:59:59.000Z

94

Plasma impedance and electron density in a pulsed laser channel  

Science Conference Proceedings (OSTI)

The representation of plasma impedance of gas laserdischarge and spark gap channels by an inductance–capacitance (L p ?C p ) tank circuit has been useful in describing the frequency response of a pulsed superradiant laser charging circuit. The impedance matching of these plasma channels can lead to resonant narrowing of the laser pulsewidth in superradiant nitrogen lasers. Using fluid equations to model the electron and ion plasmas

K. H. Tsui; G. H. Cavalcanti; A. S. Farias; M. D. S. Marinha; L. M. Soares; C. A. Massone

1996-01-01T23:59:59.000Z

95

Accurate Alignment of Plasma Channels Based on Laser Centroid Oscillations  

Science Conference Proceedings (OSTI)

A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the shift in laser centroid and angle at the channel outptut. If only the shift in centroid or angle is measured, then accurate alignment is provided by minimizing laser centroid motion at the channel exit as the channel properties are scanned. The improvement in alignment accuracy provided by this technique is important for minimizing electron beam pointing errors in laser plasma accelerators.

Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Osterhoff, Jens; Shiraishi, Satomi; Schroeder, Carl; Geddes, Cameron; Toth, Csaba; Esarey, Eric; Leemans, Wim

2011-03-23T23:59:59.000Z

96

Physics considerations for laser-plasma linear colliders  

SciTech Connect

Physics considerations for a next-generation linear collider based on laser-plasma accelerators are discussed. The ultra-high accelerating gradient of a laser-plasma accelerator and short laser coupling distance between accelerator stages allows for a compact linac. Two regimes of laser-plasma acceleration are discussed. The highly nonlinear regime has the advantages of higher accelerating fields and uniform focusing forces, whereas the quasi-linear regime has the advantage of symmetric accelerating properties for electrons and positrons. Scaling of various accelerator and collider parameters with respect to plasma density and laser wavelength are derived. Reduction of beamstrahlung effects implies the use of ultra-short bunches of moderate charge. The total linac length scales inversely with the square root of the plasma density, whereas the total power scales proportional to the square root of the density. A 1 TeV center-of-mass collider based on stages using a plasma density of 10{sup 17} cm{sup -3} requires tens of J of laser energy per stage (using 1 {micro}m wavelength lasers) with tens of kHz repetition rate. Coulomb scattering and synchrotron radiation are examined and found not to significantly degrade beam quality. A photon collider based on laser-plasma accelerated beams is also considered. The requirements for the scattering laser energy are comparable to those of a single laser-plasma accelerator stage.

Schroeder, Carl; Esarey, Eric; Geddes, Cameron; Benedetti, Carlo; Leemans, Wim

2010-06-11T23:59:59.000Z

97

Princeton Plasma Physics Lab - Laser diagnostics  

NLE Websites -- All DOE Office Websites (Extended Search)

laser-diagnostics The Multi-Point laser-diagnostics The Multi-Point Thomson Scattering (MPTS) diagnostic system has been providing time dependent Te and ne profile measurements on NSTX for ten years. en Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science http://www.pppl.gov/news/2013/09/premiere-issue-quest-magazine-details-pppls-strides-toward-fusion-energy-and-advances-0

98

Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration  

SciTech Connect

The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge of the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}z = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.

Jing, C.; Kanareykin, A. [Euclid Techlabs, LLC, Solon, OH-44139 (United States); Power, J.; Conde, M.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States)

2006-11-27T23:59:59.000Z

99

Observation of enhanced transformer ratio in collinear Wakefield acceleration.  

Science Conference Proceedings (OSTI)

The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge of the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}{sub z} = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.

Power, J.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanareykin, A.; High Energy Physics; Euclid Techlabs, LLC

2006-01-01T23:59:59.000Z

100

Survey of Advanced Dielectric Wakefield Accelerators  

NLE Websites -- All DOE Office Websites (Extended Search)

out wakefield accelerator research. Wakefield Acceleration at AATF The AATF had an electron beam produced by an L- band thermionic RF gun followed by two traveling-wave linac...

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Surfatron laser-plasma accelerator: prospects and limitations  

SciTech Connect

The surfatron laser-plasma accelerator is an extension of the plasma beat wave accelerator scheme. It utilizes very intense electric fields, 10/sup 9/ to 10/sup 10/ V/cm, associated with focussed laser beams to accelerate particles. (GHT)

Joshi, C.

1983-01-01T23:59:59.000Z

102

Effects of laser light on argon plasma in a GEC rf reference cell.  

E-Print Network (OSTI)

??Since lasers have become so powerful in dusty plasma research, it is important to determine the manner in which a laser will affect the plasma.… (more)

Price, Alexander Thomas.

2011-01-01T23:59:59.000Z

103

Laser Guiding for GeV Laser-Plasma Accelerators  

E-Print Network (OSTI)

Light pipe for high intensity laser pulses. Phys. Rev. Lett.and relativistically strong laser pulses in an underdensefrom Thomson scat- tering using laser wake?eld accelerators.

Leemans, Wim; Esarey, Eric; Geddes, Cameron; Schroeder, C.B.; Toth, Csaba

2005-01-01T23:59:59.000Z

104

Summary Report of Working Group 6: Laser-Plasma Acceleration  

Science Conference Proceedings (OSTI)

A summary is given of presentations and discussions in theLaser-Plasma Acceleration Working Group at the 2006 Advanced AcceleratorConcepts Workshop. Presentation highlights include: widespreadobservation of quasi-monoenergetic electrons; good agreement betweenmeasured and simulated beam properties; the first demonstration oflaser-plasma acceleration up to 1 GeV; single-shot visualization of laserwakefield structure; new methods for measuringpetawatt laser technology for future laser-plasmaaccelerators.

Leemans, Wim P.; Downer, Michael; Siders, Craig

2006-07-01T23:59:59.000Z

105

Experimental study of filamentation in laser-plasma interactions  

SciTech Connect

The filamentation instability can lead to regions of increased laser intensity when a spatially nonuniform laser beam interacts with a plasma. An experimental technique will be described which identifies the density perturbation produced by filaments. The growth of filaments has been investigated and, when the laser intensity is large enough, the transverse density profile of the filament can be measured. Evidence of filament growth influenced by plasma flow and density gradients is presented. 19 refs., 4 figs.

Young, P.E.

1991-01-07T23:59:59.000Z

106

Non-linear theory of laser-plasma interactions  

SciTech Connect

Research progress on each of the following areas is briefly described: (1) optical ray retracing of Brillouin backscattering from a nonisothermal plasma; (2) electromagnetic oscillating two-stream instability of laser radiation; (3) second harmonic generation of upper hybrid radiation in a plasma; (4) nonlinear scattering of upper hybrid laser radiation by electron Bernstein modes in a plasma; and (5) destructive collisions of supersonic solitons. (MOW)

Liu, C.S.

1980-01-01T23:59:59.000Z

107

Dependence of terahertz power from laser-produced plasma on laser intensity  

SciTech Connect

Power of terahertz radiation from plasma which is generated from air irradiated by coupled ({omega}, 2{omega}) femtosecond laser pulses is analyzed for high laser intensities, for which non-linear plasma effects on the pulse propagation become essential, with multidimensional particle-in-cell simulations including the self-consistent plasma kinetics. The growth rate of THz power becomes slower as the laser intensity increases. A reason of such a lowering of efficiency in THz emission is found to be ionization of air by the laser pulse, which results in poor focusing of laser pulses.

Shin, J.-H.; Zhidkov, A.; Jin, Z.; Hosokai, T.; Kodama, R. [Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Photon Pioneers Center, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Japan Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka (Japan)

2012-07-11T23:59:59.000Z

108

Laser ablation of electronic materials including the effects of energy coupling and plasma interactions  

E-Print Network (OSTI)

20, 171 5. K. Jain, Excimer laser lithography (SPIE OpticalGijbels, F. Adams (Eds. ), Laser Ionization Mass Analysis (G. Befeki, Principles of laser plasmas (Wiley Interscience,

Zeng, Xianzhong

2004-01-01T23:59:59.000Z

109

Fast Heating of Cylindrically Imploded Plasmas by Petawatt Laser Light  

Science Conference Proceedings (OSTI)

We produced cylindrically imploded plasmas, which have the same density-radius product of the imploded plasma {rho}R with the compressed core in the fast ignition experiment and demonstrated efficient fast heating of cylindrically imploded plasmas with an ultraintense laser light. The coupling efficiency from the laser to the imploded column was 14%-21%, implying strong collimation of energetic electrons over a distance of 300 {mu}m of the plasma. Particle-in-cell simulation shows confinement of the energetic electrons by self-generated magnetic and electrostatic fields excited along the imploded plasmas, and the efficient fast heating in the compressed region.

Nakamura, H.; Nakatsutsumi, M.; Yabuuchi, T. [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka (Japan); Sentoku, Y. [Nevada Terawatt Facility, Department of Physics, MS-220, University of Nevada, Reno, Nevada 89557 (United States); Matsuoka, T.; Norimatsu, T.; Shiraga, H. [Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka (Japan); Kondo, K.; Tanaka, K. A. [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka (Japan); Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka (Japan); Kodama, R. [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka (Japan); Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka (Japan); CREST, Japan Science and Technology Agency, 5-Sanbancho, Chiyoda-ku, Tokyo (Japan)

2008-04-25T23:59:59.000Z

110

Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1percent per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm2 and 0.4 pC/ps/mm2, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within +/-10 percent.

Nakamura, K.; Gonsalves, A. J.; Lin, C.; Sokollik, T.; Smith, A.; Rodgers, D.; Donahue, R.; Bryne, W.; Leemans, W. P.

2010-06-01T23:59:59.000Z

111

Charge Diagnostics for Laser Plasma Accelerators  

Science Conference Proceedings (OSTI)

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1% per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/ps/mm{sup 2}, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within {+-}10%.

Nakamura, K.; Gonsalves, A. J.; Lin, C.; Sokollik, T.; Smith, A.; Rodgers, D.; Donahue, R.; Bryne, W.; Leemans, W. P. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)

2010-11-04T23:59:59.000Z

112

Intense transient magnetic-field generation by laser plasma  

DOE Patents (OSTI)

In a laser system, the return current of a laser generated plasma is conducted near a target to subject that target to the magnetic field thereof. In alternate embodiments the target may be either a small non-fusion object for testing under the magnetic field or a laser-fusion pellet. In the laser-fusion embodiment, the laser-fusion pellet is irradiated during the return current flow and the intense transient magnetic field is used to control the hot electrons thereof to hinder them from striking and heating the core of the irradiated laser-fusion pellet.

Benjamin, R.F.

1981-08-18T23:59:59.000Z

113

Evolution of ultrashort laser pulse in large amplitude plasma waves  

Science Conference Proceedings (OSTI)

The propagation and evolution of an ultrashort laser pulse in a large amplitude plasma wave are investigated based on the photon kinetic theory. The photon number distribution function for a laser pulse in the phase space is analytically obtained by solving the photon kinetic equation in the background plasma wave. And then, the behavior of the laser pulse can be described by combining the single photon dynamics and the photon number distribution function. The evolutions of the photon number density in the coordinate and frequency domain space are discussed, and broadening or compressing of the laser pulse is also displayed in this paper. In particular, the frequency shift of the entire laser pulse is analyzed, which reflects a way of energy transformation between the laser pulse and the plasma wave.

Bu Zhigang [Department of Physics, Shanghai University, Shanghai 200444 (China); Ji Peiyong [Department of Physics, Shanghai University, Shanghai 200444 (China); The Shanghai Key Lab of Astrophysics, Shanghai 200234 (China)

2012-11-15T23:59:59.000Z

114

Progress Report on Modelling of Laser-Plasma Acceleration  

NLE Websites -- All DOE Office Websites (Extended Search)

Report on Modelling of Laser-Plasma Acceleration Karoly Nemeth presented a positive referee report from the PRL article that was submitted on Apr. 20, and discussed the most...

115

Tunable Laser Plasma Accelerator based on Longitudinal Density Tailoring  

Science Conference Proceedings (OSTI)

Laser plasma accelerators have produced high-quality electron beams with GeV energies from cm-scale devices and are being investigated as hyperspectral fs light sources producing THz to {gamma}-ray radiation and as drivers for future high-energy colliders. These applications require a high degree of stability, beam quality and tunability. Here we report on a technique to inject electrons into the accelerating field of a laser-driven plasma wave and coupling of this injector to a lower-density, separately tunable plasma for further acceleration. The technique relies on a single laser pulse powering a plasma structure with a tailored longitudinal density profile, to produce beams that can be tuned in the range of 100-400 MeV with percent-level stability, using laser pulses of less than 40 TW. The resulting device is a simple stand-alone accelerator or the front end for a multistage higher-energy accelerator.

Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Panasenko, Dmitriy; Shiraishi, Satomi; Sokollik, Thomas; Benedetti, Carlo; Schroeder, Carl; Geddes, Cameron; Tilborg, Jeroen van; Osterhoff, Jens; Esarey, Eric; Toth, Csaba; Leemans, Wim

2011-07-15T23:59:59.000Z

116

High Transformer ratios in collinear wakefield accelerators.  

Science Conference Proceedings (OSTI)

Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (sigmaz=2 mm) of the new Argonne wakefield accelerator (AWA) drive gun (where the experiment will be performed), a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structures for future wakefield accelerators.

Power, J. G.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanreykin, A.; Schoessow, P.; High Energy Physics; Euclid Techlabs, LLC

2008-01-01T23:59:59.000Z

117

Recent Experiment on Wakefield Transformer Ratio Enhancement at AWA  

SciTech Connect

One technique to enhance the transformer ratio beyond the ordinary limit of 2 in a collinear wakefield acceleration scheme is to use a ramped bunched train (RBT). The first experimental demonstration has been reported in [1]. However, due to the mismatch between the beam bunch length and frequency of the accelerating structure, the observed transformer ratio was only marginally above 2 in the earlier experiment. We recently revisited this experiment with an optimized bunch length using the laser stacking technique at Argonne Wakefield Accelerator (AWA) facility. A transformer ratio of 3.4 has been measured using two drive bunches. Attempting to use four drive bunches met with major challenges. In this article, measurement results and data analysis from these experiments are presented in detail.

Jing, C.; Kanareykin, A. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH 44139 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Power, J. G.; Conde, M.; Liu, W.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

2010-11-04T23:59:59.000Z

118

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

119

Traveling-wave laser-produced-plasma energy source for photoionization laser pumping and lasers incorporating said  

SciTech Connect

A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

Sher, Mark H. (Los Altos, CA); Macklin, John J. (Stanford, CA); Harris, Stephen E. (Palo Alto, CA)

1989-09-26T23:59:59.000Z

120

Argonne Wakefield Accelerator Facility (AWA) Upgrades  

NLE Websites -- All DOE Office Websites (Extended Search)

Facility is dedicated to the study of advanced accelerator concepts based on electron beam driven wakefield acceleration and RF power generation. The facility employs an...

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Effects of flow on density profiles in laser irradiated plasmas  

SciTech Connect

When the plasma outflow velocity relative to the critical surface is supersonic, compressional density profiles can form in the critical region. These compressions involve dissipative processes like those in collisionless shocks; associated plasma instabilities and reflected ions may inhibit energy transport and enhance laser light absorption.

Max, C.E.; McKee, C.F.

1977-10-18T23:59:59.000Z

122

Laser-Induced Underwater Plasma And Its Spectroscopic Applications  

SciTech Connect

Applications of Laser Induced Breakdown Spectroscopy (LIBS) for analysis of immersed solid and soft materials, and for liquid impurities are described. A method for improving the LIBS signal underwater and for obtaining quantitative analyses in presence of strong shot-to-shot variations of the plasma properties is proposed. Dynamic of the gas bubble formed by the laser pulse is also discussed, together with its importance in Double-Pulse (DP) laser excitation. Results of the studies relative to an application of multi-pulse sequence and its effects on the plasma and gas bubble formation are also presented.

Lazic, Violeta [ENEA, FIS-LAS, Via. E. Fermi 45, 00044 Frascati (Italy)

2008-09-23T23:59:59.000Z

123

X-ray emission from laser-produced plasmas  

SciTech Connect

The intensity and spectral characteristics of x-ray emitted from laser-produced plasmas have been investigated computatinoally and experimentally. a two-dimensional implosi code was used successfully to calculate laser-plasma radiation characteristics and to aid in the design of laser targets for high-yield x-ray production. Other computer codes, in use or under development predict lime strengths and energies for laser-plasma x-ray emission. An experimental effort is aimed at reliable measurements of x-ray yields and spectra. a wide variety of x-ray detection methods have been evaluated, and x-ray yields have been measured from plasmas produced with two dissimilar laser systems. The high energy x-ray spectrum, from about 10 to 140 keV, has been studied using high-gain scintillatino detectors and thick K-edge filters. Various supplementary measurements have provided information concerning characteristics of the target-reflected laser light, the ion energies, and the laser intensity patterns.

Violet, C.E. [ed.

1974-07-01T23:59:59.000Z

124

Guiding of Laser Beams in Plasmas by Radiation Cascade Compression  

SciTech Connect

The near-resonant heatwave excitation of an electron plasma wave (EPW) can be employed for generating trains of few-fs electromagnetic pulses in rarefied plasmas. The EPW produces a co-moving index grating that induces a laser phase modulation at the beat frequency. Consequently, the cascade of sidebands red- and blue-shifted from the fundamental by integer multiples of the beat frequency is generated in the laser spectrum. When the beat frequency is lower than the electron plasma frequency, the phase chirp enables laser beatnote compression by the group velocity dispersion [S. Kalmykov and G. Shvets, Phys. Rev. E 73, 046403 (2006)]. In the 3D cylindrical geometry, the frequency-downshifted EPW not only modulates the laser frequency, but also causes the pulse to self-focus [P. Gibbon, Phys. Fluids B 2, 2196 (1990)]. After self-focusing, the multi-frequency laser beam inevitably diverges. Remarkably, the longitudinal beatnote compression can compensate the intensity drop due to diffraction. A train of high-intensity radiation spikes with continually evolving longitudinal profile can be self-guided over several Rayleigh lengths in homogeneous plasmas. High amplitude of the EPW is maintained over the entire propagation length. Numerical experiments on the electron acceleration in the cascade-driven (cascade-guided) EPW [using the code WAKE by P. Mora and T. M. Antonsen Jr., Phys. Plasmas 4, 217 (1997)] show that achieving GeV electron energy is possible under realistic experimental parameters.

Kalmykov, Serguei; Shvets, Gennady [Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

2006-11-27T23:59:59.000Z

125

Experimental studies of laser guiding in plasma channels  

DOE Green Energy (OSTI)

The authors present results of experimental investigations of laser guiding in plasma channels. A new technique for plasma channel creation, the Ignitor-Heater scheme is proposed and experimentally tested in hydrogen and nitrogen. It makes use of two laser pulses. The Ignitor, an ultrashort (< 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used subsequently to heat the existing spark via inverse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows, creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. The channel density was diagnosed with time resolved longitudinal interferometry. From these measurements the plasma temperature was inferred. The guiding properties of the channels were tested by injecting a > 5 {times} 10{sup 17} W/cm{sup 2}, 75 fs laser pulse.

Volfbeyn, P.; Leemans, W.P.

1998-07-01T23:59:59.000Z

126

Dielectric Wakefield Accelerator to drive the future FEL Light Source.  

SciTech Connect

X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

Jing, C.; Power, J.; Zholents, A. (Accelerator Systems Division (APS)); ( HEP); (LLC)

2011-04-20T23:59:59.000Z

127

The Nitriding of Hafnium and Zirconium Using a Laser-sustained Plasma.  

E-Print Network (OSTI)

??A parametric study of laser and laser-sustained plasma interactions in nitrogen atmosphere with zirconium (Zr) and hafnium (Hf) metal was conducted to investigate the formation… (more)

Strait, Timmy

2013-01-01T23:59:59.000Z

128

Synchrotron Radiation from a Laser Plasma Accelerator in the Bubble Regime  

Science Conference Proceedings (OSTI)

A laser wakefield accelerator is shown to operate in the highly non-linear bubble regime, following the characteristic scaling of energy gain with density and leading to monoenergetic electron beams with up to 400 MeV and hundreds of pC charge. The bubble acts at the same time as a miniature undulator, causing the electrons to give off a beam of betatron x-rays with milliradian divergence, {mu}m source size, 1-100 keV photon energy and 10{sup 22} ph/mm{sup 2}/mrad{sup 2}s/0.1% BW.

Kneip, S. [Blackett Laboratory, Imperial College London, London, SW7 2BZ (United Kingdom); Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI, 48109 (United States); McGuffey, C.; Chvykov, V.; Dollar, F.; Kalintchenko, G.; Maksimchuk, T.; Matsuoka, T.; Thomas, A. G. R.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI, 48109 (United States); Mangles, S. P. D.; Nagel, S. R.; Palmer, C. A. J.; Schreiber, J.; Najmudin, Z. [Blackett Laboratory, Imperial College London, London, SW7 2BZ (United Kingdom); Ta Phuoc, K. [Laboratoire d'Optique Appliquee, ENSTA, Ecole Polytechnique, Palaiseau, 91761 (France)

2010-11-04T23:59:59.000Z

129

How much laser power can propagate through fusion plasma?  

E-Print Network (OSTI)

Propagation of intense laser beams is crucial for inertial confinement fusion, which requires precise beam control to achieve the compression and heating necessary to ignite the fusion reaction. The National Ignition Facility (NIF), where fusion will be attempted, is now under construction. Control of intense beam propagation may be ruined by laser beam self-focusing. We have identified the maximum laser beam power that can propagate through fusion plasma without significant self-focusing and have found excellent agreement with recent experimental data, and suggest a way to increase that maximum by appropriate choice of plasma composition with implication for NIF designs. Our theory also leads to the prediction of anti-correlation between beam spray and backscatter and suggests the indirect control of backscatter through manipulation of plasma ionization state or acoustic damping.

Pavel M. Lushnikov; Harvey A. Rose

2005-12-30T23:59:59.000Z

130

Positivity Preservation in the Simulation of Relativistic Laser-Plasma Interaction.  

E-Print Network (OSTI)

??With standard schemes, the plasma density in the hydrodynamic model for relativistic laser-plasma interaction can become negative. Therefore, we present a new scheme that preserves… (more)

Wortmann, Anke

2013-01-01T23:59:59.000Z

131

Laser diagnostics | Princeton Plasma Physics Lab  

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132

Spatial diagnostics of the laser induced lithium fluoride plasma  

SciTech Connect

We present spatial characteristics of the lithium fluoride plasma generated by the fundamental and second harmonic of a Nd:YAG laser. The plume emission has been recorded spatially using five spectrometers covering the spectral region from 200 nm to 720 nm. The electron density is measured from the Stark broadened line profile of the line at 610.37 nm, whereas the plasma temperature has been determined using the Boltzmann plot method including all the observed spectral lines of lithium. Both the plasma parameters; electron density and plasma temperature decrease with the increase of the distance from the target surface. The thermal conduction towards the target, the radiative cooling of the plasma, and the conversion of thermal energy into kinetic energy are the main mechanisms responsible for the spatially decrease of the plasma parameters.

Baig, M. A.; Qamar, Aisha; Fareed, M. A.; Anwar-ul-Haq, M.; Ali, Raheel [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

2012-06-15T23:59:59.000Z

133

Laser produced plasma diagnostics by cavity ringdown spectroscopy and applications  

SciTech Connect

Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity distributions within the plume. In various plasmas we have observed molecules or metastable atoms which were not present in the emission spectra.

Milosevic, S. [Institute of Physics, Zagreb (Croatia)

2012-05-25T23:59:59.000Z

134

Stark broadening in hot, dense laser-produced plasmas  

SciTech Connect

Broadened Lyman-$alpha$ x-ray lines from neon X and argon XVIII radiators, which are immersed in a hot, dense deuterium or deuterium-tritium plasma, are discussed. In particular, these lines are analyzed for several temperature-density cases, characteristic of laser-produced plasmas; special attention paid to the relative importance of ion, electron, and Doppler effects. Static ion microfield distribution functions are tabulated.

Tighe, R.J.; Hooper, C.F. Jr.

1976-01-01T23:59:59.000Z

135

Dynamic electric fields and double layers in laser-produced plasmas  

SciTech Connect

This paper traces the historical development of electric double layers. Properties of laser produced plasmas are discussed.

Soreq, S.E. (Nuclear Research Center, Plasma Physics Dept., Yavne (IL)); Hora, H. (New South Wales Univ., Kensington (Australia). Dept. of Theoretical Physics)

1989-12-01T23:59:59.000Z

136

X-ray emission from colliding laser plasmas  

SciTech Connect

Colliding Au, CD and Ti-Cr plasmas have been generated by illuminating two opposing foils each with a {approximately} 100J, 0.5 nsec, 2{omega} Nd-glass laser beam from the Trident laser facility at Los Alamos. The plasmas are being used to study plasma interactions which span the parameter regime from interpenetrating to collisional stagnation. X-ray emission during the laser target interaction and the subsequent collision is used to diagnose the initial plasma conditions and the colliding plasma properties. X-ray instrumentation consists of a 100 ps gated x-ray pinhole imager, a time-integratcd bremsstrahlung x-ray spectrograph and a gated x-ray spectrograph used to record isoelectronic spectra from the Ti-Cr plasmas. The imager has obtained multi-frame images of the collision and therefore, a measure of the stagnation length which is a function of the ion charge state and density and a strong function of the electron temperature. Other instrumentation includes a Thomson scattering spectrometer with probe beam, neutron detectors used to monitor the CD coated foil collisions and an ion spectrometer. We will describe the current status of the experiments and current results with emphasis on the x-ray emission diagnostics. We will also briefly describe the modeling using Lasnex and ISIS, a particle-in-cell code with massless fluid electrons and inter particle (classical) collisions.

Wilke, M.; Obst, A.W.; Winske, D. [and others

1995-09-01T23:59:59.000Z

137

Nonclassical hydrodynamic behavior of Sn plasma irradiated with a long duration CO2 laser pulse  

E-Print Network (OSTI)

with a long duration CO 2 laser pulse Y. Tao · M.S. Tillackwith a long duration CO 2 laser pulse is much shorter thanmass and makes a CO 2 -laser-produced Sn plasma suitable as

Tao, Y.; Tillack, M. S.; Yuseph, S.; Burdt, R.; Najmabadi, F.

2010-01-01T23:59:59.000Z

138

High transformer ratio drive beams for wakefield accelerator studies  

Science Conference Proceedings (OSTI)

For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Max Planck Institute for Physics, 80805 Munich (Germany); University of California Los Angeles, Los Angeles, CA 90095 (United States); Tsinghua University, Beijing (China)

2012-12-21T23:59:59.000Z

139

Atomic processes in plasmas under ultra-intense laser irradiation  

Science Conference Proceedings (OSTI)

Lasers delivering subpicosecond pulses with energies of a fraction of a Joule have made it possible to generate irradiance levels approaching 10{sup 20} W/cm{sup 2}. We presently operate two such systems, a KrF based excimer laser capable of producing a few 10{sup 17} W/cm{sup 2} at 248 nm with a repetition rate of 3--5 Hz and a XeCl based excimer laser capable of producing mid 10{sup 19} W/cm{sup 2} at 308 nm and 1 Hz. We will discuss some experimental results and the theory and modeling of the interaction of such intense laser pulses with aluminum. Because of a small ASE prepulse the high intensity interaction is not at the solid surface but rather at the n{sub e} = 2 {times} 10{sup 22} cm{sup {minus}3} critical density of the blowoff plasma generated by the ASE. The transient behavior of the plasma following the energy deposition by the intense subpicosecond pulse can be viewed as the energy-impulse response of the plasma. Experimental results and modeling of the x-ray emission from this plasma will be presented. 15 refs., 8 figs.

Schappert, G.T.; Casperson, D.E.; Cobble, J.A.; Comly, J.C.; Jones, L.A.; Kyrala, G.A.; LaGattuta, K.J.; Lee, P.H.Y.; Olson, G.L.; Taylor, A.J.

1989-11-01T23:59:59.000Z

140

Light reradiation in a parametrically turbulent laser plasma  

SciTech Connect

The intensity and spectrum of the light reradiated in a laser plasma are estimated from the theory of parametric turbulence. The possibility of determining the turbulence characteristics from the reradiation spectrum is discussed. It is suggested that the diffuse reflection observed experimentally is related to reradiation.

Krupnova, L.V.; Silin, V.P.; Tikhonchuk, V.T.

1979-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


141

Self Thomson Scattering in Laser Produced Plasmas  

DOE Green Energy (OSTI)

The NIF Power Conditioning System (PCS) resides in four Capacitor Bays, supplying energy to the Master and Power Amplifiers which reside in the two adjacent laser bays. Each capacitor bay will initially house 48 individual power conditioning modules, shown in Figure 2, with space reserved for expansion to 54 modules. The National Ignition Facility (NIF) Power Conditioning System (PCS) is a modular capacitive energy storage system that will be capable of storing nearly 400 MJ of electrical energy and delivering that energy to the nearly 8000 flashlamps in the NIF laser. The first sixteen modules of the power conditioning system have been built, tested and installed. Activation of the first nine power conditioning modules has been completed and commissioning of the first ''bundle'' of laser beamlines has begun. This paper will provide an overview of the power conditioning system design and describe the status and results of initial testing and activation of the first ''bundle'' of power conditioning modules.

Niemann, C; Glenzer, S H; Kauffman, R L; Meezan, N B; Oades, K; Slark, G; Stevenson, M; Suter, L J

2003-08-22T23:59:59.000Z

142

Aerosol beam-focus laser-induced plasma spectrometer device  

SciTech Connect

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

143

Nonlinear pulse propagation and phase velocity of laser-driven plasma waves  

Science Conference Proceedings (OSTI)

Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the energy gain and efficiency of laser-plasma accelerators that use a uniform plasma profile.

Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

2011-03-25T23:59:59.000Z

144

Laser wavelength effects on the charge state resolved ion energy distributions from laser-produced Sn plasma  

E-Print Network (OSTI)

Laser wavelength effects on the charge state resolved ion energy distributions from laser of laser wavelength on the charge state resolved ion energy distributions from laser-produced Sn plasma channel electron multiplier are used to record the charge state resolved ion energy distributions 100 cm

Najmabadi, Farrokh

145

Sur la propagation des ondes laser avec couplage à l'hydrodynamique pour l'interaction laser plasma.  

E-Print Network (OSTI)

??On s'intéresse à la propagation des ondes laser dans le cadre de l'interaction laser plasma. On utilise une stratégie basée sur une méthode de décomposition… (more)

Desroziers, Sylvain

2006-01-01T23:59:59.000Z

146

Wakefield Computations for the Injector (Part I)  

Science Conference Proceedings (OSTI)

In this document, we report on basic wakefield computations used to establish the impedance budget for the LCLS injector. Systematic comparisons between analytic formulae and results from ABCI are done. Finally, a comparison between 2D and 3D wakefield calculations are given for a cross. The three parts of the document are presented as follows: (1) ABCI computations for a few structures (Flange, Bellows...); (2) Comparison analytic with ABCI runs; and (3) Comparison Cross and Cavity using MAFIA.

Limborg-Deprey, C.

2010-12-13T23:59:59.000Z

147

Convective transport in laser target plasmas  

SciTech Connect

The role of guiding-center corrections in convective transport of electron energy is examined with a simple numerical model. At 10/sup 16/W cm/sup -2/ with a 60-..mu..m spot and a 10.6-..mu..m wavelength laser, the Righi-Leduc term is observed to have little effect on transport in a calculation with the thermal flux limited to the free-streaming value.

Brackbill, J.U.; Colombant, D.; Grandjouan, N.

1982-01-01T23:59:59.000Z

148

Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow  

SciTech Connect

Laser-induced energy deposition is widely discussed as a flow control technique in supersonic transportation. In case of thermal laser-plasma upstream of a blunt body, a substantial adaptation of shock wave geometry and magnitude of wave drag is predicted. Related to the research on laser supported detonation, the paper describes the implementation of laser-sustained plasma in a supersonic Argon jet. The stable plasma state is generated by the intersection of a Q-switched Nd:YAG-laser and a continuous wave CO{sub 2}-laser beams, for ignition and maintenance of the plasma respectively. A miniature supersonic Ludwieg tube test facility generates a supersonic jet at velocities of Mach 2.1. Modifications of the flow and plasma conditions are investigated and characterized by Schlieren flow visualisation, laser energy transmission and plasma radiation measurements. The results include the discussions of the flow field as well as the required laser and gas parameters.

Sperber, David; Eckel, Hans-Albert [DLR - German Aerospace Center, Institute of Technical Physics, Stuttgart (Germany); Moessinger, Peter [University of Applied Sciences, Faculty of Mechanical Engineering, Esslingen (Germany); Fasoulas, Stefanos [University of Stuttgart, Institute of Space Systems, Stuttgart (Germany)

2011-11-10T23:59:59.000Z

149

Time-resolved diagnostics of excimer laser-generated ablation plasmas used for pulsed laser deposition  

SciTech Connect

Characteristics of laser plasmas used for pulsed laser deposition (PLD) of thin films are examined with four in situ diagnostic techniques: Optical emission spectroscopy, optical absorption spectroscopy, ion probe studies, and gated ICCD (intensified charge-coupled-device array) fast photography. These four techniques are complementary and permit simultaneous views of the transport of ions, excited states, ground state neutrals and ions, and hot particulates following KrF laser ablation of YBCO, BN, graphite and Si in vacuum and background gases. The implementation and advantages of the four techniques are first described in order to introduce the key features of laser plasmas for pulsed laser deposition. Aspects of the interaction of the ablation plume with background gases (i.e., thermalization, attenuation, shock formation) and the collision of the plasma plume with the substrate heater are then summarized. The techniques of fast ICCD photography and gated photon counting are then applied to investigate the temperature, velocity, and spatial distribution of hot particles generated during KrF ablation of YBCO, BN, Si and graphite. Finally, key features of fast imaging of the laser ablation of graphite into high pressure rare gases are presented in order to elucidate internal reflected shocks within the plume, redeposition of material on a surface, and formation of hot nanoparticles within the plume.

Geohegan, D.B.

1994-09-01T23:59:59.000Z

150

Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring  

Science Conference Proceedings (OSTI)

In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO{sub 2} laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

Madjid, Syahrun Nur; Idris, Nasrullah [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Banda Aceh (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, University of Fukui, 9-1 Bunkyo 3-chome, Fukui 910-8507 (Japan)

2011-03-30T23:59:59.000Z

151

Gas laser with dual plasma mixing  

DOE Patents (OSTI)

A gas laser includes an enclosure forming a first chamber, a second chamber and a lasing chamber which communicates through a first opening to the first chamber and through a second opening to the second chamber. The lasing chamber has a pair of reflectors defining a Fabry-Perot cavity. Separate inlets enable different gases to be introduced into the first and second chambers. A first cathode within the first chamber is provided to produce positive ions which travel into the lasing chamber and a second cathode of a pin-hollow type within the second chamber is provided to produce negative ions which travel into the lasing chamber. A third inlet introduces a molecular gas into the lasing chamber, where the molecular gas becomes excited by the positive and negative ions and emits light which lases in the Fabry-Perot cavity.

Pinnaduwage, Lal A. (Knoxville, TN)

1999-01-01T23:59:59.000Z

152

Uv Thomson scattering from x-ray laser plasmas  

SciTech Connect

Plasmas produced by irradiating massive carbon targets with a 1.064 {mu}m, 1.5 ns laser pulse at incident energies of {approximately}100 J have been investigated. UV thermal Thomson scattering was used to obtain the electron and ion temperatures, as well as drift velocities. The electron density was obtained by optical interferometry. The results are compared to hydrodynamic computer modeling. 6 refs., 6 figs.

La Fontaine, B.; Baldis, H.A.; Villeneuve, D.M.; Bernard, J.E.; Enright, G.D. (National Research Council of Canada, Ottawa, ON (Canada)); Rosen, M.D.; Young, P.E.; Matthews, D.L. (Lawrence Livermore National Lab., CA (USA))

1991-01-03T23:59:59.000Z

153

Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma  

E-Print Network (OSTI)

The advent of high-intensity pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei, by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

C. Labaune; C. Baccou; S. Depierreux; C. Goyon; G. Loisel; V. Yahia; J. Rafelski

2013-10-08T23:59:59.000Z

154

Theoretical studies of some nonlinear laser-plasma interactions  

SciTech Connect

The nonlinear coupling of intense, monochromatic, electromagnetic radiation with plasma is considered in a number of special cases. The first part of the thesis serves as an introduction to three-wave interactions. A general formulation of the stimulated scattering of transverse waves by longitudinal modes in a warm, unmagnetized, uniform plasma is constructed. A general dispersion relation is derived that describes Raman and Brillouin scattering, modulational instability, and induced Thomson scattering. Raman scattering (the scattering of a photon into another photon and an electron plasma wave) is investigated as a possible plasma heating scheme. Analytic theory complemented by computer simulation is presented describing the nonlinear mode coupling of laser light with small and large amplitude, resonantly excited electron plasma waves. The simulated scattering of a coherent electromagnetic wave by low frequency density perturbations in homogeneous plasma is discussed. A composite picture of the linear dispersion relations for filamentation and Brillouin scattering is constructed. The absolute instability of Brillouin weak and strong coupling by analytic and numerical means is described. (auth)

Cohen, B.I.

1975-08-15T23:59:59.000Z

155

Increasing the transformer ratio at the Argonne wakefield accelerator.  

SciTech Connect

The transformer ratio is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss experienced by the drive bunch (or a bunch within a multidrive bunch train). This plays an important role in the collinear wakefield acceleration scheme. A high transformer ratio is desirable since it leads to a higher overall efficiency under similar conditions (e.g. the same beam loading, the same structure, etc.). One technique to enhance the transformer ratio beyond the ordinary limit of 2 is to use a ramped bunch train. The first experimental demonstration observed a transformer ratio only marginally above 2 due to the mismatch between the drive microbunch length and the frequency of the accelerating structure [C. Jing, A. Kanareykin, J. Power, M. Conde, Z. Yusof, P. Schoessow, and W. Gai, Phys. Rev. Lett. 98, 144801 (2007)]. Recently, we revisited this experiment with an optimized microbunch length using a UV laser stacking technique at the Argonne Wakefield Accelerator facility and measured a transformer ratio of 3.4. Measurements and data analysis from these experiments are presented in detail.

Power, J.G.; Conde, M.; Liu, W.; Yusof, Z.; Gai, W.; Jing, C.; Kanareykin, A. (High Energy Physics); (Euclid Techlabs, LLC)

2011-01-01T23:59:59.000Z

156

Angular emission of ions and mass deposition from femtosecond and nanosecond laser-produced plasmas  

SciTech Connect

We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.

Verhoff, B.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-06-15T23:59:59.000Z

157

Beam dynamics and wakefield simulations of the double grating accelerating structure  

Science Conference Proceedings (OSTI)

Laser-driven acceleration in dielectric structures can provide gradients on the order of GeV/m. The small transverse dimension and tiny feature sizes introduce challenges in design, fabrication, and simulation studies of these structures. In this paper we present the results of beam dynamic simulation and short range longitudinal wakefield simulation of the double grating structure. We show the linear trend of acceleration in a dielectric accelerator design and calculate the maximum achievable gradient equal to 0.47E{sub 0} where E0 is maximum electric field of the laser excitation. On the other hand, using wakefield simulations, we show that the loss factor of the structure with 400nm gap size will be 0.12GV/m for a 10fC, 100as electron bunch which is an order of magnitude less than expected gradient near damage threshold of the device.

Najafabadi, B. Montazeri; Byer, R. L.; Ng, C. K.; England, R. J.; Peralta, E. A.; Soong, K.; Noble, R.; Wu, Z. [Stanford University, Stanford, CA (United States); SLAC National Accelerator Laboratory, Menlo Park, CA (United States)

2012-12-21T23:59:59.000Z

158

Recent laser-plasma interaction experiments at the Lawrence Livermore National Laboratory  

Science Conference Proceedings (OSTI)

Recent Livermore experiments are aimed at investigating laser-plasma interaction issues which are relevant to ablatively driven fusion processes. We report the data obtained from using longer pulses and shorter laser wavelengths.

Lee, P.H.Y.

1980-01-01T23:59:59.000Z

159

Single-Trail and Multi-Trail Laser-Sustained Plasma Nitriding of ...  

Science Conference Proceedings (OSTI)

The influence of off-focal distance, gas composition, sample translation speed, relative to the laser beam and coaxial plasma, and trail overlap percentage were  ...

160

Time-resolved visible and extreme ultraviolet spectroscopy of laser-produced tin plasma  

E-Print Network (OSTI)

plasma: an optically thin corona and an optically thick conductionplasma heating occurs indirectly through radiative transfer and electron conduction.conduction carries energy in the laser absorption zone beyond the critical surface to heat the higher density plasma.

O'Shay, Joseph Fred

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W.P.

2010-06-01T23:59:59.000Z

162

Expansion of a plasma layer near a barrier irradiated by a laser in high-density gases  

SciTech Connect

The time dependence of shock waves in a laser-produced plasma are studied for a Nd laser with an energy of 80 J. (AIP)

Nemchinov, I.V.; Petrukhin, A.I.; Pleshanov, Y.E.; Rybakov, V.A.

1979-08-01T23:59:59.000Z

163

Fast Magnetic Reconnection in Laser-Produced Plasma Bubbles  

SciTech Connect

Recent experiments have observed magnetic reconnection in high-energy-density, laser-produced plasma bubbles, with reconnection rates observed to be much higher than can be explained by classical theory. Based on fully kinetic particle simulations we find that fast reconnection in these strongly driven systems can be explained by magnetic flux pileup at the shoulder of the current sheet and subsequent fast reconnection via two-fluid, collisionless mechanisms. In the strong drive regime with two-fluid effects, we find that the ultimate reconnection time is insensitive to the nominal system Alfven time.

Fox, W.; Bhattacharjee, A.; Germaschewski, K. [Center for Integrated Computation and Analysis of Reconnection and Turbulence, and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of New Hampshire, Durham, New Hampshire 03824 (United States)

2011-05-27T23:59:59.000Z

164

Particle physicist's dreams about PetaelectronVolt laser plasma accelerators  

Science Conference Proceedings (OSTI)

Present day accelerators are working well in the multi TeV energy scale and one is expecting exciting results in the coming years. Conventional technologies, however, can offer only incremental (factor 2 or 3) increase in beam energies which does not follow the usual speed of progress in the frontiers of high energy physics. Laser plasma accelerators theoretically provide unique possibilities to achieve orders of magnitude increases entering the PetaelectronVolt (PeV) energy range. It will be discussed what kind of new perspectives could be opened for the physics at this new energy scale. What type of accelerators would be required?.

Vesztergombi, G. [KFKI-RMKI. 1525-H Budapest P.O.B. 49. (Hungary)

2012-07-09T23:59:59.000Z

165

Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration  

Science Conference Proceedings (OSTI)

One approach to future high energy particle accelerators is based on the wakefield principle: a leading high-charge drive bunch is used to excite fields in an accelerating structure or plasma that in turn accelerates a trailing low-charge witness bunch. The transformer ratio R is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss of the drive bunch. In general, Rtransformer ratio limitation. We report here the first experimental study of the ramped bunch train (RBT) technique in a dielectric based accelerating structure. A single drive bunch was replaced by two bunches with charge ratio of 1 ratio 2.5 and a separation of 10.5 wavelengths of the fundamental mode. An average measured transformer ratio enhancement by a factor of 1.31 over the single drive bunch case was obtained.

Jing, C.; Kanareykin, A.; Schoessow, P. [Euclid Techlabs LLC, Solon, Ohio 44139 (United States); Power, J. G.; Conde, M.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois-60439 (United States)

2007-04-06T23:59:59.000Z

166

Propagation characteristics of a Gaussian laser beam in plasma with modulated collision frequency  

SciTech Connect

The propagation characteristics of a Gaussian laser beam in cold plasma with the electron collision frequency modulated by laser intensity are presented. The nonlinear dynamics of the ponderomotive force, which induce nonlinear self-focusing as opposed to spatial diffraction, are considered. The effective dielectric function of the Drude model and complex eikonal function are adopted in deriving coupled differential equations of the varying laser beam parameters. In the framework of ponderomotive nonlinearity, the frequency of electron collision in plasmas, which is proportional to the spatial electron density, is strongly interrelated with the laser beam propagation characteristics. Hence, the propagation properties of the laser beam and the modulated electron collision frequency distribution in plasma were studied and explained in depth. Employing this self-consistent method, the obtained simulation results approach practical conditions, which is of significance to the study of laser-plasma interactions.

Wang Ying; Yuan Chengxun; Zhou Zhongxiang; Gao Ruilin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li Lei; Du Yanwei [Shanghai Key Laboratory of Space Intelligent Control Technology, Shanghai 201108 (China)

2012-08-15T23:59:59.000Z

167

Nonlinear evolution of the plasma beat wave: Compressing the laser beat notes via electromagnetic cascading  

SciTech Connect

The near-resonant beat wave excitation of an electron plasma wave (EPW) can be employed for generating the trains of few-femtosecond electromagnetic (EM) pulses in rarefied plasmas. The EPW produces a comoving index grating that induces a laser phase modulation at the difference frequency. As a result, the cascade of sidebands red and blue shifted by integer multiples of the beat frequency is generated in the laser spectrum. The bandwidth of the phase-modulated laser is proportional to the product of the plasma length, laser wavelength, and amplitude of the electron density perturbation. When the beat frequency is lower than the electron plasma frequency, the redshifted spectral components are advanced in time with respect to the blueshifted ones near the center of each laser beat note. The group velocity dispersion of plasma compresses so chirped beat notes to a few-laser-cycle duration thus creating a train of sharp EM spikes with the beat periodicity. Depending on the plasma and laser parameters, chirping and compression can be implemented either concurrently in the same, or sequentially in different plasmas. Evolution of the laser beat wave and electron density perturbations is described in time and one spatial dimension in a weakly relativistic approximation. Using the compression effect, we demonstrate that the relativistic bistability regime of the EPW excitation [G. Shvets, Phys. Rev. Lett. 93, 195004 (2004)] can be achieved with the initially subthreshold beat wave pulse.

Kalmykov, Serguei; Shvets, Gennady [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, One University Station C1500, Austin, Texas 78712 (United States)

2006-04-15T23:59:59.000Z

168

COUNTER PROPAGATION OF ELECTRON AND CO2 LASER BEAMS IN A PLASMA CHANNEL.  

SciTech Connect

A high-energy CO{sub 2} laser is channeled in a capillary discharge. Occurrence of guiding conditions at a relatively low plasma density (<10{sup 18} cm{sup -3}) is confirmed by MHD simulations. Divergence of relativistic electron beam changes depending on the plasma density. Counter-propagation of the electron and laser beams inside the plasma channel results in intense x-ray generation.

HIROSE,T.; POGORELSKY,I.V.; BEN ZVI,I.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; KUMITA,T.; KAMIYA,Y.; ZIGLER,A.; GREENBERG,B.; ET AL

2002-11-12T23:59:59.000Z

169

Wakefield Municipal Gas & Light Department- Residential Conservation Services Program  

Energy.gov (U.S. Department of Energy (DOE))

The Wakefield Municipal Gas & Light Department (WMGLD), in cooperation with the Massachusetts Municipal Wholesale Electric Company (MMWEC), offers the "Incentive Rebate Program" to encourage...

170

Group velocity and pulse lengthening of mismatched laser pulses in plasma channels  

SciTech Connect

Analytic solutions are presented to the non-paraxial wave equation describing an ultra-short, low-power, laser pulse propagating in aplasma channel. Expressions for the laser pulse centroid motion and laser group velocity are derived, valid for matched and mismatchedpropagation in a parabolic plasma channel, as well as in vacuum, for an arbitrary Laguerre-Gaussian laser mode. The group velocity of amismatched laser pulse, for which the laser spot size is strongly oscillating, is found to be independent of propagation distance andsignificantly less than that of a matched pulse. Laser pulse lengthening of a mismatched pulse owing to laser mode slippage isexamined and found to dominate over that due to dispersive pulse spreading for sufficiently long pulses. Analytic results are shown tobe in excellent agreement with numerical solutions of the full Maxwell equations coupled to the plasma response. Implications for plasmachannel diagnostics are discussed.

Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; van Tilborg, Jeroen; Leemans, Wim

2011-07-07T23:59:59.000Z

171

Beam transport and monitoring for laser plasma accelerators  

SciTech Connect

The controlled transport and imaging of relativistic electron beams from laser plasma accelerators (LPAs) are critical for their diagnostics and applications. Here we present the design and progress in the implementation of the transport and monitoring system for an undulator based electron beam diagnostic. Miniature permanent-magnet quadrupoles (PMQs) are employed to realize controlled transport of the LPA electron beams, and cavity based electron beam position monitors for non-invasive beam position detection. Also presented is PMQ calibration by using LPA electron beams with broadband energy spectrum. The results show promising performance for both transporting and monitoring. With the proper transport system, XUV-photon spectra from THUNDER will provide the momentum distribution of the electron beam with the resolution above what can be achieved by the magnetic spectrometer currently used in the LOASIS facility.

Nakamura, K.; Sokollik, T.; Tilborg, J. van; Gonsalves, A. J.; Shaw, B.; Shiraishi, S.; Mittal, R.; De Santis, S.; Byrd, J. M.; Leemans, W. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States) and University of California, Berkeley, CA 94720 (United States)

2012-12-21T23:59:59.000Z

172

Pulse shaping of transversely excited atmospheric CO{sub 2} laser using a simple plasma shutter  

SciTech Connect

The pulse from a transversely excited atmospheric CO{sub 2} laser consists of a sharp spike followed by a long, drawn out tail region spanning about 2-5 {mu}s caused by the nitrogen gas in the laser cavity. The nitrogen tail is undesirable in many applications because it decreases the average power of the laser pulse. We employ a pinhole plasma shutter for eliminating the nitrogen tail and shortening the pulse width. The pinhole shutter optically triggers plasma at a certain point in time with respect to the temporal profile of the laser pulse. This way, a good portion of the sharp spike is transmitted, while the energy stored in the nitrogen tail is consumed in heating the plasma. This simplistic plasma shutter is easy to build and inexpensive compared to other existing plasma shutter designs.

Hurst, Noah [Hyperion Scientific, Inc., 455 Science Dr., Madison, Wisconsin 53711 (United States); College of Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States); Harilal, S. S. [Hyperion Scientific, Inc., 455 Science Dr., Madison, Wisconsin 53711 (United States); School of Nuclear Engineering, 400 Central Dr., Purdue University, West Lafayette, Indiana 47907 (United States)

2009-03-15T23:59:59.000Z

173

Determination of the transient electron temperature in a femtosecond-laser-induced air plasma filament  

Science Conference Proceedings (OSTI)

The transient electron temperature in a weakly ionized femtosecond-laser-produced air plasma filament was determined from optical absorption and diffraction experiments. The electron temperature and plasma density decay on similar time scales of a few hundred picoseconds. Comparison with plasma theory reveals the importance of inelastic collisions that lead to energy transfer to vibrational degrees of freedom of air molecules during the plasma cooling.

Sun Zhanliang; Chen Jinhai; Rudolph, Wolfgang [University of New Mexico, Department of Physics and Astronomy, Albuquerque, New Mexico 87131 (United States)

2011-04-15T23:59:59.000Z

174

Breather-like penetration of ultrashort linearly polarized laser into over-dense plasmas  

SciTech Connect

The penetration of an ultrashort laser pulse into an overdense plasma in the relativistic transparency regime is reexamined. The interaction is governed by the Maxwell and relativistic hydrodynamic equations and investigated using a fully implicit energy-conserving numerical scheme. It is found that for a circularly polarized laser, the penetrated pulse has the expected soliton structure. However, for a linearly polarized laser, the penetrated light exhibits a breather structure, and energy exchange between it and the plasma is at twice the laser frequency.

Wu Dong; Yan, X. Q. [Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Key Laboratory of High Energy Density Physics Simulation, Ministry of Education, Peking University, Beijing 100871 (China); Zheng, C. Y.; He, X. T. [Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Key Laboratory of High Energy Density Physics Simulation, Ministry of Education, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Yu, M. Y. [Institute of Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2013-03-15T23:59:59.000Z

175

Guiding of high intensity ultrashort laser pulses in plasma channels produced with the dual laser pulse ignitor-heater technique  

DOE Green Energy (OSTI)

The authors present results of experimental investigations of laser guiding in plasma channels. A new technique for plasma channel creation, the Ignitor-Heater scheme is proposed and experimentally tested in hydrogen and nitrogen. It makes use of two laser pulses. The Ignitor, an ultrashort (< 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used subsequently to heat the existing spark via inverse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. The channel density was diagnosed with time resolved longitudinal interferometry. From these measurements the plasma temperature was inferred. The guiding properties of the channels were tested by injecting a > 5 {times} 10{sup 17} W/cm{sup 2}, 75 fs laser pulse.

Volfbeyn, P.; Leemans, W.P.

1998-07-01T23:59:59.000Z

176

PRIMARY TESTS OF LASER / E BEAM INTERACTION IN A PLASMA CHANNEL.  

SciTech Connect

A high-energy CO{sub 2} laser is channeled in a capillary discharge. Plasma dynamic simulations confirm occurrence of guiding conditions at the relatively low axial plasma density 1 {divided_by} 4 x 10{sup 17} cm{sup -3}. A relativistic electron beam transmitted through the capillary changes its properties depending upon the plasma density. We observe focusing, defocusing or steering of the e-beam. Counter-propagation of the electron and laser beams in the plasma channel results in generation of intense picosecond x-ray pulses.

POGORELSKY,I.V.; BEN ZVI,I.; HIROSE,T.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; ET AL

2002-06-23T23:59:59.000Z

177

Comoving acceleration of overdense electron-positron plasma by colliding ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Particle-in-cell (PIC) simulation results of sustained acceleration of electron-positron (e+e-) plasmas by comoving electromagnetic (EM) pulses are presented. When a thin slab of overdense e+e- plasma is irradiated with linear-polarized ultra-intense short laser pulses from both sides, the pulses are transmitted when the plasma is compressed to thinner than {approx}2 relativistic skin depths. A fraction of the plasma is then captured and efficiently accelerated by self-induced JxB forces. For 1 {mu}m laser and 10{sup 21} W cm{sup -2} intensity, the maximum energy exceeds GeV in a picosecond.

Liang, Edison [Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

2006-06-15T23:59:59.000Z

178

Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma  

Science Conference Proceedings (OSTI)

During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

Ribic, B.; DebRoy, T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Burgardt, P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2011-04-15T23:59:59.000Z

179

Characterization of single and colliding laser-produced plasma bubbles using Thomson scattering and proton radiography  

E-Print Network (OSTI)

Time-resolved measurements of electron and ion temperatures using Thomson scattering have been combined with proton radiography data for comprehensive characterization of individual laser-produced plasma bubbles or the ...

Rosenberg, Michael Jonathan

180

Envelope evolution of a laser pulse in an active medium  

Science Conference Proceedings (OSTI)

The authors show that the envelope velocity, v{sub env}, of a short laser pulse can, via propagation in an active medium, be made less than, equal to, or even greater than c, the vacuum phase velocity of light. Simulation results, based on moving frame propagation equations coupling the laser pulse, active medium and plasma, are presented, as well as equations that determines the design value of super- and sub-luminous v{sub env}. In this simulation the laser pulse evolves in time in a moving frame as opposed to their earlier work where the profile was fixed. The elimination of phase slippage and pump depletion effects in the laser wakefield accelerator is discussed as a particular application. Finally they discuss media properties necessary for an experimental realization of this technique.

Fisher, D.L.; Tajima, T.; Downer, M.C.; Siders, C.W.

1994-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Feasibility of measuring density and temperature of laser produced plasmas using spectroscopic techniques.  

DOE Green Energy (OSTI)

A wide variety of experiments on the Z-Beamlet laser involve the creation of laser produced plasmas. Having a direct measurement of the density and temperature of these plasma would an extremely useful tool, as understanding how these quantities evolve in space and time gives insight into the causes of changes in other physical processes, such as x-ray generation and opacity. We propose to investigate the possibility of diagnosing the density and temperature of laser-produced plasma using temporally and spatially resolved spectroscopic techniques that are similar to ones that have been successfully fielded on other systems. Various researchers have measured the density and temperature of laboratory plasmas by looking at the width and intensity ratio of various characteristic lines in gases such as nitrogen and hydrogen, as well as in plasmas produced off of solid targets such as zinc. The plasma conditions produce two major measurable effects on the characteristic spectral lines of that plasma. The 1st is the Stark broadening of an individual line, which depends on the electron density of the plasma, with higher densities leading to broader lines. The second effect is a change in the ratio of various lines in the plasma corresponding to different ionization states. By looking at the ratio of these lines, we can gain some understanding of the plasma ionization state and consequently its temperature (and ion density when coupled with the broadening measurement). The hotter a plasma is, the higher greater the intensity of lines corresponding to higher ionization states. We would like to investigate fielding a system on the Z-Beamlet laser chamber to spectroscopically study laser produced plasmas from different material targets.

Edens, Aaron D.

2008-09-01T23:59:59.000Z

182

Measurements of the parametric decay of CO/sub 2/ laser radiation into plasma waves at quarter critical density using ruby laser Thomson scattering  

SciTech Connect

We report the results of small-angle ruby laser Thomson scattering measurements of the parametric excitation of plasma waves by CO/sub 2/ laser radiation at quarter-critical density in a laser-heated gas target plasma. From supplementary data obtained from interferometry and large-angle ruby laser scattering we infer that the threshold conditions for a convective decay are satisfied.

Schuss, J.J.; Chu, T.K.; Johnson, L.C.

1977-11-01T23:59:59.000Z

183

Plasma Channel Diagnostic Based on Laser Centroid Oscillations  

E-Print Network (OSTI)

and S. M. Hooker, Phys. Plasmas 14, 056708 (2007). W. P.C. Vaccarezza, IEEE Trans. Plasma Sci. 36, 1782 (2008). W.and Z. Najmudin, Phys. Plasmas 14, 056702 (2007). J.

Gonsalves, A.J.

2010-01-01T23:59:59.000Z

184

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network (OSTI)

7] B. A. Shadwick, et al. , Phys. Plasmas (2009). [8] B. A.Shadwick et al. , IEEE Trans. Plasma Sci. 30 (2002) 38. [9]K. Nakamura, et al. , Phys. Plasmas 14 (2007) 056708. [5] C.

Schroeder, C. B.

2010-01-01T23:59:59.000Z

185

Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas  

E-Print Network (OSTI)

Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced of laser excitation wavelength on water-window emission lines of laser- produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd

Harilal, S. S.

186

Relativistic second-harmonic generation of a laser from underdense plasmas  

Science Conference Proceedings (OSTI)

A high intensity laser obliquely incident on a vacuum-plasma interface produces second-harmonic radiation in the reflected component. The efficiency of second-harmonic generation increases with the angle of incidence, up to critical angle of incidence (our model is not valid beyond critical angle of incidence). The efficiency also depends on electron density, showing a maximum at {omega}{sub p}{sup 2}/{omega}{sup 2} congruent with 0.7, where {omega}{sub p} and {omega} are relativistic plasma frequency and laser frequency, respectively. The efficiency of second-harmonic generation increases sharply with laser intensity in the nonrelativistic regime and saturates at higher intensities. The intensity of the second harmonic is proportional to square of the laser intensity at low pump laser intensities and tends to proportional to laser intensity in the strong relativistic regime.

Singh, K.P.; Gupta, D.N.; Yadav, Sushila; Tripathi, V.K. [Computational Plasma Dynamics Laboratory, Mechanical Engineering, Kettering University, Flint, Michigan 48504 (United States); Department of Physics, Indian Institute of Technology, New Delhi 110016 (India)

2005-01-01T23:59:59.000Z

187

Ion emission and expansion in laser-produced tin plasma  

E-Print Network (OSTI)

and heat conduction within the plasma. In addition to theand heat conduction within the plasma. Second, experimentsplasma, transport towards the ablation front in the conduction

Burdt, Russell Allen

2011-01-01T23:59:59.000Z

188

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/(ps mm{sup 2}), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within {+-}8%, showing that they all can provide accurate charge measurements for LPAs.

Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

2011-06-27T23:59:59.000Z

189

Underwater cladding with laser beam and plasma arc welding  

SciTech Connect

Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses.

White, R.A.; Fusaro, R.; Jones, M.G.; Solomon, H.D. [General Electric Corporate Research and Development Center, Schenectady, NY (United States); Milian-Rodriguez, R.R. [GE Nuclear Energy, San Jose, CA (United States)

1997-01-01T23:59:59.000Z

190

Compact X-ray Free Electron Laser from a Laser-plasma Accelerator using a Transverse Gradient Undulator  

SciTech Connect

Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large energy spread hinders the potential applications for coherent FEL radiation generation. In this paper, we discuss a method to compensate the effects of beam energy spread by introducing a transverse field variation into the FEL undulator. Such a transverse gradient undulator together with a properly dispersed beam can greatly reduce the effects of electron energy spread and jitter on FEL performance. We present theoretical analysis and numerical simulations for SASE and seeded extreme ultraviolet and soft x-ray FELs based on laser plasma accelerators.

Huang, Zhirong; Ding, Yuantao; /SLAC; Schroeder, Carl B.; /LBL, Berkeley

2012-09-13T23:59:59.000Z

191

The splitted laser beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma  

Science Conference Proceedings (OSTI)

The splitted beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma is investigated. Based on Wentzel-Kramers-Brillouin (WKB) approximation and paraxial/nonparaxial ray theory, simulation results show that the steady beam width and single beam filamentation along the propagation distance in paraxial case is due to the influence of ponderomotive nonlinearity. In nonparaxial case, the influence of the off-axial of {alpha}{sub 00} and {alpha}{sub 02} (the departure of the beam from the Gaussian nature) and S{sub 02} (the departure from the spherical nature) results in more complicated ponderomotive nonlinearity and changing of the channel density and refractive index, which led to the formation of two/three splitted beam filamentation and the self-distortion of beam width. In addition, influence of several parameters on two/three splitted beam filamentation is discussed.

Xia Xiongping; Yi Lin [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Xu Bin [Department of Mathematics and Information Sciences, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Lu Jianduo [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan University of Science and Technology, Wuhan 430081 (China)

2011-10-15T23:59:59.000Z

192

Optimization of a kinetic laser-plasma interaction code for large parallel systems  

Science Conference Proceedings (OSTI)

In this work, we simulate the interaction between intense laser radiation and a fully ionized plasma by solving a Vlasov-Maxwell system using the "Particle-In-Cell" (PIC) method. This method provides a very detailed description of the plasma dynamics, ... Keywords: PIC method, high-performance computing, parallel sparse solver

Olivier Coulaud; Michaël Dussere; Pascal Hénon; Erik Lefebvre; Jean Roman

2003-09-01T23:59:59.000Z

193

Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot  

Science Conference Proceedings (OSTI)

Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.

Feng Liubin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China); Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Xi Tingting [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng Zhengming; Zhang Jie [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Key Laboratory for Laser Plasmas of the Ministry of Education of China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); He Duanwei [Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China)

2012-07-15T23:59:59.000Z

194

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile  

SciTech Connect

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

195

Guiding of relativistic laser pulses by preformed plasma channels  

E-Print Network (OSTI)

the length of the guide, as laser energy leaked outside theheater energy, the density pro?le has been matched to guidethe guide at 4 TW. Approximately 30% of the laser energy is

2004-01-01T23:59:59.000Z

196

Wakefield Municipal Gas and Light Department - Residential Conservation  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Wakefield Municipal Gas and Light Department - Residential Wakefield Municipal Gas and Light Department - Residential Conservation Services Program Wakefield Municipal Gas and Light Department - Residential Conservation Services Program < Back Eligibility Residential Savings Category Home Weatherization Commercial Weatherization Sealing Your Home Heating & Cooling Commercial Heating & Cooling Cooling Appliances & Electronics Design & Remodeling Windows, Doors, & Skylights Manufacturing Commercial Lighting Lighting Water Heating Maximum Rebate Energy Audit Recommended Measures: $300 Programmable Thermostats: 2 units Program Info State Massachusetts Program Type Utility Rebate Program Rebate Amount Energy Audit Recommended Measures: 25% of total cost Refrigerators: $50 Clothes Washer: $50 Dishwasher: $50 Room AC: $50

197

Transformer Ratio Enhancement for Structure-Based Wakefield Acceleration  

SciTech Connect

A limiting factor in the efficiency of wakefield accelerators is the fact that the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the accelerating structure to the accelerated electron beam, is less than 2 for most technologically realizable beam-structure configurations. We are planning an experiment to study transformer ratio enhancement in a 13.625 GHz dielectric wakefield structure driven by a ramped bunch train. In this paper we present an experimental program for the demonstration of this Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA)

Kanareykin, A. [Euclid Techlabs LLC, Solon OH 44139 (United States); Gai, W.; Power, J.G. [Argonne National Laboratory, Argonne IL, 60439 (United States); Schoessow, P. [Tech-X Corp., Boulder CO, 80303 (United States)

2004-12-07T23:59:59.000Z

198

Stainless Steel 18-10 CO2 Laser Welding And Plasma Diagnostics  

Science Conference Proceedings (OSTI)

The welding of materials by CO2 laser took significant considerations in industry, for the reason of the quality of the carried out weldings, and for other many advantages, but the automation of the welding operation requires a control system in real time. The operation of welding is an operation of interaction between the radiation (laser), and the matter (welded part), which is characterized by the vaporization of the matter, formation of the keyhole in material, and appearance of plasma over the material. This study relates to the relation between the welding (molten material) and the plasma which is formed on material. The light emitted by plasma during laser welding was recorded by an OMA detector (Optical Multichannel Analyzer) over a wavelength width of 450 A ring . The analysis of this light allows to determine the composition of this plasma, its dimensions, and the state of its energy according to the laser parameters. The welded material is the stainless steel 18-10, it was found that the intensity of the light emitted by plasma depends on laser power, the welding speed, the flow rate of assist gas. The relation between the plasma and the state of the bead were analyzed for on-line monitoring welding.

Amar, Taibi [Department of Mechanical Engineering, University of M'sila (Algeria); Laboratory of Industrial Physics, Thermal centre of INSA of Lyon, CETHIL (France); Michel, Laurent [Laboratory of Industrial Physics, Thermal centre of INSA of Lyon, CETHIL (France)

2008-09-23T23:59:59.000Z

199

Progress on laser plasma accelerator development using transversely and longitudinally shaped plasmas  

E-Print Network (OSTI)

For BPS data, a second laser pulse (2 TW) was present frompointing. Spectrom- eter data (no second laser), verifiedthe second laser did not affect the bunch. C.G.R. Geddes, et

Nakamura, K.

2010-01-01T23:59:59.000Z

200

Electron self-injection into an evolving plasma bubble: Quasi-monoenergetic laser-plasma acceleration in the blowout regime  

Science Conference Proceedings (OSTI)

An electron density bubble driven in a rarefied uniform plasma by a slowly evolving laser pulse goes through periods of adiabatically slow expansions and contractions. Bubble expansion causes robust self-injection of initially quiescent plasma electrons, whereas stabilization and contraction terminate self-injection thus limiting injected charge; concomitant phase space rotation reduces the bunch energy spread. In regimes relevant to experiments with hundred terawatt- to petawatt-class lasers, bubble dynamics and, hence, the self-injection process are governed primarily by the driver evolution. Collective transverse fields of the trapped electron bunch reduce the accelerating gradient and slow down phase space rotation. Bubble expansion followed by stabilization and contraction suppresses the low-energy background and creates a collimated quasi-monoenergetic electron bunch long before dephasing. Nonlinear evolution of the laser pulse (spot size oscillations, self-compression, and front steepening) can also cause continuous self-injection, resulting in a large dark current, degrading the electron beam quality.

Kalmykov, S. Y.; Shadwick, B. A.; Umstadter, D. P. [Department of Physics and Astronomy, University of Nebraska - Lincoln, Lincoln, Nebraska 68588-0299 (United States); Beck, A.; Lefebvre, E. [CEA, DAM, DIF, Arpajon F-91297 (France); Yi, S. A.; Khudik, V. N.; Downer, M. C. [Department of Physics, C1500, niversity of Texas at Austin, Austin, Texas 78712 (United States)

2011-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

On the control of filamentation of intense laser beams propagating in underdense plasma  

SciTech Connect

In indirect drive ICF ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEH), which are sized as small as practicable to minimize X-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated back-scatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192 beam (National Ignition facility) NIF laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all!) and then de-focusing the beam to expand it to fill the LEH and lower its intensity. We find significant effects from the lack of uniformity of the laser envelope out of the focal plane, from changes in the characteristic sizes of the laser speckle, and on the efficacy of additional polarization and/or SSD beam smoothing. We quantify these effects with analytic estimates and simulations using our laser plasma interaction code pF3D.

Williams, E A

2005-10-21T23:59:59.000Z

202

Controlled self-modulation of high energy beams in a plasma  

SciTech Connect

A high energy particle beam propagating in a uniform plasma is subject to the transverse two-stream instability that first transforms the beam into the train of microbunches and then quickly destroys that train by transverse wakefields. By the proper longitudinal inhomogeneity of the plasma density, it is possible to stop the instability action at the stage of microbunches and form the bunch train that can resonantly excite plasma wakefields over a long distance. The latter feature is vital for proton beam driven plasma wakefield acceleration that was recently proposed as a way to bring electrons to TeV energy range in a single plasma section.

Lotov, K. V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

2011-02-15T23:59:59.000Z

203

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10{sup 15}-10{sup 17} W/cm{sup 2} and contrast ratio 10{sup 6} is studied. Red shift of a 'mirror' reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

Andreev, A. A.; Bayanov, V. I.; Vankov, A. B.; Kozlov, A. A.; Kurnin, I. V.; Platonov, K. Y.; Solovyev, N. A.; Chizhov, S. A.; Yashin, V. E. [Research Institute for Laser Physics, SC 'Vavilov State Optical Institute', 12, Birzhevaya line, St. Petersburg, 199034 (Russian Federation)

1998-02-20T23:59:59.000Z

204

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10 15 –10 17 ? W/cm 2 and contrast ratio 10 6 is studied. Red shift of a “mirror” reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

A. A. Andreev; V. I. Bayanov; A. B. Vankov; A. A. Kozlov; I. V. Kurnin; K. Y. Platonov; N. A. Solovyev; S. A. Chizhov; V. E. Yashin

1998-01-01T23:59:59.000Z

205

Theory of a laser-plasma method for detecting terahertz radiation  

SciTech Connect

A theory is developed for calculating the spectrum and the shape of a terahertz wave packet from the temporal profile of the energy of the second harmonic of the laser field generated during nonlinear interaction of laser and terahertz pulses in an optical-breakdown plasma. The spectral and temporal characteristics of the second-harmonic envelope and a terahertz pulse are shown to coincide only for short laser pulses. For long laser pulses, the second-harmonic spectral line shifts to the red and its temporal profile is determined by the time integral of the electric field of terahertz radiation.

Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Borodin, A. V.; Esaulkov, M. N.; Kuritsyn, I. I.; Shkurinov, A. P. [Moscow State University (Russian Federation)

2012-06-15T23:59:59.000Z

206

Wakefield Breakdown Test of a Diamond-Loaded Accelerating Structure  

NLE Websites -- All DOE Office Websites (Extended Search)

WAKEFIELD BREAKDOWN TEST OF A DIAMOND-LOADED ACCELERATING STRUCTURE S. Antipov, C. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs LLC, Solon, OH, 44139 USA M. Conde, W. Gai, S....

207

Wakefield Breakdown Test of a Diamond-loaded Accelerating Structure...  

NLE Websites -- All DOE Office Websites (Extended Search)

WAKEFIELD BREAKDOWN TEST OF A DIAMOND-LOADED ACCELERATING STRUCTURE AT THE AWA S. Antipov, C. Jing, P. Schoessow, J. E. Butler, S. Zuo and A. Kanareykin, Euclid Techlabs LLC,...

208

A 26 GHz Dielectric Based Wakefield Power Extractor  

NLE Websites -- All DOE Office Websites (Extended Search)

26GHz high power rf source based on the extraction of wakefields from a relativistic electron beam. The extractor is designed to couple out rf power generated from a high charge...

209

A New High Intensity Electron Beam for Wakefield Acceleration...  

NLE Websites -- All DOE Office Websites (Extended Search)

HIGH INTENSITY ELECTRON BEAM FOR WAKEFIELD ACCELERATION STUDIES* M.E. Conde , W. Gai, C. Jing, R. Konecny, W. Liu, J.G. Power, H. Wang, Z. Yusof ANL, Argonne, IL 60439, USA...

210

Upgrade of the Argonne Wakefield Accelerator Facility (AWA) and...  

NLE Websites -- All DOE Office Websites (Extended Search)

that will enable it to further study wakefield acceleration driven by high charge electron beams. The facility employs an L-band photocathode RF gun to generate high charge...

211

Upgrade of the Argonne Wakefield Accelerator Facility (AWA):...  

NLE Websites -- All DOE Office Websites (Extended Search)

U.S.A. Abstract Research at the AWA Facility has been focused on the development of electron beam driven wakefield structures. Accelerating gradients of up to 100 MVm have been...

212

Generation of High Gradient Wakefields in Dielectric Loaded Structures  

NLE Websites -- All DOE Office Websites (Extended Search)

loaded wakefield structures to generate accelerating fields of up to 100 MVm. Short electron bunches (13 ps FWHM) of up to 86 nC are used to drive these fields, either as single...

213

Experimental Measurements of Wakefields in a Multimode, Dielectric...  

NLE Websites -- All DOE Office Websites (Extended Search)

Measurements of Wakefields in a Multimode, Dielectric Structure Driven by a Train of Electron Bunches J.G. Power, M.E. Conde, W. Gai, A. Kanareykenf, R. Konecny, and P. Schoessow...

214

Influence of electromagnetic oscillating two-stream instability on the evolution of laser-driven plasma beat-wave  

Science Conference Proceedings (OSTI)

The electrostatic oscillating two-stream instability of laser-driven plasma beat-wave was studied recently by Gupta et al. [Phys. Plasmas 11, 5250 (2004)], who applied their theory to limit the amplitude level of a plasma wave in the beat-wave accelerator. As a self-generated magnetic field is observed in laser-produced plasma, hence, the electromagnetic oscillating two-stream instability may be another possible mechanism for the saturation of laser-driven plasma beat-wave. The efficiency of this scheme is higher than the former.

Gupta, D. N.; Singh, K. P.; Suk, H. [Center for Advanced Accelerators, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Computational Plasma Dynamics Laboratory, Kettering University, Flint, Michigan 48504 (United States); Center for Advanced Accelerators, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of)

2007-01-15T23:59:59.000Z

215

Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators  

E-Print Network (OSTI)

Esarey and M. Pillo?, Phys. Plasmas 2, 1432 (1995). 13 B. A.and E. Esarey, Phys. Plasmas 14 T. Katsouleas, Phys. Rev. APegoraro, and I. V. Pogorelsky, Plasma Phys. Rep. 23, 259 16

Rittershofer, W.

2010-01-01T23:59:59.000Z

216

Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas  

SciTech Connect

Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai (China)

2012-03-01T23:59:59.000Z

217

Wakefield Damping for the CLIC Crab Cavity  

Science Conference Proceedings (OSTI)

A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

Ambattu, P.K.; Burt, G.; Dexter, A.C.; Carter, R.G.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Khan, V.; Jones, R.M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Dolgashev, V.; /SLAC

2011-12-01T23:59:59.000Z

218

Novel plasma-based frequency upshift methods for short pulse lasers  

SciTech Connect

We discuss various novel methods of frequency upshifting short ({le} 1 picosecond) pulses of laser light. All of these methods make use of either the sudden creation of a plasma or relativistic plasma waves. The first method discussed is known as photon acceleration. This method makes use of the fact that a laser pulse moving in a plasma can be thought of as a packet of photons, each possessing an effective mass of m{sub {gamma}} = {h bar}{omega}{sub pe}/c{sup 2} and moving with the group velocity of the laser pulse. These photons experience a force acting on them when in the presence of a gradient in the plasma density. By using a relativistic plasma wave (i.e., a moving density gradient) traveling with the photons, the energy of the photons (thus the frequency) can be continuously increased. We then discuss the sudden creation of a plasma in a region where there exists an electromagnetic wave. This results in a frequency shift of the wave. A similar method is the creation of an ionization front moving near the speed of light, whereby the interaction of this plasma front with an EM wave also results in a frequency upshift of the original wave. 21 refs.

Wilks, S.C. (Lawrence Livermore National Lab., CA (USA)); Dawson, J.M.; Mori, W.B. (California Univ., Los Angeles, CA (USA). Dept. of Physics)

1990-06-04T23:59:59.000Z

219

Collisionless Damping of Laser Wakes in Plasma Channels  

SciTech Connect

Excitation of accelerating modes in transversely inhomogeneous plasma channels is considered as an initial value problem. Discrete eigenmodes are supported by plasma channels with sharp density gradients. These eigenmodes are collisionlessly damped as the gradients are smoothed. Using collisionless Landau damping as the analogy, the existence and damping of these "quasi-modes" is studied by constructing and analytically continuing the causal Green's function of wake excitation into the lower half of the complex frequency plane. Electromagnetic nature of the plasma wakes in the channel makes their excitation nonlocal. This results in the algebraic decay of the fields with time due to phase-mixing of plasma oscillations with spatially-varying fequencies. Characteristic decay rate is given by the mixing time, which corresponds to the dephasing of two plasma fluid elements separated by the collisionless skin depth. For wide channels the exact expressions for the field evolution are derived. Implications for electron acceleration in plasma channels are discussed.

Li, X.; Shvets, G.

1998-08-01T23:59:59.000Z

220

A Plasma Lens for High Intensity Laser Focusing  

SciTech Connect

A plasma lens based on a short hydrogen-filled alumina capillary discharge is experimentally characterized. For a plasma length of about 5mm, the focal length, measured from the plasma entrance, was {approx} 11 to 8mm for on axis densities of {approx} 2.5 to 5 x 1018cm-3, respectively. The plasma temperature away from the walls of the 1/2mm diameter capillary was estimated to be {approx} 8eV indicating that the plasma is fully ionized. Such a lens should thus be suitable for focusing very high intensity pulses. Comparisons of the measured focusing strength to that predicted by a first-order fluid model [N. A. Bobrova, et al., Phys. Rev. E 65, 016407 (2002)] shows reasonable agreement given that some of the observed plasma parameters are not predicted by this model.

Fang, F.; Clayton, C. E.; Marsh, K. A.; Joshi, C. [UCLA Department of Electrical Engineering, Los Angeles, CA, 90095 (United States); Lopes, N. C. [Grupo de Lasers e Plasmas, ESuperior Tecnico, Lisbon (Portugal); Ito, H. [Utsunomiya University, 7-1-2 Yoto, Utsunomiya City, Zip 321-8585 (Japan)

2006-11-27T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

X-ray backlight measurement of preformed plasma by kJ-class petawatt LFEX laser  

Science Conference Proceedings (OSTI)

Foot and pedestal pulses that precede the main pulse from a high-intensity laser greatly affect laser-plasma interactions. Especially in fast ignition schemes, preceding pulses generate a plasma prior to irradiation by the main pulse. This results in a too energetic and divergent electron beam being generated in the preformed plasma, which reduces the energy coupling efficiency from the heating laser to the dense fuel core. A preformed plasma with a density scale length of 40-60 {mu}m was observed by a time- and space-resolved x-ray backlight technique using the LFEX laser system at the Institute of Laser Engineering, Osaka University. Preceding pulses (i.e., the foot and pedestal) of the LFEX were characterized by comparing observations with calculations results obtained using a two-dimension (2D) radiation-hydrodynamic simulation code. In a separate experiment, the 2D code was benchmarked with the experimentally observed hydrodynamic behavior of a gold plasma produced by a nanosecond laser pulse that mimicked foot and pedestal pulses (intensity: 1 Multiplication-Sign 10{sup 11}-1 Multiplication-Sign 10{sup 12}W/cm{sup 2}). The preceding pulses were estimated to have an intensity of 1 Multiplication-Sign 10{sup 12}-10{sup 13}W/cm{sup 2}, a duration of 2.0 ns, and a spot diameter at the target of 200-600 {mu}m by comparing the measured hydrodynamics of the preformed plasma with that calculated by the 2D hydrodynamic simulation code.

Ohira, Shinji; Fujioka, Shinsuke; Nagatomo, Hideo; Matsuo, Satoshi; Morio, Noboru; Kawanaka, Jyunji; Nakata, Yoshiki; Miyanaga, Noriaki; Shiraga, Hiroyuki; Nishimura, Hiroaki; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita Osaka 565-0871 (Japan); Sunahara, Atsushi [Institute for Laser Technology, 2-6 Yamada-oka, Suita Osaka 565-0871 (Japan); Johzaki, Tomoyuki [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739-8527 (Japan)

2012-09-15T23:59:59.000Z

222

Low Cost Processing: Plasma, Microwave, Laser, Melting and Casting  

Science Conference Proceedings (OSTI)

Mar 5, 2013 ... Cost Affordable Titanium IV: Low Cost Processing: Plasma, ... obtained by using microwave energy as the consolidation method of Mg-Ti alloys.

223

Suppression of stimulated Raman scattering due to localization of electron plasma wave in laser beam filaments  

Science Conference Proceedings (OSTI)

The filamentation of the high power laser beam by taking off-axial contribution is investigated when ponderomotive nonlinearity is taken into account. The splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. It is observed that the weak electron plasma wave (EPW) propagating in the z direction is nonlinearly coupled in the modified filamentary regions of the laser beam. The semianalytical solution of the nonlinear coupled EPW equation in the presence of laser beam filaments has been found and it is observed that the nonlinear coupling between these two waves leads to localization of the EPW. Stimulated Raman scattering (SRS) of this EPW is studied and backreflectivity has been calculated. Further, the localization of EPW affects the eigenfrequency and damping of plasma wave. As a result of this, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the backreflectivity. For the typical laser beam and plasma parameters with wavelength ({lambda}=1064 nm), power flux ({approx_equal}10{sup 16} W cm{sup -2}), and plasma density (n/n{sub cr})=0.2; the backreflectivity was found to be suppressed by a factor of around 20%.

Sharma, Prerana; Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2009-03-15T23:59:59.000Z

224

Enhancing extreme ultraviolet photons emission in laser produced plasmas for advanced lithography  

SciTech Connect

Current challenges in the development of efficient laser produced plasma sources for the next generation extreme ultraviolet lithography (EUVL) are increasing EUV power and maximizing lifetime and therefore, reducing cost of devices. Mass-limited targets such as small tin droplets are considered among the best choices for cleaner operation of the optical system because of lower mass of atomic debris produced by the laser beam. The small diameter of droplets, however, decreases the conversion efficiency (CE) of EUV photons emission, especially in the case of CO{sub 2} laser, where laser wavelength has high reflectivity from the tin surface. We investigated ways of improving CE in mass-limited targets. We considered in our modeling various possible target phases and lasers configurations: from solid/liquid droplets subjected to laser beam energy with different intensities and laser wavelength to dual-beam lasers, i.e., a pre-pulse followed by a main pulse with adjusted delay time in between. We studied the dependence of vapor expansion rate, which can be produced as a result of droplet heating by pre-pulse laser energy, on target configuration, size, and laser beam parameters. As a consequence, we studied the influence of these conditions and parameters on the CE and debris mass accumulation. For better understanding and more accurate modeling of all physical processes occurred during various phases of laser beam/target interactions, plasma plume formation and evolution, EUV photons emission and collection, we have implemented in our heights package state-of-the art models and methods, verified, and benchmarked against laboratory experiments in our CMUXE center as well as various worldwide experimental results.

Sizyuk, T.; Hassanein, A. [Center for Materials under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-08-15T23:59:59.000Z

225

Plume splitting and rebounding in a high-intensity CO{sub 2} laser induced air plasma  

Science Conference Proceedings (OSTI)

The dynamics of plasma plume formed by high-intensity CO{sub 2} laser induced breakdown of air at atmospheric pressure is investigated. The laser wavelength is 10.6 {mu}m. Measurements were made using 3 ns gated fast photography as well as space and time resolved optical emission spectroscopy. The behavior of the plasma plume was studied with a laser energy of 3 J and 10 J. The results show that the evolution of the plasma plume is very complicated. The splitting and rebounding of the plasma plume is observed to occur early in the plumes history.

Chen Anmin; Jiang Yuanfei; Liu Hang; Jin Mingxing; Ding Dajun [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

2012-07-15T23:59:59.000Z

226

Sustained Acceleration of Over-dense Plasmas by Colliding Laser Pulses  

Science Conference Proceedings (OSTI)

We review recent PIC simulation results which show that double-sided irradiation of a thin overdense plasma slab by ultra-intense laser pulses from both sides can lead to sustained comoving acceleration of surface electrons to energies much higher than the conventional ponderomotive limit. The acceleration stops only when the electrons drift transversely out of the laser beam. We show results of parameter studies based on this concept and discuss future laser experiments that can be used to test these computer results.

Liang, Edison [Rice University, Houston, TX 77005-1892 (United States)

2006-04-07T23:59:59.000Z

227

Compact cryogenic source of periodic hydrogen and argon droplet beams for relativistic laser-plasma generation  

Science Conference Proceedings (OSTI)

We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses.

Fraga, R. A. Costa; Kalinin, A.; Kuehnel, M.; Schottelius, A. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Hochhaus, D. C.; Neumayer, P. [EMMI Extreme Matter Institute and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); FIAS Frankfurt Institute for Advanced Studies, J. W. Goethe-Universitaet, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Polz, J. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Kaluza, M. C. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz-Institut Jena, Froebelstieg 3, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

2012-02-15T23:59:59.000Z

228

Strongly driven ion acoustic waves in laser produced plasmas  

Science Conference Proceedings (OSTI)

This paper present an experimental study of ion acoustic waves with wavenumbers corresponding to stimulated Brillouin scattering. Time resolved Thomson scattering in frequency and wavenumber space, has permitted to observe the dispersion relation of the waves as a function of the laser intensity. Apart from observing ion acoustic waves associated with a strong second component is observed at laser intensities above 10{sup 13}Wcm{sup {minus}2}.

Baldis, H.A.; Labaune, C.; Renard, N. [Ecole Polytechnique, 91 - Palaiseau (France)] [and others

1994-09-20T23:59:59.000Z

229

Evidence of plasma fluctuations and their effect on the growth of stimulated Brillouin and stimulated Raman scattering in laser plasmas  

SciTech Connect

The reflectivity levels of stimulated Brillouin scattering (SBS) in recent large scale length laser plasma experiments is much lower than expected for conditions where the convective gain exponent is expected to be large. Long wavelength velocity fluctuations caused during the plasma formation process, or by parametric instabilities themselves, have been proposed as a mechanism to detune SBS in these experiments and reduce its gain. Evidence of large velocity fluctuation levels is found in the time-resolved SBS spectra from these experiments, and correlates with observed changes in the reflectivity of both SBS and stimulated Raman scattering (SRS). The authors present evidence of fluctuations which increase as the plasma density systematically increases, and discuss their effect on the growth of parametric instabilities.

Montgomery, D.S.; Fernandez, J.C.; Cobble, J.A. [and others

1997-11-01T23:59:59.000Z

230

Laser and pinching discharge plasmas spectral characteristics in water window region 2  

E-Print Network (OSTI)

Water window emission spectra of two laboratory nitrogen plasma sources were examined with a free standing grating spectrometer (FSGS). The highest line intensities at the wavelength 2.88 nm achievable with the sources were compared. Pulse energies for this line were judged as 0.02 mJ/srad and 0.16 mJ/srad with laser produced plasma system and pinching discharge plasma, respectively. The spectral resolution was found about 0.01 nm at 3rd order of spectral lines around wavelength 2.5 nm.

Kolar, Petr; Nevrkla, Michal; Vrba, Pavel; Jancarek, Alexandr

2011-01-01T23:59:59.000Z

231

Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments  

Science Conference Proceedings (OSTI)

Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2012-07-15T23:59:59.000Z

232

Simulation of laser propagation in a plasma with a frequency wave equation  

Science Conference Proceedings (OSTI)

The aim of this work is to perform numerical simulations of the propagation of a laser beam in a plasma. At each time step, one has to solve a Helmholtz equation with variable coefficients in a domain which may contain more than hundred millions of cells. ... Keywords: cyclic reduction method, domain decomposition method, helmholtz equation, non-hermitian linear solver, separable matrix

R. Sentis; S. Desroziers; F. Nataf

2006-06-01T23:59:59.000Z

233

Novel method for characterizing relativistic electron beams in a harsh laser-plasma environment  

E-Print Network (OSTI)

repetition rates and which, at the same time, allow for usage in very space-limited environments. Various ultrashort la- ser pulses that yield electric fields of the order of TV/m when focused to spots of a few almost 30 years ago1 to use the ultrahigh electric fields in laser-produced plasmas to ac- celerate

Kroupp, Eyal

234

Alumina reduction by laser sustained plasma for aluminum-based renewable energy cycling  

Science Conference Proceedings (OSTI)

A novel alumina (Al 2O3) reduction technique for a renewable energy cycling system based on aluminum is proposed. Al 2O3 powder was fed into laser-sustained plasma and thermally dissociated. The produced Al was expanded to supersonic speeds through a nozzle. From the Al and argon line distributions in the flow direction

2013-01-01T23:59:59.000Z

235

Characterization of plasma and laser conditions for single hot spot interaction experiments  

Science Conference Proceedings (OSTI)

The LANL TRIDENT laser system is being used for fundamental experiments which study the interaction of self-focusing, stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in a single (diffraction limited) laser hot spot in order to better understand the coupling between these plasma instabilities. The diffraction limited beam mimics a single hot spot found in speckle distributions that are typical of random or kinoform phase plate (RPP or KPP) smoothing. A long scale length, hot plasma ({approximately} 1 mm, {approximately} 0.5 keV) is created by a separate heater beam, and the single hot spot beam is used to drive parametric instabilities. The focal plane distribution and wavefront of the single hot spot beam are characterized, and the intensity of the single hot spot can be varied between 10{sup 14}--10{sup 16} W/cm{sup 2}. The plasma density, temperature, and flow profiles are measured using gated imaging spectroscopy of collective Thomson scattering. Results of the laser and plasma characterization, and initial results of backscattered SRS, SBS, and beam steering in a flowing plasma are presented.

Montgomery, D.S.; Johnson, R.P.; Cobble, J.A.; Fernandez, J.C.; Lindman, E.L.; Rose, H.A. [Los Alamos National Lab., NM (United States); Estabrook, K.G. [Lawrence Livermore National Lab., CA (United States)

1998-11-01T23:59:59.000Z

236

Measurement of xenon plasma properties in an ion thruster using laser Thomson scattering technique  

Science Conference Proceedings (OSTI)

This paper reports on the development of a method for measuring xenon plasma properties using the laser Thomson scattering technique, for application to ion engine system design. The thresholds of photo-ionization of xenon plasma were investigated and the number density of metastable atoms, which are photo-ionized by a probe laser, was measured using laser absorption spectroscopy, for several conditions. The measured threshold energy of the probe laser using a plano-convex lens with a focal length of 200 mm was 150 mJ for a xenon mass flow rate of 20 {mu}g/s and incident microwave power of 6 W; the probe laser energy was therefore set as 80 mJ. Electron number density was found to be (6.2 {+-} 0.4) Multiplication-Sign 10{sup 17} m{sup -3} and electron temperature was found to be 2.2 {+-} 0.4 eV at a xenon mass flow rate of 20 {mu}g/s and incident microwave power of 6 W. The threshold of the probe laser intensity against photo-ionization in a miniature xenon ion thruster is almost constant for various mass flow rates, since the ratio of population of the metastable atoms to the electron number density is little changed.

Yamamoto, N.; Tomita, K.; Sugita, K.; Kurita, T.; Nakashima, H.; Uchino, K. [Kyushu University, 6-1 Kasuga-kouen, Kasuga, Fukuoka 816-8580 (Japan)

2012-07-15T23:59:59.000Z

237

Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources  

DOE Patents (OSTI)

Method and apparatus for producing extreme ultraviolet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10{sup 11}--10{sup 12} watts/cm{sup 2}) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10--30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle. 5 figs.

Kublak, G.D.; Richardson, M.C.

1996-11-19T23:59:59.000Z

238

Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources  

DOE Patents (OSTI)

Method and apparatus for producing extreme ultra violet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10.sup.11 -10.sup.12 watts/cm.sup.2) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10-30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle.

Kublak, Glenn D. (124 Turquoise Way, Livermore, Alameda County, CA 94550); Richardson, Martin C. (CREOL

1996-01-01T23:59:59.000Z

239

Town of Wakefield, Massachusetts (Utility Company) | Open Energy  

Open Energy Info (EERE)

Wakefield Wakefield Place Massachusetts Utility Id 19979 Utility Location Yes Ownership M NERC Location NPCC NERC NPCC Yes Activity Buying Transmission Yes Activity Distribution Yes Activity Retail Marketing Yes Activity Bundled Services Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png Commercial Rate B Commercial Domestic Electric Rate A Residential Power Rate C Industrial Average Rates Residential: $0.1510/kWh Commercial: $0.1410/kWh Industrial: $0.1240/kWh References ↑ "EIA Form EIA-861 Final Data File for 2010 - File1_a" Retrieved from "http://en.openei.org/w/index.php?title=Town_of_Wakefield,_Massachusetts_(Utility_Company)&oldid=41183

240

Town of Wakefield, Virginia (Utility Company) | Open Energy Information  

Open Energy Info (EERE)

Wakefield, Virginia (Utility Company) Wakefield, Virginia (Utility Company) Jump to: navigation, search Name Town of Wakefield Place Virginia Utility Id 19978 Utility Location Yes Ownership M NERC Location SERC NERC SERC Yes Activity Distribution Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png Commercial Commercial Large Service Demand Industrial Out Town Residential Elec Residential Residential Residential Small Commercial Demand Commercial Average Rates Residential: $0.0855/kWh Commercial: $0.0855/kWh References ↑ "EIA Form EIA-861 Final Data File for 2010 - File1_a" Retrieved from

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241

Synergetic effects of double laser pulses for the formation of mild plasma in water: Toward non-gated underwater laser-induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

We experimentally study the dynamics of the plasma induced by the double-laser-pulse irradiation of solid target in water, and find that an appropriate choice of the pulse energies and pulse interval results in the production of an unprecedentedly mild (low-density) plasma, the emission spectra of which are very narrow even without the time-gated detection. The optimum pulse interval and pulse energies are 15-30 {mu}s and about {approx}1 mJ, respectively, where the latter values are much smaller than those typically employed for this kind of study. In order to clarify the mechanism for the formation of mild plasma we examine the role of the first and second laser pulses, and find that the first pulse produces the cavitation bubble without emission (and hence plasma), and the second pulse induces the mild plasma in the cavitation bubble. These findings may present a new phase of underwater laser-induced breakdown spectroscopy.

Sakka, Tetsuo [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Institute of Sustainability Science, Kyoto University, Uji, Kyoto 611-0011 (Japan); Tamura, Ayaka; Nakajima, Takashi; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2012-05-07T23:59:59.000Z

242

Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma  

Science Conference Proceedings (OSTI)

We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 {mu}m laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight signals for ions from plasmas generated by each laser. Ion kinetic energy was lower for shorter pulse durations, which yielded higher electron temperatures required for efficient EUV emission, due to higher laser intensity. Picosecond laser pulses were found to be the best suited to 6.7 nm EUV source generation.

Cummins, Thomas; Li Bowen; O'Gorman, Colm; Dunne, Padraig; Sokell, Emma; O'Sullivan, Gerry [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Otsuka, Takamitsu [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Yugami, Noboru; Higashiguchi, Takeshi [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Jiang Weihua [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan); Endo, Akira [Research Institute for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

2012-02-06T23:59:59.000Z

243

Development of critical surface diagnostic based on the ion acoustic decay instability in laser produced high density plasma  

SciTech Connect

We have developed a large angle, UV collective Thomson scattering (CTS) diagnostic for high density, hot plasma relevant to laser fusion. The CTS measured the basic parameters of the plasma waves (frequency, wave number), or the spectral density function for selected wave vectors of plasma waves, which were excited by the IADI (ion acoustic parametric decay instability). It is a good diagnostic tool for a local electron temperature measurement. The electron temperature was estimated by measuring either ion acoustic wave or electron plasma wave in the laser intensity window of 1plasma waves in laser produced high density plasma.

Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.; Craxton, R.S.; Estabrook, K.G.

1994-12-31T23:59:59.000Z

244

Production of high-density high-temperature plasma by collapsing small solid-density plasma shell with two ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Three-dimensional particle-in-cell simulations show that the anisotropic collapse of a plasma microshell by impact of two oppositely directed intense laser pulses can create at the center of the shell cavity a submicron-sized plasma of high density and temperature suitable for generating fusion neutrons.

Xu, H. [National Laboratory for Parallel and Distributed Processing, School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, Bochum D-44780 (Germany); Wong, A. Y. [Department of Physics, University of California, Los Angeles, California 90095 (United States); Sheng, Z. M.; Zhang, J. [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)

2012-04-02T23:59:59.000Z

245

Subpicosecond 41.8-nm X-ray laser in the plasma produced by femtosecond laser irradiation of a xenon cluster jet  

SciTech Connect

Model calculations are performed of the radiation gain for the 4d5d (J = 0) - 4d5p (J = 1) transition with a wavelength of 41.8 nm in Pd-like xenon ions in the plasma produced by femtosecond laser irradiation of a xenon cluster jet. Conditions for the excitation of an ultrashort-pulse ({approx}1 ps) X-ray laser are discussed. (lasers)

Ivanova, E P [Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region (Russian Federation)

2012-12-31T23:59:59.000Z

246

Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas  

Science Conference Proceedings (OSTI)

We investigated the effects of laser excitation wavelength on water-window emission lines of laser-produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd:YAG laser on BN target in vacuum. Soft x-ray emission lines in the water-window region are recorded using a grazing-incidence spectrograph. Filtered photodiodes are used to obtain complementary data for water-window emission intensity and angular dependence. Spectral emission intensity changes in nitrogen Ly-{alpha} and He-{alpha} are used to show how laser wavelength affects emission. Our results show that the relative intensity of spectral lines is laser wavelength dependent, with the ratio of Ly-{alpha} to He-{alpha} emission intensity decreasing as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission.

Crank, M.; Harilal, S. S.; Hassan, S. M.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-02-01T23:59:59.000Z

247

The flip-over effect in self-similar laser-induced plasma expansion  

Science Conference Proceedings (OSTI)

We present a rigorous study of a dynamical model for a nonsymmetric expansion of laser-induced plasma plumes into the vacuum. The model is used in the laser film deposition technique and for remote chemical analysis in the so-called laser-induced breakdown spectroscopy. It defines a particular class of solutions of the hydrodynamics equations when the (plasma) mass density, pressure, and temperature as functions of position have level surfaces that are ellipsoids. The time evolution of ellipsoid semiaxes is determined by the dynamical model. In this model we investigate the flip-over effect: A pancakelike shape of the plasma plume turns into a cigarlike shape and vice versa in due course of its expansion. The effect has been observed in experiments as well as in numerical simulations. In many practical cases, axially symmetric plasma plumes with the adiabatic constant of (5/3) (ideal gas) are used. For this case we prove that the flip-over effect occurs exactly once in the above dynamical model. This rigorous result agrees with the earlier experimental and numerical evidence and, hence, validates a wide applicability of the model.

Baxter, Nathan P.; Shabanov, Sergei V. [Department of Mathematics, University of Florida, Gainesville, Florida 32611 (United States)

2008-09-15T23:59:59.000Z

248

Study of second harmonic generation by high power laser beam in magneto plasma  

SciTech Connect

This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency {omega}{sub c}=eB{sub 0}/mc over the laser frequency {omega}{sub 0} has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B{sub 0} is the externally applied magnetic field.

Sharma, Prerana [Ujjain Engineering College, Ujjain, Madhya Pradesh 465010 (India); Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2012-12-15T23:59:59.000Z

249

Sources of hot electrons in laser-plasma interaction with emphasis on Raman and turbulence absorption  

SciTech Connect

Heating targets with high power lasers results in a sizable fraction of the absorbed energy going into electrons of temperature much greater than thermal which can pre-heat the pellet core and accelerate fast ion blowoff which results in poor momentum transfer and hence poor compression efficiency. The present emphasis is to build lasers of higher frequency, ..omega../sub 0/, which at the same W/cm/sup 2/ results in more absorption into cooler electrons. Two physical reasons are that the laser can propagate to a higher electron density, n, infinity..omega../sub 0//sup 2/ resulting in more collisional inverse bremsstrahlung absorption proportional to n, and because the hot temperatures from some plasma absorption processes increase as the oscillatory velocity of an electron in the laser electric field v/sub 0//c = eE/(m/sub e/..omega../sub 0/). The heated electron temperatures from other plasma processes (Raman for example approx.(m/sub e//2)v/sup 2//sub phase/ and the higher laser frequency helps by increasing the competing collisional absorption and decreasing the Raman gain.

Estabrook, K.; Kruer, W.L.; Phillion, D.W.; Turner, R.E.; Campbell, E.M.

1982-04-06T23:59:59.000Z

250

A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation  

SciTech Connect

Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

2012-05-01T23:59:59.000Z

251

Electron spectra of xenon clusters irradiated with a laser-driven plasma soft-x-ray laser pulse  

Science Conference Proceedings (OSTI)

Xenon clusters were irradiated with plasma soft-x-ray laser pulses (having a wavelength of 13.9 nm, time duration of 7 ps, and intensities of up to 10 GW/cm{sup 2}). The laser photon energy was high enough to photoionize 4d core electrons. The cross section is large due to a giant resonance. The interaction was investigated by measuring the electron energy spectra. The photoelectron spectra for small clusters indicate that the spectral width due to the 4d hole significantly broadens with increasing cluster size. For larger clusters, the electron energy spectra evolve into a Maxwell-Boltzmann distribution, as a strongly coupled cluster nanoplasma is generated.

Namba, S.; Takiyama, K. [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Hasegawa, N.; Kishimoto, M.; Nishikino, M.; Kawachi, T. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)

2011-11-15T23:59:59.000Z

252

Versatile shaping of a relativistic laser pulse from a nonuniform overdense plasma  

Science Conference Proceedings (OSTI)

We studied the versatile shaping of a petawatt laser pulse using its relativistic transparency in a thin overdense plasma slab. The novel concept here is to use the nonuniformity of the plasma slab in its density or thickness in the transverse direction to control the pulse shaping in both the longitudinal and transverse directions. From 2-dimensional particle-in-cell simulations, we succeeded in fabricating a front shape concave to the propagation direction, an extreme case of transverse shaping. A 1-dimensional analytic formula was then applied to predict the transverse shape, which showed good agreement with the simulations.

Hur, Min Sup; Kim, Young-Kuk [School of Electrical and Computer Engineering, UNIST, BanYeon-Ri 100, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Kulagin, Victor V. [Sternberg Astronomical Institute, Moscow State University, Universitetsky prosp. 13, Moscow 119992 (Russian Federation); Nam, Inhyuk; Suk, Hyyong [APRI, GIST, 261 Cheomdan-gwangiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

2012-07-15T23:59:59.000Z

253

Estimating the pressure of laser-induced plasma shockwave by stimulated Raman shift of lattice translational modes  

Science Conference Proceedings (OSTI)

The current paper investigates stimulated Raman scattering (SRS) when laser-induced plasma is formed in heavy water by focusing an intense pulsed 532 nm Nd:YAG laser beam at room temperature. An unexpected low-frequency SRS line attributed to the lattice translational modes of ice-VII (D{sub 2}O) is observed. The pressure of the plasma shockwave is estimated using low-frequency SRS line shift.

Li Zhanlong [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Shan Xiaoning; Li Zuowei; Zhou Mi; Men Zhiwei [College of Physics, Jilin University, Changchun 130012 (China); Cao Junsheng [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Wang Yiding [College of Electronic Science and Engineering and Key Laboratory on Integrated Optoelectronics, Jilin University, Changchun 130012 (China); Sun Chenglin [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)

2012-07-09T23:59:59.000Z

254

Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF  

SciTech Connect

The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

Ma, T

2010-04-21T23:59:59.000Z

255

Parabolic lithium mirror for a laser-driven hot plasma producing device  

DOE Patents (OSTI)

A hot plasma producing device is provided, wherein pellets, singly injected, of frozen fuel are each ignited with a plurality of pulsed laser beams. Ignition takes place within a void area in liquid lithium contained within a pressure vessel. The void in the liquid lithium is created by rotating the pressure vessel such that the free liquid surface of molten lithium therein forms a paraboloid of revolution. The paraboloid functions as a laser mirror with a reflectivity greater than 90%. A hot plasma is produced when each of the frozen deuterium-tritium pellets sequentially arrive at the paraboloid focus, at which time each pellet is illuminated by the plurality of pulsed lasers whose rays pass through circular annuli across the top of the paraboloid. The beams from the lasers are respectively directed by associated mirrors, or by means of a single conical mirror in another embodiment, and by the mirror-like paraboloid formed by the rotating liquid lithium onto the fuel pellet such that the optical flux reaching the pellet can be made to be uniform over 96% of the pellet surface area. The very hot plasma produced by the action of the lasers on the respective singly injected fuel pellets in turn produces a copious quantity of neutrons and X-rays such that the device has utility as a neutron source or as an x-ray source. In addition, the neutrons produced in the device may be utilized to produce tritium in a lithium blanket and is thus a mechanism for producing tritium.

Baird, James K. (Clinton, TN)

1979-06-19T23:59:59.000Z

256

Crater effects on H and D emission from laser induced low-pressure helium plasma  

Science Conference Proceedings (OSTI)

An experimental study has been performed on the effects of crater depth on the hydrogen and deuterium emission intensities measured from laser plasmas generated in low-pressure helium ambient gas from zircaloy-4 samples doped with different H and D impurity concentrations as well as a standard brass sample for comparison. The results show that aside from emission of the host atom, the emission intensities of other ablated atoms of significantly smaller masses as well as that of the He atom generally exhibit relatively rapid initial decline with increasing crater depth. This trend was found to have its origin in the decreasing laser power density arriving at the crater bottom and thereby weakened the shock wave generated in the crater. As the crater deepened, the declining trend of the intensity appeared to level off as a result of compensation of the decreasing laser power density by the enhanced plasma confinement at increasing crater depth. Meanwhile, the result also reveals the significant contribution of the He-assisted excitation process to the doped hydrogen and deuterium emission intensities, leading to similar crater-depth dependent variation patterns in contrast to that associated with the surface water, with growing dominance of this common feature at the later stage of the plasma expansion. Therefore, a carefully chosen set of gate delay and gate width which are properly adapted to the crater-depth dependent behavior of the emission intensity may produce the desired intrinsic emission data for quantitative depth profiling of H impurity trapped inside the zircaloy wall.

Pardede, Marincan; Lie, Tjung Jie; Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Niki, Hideaki; Fukumoto, Kenichi [Program of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, Fukui University, Fukui 910-8507 (Japan); Maruyama, Tadashi [Integrated Research Institute, Tokyo Institute of Technology, 4259 Nagatsuda-cho, Midori-ku, Yokohama 226-8503 (Japan); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Physics of Magnetism and Photonics Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

2009-09-15T23:59:59.000Z

257

Direct evidence of mismatching effect on H emission in laser-induced atmospheric helium gas plasma  

Science Conference Proceedings (OSTI)

A time-resolved orthogonal double pulse laser-induced breakdown spectroscopy (LIBS) with helium surrounding gas is developed for the explicit demonstration of time mismatch between the passage of fast moving impurity hydrogen atoms and the formation of thermal shock wave plasma generated by the relatively slow moving major host atoms of much greater masses ablated from the same sample. Although this so-called 'mismatching effect' has been consistently shown to be responsible for the gas pressure induced intensity diminution of hydrogen emission in a number of LIBS measurements using different ambient gases, its explicit demonstration has yet to be reported. The previously reported helium assisted excitation process has made possible the use of surrounding helium gas in our experimental set-up for showing that the ablated hydrogen atoms indeed move faster than the simultaneously ablated much heavier major host atoms as signaled by the earlier H emission in the helium plasma generated by a separate laser prior to the laser ablation. This conclusion is further substantiated by the observed dominant distribution of H atoms in the forward cone-shaped target plasma.

Zener Sukra Lie; Koo Hendrik Kurniawan [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); May On Tjia [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Rinda, Hedwig [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan PUSPIPTEK, Serpong, Tangerang Selatan 15314, Banten (Indonesia); Syahrun Nur Abdulmadjid; Nasrullah Idris [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Alion Mangasi Marpaung [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Marincan Pardede [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Muliadi Ramli [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Heri Suyanto [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Fukumoto, Kenichi; Kagawa, Kiichiro [Research Institute of Nuclear Engineering, University of Fukui, Fukui 910-8507 (Japan)

2013-02-07T23:59:59.000Z

258

Controlling the Expansion of Laser-Fusion Plasma to Minimize Impact Damage  

DOE Green Energy (OSTI)

I propose to analytically model the rapid, nonequilibrium expansion of laser-fusion plasma from an initial diameter of 1 mm to a final diameter of 10 m. The aim is to devise a counterforce that minimizes the impact damage on optics by laser-plasma debris. This flow model is the basis of an idea for a dynamic target that efficiently converts laser energy to x-rays while minimizing the total mass propelled as debris. Also, the flow model is the basis of an idea to magnetically deflect material away from the optic ports in the vacuum chamber wall. The model combines results for supersonic one-dimensional gas flow of cylindrical-hemispherical symmetry, with a transition from thermal to nonequilibrium (''frozen'') plasma flow, which is set differently along each characteristic line (the ''Bray criterion'' as a Riemann invariant). The model shows how density, pressure, velocity, ionization fraction, electron temperature, and electrical conductivity vary over space and time, given an impulsively-heated source mass. The model is analytical, and examples are calculated on a desktop computer. This ease-of-use makes it possible to iterate quickly when refining ideas, such as a dynamic metal-vapor target that propels minimal debris, and a magnetohydrodynamic generator as a brake on the flow speed directed at the optic ports. The work involved here is that of an individual refining his analysis.

Garcia, M.

1999-03-18T23:59:59.000Z

259

Numerical modeling of radiation-dominated and quantum-electrodynamically strong regimes of laser-plasma interaction  

Science Conference Proceedings (OSTI)

Ultra-strong laser pulses can be so intense that an electron in the focused beam loses significant energy due to {gamma}-photon emission while its motion deviates via the radiation back-reaction. Numerical methods and tools designed to simulate radiation-dominated and quantum-electrodynamically strong laser-plasma interactions are summarized here.

Sokolov, Igor V. [Space Physics Research Laboratory, University of Michigan, Ann Arbor, Michigan 48109 (United States); Naumova, Natalia M. [Laboratoire d'Optique Appliquee, UMR 7639 ENSTA, Ecole Polytechnique, CNRS, 91761 Palaiseau (France); Nees, John A. [Center for Ultrafast Optical Science and FOCUS Center, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-09-15T23:59:59.000Z

260

Relativistic effects in the interaction of high intensity ultra-short laser pulse with collisional underdense plasma  

SciTech Connect

In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.

Abedi, Samira [Physics Department, North Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Abari, Mehdi Etehadi [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Shokri, Babak [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

2011-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Three-dimensional simulations of anomalous absorption of laser radiation by plasma with supercritical density  

Science Conference Proceedings (OSTI)

A three-dimensional (3D) model of the interaction of laser radiation with plasma in the framework of Maxwell-Vlasov equations has been used to calculate the anomalous optical absorption in plasma of supercritical density. The results of calculations confirmed the development of anomalous absorption that was previously revealed by 2D models, which were insufficient for comparison to the experiment. Calculations were performed for a system containing about 10{sup 6} macroparticles that allowed the absorption coefficient and other characteristics of anomalous absorption in plasma with an inhomogeneous surface to be determined as functions of various parameters of the incident radiation and plasma target. Results are analyzed and estimations are obtained for the contributions of ionization processes and pair collisions of electrons, which show that these factors were quite reasonably ignored in the model. All quantitative results are obtained for the third harmonic of neodymium laser ({lambda} = 0.351 {mu}m) at a tenfold excess of the substance density over a critical value for this radiation.

Ginzburg, S. L.; Dyachenko, V. F. [Russian Academy of Sciences, Keldysh Institute for Applied Mathematics (Russian Federation); Imshennik, V. S. [Alikhanov Institute for Theoretical and Experimental Physics (Russian Federation); Paleychik, V. V.

2012-02-15T23:59:59.000Z

262

0.374 Pflop/s trillion-particle kinetic modeling of laser plasma interaction on Roadrunner  

Science Conference Proceedings (OSTI)

We demonstrate the outstanding performance and scalability of the VPIC kinetic plasma modeling code on the heterogeneous IBM Roadrunner supercomputer at Los Alamos National Laboratory. VPIC is a three-dimensional, relativistic, electromagnetic, particle-in-cell ... Keywords: heterogeneous architecture, high performance computing, inertial confinement fusion, laser plasma instability, memory management, particle in cell, petaflop

K. J. Bowers; B. J. Albright; B. Bergen; L. Yin; K. J. Barker; D. J. Kerbyson

2008-11-01T23:59:59.000Z

263

Particle-in-cell modeling of relativistic laser-plasma interaction with the adjustable-damping, direct implicit method  

Science Conference Proceedings (OSTI)

Implicit particle-in-cell codes offer advantages over their explicit counterparts in that they suffer weaker stability constraints on the need to resolve the higher frequency modes of the system. This feature may prove particularly valuable for modeling ... Keywords: Implicit scheme, Laser-plasma interaction, Particle-in-cell method, Relativistic plasma

M. Drouin; L. Gremillet; J. -C. Adam; A. Héron

2010-06-01T23:59:59.000Z

264

Method and apparatus for fast laser pulse detection using gaseous plasmas  

SciTech Connect

The method and device of the instant invention is a detector of pulsed laser radiation which utilizes the electromotive force generated by the plasma formed when such radiation is focused onto a surface (1). Measurements are made with a 10.6 .mu.m CO.sub.2 laser capable of producing peak intensities of 10.sup.13 W/cm.sup.2 when directed through a converging lens (2). Evacuated detector response to such laser intensity is 1 kV signal peak amplitude and subnanosecond risetimes into a 50.OMEGA. load (3). Detector performance is found to be greatly altered with the introduction of a background gas (4). For example, with one atmosphere of air, the detector produces prompt signals of the order of 1 V with subnanosecond response for pulse trains lasting 100 ns. With argon, krypton, or zenon at pressures of the order of 10 torr, the detector generates "trigger pulses" of about 250 V amplitude and 0.2 ns risetimes. Such detectors are quite robust when irradiated with high intensity laser radiation and are useful for qualitative laser beam monitoring.

McLellan, Edward J. (Los Alamos, NM); Webb, John A. (Albuquerque, NM)

1984-01-01T23:59:59.000Z

265

Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime  

SciTech Connect

Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate the performances of a possible experiment under consideration at the FLASH facility in DESY to explore wakefield acceleration with an enhanced transformer ratio. The experiment capitalizes on a unique pulse shaping capability recently demonstrated at this facility. In addition, the facility incorporates a superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of potential dynamical effects in dielectric wakefield accelerators.

Lemery, F.; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Fermilab; Behrens, C.; Elsen, E.; Flottmann, K.; Gerth, C.; Kube, G.; Schmidt, B.; /DESY; Osterhoff, J.; /Hamburg U., Inst. Theor. Phys. II; Stoltz, P.

2011-09-07T23:59:59.000Z

266

Pulsed laser ablation plasmas generated in CO{sub 2} under high-pressure conditions up to supercritical fluid  

Science Conference Proceedings (OSTI)

Pulsed laser ablation of solids in supercritical media has a large potential for nanomaterials fabrication. We investigated plasmas generated by pulsed laser ablation of Ni targets in CO{sub 2} at pressures ranging from 0.1 to 16 MPa at 304.5 K. Plasma species were characterized by optical emission spectroscopy, and the evolution of cavitation bubbles and shockwaves were observed by time-resolved shadowgraph imaging. Ni and O atomic emissions decreased with increasing gas pressure; however, near the critical point the intensities reached local maxima, probably due to the enhancement of the plasma excitation and effective quenching resulting from the large density fluctuation.

Kato, Toru; Stauss, Sven; Kato, Satoshi; Urabe, Keiichiro; Terashima, Kazuo [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Baba, Motoyoshi; Suemoto, Tohru [Division of Advanced Spectroscopy, Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

2012-11-26T23:59:59.000Z

267

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

NLE Websites -- All DOE Office Websites (Extended Search)

and assist in the planning of the next generation of particle accelerators and ultrafast applications in chemistry and biology. This image shows a horizontal slice through...

268

Modeling laser wakefield accelerators in a Lorentz boosted frame  

E-Print Network (OSTI)

on axis, beam average energy history and momentum spread aton the mean beam energy histories and on the lon- gitudinalgave the same beam energy history within a few percents, and

Vay, J.-L.

2010-01-01T23:59:59.000Z

269

Modeling laser wakefield accelerators in a Lorentz boosted frame  

E-Print Network (OSTI)

on axis, beam average energy history and momentum spread aton the mean beam energy histories and on the longitudinalgave the same beam energy history within a few percents, and

Vay, J.-L.

2010-01-01T23:59:59.000Z

270

An empirical model of collective electrostatic effects for laser-beam channeling in long-scale-length relativistic plasmas  

Science Conference Proceedings (OSTI)

This work investigates the capability of ultraintense lasers with irradiance from 10{sup 18} to 10{sup 21} W cm{sup -2} to produce highly energetic electron beams from a Gaussian focus in a low-density plasma. A simple particle simulation code including a physical model of collective electrostatic effects in relativistic plasmas has been developed. Without electrostatic fields, free electrons escape from the Gaussian focal region of a 10-ps petawatt laser pulse very quickly, well before the laser field reaches its maximum amplitude. However, it has been demonstrated that the electrostatic field generated by the electron flow is able to strongly modify the range and direction of the laser-generated MeV electrons by allowing trapped electrons to experience much higher laser-intensity peaks along their trajectories. This modeling predicts some collimation but not enough to meet the requirements of fast ignition.

Yang, Jeong-Hoon; Craxton, R. Stephen [Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623 (United States)

2011-08-15T23:59:59.000Z

271

Measuring the coherence properties of light emission from laser-plasma interactions. Final report  

Science Conference Proceedings (OSTI)

Several detrimental instabilities can be excited when a high-intensity laser interacts with plasma. The temporal evolution and spectra of the scattered light emitted by many of these instabilities are used to characterize the instabilities and to benchmark theories. It has been difficult to image the emission region with sufficient resolution to make quantitative comparisons with theory. Direct measurement of the emission region would yield information on ponderomotive steepening phenomena, the true emission zone of convective instabilities, and on the saturation of absolute instabilities. The increase in laser intensity caused by the filamentation instability is conjectured to elevate the levels of parametric instabilities found in high-energy laser-plasma interactions. Because the diameter of the filaments is very small (on the order of 10 {micro}m), it is impossible to image the emission sites directly and either to prove or to disprove this conjecture. The research reported here examines an alternate method of measuring the emission region of scattered light from parametric instabilities. This report provides a brief background of coherence theory by defining the relevant parameters in Section 2. A concrete example of the effect that multiple scattering sites would have on the proposed measurement is provided in Section 3. The following section briefly describes experiments that might be able to demonstrate the proposed technique. The conclusion raises the issue of coherence and its effect on the expected angular distribution of scattering light from parametric instabilities.

Batha, S.H.

1998-03-06T23:59:59.000Z

272

Underwater pressure amplification of laser-induced plasma shock waves for particle removal applications  

Science Conference Proceedings (OSTI)

Underwater amplification of laser-induced plasma (LIP)-generated transient pressure waves using shock tubes is introduced and demonstrated. Previously, it has been shown that LIP for noncontact particle removal is possible on the sub-100-nm level. This is now enhanced through shock tube utilization in a medium such as water by substantially increasing shock wave pressure for the same pulse energy. A shock tube constrains the volume and changes the propagation direction of the expanding plasma core by focusing a pulsed-laser beam inside a tube with a blind end, thus increasing the wave front pressure generated. Current amplification approach can reduce radiation exposure of the substrate from the shock wave because of the increased distance from the LIP core to the substrate provided by the increased pressure per unit pulse energy. For the same pulsed laser, with the aid of a shock tube, substantial levels of pressure amplitude amplification (8.95) and maximum pressure (6.48 MPa) are observed and reported.

Dunbar, Thomas J.; Cetinkaya, Cetin [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, New York 13699-5725 (United States) and Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5725 (United States)

2007-07-30T23:59:59.000Z

273

Cushman & Wakefield Environmental Challenge | ENERGY STAR Buildings &  

NLE Websites -- All DOE Office Websites (Extended Search)

Cushman & Wakefield Environmental Challenge Cushman & Wakefield Environmental Challenge Secondary menu About us Press room Contact Us Portfolio Manager Login Facility owners and managers Existing buildings Commercial new construction Industrial energy management Small business Service providers Service and product providers Verify applications for ENERGY STAR certification Design commercial buildings Energy efficiency program administrators Commercial and industrial program sponsors Associations State and local governments Federal agencies Tools and resources Training In this section How can we help you? Build an energy program Improve building and plant performance Earn the ENERGY STAR and other recognition Benchmark energy use ENERGY STAR in action Communicate and educate ENERGY STAR communications toolkit Bring Your Green to Work with ENERGY STAR

274

Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields  

E-Print Network (OSTI)

Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields

Reiche, S; Emma, P; Fawley, W M; Huang, Z; Nuhn, H D; Stupakov, G V

2005-01-01T23:59:59.000Z

275

The Wakefield Effects of Pulsed Crab Cavities at the Advanced Photon Source for Short-X-ray Pulse Generation  

E-Print Network (OSTI)

The Wakefield Effects of Pulsed Crab Cavities at the Advanced Photon Source for Short-X-ray Pulse Generation

Chae, Y C; Dolgashev, V

2007-01-01T23:59:59.000Z

276

Observation of exclusively He-induced H emission in cooled laser plasma  

Science Conference Proceedings (OSTI)

An experiment was performed for the observation of H emission induced in a cooled laser-induced atmospheric pressure gas plasma of He atoms in their metastable excited state. The strong H emission detected clearly established, to the exclusion of other well known major excitation processes, the exclusive contribution of the He-induced excitation (HIE) mechanism. The process is suggested to take place by means of energy transfer from the excited He atoms to the H atoms via Penning collision induced ionization involving electron exchange. The result further shows that this mechanism may also work for elements other than H and thereby strongly suggests the use of ambient He gas to broaden and complement the applications of standard laser-induced breakdown spectroscopy.

Lie, Z. S.; Niki, H. [Program of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, Fukui University, Fukui 910-8507 (Japan); Kagawa, K. [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Physics of Magnetism and Photonics Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Hedwig, R. [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Pardede, M. [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Jobiliong, E. [Industrial Engineering Department, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Suliyanti, M. M. [Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK, Serpong Tangerang Selatan 15314, Banten (Indonesia); Abdulmadjid, S. N.; Kurniawan, K. H. [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia)

2011-05-15T23:59:59.000Z

277

Systems and methods for imaging using radiation from laser produced plasmas  

DOE Patents (OSTI)

In particular embodiments, the present disclosure provides systems and methods for imaging a subject using radiation emitted from a laser produced plasma generating by irradiating a target with a laser. In particular examples, the target includes at least one radiation enhancing component, such as a fluor, cap, or wire. In further examples, the target has a metal layer and an internal surface defining an internal apex, the internal apex of less than about 15 .mu.m, such as less than about 1 .mu.m. The targets may take a variety of shapes, including cones, pyramids, and hemispheres. Certain aspects of the present disclosure provide improved imaging of a subject, such as improved medical images of a radiation dose than typical conventional methods and systems.

Renard-Le Galloudec, Nathalie (Reno, NV); Cowan, Thomas E. (Reno, NV); Sentoku, Yasuhiko (Reno, NV); Rassuchine, Jennifer (Reno, NV)

2009-06-30T23:59:59.000Z

278

Status of Plasma Electron Hose Instability Studies in FACET  

SciTech Connect

In the FACET plasma-wakefield acceleration experiment a dense 23 GeV electron beam will interact with lithium and cesium plasmas, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons may lead to a fast growing electron hose instability. By using optics dispersion knobs to induce a controlled z-x tilt along the beam entering the plasma, we investigate the transverse behavior of the beam in the plasma as function of the tilt. We seek to quantify limits on the instability in order to further explore potential limitations on future plasma wakefield accelerators due to the electron hose instability. The FACET plasma-wakefield experiment at SLAC will study beam driven plasma wakefield acceleration. A dense 23 GeV electron beam will interact with lithium or cesium plasma, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons drives the electron hose instability, as first studied by Whittum. While Ref. [2] indicates the possibility of a large instability growth rate for typical beam and plasma parameters, other studies including have shown that several physical effects may mitigate the hosing growth rate substantially. So far there has been no quantitative benchmarking of experimentally observed hosing in previous experiments. At FACET we aim to perform such benchmarking by for example inducing a controlled z-x tilt along the beamentering the plasma, and observing the transverse behavior of the beam in the plasma as function. The long-term objective of these studies is to quantify potential limitations on future plasma wakefield accelerators due to the electron hose instability.

Adli, Erik; /U. Oslo; England, Robert Joel; Frederico, Joel; Hogan, Mark; Li, Selina Zhao; Litos, Michael Dennis; Nosochkov, Yuri; /SLAC; An, Weiming; Mori, Warren; /UCLA

2011-12-13T23:59:59.000Z

279

Investigation of non-stationary self-focusing of intense laser pulse in cold quantum plasma using ramp density profile  

SciTech Connect

The authors have investigated the non-stationary self-focusing of Gaussian laser pulse in cold quantum plasma. In case of high dense plasma, the nonlinearity in the dielectric constant is mainly due to relativistic high intense interactions and quantum effects. In this paper, we have introduced a ramp density profile for plasma and presented graphically the behavior of spot size oscillations of pulse at rear and front portions of the pulse. It is observed that the ramp density profile and quantum effects play a vital role in stronger and better focusing at the rear of the pulse than at the front in cold quantum plasmas.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-11-15T23:59:59.000Z

280

Time-resolved studies of particle effects in laser ablation inductively coupled plasma-mass spectrometry  

Science Conference Proceedings (OSTI)

Time resolved signals in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are studied to determine the influence of experimental parameters on ICP-induced fractionation effects. Differences in sample composition and morphology, i.e., ablating brass, glass, or dust pellets, have a profound effect on the time resolved signal. Helium transport gas significantly decreases large positive signal spikes arising from large particles in the ICP. A binder for pellets also reduces the abundance and amplitude of spikes in the signal. MO{sup +} ions also yield signal spikes, but these MO{sup +} spikes generally occur at different times from their atomic ion counterparts.

Perdian, D.; Bajic, S.; Baldwin, D.; Houk, R.

2007-11-13T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas  

Science Conference Proceedings (OSTI)

A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of {approx}10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)]. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)].

Morita, T.; Sakawa, Y.; Kuramitsu, Y.; Sano, T.; Takabe, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Dono, S.; Ide, T.; Tanji, H.; Shiroshita, A. [Graduate School of Engineering, Osaka University, 1-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Shibata, S.; Aoki, H. [Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan); Waugh, J. N.; Woolsey, N. C. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Gregory, C. D. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128 Palaiseau (France)

2012-10-15T23:59:59.000Z

282

Magnetic reconnection in high-energy-density laser-produced plasmas  

SciTech Connect

Recently, novel experiments on magnetic reconnection have been conducted in laser-produced plasmas in a high-energy-density regime. Individual plasma bubbles self-generate toroidal, mega-gauss-scale magnetic fields through the Biermann battery effect. When multiple bubbles are created at small separation, they expand into one another, driving reconnection of this field. Reconnection in the experiments was reported to be much faster than allowed by both Sweet-Parker, and even Hall-MHD theories, when normalized to the nominal magnetic fields self-generated by single bubbles. Through particle-in-cell simulations (both with and without a binary collision operator), we model the bubble interaction at parameters and geometry relevant to the experiments. This paper discusses in detail the reconnection regime of the laser-driven experiments and reports the qualitative features of simulations. We find substantial flux-pileup effects, which boost the relevant magnetic field for reconnection in the current sheet. When this is accounted for, the normalized reconnection rates are much more in line with standard two-fluid theory of reconnection. At the largest system sizes, we additionally find that the current sheet is prone to breakup into plasmoids.

Fox, W.; Bhattacharjee, A.; Germaschewski, K. [Center for Integrated Computation and Analysis of Reconnection and Turbulence, and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of New Hampshire, Durham, New Hampshire 03824 (United States)

2012-05-15T23:59:59.000Z

283

Analysis of neon soft x-ray spectra from short-pulse laser-produced plasmas  

Science Conference Proceedings (OSTI)

We report preliminary results from the analysis of streaked soft x-ray neon spectra obtained from the interaction of a picosecond Nd:glass laser with a gas jet target. In these experiments streaked spectra show prompt harmonic emission followed by longer time duration soft x-ray line emission. The majority of the line emission observed was found to originate from Li- and Be-like Ne and the major transitions in the observed spectra have been identified. Li-like emission lines were observed to decay faster in time than Be-like transitions, suggesting that recombination is taking place. Line ratios of n=4-2 and n=3-2 transitions supported the view that these lines were optically thin and thick, respectively. The time history of Li-like Ne 2p-4d and 2p-3d lines is in good agreement with a simple adiabatic expansion model coupled to a time dependent collisional-radiative code. Further x-ray spectroscopic analysis is underway which is aimed at diagnosing plasma conditions and assessing the potential of this recombining neon plasma as a quasi-steady-state recombination x-ray laser medium.

Abare, A.C. [Florida Univ., Gainesville, FL (United States); Keane, C.J.; Crane, J.K.; DaSilva, L.B.; Lee, R.W.; Perry, M.D. [Lawrence Livermore National Lab., CA (United States); Falcone, R.W. [California Univ., Berkeley, CA (United States). Dept. of Physics

1993-04-01T23:59:59.000Z

284

Developing the model of laser ablation by considering the interplay between emission and expansion of aluminum plasma  

SciTech Connect

In the present study, the ablation behavior of aluminum target and its plasma radiation in noble ambient gases by a laser pulse with wavelength of 266 nm and pulse duration of 10 ns are numerically studied. A thermal model of laser ablation considering heat conduction, Euler equations, Saha-Eggert equations, Knudsen layer, mass and energy balance relations and optical shielding effects are used for calculation of plasma parameters. Effects of excitation energy on plasma expansion and its emissivity are investigated. Time and spatial-resolved plasma emission including bremsstrahlung, recombination and spectral emission at early delay times after laser irradiation is obtained. Effects of two ambient gases (He and Ar) as well as different gas pressures of 100, 300, 500, and 760 Torr on plasma expansion and its spectrum are studied. Results illustrate that at initial delay times, especially at high noble gas pressures, ionic lines have the maximum intensities, while at later times neutral lines dominate. When the pressure of ambient gas increases, a confinement of the plasma plume is predicted and the intensity of neutral lines decreases. Continuous emission increases with wavelength in both ambient gases. Spatially resolved analysis shows that an intense continuous emission is predicted next to the sample surface decreasing with distance from the latter.

Rezaei, F.; Tavassoli, S. H. [Laser and Plasma Research Institute, ShahidBeheshti University, 19396 4716, G. C., Evin, Tehran (Iran, Islamic Republic of)

2013-01-15T23:59:59.000Z

285

Photocathode Studies at the Argonne Wakefield Accelerator  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Quantum Efficiency Photocathodes for the AWA High Energy Physics Division, ANL Zikri Yusof, Manoel Conde, Felipe Franchini Matt Virgo DOE Review April 26-27 2007 Energy Systems Division, ANL 2 PHOTOCATHODE REQUIREMENT FOR BUNCH TRAIN For the near future, creation of charge bunch train of 16 bunches in a single RF pulse 50 nC 16 micro pulses 5 eV Laser 10 mJ Want 50 nC in each charge microbunch. This is equal to ~ 3×10 11 electrons. * 10 mJ of laser energy per pulse; * Estimate 80% loss due to beam splitter, mirrors, etc.; * Beam is split into 16 micro pulses; * Number of photons in each micro pulse is ~1.5×10 14 . QE of photocathode to be able to supply that amount of charge: % 2 . 0 10 2 10 5 . 1 10 3 3 14 11 = × ≈ × × = - QE Need high QE photocathode - choose Cs 2 Te 770 ps 3 Cs 2 Te RECIPE

286

Characterisation of electron beams from laser-driven particle accelerators  

Science Conference Proceedings (OSTI)

The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-12-21T23:59:59.000Z

287

Laser-Driven Hydrodynamic Experiments in the Turbulent Plasma Regime: from OMEGA to NIF  

Science Conference Proceedings (OSTI)

There is a great deal of interest in studying the evolution of hydrodynamic phenomena in high energy density plasmas that have transitioned beyond the initial phases of instability into a fully developed turbulent state. Motivation for this study arises both in fusion plasmas as well as in numerous astrophysical applications where the understanding of turbulent mixing is essential. Double-shell ignition targets, for example, are subject to large growth of short wavelength perturbations on both surfaces of the high-Z inner shell. These perturbations, initiated by Richtmyer-Meshkov and Rayleigh-Taylor instabilities, can transition to a turbulent state and will lead to deleterious mixing of the cooler shell material with the hot burning fuel. In astrophysical plasmas, due to the extremely large scale, turbulent hydrodynamic mixing is also of widespread interest. The radial mixing that occurs in the explosion phase of core-collapse supernovae is an example that has received much attention in recent years and yet remains only poorly understood. In all of these cases, numerical simulation of the flow field is very difficult due to the large Reynolds number and corresponding wide range of spatial scales characterizing the plasma. Laboratory experiments on high energy density facilities that can access this regime are therefore of great interest. Experiments exploring the transition to turbulence that are currently being conducted on the Omega laser will be described. We will also discuss experiments being planned for the initial commissioning phases of the NIF as well as the enhanced experimental parameter space that will become available, as additional quads are made operational.

Robey, H F; Miles, A R; Hansen, J F; Blue, B E; Drake, R P

2003-08-25T23:59:59.000Z

288

Development of laser-plasma diagnostics using ultrafast atomic-scale dynamics. 96-ERD-046 final report  

Science Conference Proceedings (OSTI)

Ultrashort laser pulse systems allow examination of intense, ultrafast laser-plasma interactions. More specifically, intense laser irradiation can induce short xuv/x-ray bursts from the surface of condensed phase targets. Ultrafast xuv/x-ray detection is needed to understand laser-plasma interactions in this dynamic regime. Support of the Stockpile Stewardship and Management Program requires this critical understanding. Our effort here has been to extend understanding of atomic-scale dynamics in such environments with the goal of developing next generation ultrafast xuv/x-ray diagnostics where the sensors will be the atoms and ions themselves and the time resolution will approach that of the induced atomic transitions ({approx} a few femtoseconds). Pivotal contributions to the rapidly developing field of highly nonperturbative interactions of ultrashort pulse lasers with atoms/ions have been made at this laboratory. In the visible/infrared wavelength regions the temporal and spectral content of ultrashort laser pulses are now reliably monitored within a single pulse using frequency resolved optical gating (FROG) which is based on rapid nonlinear optical processes such as the Kerr effect. New applications of this basic concept are still being developed. Corresponding detection for the xuv/x-ray wavelengths does not exist and is urgently needed in many laboratory programs. The FROG technique cannot be applied in the xuv/x-ray region. Current x-ray streak camera technology is limited to {approx}0.5 picosecond resolution.

Bolton, P.R.; Kulander, K.C. [Lawrence Livermore National Lab., CA (United States); Boreham, B.W. [Central Queensland Univ., Rockhampton, QLD (Australia). Dept. of Applied Physics

1997-03-01T23:59:59.000Z

289

Experimental demonstration of wakefield effects in a THz planar diamond accelerating structure  

Science Conference Proceedings (OSTI)

We have directly measured THz wakefields induced by a subpicosecond, intense relativistic electron bunch in a diamond loaded accelerating structure via the wakefield acceleration method. We present here the beam test results from the diamond based structure. Diamond has been chosen for its high breakdown threshold and unique thermoconductive properties. Fields produced by a leading (drive) beam were used to accelerate a trailing (witness) electron bunch, which followed the drive bunch at a variable distance. The energy gain of a witness bunch as a function of its separation from the drive bunch describes the time structure of the generated wakefield.

Antipov, S.; Jing, C. [Euclid Techlabs LLC, Solon, Ohio 44139 (United States); Argonne Wakefield Accelerator Facility, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kanareykin, A.; Butler, J. E. [Euclid Techlabs LLC, Solon, Ohio 44139 (United States); Yakimenko, V.; Fedurin, M.; Kusche, K. [Accelerator Test Facility, Brookhaven National Laboratory, Upton, New York 11973 (United States); Gai, W. [Argonne Wakefield Accelerator Facility, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2012-03-26T23:59:59.000Z

290

Deuterium analysis in zircaloy using ps laser-induced low pressure plasma  

SciTech Connect

An experimental study on picosecond laser induced plasma spectroscopy of a zircaloy sample with low-pressure surrounding helium gas has been carried out to demonstrate its potential applicability to three-dimensional quantitative micro-analysis of deuterium impurities in zircaloy. This was achieved by adopting the optimal experimental condition ascertained in this study, which is specified as 7 mJ laser energy, 1.3 kPa helium pressure, and 50 {mu}s measurement window, and which was found to result in consistent D emission enhancement. Employing these operational parameters, a linear calibration line exhibiting a zero intercept was obtained from zircaloy-4 samples doped with various concentrations of D impurity, regarded as surrogates for H impurity. An additional measurement also yielded a detection limit of about 10 {mu}g/g for D impurity, well below the acceptable threshold of damaging H concentration in zircaloy. Each of these measurements was found to produce a crater size of only 25 {mu}m in diameter, promising its application for performing less-destructive measurements. The result of this study has thus paved the way for conducting a further experiment with hydrogen-doped zircaloy samples and the further technical development of a three-dimensional quantitative micro-analysis of detrimental hydrogen impurity in zircaloy vessels used in nuclear power plants.

Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta (Indonesia); Lie, Zener Sukra; Niki, Hideaki [Department of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, University of Fukui, Fukui 910-8507 (Japan); Kagawa, Kiichiro; Fukumoto, Ken-ichi [Research Institute of Nuclear Engineering, University of Fukui, Fukui 910-8507 (Japan); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Abdulmadjid, Syahrun Nur; Idris, Nasrullah [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K. H. Syahdan, Jakarta 14810 (Indonesia); Tjia, May On [Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M. H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK, Serpong Tangerang Selatan 15314, Banten (Indonesia); Jobiliong, Eric [Industrial Engineering Department, University of Pelita Harapan, 1100 M. H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia)

2011-09-15T23:59:59.000Z

291

Efficient electron injection into plasma waves using higher-order laser modes  

E-Print Network (OSTI)

waves using higher-order laser modes P. Michel, E. Esarey, ?higher-order transverse laser modes as drivers for plasmaparticu- lar, using a ring laser beam with maximum intensity

Michel, P.; Esarey, E.; Schroeder, C.B.; Shadwick, B.A.; Leemans, W.P.

2006-01-01T23:59:59.000Z

292

Collimator Wakefield Calculations for ILC-TRC Report(LCC-0101)  

SciTech Connect

We summarize the formalism of collimator wakefields and their effect on beams that are near the center of the collimator gap, and apply the formalism to the TESLA, NLC, and CLIC collimation systems.

Tenenbaum, P

2003-10-07T23:59:59.000Z

293

Calculation of wakefields in a 17 GHz beam-driven photonic band-gap accelerator structure  

E-Print Network (OSTI)

We present the theoretical analysis and computer simulation of the wakefields in a 17 GHz photonic band-gap (PBG) structure for accelerator applications. Using the commercial code CST Particle Studio, the fundamental ...

Hu, Min

294

A Test-bed for Future Linear Collider Technology: Argonne Wakefield...  

NLE Websites -- All DOE Office Websites (Extended Search)

U.S.A. Abstract Research at the AWA Facility has been focused on the development of electron beam driven wakefield structures. Accelerating gradients of up to 100 MVm have been...

295

5. Kodama, R. et al. Fast heating of ultrahigh-density plasma as a step towards laser fusion ignition. Nature 412, 798802 (2001).  

E-Print Network (OSTI)

5. Kodama, R. et al. Fast heating of ultrahigh-density plasma as a step towards laser fusion. J. Geophys. Res. 100, 23567­23581 (1995). 13. Hirahara, M. et al. Acceleration and heating of cold

Davis, James C.

296

Cushman & Wakefields Client Solutions Group presents:  

NLE Websites -- All DOE Office Websites (Extended Search)

OCTOBER 2009 OCTOBER 2009 Updated January 2010 A CALL TO ACTION TO IMPROVE THE ENVIRONMENTAL EFFICIENCY OF CUSHMAN &WAKEFIELD'S MANAGED PROPERTIES Take the C&W Environmental Challenge and help us find out: * Who can quantify improvements in environmental performance over time? * Who can take environmental performance to the next level? * Which buildings are the highest performers across C&W managed portfolio? WHAT IS THE C&W ENVIRONMENTAL CHALLENGE? WHY PARTICIPATE? IMPROVE YOUR BOTTOM LINE: Increased energy and water efficiency, and reduced waste in commercial real estate can reduce operating expenses and increase property asset value. DO YOUR PART TO ADDRESS CLIMATE CHANGE: Commercial buildings generate about 17% of total greenhouse gas emissions.

297

High resolution soft x-ray spectroscopy of low Z K-shell emission from laser-produced plasmas  

SciTech Connect

A large radius, R = 44.3 m, High Resolution Grating Spectrometer (HRGS) with 2400 line/mm variable line spacing has been designed for laser-produced plasma experiments conducted at the Lawrence Livermore National Laboratory Jupiter Laser Facility. The instrument has been run with a low-noise, charge-coupled device detector to record high signal-to-noise spectra in the 10-50 {angstrom} wavelength range. The instrument can be run with a 10-20 {micro}m wide slit to achieve the best spectral resolving power, approaching 1000 and similar to crystal spectrometers at 12-20 {angstrom}, or in slitless operation with a small symmetrical emission source. We describe preliminary spectra emitted from various H-like and He-like low Z ion plasmas heated by 100-500 ps (FWHM), 527 nm wavelength laser pulses. This instrument can be developed as a useful spectroscopy platform relevant to laboratory-based astrophysics as well as high energy density plasma studies.

Dunn, J; Magee, E W; Shepherd, R; Chen, H; Hansen, S B; Moon, S J; Brown, G V; Gu, M; Beiersdorfer, P; Purvis, M A

2008-05-21T23:59:59.000Z

298

Measurement of H and H sub 2 populations in a low-temperature plasma by vacuum ultraviolet laser absorption spectroscopy  

DOE Green Energy (OSTI)

A new technique, vacuum ultraviolet laser absorption spectroscopy, has been developed to quantitatively determine the absolute density of H and H{sub 2} within a plasma. The technique is particularly well suited to measurement in a plasma, where high charged particle and photon backgrounds complicate other methods of detection. The high selectivity and sensitivity of the technique allows for the measurement of the rotational-vibrational state distribution of H{sub 2} as well as the translational temperature of the atoms and molecules. The technique has been used to study both pulsed and continuous plasma discharges. H{sub 2} state distributions show a high degree of internal excitation, with levels up to v=5 and J=8 being observed. Hydrogen atom measurements indicate that, even for modest discharge currents, the fraction of H{sub 2} molecules dissociated can be greater than 0.15.

Young, A.T.; Stutzin, G.C.; Schlachter, A.S.; Stearns, J.W.; Leung, K.N.; Kunkel, W.B. (Lawrence Berkeley Laboratory, Berkeley, California 94720 (US)); Worth, G.T.; Stevens, R.R. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (USA))

1989-10-20T23:59:59.000Z

299

Estimation of electron temperature and density of the decay plasma in a laser-assisted discharge plasma extreme ultraviolet source by using a modified Stark broadening method  

Science Conference Proceedings (OSTI)

In order to investigate the plasma expansion behaviors and the electrical recovery process after the maximum implosion in our tin fueled laser-assisted discharge plasma (LDP) 13.5 nm EUV source, we developed and evaluated a cost-efficient spectroscopic method to determine the electron temperature T{sub e} and density n{sub e} simultaneously, by using Stark broadenings of two Sn II isolated lines (5s{sup 2}4f{sup 2}F{sup o}{sub 5/2} - 5s{sup 2}5d{sup 2}D{sub 3/2} 558.9 nm and 5s{sup 2}6d{sup 2}D{sub 5/2} - 5s{sup 2}6p{sup 2}P{sup o}{sub 3/2} 556.2 nm) spontaneously emitted from the plasma. The spatial-resolved evolutions of T{sub e} and n{sub e} of the expansion plasma over 50 to 900 ns after the maximum implosion were obtained using this modified Stark broadening method. According to the different n{sub e} decay characteristics along the Z-pinch axis, the expansion velocity of the electrons was estimated as {approx}1.2 x 10{sup 4} ms{sup -1} from the plasma shell between the electrodes towards the cathode and the anode. The decay time constant of n{sub e} was measured as 183 {+-} 24 ns. Based on the theories of plasma adiabatic expansion and electron-impact ionization, the minimum time-span that electrical recovery between the electrodes needs in order to guarantee the next succeeding regular EUV-emitting discharge was estimated to be 70.5 {mu}s. Therefore, the maximum repetition rate of our LDP EUV source is {approx}14 kHz, which enables the output to reach 125 W/(2{pi}sr).

Zhu Qiushi; Muto, Takahiro; Yamada, Junzaburo; Kishi, Nozomu; Watanabe, Masato; Okino, Akitoshi; Horioka, Kazuhiko; Hotta, Eiki [Department of Energy Sciences, Tokyo Institute of Technology, Yokohama (Japan)

2011-12-15T23:59:59.000Z

300

Spectrum and conversion efficiency measurements of suprathermal electrons from relativistic laser plasma interactions  

E-Print Network (OSTI)

Fast Ignition is an alternative scheme for Inertial Confinement Fusion (ICF) that uses a petawatt laser to ignite a hot spot in precompressed fuel. The laser delivers its energy into relativistic electrons at the critical ...

Chen, Cliff D. (Cliff Ding Yu)

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A Radiation-Hydrodynamics Code Comparison for Laser-Produced Plasmas: FLASH versus HYDRA and the Results of Validation Experiments  

E-Print Network (OSTI)

The potential for laser-produced plasmas to yield fundamental insights into high energy density physics (HEDP) and deliver other useful applications can sometimes be frustrated by uncertainties in modeling the properties and expansion of these plasmas using radiation-hydrodynamics codes. In an effort to overcome this and to corroborate the accuracy of the HEDP capabilities recently added to the publicly available FLASH radiation-hydrodynamics code, we present detailed comparisons of FLASH results to new and previously published results from the HYDRA code used extensively at Lawrence Livermore National Laboratory. We focus on two very different problems of interest: (1) an Aluminum slab irradiated by 15.3 and 76.7 mJ of "pre-pulse" laser energy and (2) a mm-long triangular groove cut in an Aluminum target irradiated by a rectangular laser beam. Because this latter problem bears a resemblance to astrophysical jets, Grava et al., Phys. Rev. E, 78, (2008) performed this experiment and compared detailed x-ray int...

Orban, Chris; Chawla, Sugreev; Wilks, Scott C; Lamb, Donald Q

2013-01-01T23:59:59.000Z

302

Optimization of extreme ultraviolet photons emission and collection in mass-limited laser produced plasmas for lithography application  

SciTech Connect

The progress in development of commercial system for next generation EUV lithography requires, among other factors, significant improvement in EUV photon sources such as discharge produced plasma (DPP) and laser produced plasma (LPP) devices. There are still many uncertainties in determining the optimum device since there are many parameters for the suitable and efficient energy source and target configuration and size. Complex devices with trigger lasers in DPP or with pre-pulsing in LPP provide wide area for optimization in regards to conversion efficiency (CE) and components lifetime. We considered in our analysis a promising LPP source configuration using 10-30 {mu}m tin droplet targets, and predicted conditions for the most efficient EUV radiation output and collection as well as calculating photons source location and size. We optimized several parameters of dual-beam lasers and their relationship to target size. We used our HEIGHTS comprehensive and integrated full 3D simulation package to study and optimize LPP processes with various target sizes to maximize the CE of the system.

Sizyuk, T.; Hassanein, A. [Center for Materials under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-08-01T23:59:59.000Z

303

Residual ionization in the expansion of a laser-produced plasma  

SciTech Connect

A condition is found for determining the stage of plasma expansion in vacuum at which ionization quenching occurs.

Busygin, A.I.

1977-11-01T23:59:59.000Z

304

Generation of laser-induced plasma in supercritical water and vibrational spectroscopic study of accompanying stimulated Raman scattering  

Science Conference Proceedings (OSTI)

We have formed a laser-induced plasma (LIP) in supercritical water (SCW) and studied associated molecular vibrations using spectroscopic methods. The accompanying forward and backward stimulated Raman scattering (SRS) of water molecules showed anisotropic behavior at supercritical conditions (>647 K and >22.1 MPa). The Raman shift of the backward SRS indicated that attractive interactions between water molecules and excess electrons generated by the LIP were dominant in the SCW. The backward SRS spectrum provided a microscopic view of the hydration environment around an excess electron, which is useful for controlling electron-driven chemical reactions and materials processing in SCW.

Yui, Hiroharu [Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjyuku-ku, Tokyo 162-8601 (Japan); PRESTO-JST, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075 (Japan); Tomai, Takaaki; Sawada, Masayoshi; Terashima, Kazuo [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8561 (Japan)

2011-08-29T23:59:59.000Z

305

2012 SG Peer Review - Day 2 Panel Discussion: Matt Wakefield, EPRI  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Matt Wakefield Matt Wakefield Senior Program Manager, Smart Grid June 7, 2012 Overview & Industry Coordination of EPRI IntelliGrid & Security Research & Smart Grid Demonstrations 2 © 2012 Electric Power Research Institute, Inc. All rights reserved. IntelliGrid Program Information & Communication Technologies (ICT) to Enable..... The IntelliGrid Program conducts research, development and demonstrations on the Information and Communications Technologies (ICT) that Enable Smart Grid applications IntelliGrid * Transmission * Distribution * End-Use (AMI/DR) 3 © 2012 Electric Power Research Institute, Inc. All rights reserved. * Reliability and performance characteristics the various technology

306

Plasma/Laser Assisted Template Free Synthesis of ZnO Pillars  

Science Conference Proceedings (OSTI)

The pillar morphology is achieved via pulsed lasing of plasma synthesized ZnO ... decreasing transmittance with increasing the energy of photon radiation.

307

Effects of finite beam and plasma temperature on the growth rate of a two-stream free electron laser with background plasma  

SciTech Connect

A fluid theory is used to derive the dispersion relation of two-stream free electron laser (TSFEL) with a magnetic planar wiggler pump in the presence of background plasma (BP). The effect of finite beams and plasma temperature on the growth rate of a TSFEL has been verified. The twelve order dispersion equation has been solved numerically. Three instabilities, FEL along with the TS and TS-FEL instabilities occur simultaneously. The analysis in the case of cold BP shows that when the effect of the beam temperature is taken into account, both instable bands of wave-number and peak growth rate in the TS instability increase, but peak growth of the FEL and TS-FEL instabilities decreases. Thermal motion of the BP causes to diminish the TS instability and it causes to decrease the FEL and TS-FEL instabilities. By increasing the beam densities and lowering initial velocities (in the collective Raman regime), growth rate of instabilities increases; however, it has opposite behavior in the Campton regime.

Mahdizadeh, N. [Department of Physics, Sabzevar Branch, Islamic Azad University, Sabzevar (Iran, Islamic Republic of); Aghamir, F. M. [Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of)

2013-02-28T23:59:59.000Z

308

Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule  

E-Print Network (OSTI)

1 Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule M.Dohlus,H.-P.Wedekind,K.Zapfe DeutschesElektronenSynchrotron Notkestr.85,D-22603Hamburg,Germany Abstract The beam pipe of the TESLA valves with spring type rf-shield which are presently used in the linac of the TESLA Test Facility

309

Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas  

E-Print Network (OSTI)

The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T.?R. Boehly et al., Opt. Commun. ...

Gotchev, O. V.

310

Thermal processes generated in quark-gluon plasma by yoctosecond laser pulses  

E-Print Network (OSTI)

In this paper the thermal processes generated by yoctosecond (10-24 s) laser pulses in QGP are investigated. Considering that the relaxation time in QGP is of the order of 1 ys it is shown that in QGP the yoctosecond laser pulses can generate the thermal waves with velocity v = c (0.3 fm/ys). Key words: QGP, thermal waves, yoctosecond pulses

Marciak-Kozlowska, J

2011-01-01T23:59:59.000Z

311

Thermal processes generated in quark-gluon plasma by yoctosecond laser pulses  

E-Print Network (OSTI)

In this paper the thermal processes generated by yoctosecond (10-24 s) laser pulses in QGP are investigated. Considering that the relaxation time in QGP is of the order of 1 ys it is shown that in QGP the yoctosecond laser pulses can generate the thermal waves with velocity v = c (0.3 fm/ys). Key words: QGP, thermal waves, yoctosecond pulses

J. Marciak-Kozlowska; M. Kozlowski

2011-07-03T23:59:59.000Z

312

Instability Versus Equilibrium Propagation of a Laser Beam in Plasma Pavel M. Lushnikov1,2  

E-Print Network (OSTI)

) at the National Ignition Facility (NIF) [1]. NIF's plasma environment, in the indirect drive approach to ICF, has that of actual experiments, as in the idealized ``top hat'' model of NIF optics: j ^EEkj const; k

Lushnikov, Pavel

313

Laser ablation of electronic materials including the effects of energy coupling and plasma interactions  

E-Print Network (OSTI)

conduction, (2) electron-ion (exothermic) recombination on the cavity walls, (3) short-wavelength thermal plasmaconduction, electron-ion recombination and condensation of vapor on the cavity walls, and the plasma

Zeng, Xianzhong

2004-01-01T23:59:59.000Z

314

Rayleigh-Taylor-Induced electromagnetic fields in laser-produced plasmas  

E-Print Network (OSTI)

Spontaneous electromagnetic fields can be important to the dynamic evolution of a plasma by directing heat flow as well as providing additional pressures on the conducting fluids through the Lorentz force. Electromagnetic ...

Manuel, Mario John-Errol

2013-01-01T23:59:59.000Z

315

Wakefield Calculations for the LCLS in Multbunch Operation  

SciTech Connect

Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode, which is initially the most likely scenario. The longitudinal wake changes the average energy at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse. In the LCLS the bunch is created in an rf gun, and then passes in sequence through Linac 0, Linac 1, Linac X, Bunch Compressor 1 (BC 1), Linac 2, BC 2, Linac 3, and finally the undulator. In the process the bunch energy reaches 13.5 GeV and peak current 3 kA. In Table 1 we present some machine and beam parameters in three of the linacs that we will use in the calculations: initial beam energy E{sub 0}, total accelerator length L, average beta function {beta}{sub y}, bunch peak current I, and rf phase (with respect to crest) {phi}; the final energy of a linac equals E{sub 0} of the following linac, and in Linac 3 is E{sub f} = 13.5 GeV. (The X-band linac, with L = 60 cm, has wake effects that are small compared to the other linacs, and will not be discussed.) In this report we limit our study to trains of equally populated, equally spaced bunches with a total length of less than 100 ns. The charge of each bunch is eN{sub b} = 250 pC.

Bane, K; /SLAC

2011-10-17T23:59:59.000Z

316

MAGNETIC CONFINEMENT OF AN EXPANDING LASER-PRODUCED PLASMA M. S. Tillack, S. S. Harilal, F. Najmabadi and J. O'Shay  

E-Print Network (OSTI)

- sions has been considered from the early days of IFE power plant research1 . It has been postulated2 direction. Plasma was produced using pulses from a Q-switched Nd:YAG laser supplying power density appeared to be insensitive to the field strength as well. The experimental linear growth rate

Tillack, Mark

317

Comment on ''Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding'' [Phys. Plasmas 17, 093103 (2010)  

Science Conference Proceedings (OSTI)

The chaotic electron dynamics in a free-electron laser with electromagnetic-wave wiggler and ion-channel has been recently reported by A. Taghavi et al.[Phys. Plasmas 17, 093103 (2010)]. We comment on the authors use of a set of initial condition that is not correct based on the dispersion relation and steady-state orbits.

Nasr, N.; Hasanbeigi, A. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

2011-05-15T23:59:59.000Z

318

Absolutely Calibrated Vacuum Ultraviolet Spectra in the 150 nm to 250 nm Range from Plasmas Generated by the NIKE KrF Laser  

E-Print Network (OSTI)

Generated by the NIKE KrF Laser J. F. Seely Space Science Division, Naval Research Laboratory, Washington DC. Lehmberg Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 Benjawan were recorded with a protective window between the target and the spectrometer slit

319

Study of nonlinear ohmic heating and ponderomotive force effects on the self-focusing and defocusing of Gaussian laser beams in collisional underdense plasmas  

Science Conference Proceedings (OSTI)

In the present paper, the propagation characteristics of a linearly polarized gaussian laser beam in a non-isothermal underdense collisional plasma is studied. By considering the effects of the ponderomotive force and ohmic heating of plasma electrons as the nonlinear mechanisms, the second order differential equation of the dimensionless beam width parameter has been obtained and solved at several initial ion temperatures. Furthermore, by using the nonlinear dielectric permittivity of the mentioned plasma medium in the paraxial approximation and its dependence on the propagation characteristics of the gaussian laser pulse, the perturbed electron density n{sub e}/n{sub 0e} is obtained and its variation in terms of the dimensionless plasma length is analyzed at different initial ion temperatures. Our results show that the dimensionless beam width parameter is strongly influenced by the initial plasma ion temperature. It is found that, for the self-focusing regime, the plasma electron density perturbation continuously oscillates between the initial density distribution and a minimum, and for the defocusing regime, the plasma electron density perturbation continuously oscillates between the initial density distribution and a maximum.

Etehadi Abari, M.; Shokri, B. [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of)

2012-11-15T23:59:59.000Z

320

Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses  

SciTech Connect

Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

2013-05-13T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Start-to-end beam dynamics simulation of double triangular current profile generation in Argonne Wakefield Accelerator  

Science Conference Proceedings (OSTI)

Double triangular current profile (DT) gives a high transformer ratio which is the determining factor of the performance of collinear wakefield accelerator. This current profile can be generated using the emittance exchange (EEX) beam line. Argonne Wakefield Accelerator (AWA) facility plans to generate DT using the EEX beam line. We conducted start-to-end simulation for the AWA beam line using PARMELA code. Also, we discuss requirements of beam parameters for the generation of DT.

Ha, G.; Power, J.; Kim, S. H.; Gai, W.; Kim, K.-J.; Cho, M. H.; Namkung, W. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of)

2012-12-21T23:59:59.000Z

322

Three-halves harmonic emission from a laser filament in a plasma channel  

SciTech Connect

A self-trapped laser filament is susceptible to decay-producing radially localized Langmuir waves. A nonlinear interaction of the pump wave with the density oscillation at the Langmuir frequency gives rise to three-halves harmonic emissions. Using a basis-function expansion technique, the emitted power in the backward direction is obtained. It decreases with the increasing size of the filament.

Mishra, G.; Talukdar, I.; Tripathi, V.; Tripathi, V.K. (Indian Inst. of Tech., New Delhi (India). Dept. of Physics)

1989-12-01T23:59:59.000Z

323

Effect of plasma density scale length on the properties of bremsstrahlung x-ray sources created by picosecond laser pulses  

Science Conference Proceedings (OSTI)

Results of an experimental study of multi-MeV bremsstrahlung x-ray sources created by picosecond laser pulses are presented. The x-ray source is created by focusing the short pulse in an expanding plasma obtained by heating a solid target with a time-delayed nanosecond laser beam. The high-energy part of the x-ray spectrum and emission lobe are inferred from photonuclear activation techniques. The x-ray dose is measured with silicon diodes. Two-dimensional images of the source are reconstructed from a penumbral imaging technique. These results indicate the creation of a relatively small source, below 200 {mu}m diameter, delivering doses up to 12 mrad in air at 1 m with x-ray temperature up to 2.8 MeV. The diagnostics used give access to a whole set of coherent experimental results on the x-ray source properties which are compared to extensive numerical simulations. X-ray intensity and temperature are found to increase with the size of the preplasma.

Courtois, C.; Compant La Fontaine, A.; Landoas, O.; Lidove, G.; Meot, V.; Morel, P.; Nuter, R.; Lefebvre, E. [CEA, DAM, DIF, F-91297 Arpajon (France); Boscheron, A.; Grenier, J. [CEA, DAM, CESTA, F-33114 Le Barp (France); Aleonard, M. M.; Gerbaux, M.; Gobet, F.; Hannachi, F.; Malka, G.; Scheurer, J. N.; Tarisien, M. [Universite de Bordeaux, Centre d'Etudes Nucleaires Bordeaux Gradignan, UMR 5797 CNRS/IN2P3, Gradignan F-33175 (France)

2009-01-15T23:59:59.000Z

324

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths  

SciTech Connect

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15T23:59:59.000Z

325

Synthesis of higher diamondoids by pulsed laser ablation plasmas in supercritical CO{sub 2}  

Science Conference Proceedings (OSTI)

Pulsed laser ablation (wavelength 532 nm; fluence 18 J/cm{sup 2}; pulse width 7 ns; repetition rate 10 Hz) of highly oriented pyrolytic graphite was conducted in adamantane-dissolved supercritical CO{sub 2} with and without cyclohexane as a cosolvent. Micro-Raman spectroscopy of the products revealed the presence of hydrocarbons possessing sp{sup 3}-hybridized carbons similar to diamond structures. The synthesis of diamantane and other possible diamondoids consisting of up to 12 cages was confirmed by gas chromatography-mass spectrometry. Furthermore, gas chromatography-mass spectrometry measurements of samples before and after pyrolysis treatment indicate the synthesis of the most compact decamantane, namely, superadamantane. It is thought that oxidant species originating from CO{sub 2} during pulsed laser ablation might lead to the selective dissociation of C-H bonds, enabling the synthesis of low H/C ratio molecules. Therefore, laser ablation in supercritical CO{sub 2} is proposed as a practical method for synthesizing diamondoids.

Nakahara, Sho; Stauss, Sven; Kato, Toru; Terashima, Kazuo [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561 Chiba (Japan); Sasaki, Takehiko [Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561 Chiba (Japan)

2011-06-15T23:59:59.000Z

326

Numerical Verification of the Power Transfer and Wakefield Coupling in the Clic Two-Beam Accelerator  

SciTech Connect

The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator (TBA) concept envisions complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC's parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.

Candel, Arno; Li, Z.; Ng, C.; Rawat, V.; Schussman, G.; Ko, K.; /SLAC; Syratchev, I.; Grudiev, A.; Wuensch, W.; /CERN

2011-08-19T23:59:59.000Z

327

Electron acceleration & laser pulse compression using a laser...  

NLE Websites -- All DOE Office Websites (Extended Search)

acceleration & laser pulse compression using a laser-plasma accelerator Wednesday, August 14, 2013 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Andreas Walker, Oxford...

328

Analysis of a laser induced plasma in high pressure SF6 gas for high-voltage, high-current switching.  

E-Print Network (OSTI)

??The Laser Triggered Switch Program at Sandia National Laboratories is an intensive development study to understand and optimize the laser triggered gas switch (LTGS) for… (more)

Clark, Waylon

2007-01-01T23:59:59.000Z

329

Laser Plasma Interaction and Non-classical Properties of Radiation Field  

E-Print Network (OSTI)

We show by explicit calculations that non-classical states of the radiation field can be produced by allowing short term interaction between a coherent state of the radiation field with plasma. Whereas, long term interaction, which thermalizes the radiation field, can produce non-classical states of the radiation field only at sufficiently small temperatures. A measure of k-th order squeezing, stricter than the one proposed by Zhang et al, is used to check the emergence of squeezing. It is also shown that photons in the considered thermalized field would follow super-Poissonian statistics.

Aabhaas Vineet Mallik; Pratyay Ghosh; Ananda Dasgupta

2011-05-24T23:59:59.000Z

330

Advances in laser driven accelerator R&D  

E-Print Network (OSTI)

and Zgadzaj, R. , “Plasma Channels and Laser Pulse Tailoringfor GeV Laser-Plasma Accelerators,” in Advanced Acceleratormulti-terawatt ti:sapphire laser system for laser wake-?eld

Leemans, Wim

2004-01-01T23:59:59.000Z

331

Simulation of the excitation of quasi-plane wake waves in a plasma by a resonant sequence of laser pulses with a variable envelope  

SciTech Connect

Results are presented from full-scale numerical simulations of the excitation of wake waves by a sequence of weakly relativistic laser pulses in a subcritical plasma. Computations were carried out with a 2D3V version of the SUR-CA code that is based on the local-recursive nonlocal-asynchronous algorithm of the particle-in-cell method. The parameters of a train of laser pulses were chosen to correspond to the resonant excitation of the wake field. The curvature of the envelope of the pulses was chosen to depend on the number of the pulse in the train. Numerical simulations showed that there are plane waves during the first period of the plasma wave behind the pulse train.

Kalinnikova, E. I. [Moscow Engineering Physics Institute (Russian Federation); Levchenko, V. D. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation)

2008-04-15T23:59:59.000Z

332

Relativistic theory of frequency blue-shift of an intense ionizing laser beam in a plasma  

SciTech Connect

Frequency up-conversion of a laser beam causing gas ionization in a cavity is considered in a fully relativistic fashion. A simple ionization model, based on one-photon and multiphoton processes is used. A Vlasov fully nonlinear and ionization-model independent description is used in calculating the current which drives the wave equation for the electric field. The evolution of the wave frequency and its upshift are contrasted with those obtained in the nonrelativistic limit. It is found that the nonrelativistic treatment overestimates the frequency upshift by a factor more than two. Purely relativistic effects, such as a significant frequency modulation and a respective temporal pulse compression, are observed in the exact case.

Hizanidis, K.; Vomvoridis, J.L. [National Technical Univ. of Athens (Greece); Mendonca, J.T. [Instituto Superior Tecnico, Lisbon (Portugal). Dept. of Physics; Frantzeskakis, D.J. [Univ. of Athens (Greece). Dept. of Physics

1996-04-01T23:59:59.000Z

333

Polarisation response of a gas medium in the field of a high-intensity ultrashort laser pulse: high order Kerr nonlinearities or plasma electron component?  

SciTech Connect

The polarisation response of quantum systems modelling silver and xenon atoms in the field of a high-intensity femtosecond Ti : sapphire laser (photon energy h{omega} Almost-Equal-To 1.5 eV), has been investigated by direct numerical integration of the Schroedinger equation. The applicability ranges of the perturbation theory and polarisation expansion in powers of field are determined. The contributions of excited atoms and electrons in the continuous-spectrum states to the polarisation response at the fundamental frequency, which arise as a result of excitation and photoionisation, are analysed. It is shown that specifically ionisation changes the sign of dielectric susceptibility with an increase in radiation intensity for the systems under consideration. (interaction of laser radiation with matter. laser plasmas)

Volkova, E A; Popov, Alexander M; Tikhonova, O V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2012-08-31T23:59:59.000Z

334

High average power CW FELs (Free Electron Laser) for application to plasma heating: Designs and experiments  

SciTech Connect

A short period wiggler (period {approximately} 1 cm), sheet beam FEL has been proposed as a low-cost source of high average power (1 MW) millimeter-wave radiation for plasma heating and space-based radar applications. Recent calculation and experiments have confirmed the feasibility of this concept in such critical areas as rf wall heating, intercepted beam ( body'') current, and high voltage (0.5 - 1 MV) sheet beam generation and propagation. Results of preliminary low-gain sheet beam FEL oscillator experiments using a field emission diode and pulse line accelerator have verified that lasing occurs at the predicted FEL frequency. Measured start oscillation currents also appear consistent with theoretical estimates. Finally, we consider the possibilities of using a short-period, superconducting planar wiggler for improved beam confinement, as well as access to the high gain, strong pump Compton regime with its potential for highly efficient FEL operation.

Booske, J.H.; Granatstein, V.L.; Radack, D.J.; Antonsen, T.M. Jr.; Bidwell, S.; Carmel, Y.; Destler, W.W.; Latham, P.E.; Levush, B.; Mayergoyz, I.D.; Zhang, Z.X. (Maryland Univ., College Park, MD (USA). Lab. for Plasma Research); Freund, H.P. (Science Applications International Corp., McLean, VA (USA))

1989-01-01T23:59:59.000Z

335

Absolute energy calibration for relativistic electron beams with pointing instability from a laser-plasma accelerator  

Science Conference Proceedings (OSTI)

The pointing instability of energetic electron beams generated from a laser-driven accelerator can cause a serious error in measuring the electron spectrum with a magnetic spectrometer. In order to determine a correct electron spectrum, the pointing angle of an electron beam incident on the spectrometer should be exactly defined. Here, we present a method for absolutely calibrating the electron spectrum by monitoring the pointing angle using a scintillating screen installed in front of a permanent dipole magnet. The ambiguous electron energy due to the pointing instability is corrected by the numerical and analytical calculations based on the relativistic equation of electron motion. It is also possible to estimate the energy spread of the electron beam and determine the energy resolution of the spectrometer using the beam divergence angle that is simultaneously measured on the screen. The calibration method with direct measurement of the spatial profile of an incident electron beam has a simple experimental layout and presents the full range of spatial and spectral information of the electron beams with energies of multi-hundred MeV level, despite the limited energy resolution of the simple electron spectrometer.

Cha, H. J.; Choi, I. W.; Kim, H. T.; Kim, I J.; Nam, K. H.; Jeong, T. M.; Lee, J. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

2012-06-15T23:59:59.000Z

336

Plasma-based accelerator structures  

E-Print Network (OSTI)

Particle Beam Dynamics in. a Hollow Plasma Channel 3.1Structure of the Hollow Plasma Channel . . . . 2.2.1 ChannelLimit . . 5.2.6 Laser-Plasma Instabilities . . . 5.3

Schroeder, C.B.

2011-01-01T23:59:59.000Z

337

Measurement of H and H/sub 2/ populations in-situ in a low-temperature plasma by vacuum-ultraviolet laser-absorption spectroscopy  

DOE Green Energy (OSTI)

A new technique, vacuum-ultraviolet laser-absorption spectroscopy, has been developed to quantitatively determine the absolute density of H and H/sub 2/ within a plasma. The technique is particularly well suited to measurement in a plasma, where high charged particle and photon background complicate other methods of detection. The high selectivity and sensitivity of the technique allows for the measurement of the rotational-vibrational state distribution of H/sub 2/ as well as the translational temperature of the atoms and molecules. The technique has been used to study both pulsed and continuous H/sup /minus// ion-source plasma discharges. H/sub 2/ state distributions in a multicusp ''volume'' H/sup /minus// ion- source plasma show a high degree of internal excitation, with levels up to v = 5 and J = 8 being observed. The method is applicable for a very wide range of plasma conditions. Emission measurements from excited states of H are also reported. 17 refs., 9 figs.

Schlachter, A.S.; Young, A.T.; Stutzin, G.C.; Stearns, J.W.; Doebele, H.G.; Leung, K.N.; Kunkel, W.B.

1988-12-01T23:59:59.000Z

338

The ion acoustic decay instability in a large scale, hot plasma relevant to direct drive laser fusion -- Application to a critical surface diagnostic. Final report  

SciTech Connect

The authors have studied the ion acoustic decay instability in a large ({approximately} 1 mm) scale, hot ({approximately} 1 keV) plasma, which is relevant to a laser fusion reactor target. They have shown that the instability threshold is low. They have developed a novel collective Thomson scattering diagnostic at a 90{degree} scattering angle. The scattering is nonetheless coherent, because of the modest ratio of the frequency of the probe laser to that of the pump laser, such that even for such a large angle, (k{lambda}{sub De}){sup 2} is much less than one. With this system they have measured the electron plasma wave excited by the ion acoustic decay instability near the critical density (n{sub e} {approximately} 0.86 n{sub c}). This allows them to use the frequency of the detected wave to measure the electron temperature in the interaction region, obtaining a result reasonably close to that predicted by the SAGE computer code.

Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.; Craxton, R.S.; Estabrook, K.G.

1996-08-01T23:59:59.000Z

339

Optimizing electron-positron pair production on kilojoule-class high-intensity lasers for the purpose of pair-plasma creation  

Science Conference Proceedings (OSTI)

Expressions for the yield of electron-positron pairs, their energy spectra, and production rates have been obtained in the interaction of multi-kJ pulses of high-intensity laser light interacting with solid targets. The Bethe-Heitler conversion of hard x-ray bremsstrahlung [D. A. Gryaznykh, Y. Z. Kandiev, and V. A. Lykov, JETP Lett. 67, 257 (1998); K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505 (2002)] is shown to dominate over direct production (trident process) [E. P. Liang, S. C. Wilks, and M. Tabak, Phys. Rev. Lett. 81, 4887 (1998)]. The yields and production rates have been optimized as a function of incident laser intensity by the choice of target material and dimensions, indicating that up to 5x10{sup 11} pairs can be produced on the OMEGA EP laser system [L. J. Waxer et al., Opt. Photonics News 16, 30 (2005)]. The corresponding production rates are high enough to make possible the creation of a pair plasma.

Myatt, J.; Delettrez, J. A.; Maximov, A. V.; Meyerhofer, D. D.; Short, R. W.; Stoeckl, C.; Storm, M. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2009-06-15T23:59:59.000Z

340

Energy spread reduction of electron beams produced via laser wakefield acceleration  

E-Print Network (OSTI)

The energy in each pulse entering the regenerative ampli?erenergy to 250 mJ. The Ti:Sapphire crystal in the regenerative (

Pollock, Bradley Bolt

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Energy Spread Reduction of Electron Beams Produced via Laser Wake  

Science Conference Proceedings (OSTI)

Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give >1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3 x 10{sup 18} cm{sup -3} in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a limited, defined region. Using this technique a 460 MeV electron beam was produced with an energy spread of 5%. This technique is directly scalable to multi-GeV electron beam generation with sub-percent energy spreads.

Pollock, B

2012-03-19T23:59:59.000Z

342

High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL  

Science Conference Proceedings (OSTI)

Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in {approx}33 cm DWA tubes. In the nearer term before FACET's commissioning, we are planning measurements at the BNL ATF, in which we drive {approx}50-200 MV/m fields with single pulses or pulse trains. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for efficient operation with pulse trains.

Rosenzweig, James; /UCLA; Travish, Gil; /UCLA; Hogan, Mark; /SLAC; Muggli, Patric; /Southern California U.

2012-07-05T23:59:59.000Z

343

LASER ABLATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY STUDY AT THE 222-S LABORATORY USING HOT-CELL GLOVE BOX PROTOTYPE SYSTEM  

SciTech Connect

This report describes the installation, testing, and acceptance of the Waste Treatment and Immobilization Plant (WTP) procured laser ablation-inductively coupled plasma-atomic emission spectroscopy (LA-ICP-AES) system for remotely analyzing high-level waste (HLW) samples in a hot cell environment. The work was completed by the Analytical Process Development (APD) group in accordance with Task Order 2005-003; ATS MP 1027, Management Plan for Waste Treatment Plant Project Work Performed by Analytical Technical Services. The APD group at the 222-S Laboratory demonstrated acceptable turnaround time (TAT) and provide sufficient data to assess sensitivity, accuracy, and precision of the LA-ICP-AES method.

SEIDEL CM; JAIN J; OWENS JW

2009-02-23T23:59:59.000Z

344

LASER ABLATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY STUDY AT THE 222-S LABORATORY USING HOT-CELL GLOVE BOX PROTOTYPE SYSTEM  

SciTech Connect

This report describes the installation, testing and acceptance of the Waste Treatment and Immobilization Plant procured laser ablation-inductively coupled plasma-atomic emission spectroscopy (LA-ICP-AES) system for remotely analyzing high-level waste samples in a hot cell environment. The 2005-003; ATS MP 1027, Management Plan for Waste Treatment Plant Project Work Performed by Analytical Technical Services. The APD group at the 222-S laboratory demonstrated acceptable turnaround time (TAT) and provide sufficient data to assess sensitivity, accuracy, and precision of the LA-ICP-AES method.

LOCKREM LL; OWENS JW; SEIDEL CM

2009-03-26T23:59:59.000Z

345

Laser research shows promise for cancer treatment  

NLE Websites -- All DOE Office Websites (Extended Search)

treatment Laser research shows promise for cancer treatment Scientists have observed for the first time how a laser penetrates dense, electron-rich plasma to generate ions. August...

346

Ultra high-gradient energy loss by a pulsed electron beam in a plasma  

SciTech Connect

The plasma wake-field mechanism can be used to couple energy at a high rate from a bunched electron beam into a plasma wave. We will present results from the Fermilab A0 facility where a beam with an initial energy of 14 MeV passes through the plasma to emerge with a much broader energy spread, spanning from a low of 3 MeV to a high of over 20 MeV. Over the 8 cm length of the 10{sup 14} cm{sup -3} plasma, this implies a 140 MeV/m deceleration and 72 MeV/m acceleration gradient.

Nikolai Barov et al.

2001-12-19T23:59:59.000Z

347

The ion acoustic decay instability, and anomalous laser light absorption for the OMEGA upgrade, large scale hot plasma application to a critical surface diagnostic, and instability at the quarter critical density. Final report  

SciTech Connect

It is shown that laser light can be anomalously absorbed with a moderate intensity laster (I{lambda}{sup 2}{approx}10{sup 14} W/cm{sup 2}-{mu}m{sup 2}) in a large scale, laser produced plasma. The heating regime, which is characterized by a relatively weak instability in a large region, is different from the regime studied previously, which is characterized by a strong instability in a narrow region. The two dimensional geometrical effect (lateral heating) has an important consequence on the anomalous electron heating. The characteristics of the IADI, and the anomalous absorption of the laser light were studied in a large scale, hot plasma applicable to OMEGA upgrade plasma. These results are important for the diagnostic application of the IADI.

Mizuno, K.; DeGroot, J.S.; Seka, W. [and others

1996-11-01T23:59:59.000Z

348

Laser Shock Processing of Metallic Materials: Coupling of Laser-Plasma Interaction and Material Behaviour Models for the Assessment of Key Process Issues  

SciTech Connect

Profiting by the increasing availability of laser sources delivering intensities above 109 W/cm{sup 2} with pulse energies in the range of several Joules and pulse widths in the range of nanoseconds, laser shock processing (LSP) is consolidating as an effective technology for the improvement of surface mechanical and corrosion resistance properties of metals. The main advantage of the laser shock processing technique consists on its capability of inducing a relatively deep compression residual stresses field into metallic alloy pieces allowing an improved mechanical behaviour, explicitly, the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Although significant work from the experimental side has been contributed to explore the optimum conditions of application of the treatments and to assess their ultimate capability to provide enhanced mechanical behaviour to work-pieces of typical materials, only limited attempts have been developed in the way of full comprehension and predictive assessment of the characteristic physical processes and material transformations with a specific consideration of real material properties. In the present paper, a review on the physical issues dominating the development of LSP processes from a high intensity laser-matter interaction point of view is presented along with the theoretical and computational methods developed by the authors for their predictive assessment and practical results at laboratory scale on the application of the technique to different materials.

Ocana, J. L.; Morales, M.; Molpeceres, C.; Porro, J. A. [Centro Laser UPM. Universidad Politecnica de Madrid, Campus Sur UPM. Edificio La Arboleda. Ctra. de Valencia, km. 7.3. 28031 Madrid (Spain)

2010-10-08T23:59:59.000Z

349

INTERACTION OF MUON BEAM WITH PLASMA DEVELOPED DURING IONIZATION COOLING  

Science Conference Proceedings (OSTI)

Particle-in-cell simulations involving the interaction of muon beam (peak density 10{sup 18} m{sup 3}) with Li plasma (ionized medium) of density 10{sup 16}-10{sup 22} m{sup -3} have been performed. This study aimed to understand the effects of plasma on an incoming beam in order to explore scenario developed during the process of ionization cooling. The computer code takes into account the self-consistent electromagnetic effects of beam interacting with plasma. This study shows that the beam can pass through the plasma of densities four order of magnitude higher than its peak density. The low density plasmas are wiped out by the beam, however, the resonance is observed for densities of similar order. Study reveals the signature of plasma wakefield acceleration.

S. Ahmed, D. Kaplan, T. Roberts, L. Spentzouris, K. Beard

2012-07-01T23:59:59.000Z

350

Breakdown Limits on Gigavolt-per-Meter Electron-Beam-Driven Wakefields in Dielectric Structures  

SciTech Connect

First measurements of the breakdown threshold in a dielectric subjected to GV/m wakefields produced by short (30-330 fs), 28.5 GeV electron bunches have been made. Fused silica tubes of 100 {micro}m inner diameter were exposed to a range of bunch lengths, allowing surface dielectric fields up to 27 GV/m to be generated. The onset of breakdown, detected through light emission from the tube ends, is observed to occur when the peak electric field at the dielectric surface reaches 13.8 {+-} 0.7 GV/m. The correlation of structure damage to beam-induced breakdown is established using an array of postexposure inspection techniques.

Thompson, M.C.; /UCLA /LLNL, Livermore; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; /UCLA; Blumenfeld, I.; Hogan, M.J.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Muggli, P.; /Southern California U.; Scott, A.; /UC, Santa Barbara; Yoder, R.B.; /Manhattan Coll., Riverdale

2008-06-17T23:59:59.000Z

351

Three regimes of relativistic beam - plasma interaction  

SciTech Connect

Three regimes of relativistic beam - plasma interaction can in principle be reached at the ATF depending on the relative transverse and longitudinal size of the electron bunch when compared to the cold plasma collisionless skin depth c?{omega}{sub pe}: the plasma wakefield accelerator (PWFA), the self-modulation instability (SMI), and the current filamentation instability (CFI) regime. In addition, by choosing the bunch density, the linear, quasi-nonlinear and non linear regime of the PWFA can be reached. In the case of the two instabilities, the bunch density determines the growth rate and therefore the occurrence or not of the instability. We briefly describe these three regimes and outline results demonstrating that all these regime have or will be reached experimentally. We also outline planned and possible follow-on experiments.

Muggli, P.; Allen, B.; Fang, Y.; Yakimenko, V.; Babzien, M.; Kusche, K.; Fedurin, M.; Vieira, J.; Martins, J.; Silva, L. [Max Planck Institute for Physics, 80805 Munich (Germany) and University of Southern California, Los Angeles, CA 90089 (United States); University of Southern California, Los Angeles, CA 90089 (United States); Brookhaven National Laboratory, Upton, NY 11973 (United States); GoLP/Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado Instituto Superior Tecnico (IST), Technical University of Lisbon, Lisboa (Portugal)

2012-12-21T23:59:59.000Z

352

Role of cavitons in laser-plasma interactions: Final report for the period August 15, 1984-August 14, 1985  

Science Conference Proceedings (OSTI)

We have observed three new phenomena associated with cavitons generated at the critical layer in an inhomogeneous plasma. Half-harmonic ((1/2)..omega../sub 0/, (3/2)..omega../sub 0/, etc.) electromagnetic (em) radiation, accompanying the resonant absorption of the high-power microwave at ..omega../sub 0/ by an inhomogeneous plasma, appears to originate from the cavitons. Double layers have been found to develop near the locations of cavitons. Acceleration of ions by these double layers has also been observed. The evolution of resonantly excited electron plasma waves and density profile modification at the critical layer has been studied in detail. Conditions under which the role of cavitons becomes significant in em wave-plasma interactions are discussed.

Wong, A.Y.; Tanikawa, T.

1986-09-01T23:59:59.000Z

353

Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays  

E-Print Network (OSTI)

by an intense ultrashort laser pulse,” Science, vol. 298,generated from intense laser-plasma interactions,” Appl.monochromatic x-rays in the laser synchrotron source

2004-01-01T23:59:59.000Z

354

Nanosecond component in a femtosecond laser pulse  

Science Conference Proceedings (OSTI)

Experimental and computational results show that the coherent microwave scattering from a laser-induced plasma can be used for measuring the quality of a fs laser pulse. The temporal dynamics of the microwave scattered signal from the fs-laser induced plasma can be related to the effect of nanosecond tail of the fs laser pulse.

Shneider, M. N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Semak, V. V. [ARL, Pennsylvania State University, University Park, Pennsylvania 16801 (United States); Zhang Zhili [Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2012-11-15T23:59:59.000Z

355

Laser ablation-inductively coupled plasma-mass spectrometry: Examinations of the origins of polyatomic ions and advances in the sampling of particulates  

SciTech Connect

This dissertation provides a general introduction to Inductively coupled plasma-mass spectrometry (ICP-MS) and laser ablation (LA) sampling, with an examination of analytical challenges in the employment of this technique. It discusses the origin of metal oxide ions (MO+) in LA-ICP-MS, as well as the effect of introducing helium and nitrogen to the aerosol gas flow on the formation of these polyatomic interferences. It extends the study of polyatomic ions in LA-ICP-MS to metal argide (MAr+) species, an additional source of possible significant interferences in the spectrum. It describes the application of fs-LA-ICP-MS to the determination of uranium isotope ratios in particulate samples.

Witte, Travis

2011-11-30T23:59:59.000Z

356

Positron Beam Propagation in a Meter Long Plasma Channel  

SciTech Connect

Recent experiments and simulations have shown that positron beams propagating in plasmas can be focused and also create wakes with large accelerating gradients. For similar parameters, the wakes driven by positron beams are somewhat smaller compared to the case of an electron beam. Simulations have shown that the wake amplitude can be increased if the positron beam is propagated in a hollow plasma channel (Ref. 1). This paper, compares experimentally, the propagation and beam dynamics of a positron beam in a meter scale homogeneous plasma, to a positron beam hollow channel plasma. The results show that positron beams in hollow channels are less prone to distortions and deflections. Hollow channels were observed to guide the positron beam onto the channel axis. Beam energy loss was also observed implying the formation of a large wake amplitude. The experiments were carried out as part of the E-162 plasma wakefield experiments at SLAC.

Marsh, K.A.; Blue, B.E.; Clayton, C.E.; Joshi, C.; Mori, W.B.; /UCLA; Decker, F.-J.; Hogan, M.J.; Iverson, R.; O' Connell, C.; Raimondi, P.; Siemann, Robert H.; Walz, D.; /SLAC; Katsouleas, T.C.; Muggli, P.; /Southern California U.

2008-03-17T23:59:59.000Z

357

Design of a 50 TW/20 J chirped-Pulse Amplification Laser for High-Energy-Density Plasma Physics Experiments at the Nevada Terawatt Facility of the University of Nevada  

DOE Green Energy (OSTI)

We have developed a conceptual design for a 50 TW/20 J short-pulse laser for performing high-energy-density plasma physics experiments at the Nevada Terawatt Facility of the University of Nevada, Reno. The purpose of the laser is to develop proton and x-ray radiography techniques, to use these techniques to study z-pinch plasmas, and to study deposition of intense laser energy into both magnetized and unmagnetized plasmas. Our design uses a commercial diode-pumped Nd:glass oscillator to generate 3-nJ. 200-fs mode-locked pulses at 1059 m. An all-reflective grating stretcher increases pulse duration to 1.1 ns. A two-stage chirped-pulse optical parametric amplifier (OPCPA) using BBO crystals boosts pulse energy to 12 mJ. A chain using mixed silicate-phosphate Nd:glass increases pulse energy to 85 J while narrowing bandwidth to 7.4 nm (FWHM). About 50 J is split off to the laser target chamber to generate plasma while the remaining energy is directed to a roof-mirror pulse compressor, where two 21 cm x 42 cm gold gratings recompress pulses to {approx}350 fs. A 30-cm-focal-length off-axis parabolic reflector (OAP) focuses {approx}20 J onto target, producing an irradiance of 10{sup 19} W/cm{sup 2} in a 10-{micro}m-diameter spot. This paper describes planned plasma experiments, system performance requirements, the laser design, and the target area design.

Erlandson, A C; Astanovitskiy, A; Batie, S; Bauer, B; Bayramian, A; Caird, J A; Cowan, T; Ebbers, C; Fuchs, J; Faretto, H; Glassman, J; Ivanov, V; LeGalloudec, B; LeGalloudec, N; Letzring, S; Payne, S; Stuart, B

2003-09-07T23:59:59.000Z

358

Plasma-based accelerator structures  

SciTech Connect

Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

Schroeder, Carl B.

1999-12-01T23:59:59.000Z

359

Laser-fusion program. Semiannual report, January--June 1973  

SciTech Connect

Brief discussions are given for each of the following areas of research covered during this report period: solid-state laser program, design analysis, component development, diagnostics, gas lasers, chemical lasers---the iodine laser, basic studies and advanced concepts, laser propagation, laser plasmas, laser fusion, isotope separation, and program resources. (MOW)

Sussman, S.S. (ed.)

1973-08-22T23:59:59.000Z

360

Electron Self-Injection into an Evolving Plasma Bubble: The Way to a Dark Current Free GeV-Scale Laser Accelerator  

Science Conference Proceedings (OSTI)

A time-varying electron density bubble created by the radiation pressure of a tightly focused petawatt laser pulse traps electrons of ambient rarefied plasma and accelerates them to a GeV energy over a few-cm distance. Expansion of the bubble caused by the shape variation of the self-guided pulse is the primary cause of electron self-injection in strongly rarefied plasmas (n{sub e{approx}}10{sup 17} cm{sup -3}). Stabilization and contraction of the bubble extinguishes the injection. After the bubble stabilization, longitudinal non-uniformity of the accelerating gradient results in a rapid phase space rotation that produces a quasi-monoenergetic bunch well before the de-phasing limit. Combination of reduced and fully self-consistent (first-principle) 3-D PIC simulations complemented with the Hamiltonian diagnostics of electron phase space shows that the bubble dynamics and the self-injection process are governed primarily by the driver evolution; collective transverse fields of the trapped electron bunch reduce the accelerating gradient, slow down phase space rotation, and result in a formation of monoenergetic electron beam with higher energy than test-particle modeling predicts.

Kalmykov, S. Y.; Shadwick, B. A. [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588-0299 (United States); Beck, A.; Lefebvre, E. [CEA, DAM, DIF, Bruyeres-le-Chatel, 91297 Arpajon Cedex (France); Yi, S. A.; Khudik, V.; Downer, M. C. [Department of Physics, C1500, University of Texas at Austin, Austin, TX 78712 (United States)

2010-11-04T23:59:59.000Z

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361

Wim Leemans, 2009 | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

2000's Wim Leemans, 2009 Print Text Size: A A A RSS Feeds FeedbackShare Page High Energy and Nuclear Physics: For breakthrough work in developing the laser plasma wakefield...

362

Theoretical Investigations of Plasma-Based Accelerators and Other Advanced Accelerator Concepts  

SciTech Connect

Theoretical investigations of plasma-based accelerators and other advanced accelerator concepts. The focus of the work was on the development of plasma based and structure based accelerating concepts, including laser-plasma, plasma channel, and microwave driven plasma accelerators.

Shuets, G.

2004-05-21T23:59:59.000Z

363

Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities  

SciTech Connect

In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

Bane, K.L.F.; Adolphsen, C.; Li, Z.; /SLAC; Dohlus, M.; Zagorodnov, I.; /DESY; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; /Fermilab; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

2008-07-07T23:59:59.000Z

364

The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment  

SciTech Connect

An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC/USC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {delta}{sub z} = 20 {micro}m at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields.

Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; /UCLA; Hogan, M.; Ischebec, R.; Siemann, R.; Walz, D.; /SLAC; Scott, A.; /UC, Santa Barbara; Yoder, R.; /Manhattan Coll., Riverdale

2006-01-25T23:59:59.000Z

365

Carbon Isotope Separation and Molecular Formation in Laser-Induced...  

NLE Websites -- All DOE Office Websites (Extended Search)

Carbon Isotope Separation and Molecular Formation in Laser-Induced Plasmas by Laser Ablation Molecular Isotopic Spectrometry Title Carbon Isotope Separation and Molecular Formation...

366

Nonlinear increase in the interaction efficiency of a second pulse with a target upon excitation of a plasma by a train of pulses from a Nd:YAG laser  

SciTech Connect

The efficiency of hole drilling in an aluminium plate was studied experimentally upon excitation of a plasma on its surface in air by a train of pulses from a Nd:YAG laser, the interval between pulses being 15-20 {mu}s. It was found that the crater depth increases nonmonotonically with each successive pulse of the train. A nonlinear, more than by a factor of six, increase in the depth was detected upon interaction of the second pulse with the target. The mechanism explaining this increase in the interaction efficiency of the second pulse in the train with the target is proposed. (interaction of laser radiation with matter)

Pershin, Sergei M [Wave Research Centre, A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2009-01-31T23:59:59.000Z

367

Submillimeter-Resolution Radiography of Shielded Structures with Laser-Accelerated Electron Beams  

SciTech Connect

We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100 MeV) was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

Ramanathan, Vidya [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Cummingham, N. J. [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Zhao, Kun [University of Nebraska, Lincoln; Brown, Kevin [University of Nebraska, Lincoln; Umstadter, Donald [University of Nebraska, Lincoln; Clarke, Shaun [University of Michigan; Pozzi, Sara [University of Michigan; Beene, James R [ORNL; Vane, C Randy [ORNL; Schultz, David Robert [ORNL

2010-10-01T23:59:59.000Z

368

Guiding of Intense Laser Pulses in Efficient End-pumped Plasma Channels Generated by Self-guiding in Ar and H2 Clusters  

Science Conference Proceedings (OSTI)

We demonstrate that self-guiding of intense short pulses in clustered gases can be utilized to generate long plasma channels, which upon expansion form waveguides suitable for propagation of laser pulses at high intensity. This scheme has several advantages over waveguide-generation in non-clustered gases. The absorption of energy by the target depends on the size of the clusters and not on the average density of the gas, which allows greater control of the density encountered by the guided pulse. In particular, electron densities less than 1018 cm-3 are feasible. Moreover, since clusters absorb sub-picosecond pulses very efficiently, channel generation by an auxiliary long-pulse laser is no longer necessary and a considerably simpler setup suffices. The problem of taper at the channel entrance, an old bugbear of side-pumped waveguides in gases, is shown to be significantly reduced. Evidence will be presented of waveguide generation in gases of argon and hydrogen clusters, using different cryogenic sources. A slit source is used for argon, and waveguides 1017 Wcm-2 were guided. The results of a propagation code suggest that even longer channels are well within experimental reach. Argon, however, has the disadvantage that a super-intense pulse would likely produce further ionization, and hence suffer ionization induced defocusing. Hydrogen clusters, which can easily be fully ionized, were formed using a more efficient conical nozzle cooled to 90 K, limiting maximum waveguide lengths to < 3 mm. Though these channels are short, there is no obvious reason why a longer target would not allow longer waveguides to be generated, and the experiments demonstrate the utility of this novel scheme.

Kumarappan, V.; Kim, K.-Y.; Milchberg, H.M. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Antonsen, T.M. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States)

2004-12-07T23:59:59.000Z

369

Self-modulation of long electron beams in plasma at PITZ  

Science Conference Proceedings (OSTI)

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), offers the unique possibility to study and demonstrate the self-modulation of long electron bunches in plasma. A set of numerical simulations with the particle-in-cell code OSIRIS has been carried out for a better understanding of the process. Of particular interest is the measurement of the energy modulation induced to the beam itself by means of the generated wakefields in plasma. It will reflect the key properties of the accelerating electric fields such as their magnitude and their phase velocity, both of significant importance in the design of experiments relying on this technique.

Martinez de la Ossa, A.; Gross, M.; Gruener, F.; Khojoyan, M.; Krasilnikov, M.; Oppelt, A.; Stephan, F.; Schroeder, C. B.; Osterhoff, J. [Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany)

2012-12-21T23:59:59.000Z

370

STUDY OF PLASMA PHENOMENA AT HIGH ELECTRIC FIELDS IN APPLICATIONS FOR ACTIVE FLOW CONTROL AND ULTRA-SHORT PULSE LASER DRILLING.  

E-Print Network (OSTI)

??Plasma engineering is one of the most actively growing research areas in modern science. Over the past decade, plasma engineering became a significant part of… (more)

Likhanskii, Alexandre

2009-01-01T23:59:59.000Z

371

Interferometric measurements of plasma density in high-. beta. plasmas  

SciTech Connect

The coupled-cavity laser interferometer technique is particularly applicable to the measurement of pulsed plasma densities. This technique is based on the fact that if a small fraction of a gas laser's output radiation is reflected into the laser with an external mirror, the intensity of the laser output is modulated. These amplitude or intensity modulations are produced by changes in the laser gain. A rotating corner mirror or an oscillating mirror can be used to produce a continuous feedback modulation of the interferometer which produces a continuous background fringe pattern. The presence of plasma in the outer cavity causes an additional change which results in a phase shift of the regular period of the background fringe pattern. The integral of the plasma density along the line of sight can be evaluated by comparison of the time history of the fringes obtained with and without plasma.

Quinn, W.E.

1977-01-01T23:59:59.000Z

372

A new electron temperature diagnostic of critical surface based on the ion acoustic decay instability in hot, high density plasma relevant to laser fusion. Semiannual report, April 1--September 29, 1994  

Science Conference Proceedings (OSTI)

The authors made analysis of the IADI experiments previously made using OMEGA laser system. They obtained two important new results: the first direct observation of the epw excited by the Ion Acoustic Decay Instability, and the first study of the IADI in a plasma that approaches laser-fusion conditions, in the sense of having a density scale length of order 1 mm and an electron temperature, T{sub e}, in excess of 1 keV. Previous observations of the epw`s have been based on the second harmonic emission, from which little can be inferred because the emission is produced by unknown pairs of epw`s, integrated in a complicated way over wavenumber space and real space. In contrast, they have directly observed the epw by using the 90{degree}, collective Thomson scattering (CTS) of a UV laser (at the third harmonic of the pump) from the epw`s. Because the ratio of probe frequency to electron plasma frequency is only about three, the scattering is collective (i.e. k{sub epw}{lambda}{sub De} is small, where k{sub epw} is the epw wave number and {lambda}{sub De} is the Debye length),m even though the scattering angle is large. The electron temperature can then be deduced from the ion sound velocity, obtained from the measurement of the frequency at which growth is maximum at the scattering wavenumber.

Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.; Craxton, R.S.; Estabrook, K.G.

1994-12-31T23:59:59.000Z

373

ORION laser target diagnostics  

SciTech Connect

The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K. [Plasma Physics Department, Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); and others

2012-10-15T23:59:59.000Z

374

Visualization and Diagnostics of Thermal Plasma Flows  

Science Conference Proceedings (OSTI)

Flow visualization is a key tool for the study of thermal plasma flows. Because of their high temperature and associated self emission, standard and high speed photography is commonly used for flow and temperature field visualization. Tracer techniques ... Keywords: d.c. plasma jet, enthalpy probe techniques, induction plasma, laser strobe, photographic techniques, schlieren, thermal plasma flows

M. I. Boulos

2001-01-01T23:59:59.000Z

375

Current developments in laser ablation-inductively coupled plasma-mass spectrometry for use in geology, forensics, and nuclear nonproliferation research  

SciTech Connect

This dissertation focused on new applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The diverse fields that were investigated show the versatility of the technique. In Chapter 2, LA-ICP-MS was used to investigate the rare earth element (REE) profiles of garnets from the Broken Hill Deposit in New South Wales, Australia. The normalized REE profiles helped to shed new light on the formation of deposits of sulfide ores. This information may be helpful in identifying the location of sulfide ore deposits in other locations. New sources of metals such as Pg, Zn, and Ag, produced from these ores, are needed to sustain our current technological society. The application of LA-ICP-MS presented in Chapter 3 is the forensics analysis of automotive putty and caulking. The elemental analysis of these materials was combined with the use of Principal Components Analysis (PCA). The PCA comparison was able to differentiate the automotive putty samples by manufacturer and lot number. The analysis of caulk was able to show a differentiation based on manufacturer, but no clear differentiation was shown by lot number. This differentiation may allow matching of evidence in the future. This will require many more analyses and the construction of a database made up of many different samples. The 4th chapter was a study of the capabilities of LA-ICP-MS for fast and precise analysis of particle ensembles for nuclear nonproliferation applications. Laser ablation has the ability to spatially resolve particle ensembles which may contain uranium or other actinides from other particles present in a sample. This is of importance in samples obtained from air on filter media. The particle ensembles of interest may be mixed in amongst dust and other particulates. A problem arises when ablating these particle ensembles directly from the filter media. Dust particles other than ones of interest may be accidentally entrained in the aerosol of the ablated particle ensemble. This would cause the analysis to be skewed. The use of a gelatin substrate allows the ablation a particle ensemble without disturbing other particles or the gelatin surface. A method to trap and ablate particles on filter paper using collodion was also investigated. The laser was used to dig through the collodion layer and into the particle ensemble. Both of these methods fix particles to allow spatial resolution of the particle ensembles. The use of vanillic acid as a possible enhancement to ablation was also studied. A vanillic acid coating of the particles fixed on top of the gelatin substrate was not found to have any positive effect on either signal intensity or precision. The mixing of vanillic acid in the collodion solution used to coat the filter paper increased ablation signal intensity by a factor of 4 to 5. There was little effect on precision, though. The collodion on filter paper method and the gelatin method of resolving particles have shown themselves to be possible tools in fighting proliferation of nuclear weapons and material. Future applications of LA-ICP-MS are only limited by the imagination of the investigator. Any material that can be ablated and aerosolized is a potential material for analysis by LA-ICP-MS. Improvements in aerosol transport, ablation chamber design, and laser focusing can make possible the ablation and analysis of very small amounts of material. This may perhaps lead to more possible uses in forensics. A similar method to the one used in Chapter 3 could perhaps be used to match drug residue to the place of origin. Perhaps a link could be made based on the elements leached from the soil by plants used to make drugs. This may have a specific pattern based on where the plant was grown. Synthetic drugs are produced in clandestine laboratories that are often times very dirty. The dust, debris, and unique materials in the lab environment could create enough variance to perhaps match drugs produced there to samples obtained off the street. Even if the match was not strong enough to be evidence, the knowledge that many sa

Messerly, Joshua D.

2008-08-26T23:59:59.000Z

376

Charge state evolution and energy losses in a beam?plasma interaction experiment  

Science Conference Proceedings (OSTI)

To study the charge state and energy evolutions of heavy ions travelling through the laser created plasma

R. Dei?Cas; J. M. Guihaumé; M. Beau; M. A. Beuve; J. F. Glicenstein; J. P. Laget; C. Moreau; J. P. Mosnier; M. Renaud; R. Barchewitz; M. Cukier

1986-01-01T23:59:59.000Z

377

ccsd00001732, Development behavior of liquid plasma produced by  

E-Print Network (OSTI)

water with a melted NaCl is used as a test liquid. The liquid plasma is produced by the fundamental waveccsd­00001732, version 2 ­ 7 Nov 2004 Development behavior of liquid plasma produced by YAG laser the hazardous material called the environment material. Then, the plasma produced in liquid by the laser light

378

Observation of the scattering of a CO/sub 2/ laser beam by small-scale plasma waves in the FT-2 tokamak  

SciTech Connect

Scattering of a laser beam by fluctuations with a scale of 0.7-5mm in the frequency range 3-15 MHz in the FT-2 tokamak is observed. (AIP)

Askinazi, L.G.; Budnikov, V.N.; Bulanin, V.V.; Esipov, L.A.; Korneev, D.O.; Sakharov, I.E.; Stepanov, A.Y.; Ushakov, S.N.

1984-12-01T23:59:59.000Z

379

Master Thesis: Fusion Plasma Thermal Transport  

E-Print Network (OSTI)

Master Thesis: Fusion Plasma Thermal Transport Radial and Poloidal Profile Modeling Martin Olesen-axis localised ion cyclotron resonance heating source. 2. Cold pulse shock induction at the plasma edge via laser wave propagation from heat modulation and the fast propagation of a cold pulse, at the same plasma

380

Super-high density laser fusion CTR  

SciTech Connect

From sixth European conference on controlled fusion and plasma physics; Moscow, USSR (30 Jul 1973). A basic discussion of laser-induced fusion is presented. Implosion development and applications are described. Implosion and thermonuclear physics are discussed in some detail along with laser technology, laser fusion reactors, and fusion energy conversion. (MOW)

Thiessen, A.; Zimmerman, G.; Weaver, T.; Emmett, J.; Nuckolls, J.; Wood, L.

1973-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Laser Ignition  

NLE Websites -- All DOE Office Websites (Extended Search)

Ignition Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel...

382

Laser controlled flame stabilization  

DOE Patents (OSTI)

A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

Early, James W. (Los Alamos, NM); Thomas, Matthew E. (Huntsville, AL)

2001-01-01T23:59:59.000Z

383

Mobile inductively coupled plasma system  

DOE Patents (OSTI)

A system is described for sampling and analyzing a material located at a hazardous site. A laser located remotely from the hazardous site is connected to an optical fiber, which directs laser radiation proximate the material at the hazardous site. The laser radiation abates a sample of the material. An inductively coupled plasma is located remotely from the material. An aerosol transport system carries the ablated particles to a plasma, where they are dissociated, atomized and excited to provide characteristic optical reduction of the elemental constituents of the sample. An optical spectrometer is located remotely from the site. A second optical fiber is connected to the optical spectrometer at one end and the plasma source at the other end to carry the optical radiation from the plasma source to the spectrometer. 10 figs.

D`Silva, A.P.; Jaselskis, E.J.

1999-03-30T23:59:59.000Z

384

Bright High Average Power Table-top Soft X-Ray Lasers  

Science Conference Proceedings (OSTI)

We have demonstrated the generation of bright soft x-ray laser pulses with record-high average power from compact plasma amplifiers excited by ultrafast solid state lasers. These lasers have numerous applications in nanoscience and nanotechnology.

Rocca, Jorge [Colorado State University, Fort Collins; Reagan, Brendon [Colorado State University, Fort Collins; Wernsing, Keith [Colorado State University, Fort Collins; Luther, Brad [Colorado State University, Fort Collins; Curtis, Alden [Colorado State University, Fort Collins; Nichols,, Anthony [Colorado State University, Fort Collins; Wang, Yong [Colorado State University, Fort Collins; Alessi, David [Colorado State University, Fort Collins; Martz, Dale [Colorado State University, Fort Collins; Yin, Liang [Colorado State University, Fort Collins; Wang, Shoujun [Colorado State University, Fort Collins; Berrill, Mark A [ORNL; Furch, Federico [Colorado State University, Fort Collins; Woolston, Mark [Colorado State University, Fort Collins; Patel, Dinesh [Colorado State University, Fort Collins; Marconi, Mario [Colorado State University, Fort Collins; Menoni, Carmen [Colorado State University, Fort Collins

2012-01-01T23:59:59.000Z

385

Reserach activities of the institute of plasma research forschungsbericht 1976. Annual report, 1976  

SciTech Connect

The activities of the Plasma Research Institute of the University of Stuttgart during 1976 are described. Topics discussed, with emphasis on waves and plasma heating, are high voltage-belt-pinch plasmas, laser diagnostics, development of short duration pulse lasers, and plasma focus techniques.

1976-01-01T23:59:59.000Z

386

Plasma density gradient injection of low absolute momentum spread electron bunches  

E-Print Network (OSTI)

Esarey et al. , IEEE Trans. Plasma Sci. 24, 252 (1996). [3]G. R. Geddes et al. , Phys. Plasmas 12, 056709 (2005). [13]laser (A, red) drives a plasma density wake (grey) in the

Geddes, C.G.R.

2008-01-01T23:59:59.000Z

387

Plasma channel optical pumping device and method  

SciTech Connect

A device and method for optically pumping a gaseous laser using blackbody radiation produced by a plasma channel which is formed from an electrical discharge between two electrodes spaced at opposite longitudinal ends of the laser. A preionization device which can comprise a laser or electron beam accelerator produces a preionization beam which is sufficient to cause an electrical discharge between the electrodes to initiate the plasma channel along the preionization path. The optical pumping energy is supplied by a high voltage power supply rather than by the preionization beam. High output optical intensities are produced by the laser due to the high temperature blackbody radiation produced by the plasma channel, in the same manner as an exploding wire type laser. However, unlike the exploding wire type laser, the disclosed invention can be operated in a repetitive manner by utilizing a repetitive pulsed preionization device.

Judd, O' Dean P. (Los Alamos, NM)

1983-06-28T23:59:59.000Z

388

Transformer ratio improvement for beam based plasma accelerators  

SciTech Connect

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl [University of California, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); University of Southern California, Department of Electrical Engineering, Los Angeles, CA 90089 U.S.A. and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Accelerator Test Facility, Brookhaven National Lab, Upton, NY, 11973 (United States)

2012-12-21T23:59:59.000Z

389

Response to ''Comment on 'Chaotic electron trajectories in an electromagnetic wiggler free-electron laser with ion-channel guiding''' [Phys. Plasmas 17, 093103 (2010)  

Science Conference Proceedings (OSTI)

Nasr and Hasanbeigi in their comment [Phys. Plasmas 17, 093103 (2010)] have claimed that, in our recent paper [Phys. Plasmas 17, 093103 (2010)], incorrect initial conditions have been used based on dispersion relation (or normalized electromagnetic wave frequency {omega}{sub w}) and mean axial velocity {beta}{sub b}. We use a self-consistent method to calculate more accurate values of {omega}{sub w} and {beta}{sub b} and show that all results presented in our recent paper are correct.

Esmaeilzadeh, Mahdi; Taghavi, Amin [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of)

2011-05-15T23:59:59.000Z

390

Fast-ion spectrometry of ICF implosions and laser-foil experiments at the omega and MTW laser facilities  

E-Print Network (OSTI)

Fast ions generated from laser-plasma interactions (LPI) have been used to study inertial confinement fusion (ICF) implosions and laser-foil interactions. LPI, which vary in nature depending on the wavelength and intensity ...

Sinenian, Nareg

2013-01-01T23:59:59.000Z

391

Laser fusion experiments at LLL  

Science Conference Proceedings (OSTI)

These notes present the experimental basis and status for laser fusion as developed at LLL. Two other chapters, one authored by K.A. Brueckner and the other by C. Max, present the theoretical implosion physics and laser plasma interaction physics. The notes consist of six sections. The first is an introductory section which provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

Ahlstrom, H.G.

1980-06-16T23:59:59.000Z

392

Future scientific applications for high-energy lasers  

Science Conference Proceedings (OSTI)

This report discusses future applications for high-energy lasers in the areas of astrophysics and space physics; hydrodynamics; material properties; plasma physics; radiation sources; and radiative properties.

Lee, R.W. [comp.

1994-08-01T23:59:59.000Z

393

Commercial application of laser fusion  

SciTech Connect

The fundamentals of laser-induced fusion, some laser-fusion reactor concepts, and attendant means of utilizing the thermonuclear energy for commercial electric power generation are discussed. Theoretical fusion-pellet microexplosion energy release characteristics are described and the effects of pellet design options on pellet-microexplosion characteristics are discussed. The results of analyses to assess the engineering feasibility of reactor cavities for which protection of cavity components is provided either by suitable ablative materials or by diversion of plasmas by magnetic fields are presented. Two conceptual laser-fusion electric generating stations, based on different laser-fusion reactor concepts, are described.

Booth, L.A.

1976-01-01T23:59:59.000Z

394

Large-scale pulsed laser deposition Nini Pryds, AFM, Jrgen Schou, OPL, Finn Saxild, AFM and Sren Linderoth,AFM  

E-Print Network (OSTI)

; OPL, Department of Optics and Plasma Research) e-mail: j.schou@risoe.dk Pulsed laser deposition (PLD

395

Thomson scattering in short pulse laser experiments  

SciTech Connect

Thomson scattering is well used as a diagnostic in many areas of high energy density physics. In this paper, we quantitatively demonstrate the practicality of using Thomson scattering as a diagnostic of short-pulse laser-plasma experiments in the regime, where the plasmas probed are at solid density and have temperatures of many hundreds of eV using a backlighter produced with an optical laser. This method allows a diagnosis both spatially and temporally of the density and temperature distributions in high energy density laser-plasma interactions which is independent from, and would act as a useful complement to, the existing spectroscopic methods.

Hill, E. G.; Rose, S. J. [Plasma Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

2012-08-15T23:59:59.000Z

396

Princeton Plasma Physics Laboratory:  

SciTech Connect

This paper discusses progress on experiments at the Princeton Plasma Physics Laboratory. The projects and areas discussed are: Principal Parameters Achieved in Experimental Devices, Tokamak Fusion Test Reactor, Princeton Large Torus, Princeton Beta Experiment, S-1 Spheromak, Current-Drive Experiment, X-ray Laser Studies, Theoretical Division, Tokamak Modeling, Spacecraft Glow Experiment, Compact Ignition Tokamak, Engineering Department, Project Planning and Safety Office, Quality Assurance and Reliability, and Administrative Operations.

Phillips, C.A. (ed.)

1986-01-01T23:59:59.000Z

397

PLASMA GENERATOR  

DOE Patents (OSTI)

This patent describes apparatus for producing an electricity neutral ionized gas discharge, termed a plasma, substantially free from contamination with neutral gas particles. The plasma generator of the present invention comprises a plasma chamber wherein gas introduced into the chamber is ionized by a radiofrequency source. A magnetic field is used to focus the plasma in line with an exit. This magnetic field cooperates with a differential pressure created across the exit to draw a uniform and uncontaminated plasma from the plasma chamber.

Foster, J.S. Jr.

1958-03-11T23:59:59.000Z

398

Laser Ignition  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Ignition Laser Ignition Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Available for thumbnail of Feynman Center (505) 665-9090 Email Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In two embodiments the beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion

399

Geometrical Constraints on Plasma Couplers for Raman Compression  

SciTech Connect

Backward Raman compression in plasma is based on a 3-wave resonant interaction, which includes two- counter propagating laser pulses (pump and seed pulses) and an electron plasma wave (Langmuir wave). A high-density, roughly homogeneous, plasma mediates the energy transfer between the lasers by ensuring resonance with the plasma wave. However, in practice, a laser pulse entering or leaving plasma source encounters plasma at the edges of the homogeneous section that is far too tenuous to maintain resonance. When these tenuous plasma regions are extensive, such as for the wider plasma necessary for compression at higher powers, significant inverse bremsstrahlung and seed dispersion may occur. These deleterious effects may, however, be mitigated by chirping the seed and pump pulses.

Z. Toroker, V.M. Malkin, G.M. Fraiman, A.A. Balakin, and N.J. Fisch

2012-07-18T23:59:59.000Z

400

Laser Radiometry  

Science Conference Proceedings (OSTI)

... over a wide range of powers, energies, and wavelengths. ... the SI units for laser power and energy. ... Novel power meter for high-efficiency laser diode ...

2012-04-18T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Fabrication of nanoscale patterns in lithium fluoride crystal using a 13.5 nm Schwarzschild objective and a laser produced plasma source  

Science Conference Proceedings (OSTI)

Lithium fluoride (LiF) crystal is a radiation sensitive material widely used as EUV and soft x-ray detector. The LiF-based detector has high resolution, in principle limited by the point defect size, large field of view, and wide dynamic range. Using LiF crystal as an imaging detector, a resolution of 900 nm was achieved by a projection imaging of test meshes with a Schwarzschild objective operating at 13.5 nm. In addition, by imaging of a pinhole illuminated by the plasma, an EUV spot of 1.5 {mu}m diameter in the image plane of the objective was generated, which accomplished direct writing of color centers with resolution of 800 nm. In order to avoid sample damage and contamination due to the influence of huge debris flux produced by the plasma source, a spherical normal-incidence condenser was used to collect EUV radiation. Together with a description of experimental results, the development of the Schwarzschild objective, the influence of condenser on energy density and the alignment of the imaging system are also reported.

Wang Xin [Key Laboratory of Advanced Micro-structured Materials, MOE, Department of Physics, Institute of Precision Optical Engineering, Tongji University, Shanghai 200092 (China); School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China); Mu Baozhong; Jiang Li; Zhu Jingtao; Yi Shengzhen; Wang Zhanshan [Key Laboratory of Advanced Micro-structured Materials, MOE, Department of Physics, Institute of Precision Optical Engineering, Tongji University, Shanghai 200092 (China); He Pengfei [School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China)

2011-12-15T23:59:59.000Z

402

Parallelization and I/O optimization for a 3-D plasma simulation code  

Science Conference Proceedings (OSTI)

LARED-P, a three-dimensional laser plasma electromagnitic simulation code, largely simulates the interaction of intense laser and plasma. It uses partical-in-cell simulation method and needs immense computing resource, one CPU can do nothing about the ... Keywords: I/O performance, data management, numerical simulation, parallelization, plasma, post processing

Hong Chen; Weimin Zheng; Aiqing Zhang

2009-07-01T23:59:59.000Z

403

Quantum cascade laser investigations of CH{sub 4} and C{sub 2}H{sub 2} interconversion in hydrocarbon/H{sub 2} gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond  

Science Conference Proceedings (OSTI)

CH{sub 4} and C{sub 2}H{sub 2} molecules (and their interconversion) in hydrocarbon/rare gas/H{sub 2} gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm{sup -1} using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H{sub 2} plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH{sub 4} and C{sub 2}H{sub 2} molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH{sub 4} and C{sub 2}H{sub 2}. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH{sub 4}->C{sub 2}H{sub 2} conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400CH{sub 4} is favored in the more distant regions where T{sub gas}C{sub 2}H{sub 2} conversion, whereas the reverse C{sub 2}H{sub 2}->CH{sub 4} process only requires H atoms to drive the reactions; H atoms are not consumed by the overall conversion.

Ma Jie; Cheesman, Andrew; Ashfold, Michael N. R. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey [Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Mankelevich, Yuri A. [Skobel'tsyn Institute of Nuclear Physics, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

2009-08-01T23:59:59.000Z

404

Magnetic instabilities in accelerating plasma surfaces  

SciTech Connect

The existence of an interchange instability strictly associated with electron inertia is demonstrated. This is characterized by a growth rate significantly larger than the usual ion-inertial Rayleigh-Taylor rate and by self-generated magnetic fields localized around the accelerating plasma surface. This novel instability may be partially responsible for the observed magnetic fields in ablatively accelerated laser plasmas.

Amendt, P.; Rahman, H.U.; Strauss, M.

1984-09-24T23:59:59.000Z

405

Guest Editorial: Laser Damage  

SciTech Connect

Laser damage of optical materials, first reported in 1964, continues to limit the output energy and power of pulsed and continuous-wave laser systems. In spite of some 48 years of research in this area, interest from the international laser community to laser damage issues remains at a very high level and does not show any sign of decreasing. Moreover, it grows with the development of novel laser systems, for example, ultrafast and short-wavelength lasers that involve new damage effects and specific mechanisms not studied before. This interest is evident from the high level of attendance and presentations at the annual SPIE Laser Damage Symposium (aka, Boulder Damage Symposium) that has been held in Boulder, Colorado, since 1969. This special section of Optical Engineering is the first one devoted to the entire field of laser damage rather than to a specific part. It is prepared in response to growing interest from the international laser-damage community. Some papers in this special section were presented at the Laser Damage Symposium; others were submitted in response to the general call for papers for this special section. The 18 papers compiled into this special section represent many sides of the broad field of laser-damage research. They consider theoretical studies of the fundamental mechanisms of laser damage including laser-driven electron dynamics in solids (O. Brenk and B. Rethfeld; A. Nikiforov, A. Epifanov, and S. Garnov; T. Apostolova et al.), modeling of propagation effects for ultrashort high-intensity laser pulses (J. Gulley), an overview of mechanisms of inclusion-induced damage (M. Koldunov and A. Manenkov), the formation of specific periodic ripples on a metal surface by femtosecond laser pulses (M. Ahsan and M. Lee), and the laser-plasma effects on damage in glass (Y. Li et al). Material characterization is represented by the papers devoted to accurate and reliable measurements of absorption with special emphasis on thin films (C. Mühlig and S. Bublitz; B. Cho, E. Danielewicz, and J. Rudisill; W. Palm et al; and J. Lu et al.). Statistical treatment of measurements of the laser-damage threshold (J. Arenberg) and the relationship to damage mechanisms (F. Wagner et al.) represent the large subfield of laser-damage measurements. Various aspects of multilayer coating and thin-film characterization are considered in papers by B. Cho, J. Rudisill, and E. Danielewicz (spectral shift in multilayer mirrors) and R. Weber et al. (novel approach to damage studies based on third-harmonic generation microscopy). Of special interest for readers is the paper by C. Stolz that summarizes the results of four “thin-film damage competitions” organized as a part of the Laser Damage Symposium. Another paper is devoted to thermal annealing of damage precursors (N. Shen et al.). Finally, the influence of nano-size contamination on initiation of laser damage by ultrashort pulses is considered in paper of V. Komolov et al.

Vitaly Gruzdev, Michelle D. Shinn

2012-12-01T23:59:59.000Z

406

Intensity clamping in the filament of femtosecond laser radiation  

SciTech Connect

We have studied numerically the evolution of the light field intensity and induced refractive index of a medium upon filamentation of femtosecond laser radiation in air. It is shown that the intensity clamping results from the dynamic balance of optical powers of nonlinear lenses, induced by radiation due to the Kerr nonlinearity of air, and laser plasma produced during photoionisation. We have found the relation between the peak values of the light field intensity and the electron density in laser-produced plasma, as well as the transverse sizes of the filament and the plasma channel. (effects of laser radiation on matter)

Kandidov, V P; Fedorov, V Yu; Tverskoi, O V; Kosareva, O G; Chin, S L

2011-04-30T23:59:59.000Z

407

Mars mission laser tool heads to JPL  

NLE Websites -- All DOE Office Websites (Extended Search)

Mars mission laser tool Mars mission laser tool Mars mission laser tool heads to JPL Curiosity will carry the newly delivered laser instrument to reveal which elements are present in Mars' rocks and soils. September 21, 2010 A bright ball of plasma is produced by ChemCam's invisible laser beam striking a rock within the Mars sample chamber. A bright ball of plasma is produced by ChemCam's invisible laser beam striking a rock within the Mars sample chamber. Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email "ChemCam will act as a geochemical observatory, providing composition data to understand if Mars was, is, or will be a habitable world." Star Wars photon gun will give Mars rover hands-free rock ID LOS ALAMOS, New Mexico, September 21, 2010-The ChemCam instrument has

408

Ablative Laser Propulsion: An Update, Part II  

Science Conference Proceedings (OSTI)

This paper presents an updated review of studies on Ablative Laser Propulsion conducted by the Laser Propulsion Group (LPG) at the University of Alabama in Huntsville. In particular, we describe the experimental technique developed for determination of specific impulses from plasma plume imaging with an intensified CCD camera.

Pakhomov, Andrew V.; Lin Jun; Thompson, M. Shane [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Information Systems Laboratories, Inc., Brownsboro, Alabama, 35741 (United States)

2004-03-30T23:59:59.000Z

409

Method for producing laser targets  

DOE Patents (OSTI)

An apparatus and method for producing deuterium targets or pellets of 25.mu. to 75.mu. diameter. The pellets are sliced from a continuously spun solid deuterium thread at a rate of up to 10 pellets/second. The pellets after being sliced from the continuous thread of deuterium are collimated and directed to a point of use, such as a laser activated combustion or explosion chamber wherein the pellets are imploded by laser energy or laser produced target plasmas for neutral beam injection.

Jarboe, Thomas R. (Oakland, CA); Baker, William R. (Orinda, CA)

1977-01-01T23:59:59.000Z

410

Expert Topics | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

AC power Education Emergency planning Engineering Fusion energy Fusion reactor design Fusion roadmapping ITER Inertial confinement fusion International collaborations Laser diagnostics Lithium Magnetic reconnection Nuclear energy Nuclear safety Particle beam dynamics Plasma astrophysics Plasma diagnostics Plasma physics Power system design Power systems Quality assurance STEM Science literacy Stellarators Surface science Sustainability Tokamaks Visiting PPPL History Fusion Basics DOE and Fusion Links Contract Documents Speakers Bureau Tours News Events Research Education Organization Contact Us Overview Learn More AC power Education Emergency planning Engineering Fusion energy Fusion reactor design Fusion roadmapping ITER Inertial confinement fusion International collaborations Laser diagnostics

411

Magnetron cathodes in plasma electrode pockels cells  

DOE Patents (OSTI)

Magnetron cathodes, which produce high current discharges, form greatly improved plasma electrodes on each side of an electro-optic crystal. The plasma electrode has a low pressure gas region on both sides of the crystal. When the gas is ionized, e.g., by a glow discharge in the low pressure gas, the plasma formed is a good conductor. The gas electrode acts as a highly uniform conducting electrode. Since the plasma is transparent to a high energy laser beam passing through the crystal, the plasma is transparent. A crystal exposed from two sides to such a plasma can be charged up uniformly to any desired voltage. A typical configuration utilizes helium at 50 millitorr operating. pressure and 2 kA discharge current. The magnetron cathode produces a more uniform plasma and allows a reduced operating pressure which leads to lower plasma resistivity and a more uniform charge on the crystal.

Rhodes, Mark A. (Pleasanton, CA)

1995-01-01T23:59:59.000Z

412

CO{sub 2} laser pulse shortening by laser ablation of a metal target  

Science Conference Proceedings (OSTI)

A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO{sub 2} laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to {approx}2 ns and to remove the low power, long duration tails that are present in TEA CO{sub 2} pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is {approx}10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

Donnelly, T.; Mazoyer, M.; Lynch, A.; O'Sullivan, G.; O'Reilly, F.; Dunne, P.; Cummins, T. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

2012-03-15T23:59:59.000Z

413

Stimulated Raman scattering in large plasmas  

Science Conference Proceedings (OSTI)

Stimulated Raman scattering is of concern to laser fusion since it can create a hot electron environment which can increase the difficulty of achieving high final fuel densities. In earlier experiments with one micron laser light, the energy measured in Raman-scattered light has been insignificant. But these experiments were done with, at most, about 100 joules of laser energy. The Raman instability has a high threshold which also requires a large plasma to be irradiated with a large diameter spot. Only with a long interaction length can the Raman-scattered light wave convectively grow to a large amplitude, and only in recent long pulse, high energy experiments (4000 joules in 2 ns) at the Shiva laser facility have we observed as much as several percent of the laser light to be Raman-scattered. We find that the Raman instability has a much lower intensity threshold for longer laser pulselength and larger laser spot size on a solid target.

Phillion, D.W.; Banner, D.L.

1980-11-06T23:59:59.000Z

414

Betatron Radiation from a Beam Driven Plasma Source  

SciTech Connect

Photons produced by the betatron oscillation of electrons in a beam-driven plasma wake provide a uniquely intense and high-energy source of hard X-rays and gamma rays. This betatron radiation is interesting not only for its high intensity and spectral characteristics, but also because it can be used as a diagnostic for beam matching into the plasma, which is critical for maximizing the energy extraction efficiency of a plasma accelerator stage. At SLAC, gamma ray detection devices have been installed at the dump area of the FACET beamline where the betatron radiation from the plasma source used in the E200 plasma wakefield acceleration experiment may be observed. The ultra-dense, high-energy beam at FACET (2 x 10{sup 10} electrons, 20 x 20 {micro}m{sup 2} spot, 20-100 {micro}m length, 20 GeV energy) when sent into a plasma source with a nominal density of {approx} 1 x 10{sup 17} cm{sup -3} will generate synchrotron-like spectra with critical energies well into the tens of MeV. The intensity of the radiation can be increased by introducing a radial offset to the centroid of the witness bunch, which may be achieved at FACET through the use of a transverse deflecting RF cavity. The E200 gamma ray detector has two main components: a 30 x 35 cm{sup 2} phosphorescent screen for observing the transverse extent of the radiation, and a sampling electromagnetic calorimeter outfitted with photodiodes for measuring the on-axis spectrum. To estimate the spectrum, the observed intensity patterns across the calorimeter are fit with a Gaussian-integrated synchrotron spectrum and compared to simulations. Results and observations from the first FACET user run (April-June 2012) are presented.

Litos, M.; Corde, S.; /SLAC

2012-08-13T23:59:59.000Z

415

Hot-electron refluxing enhanced relativistic transparency of overdense plasmas  

E-Print Network (OSTI)

A new phenomenon of enhancing the relativistic transparency of overdense plasmas by the influence of hot-electron refluxing has been found via particle-in-cell simulations. When a p-polarized laser pulse, with intensity below the self-induced-transparency (SIT) threshold, obliquely irradiates a thin overdense plasma, the initially opaque plasma would become transparent after a time interval which linearly relies on the thickness of the plasma. This phenomenon can be interpreted by the influence of hot-electron refluxing. As the laser intensity is higher than the SIT threshold, the penetration velocity of the laser in the plasma is enhanced when the refluxing is presented. Simulation data with ion motion considered is also consistent with the assumption that hot-electron refluxing enhances transparency. These results have potential applications in laser shaping.

Yu, Yong; Chen, Zi-Yu; Wang, Jia-Xiang; Zhu, Wen-Jun

2013-01-01T23:59:59.000Z

416

Microwave scattering from laser spark in air  

Science Conference Proceedings (OSTI)

In this paper, microwave Mie scattering from a laser-induced plasma in atmospheric air is computed. It shows that the scattered microwave transitions from coherent Rayleigh scattering to Mie scattering based on the relative transparency of the laser-induced plasma at the microwave frequency. The microwave penetration in the plasma alters from total transparency to partial shielding due to the sharp increase of the electron number density within the avalanche ionization phase. The transition from Rayleigh scattering to Mie scattering is verified by both the temporal evolution of the scattered microwave and the homogeneity of polar scattering plots.

Sawyer, Jordan; Zhang Zhili [Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Shneider, Mikhail N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

2012-09-15T23:59:59.000Z

417

Direct observation of the structure of global Alfven eigenmodes in a tokamak plasma  

SciTech Connect

We present the first direct observation of the structure of a driven global Alfven eigenmode in a tokamak plasma using CO/sub 2/ laser interferometry.

Evans, T.E.; Valanju, P.M.; Benesch, J.F.; Bengtson, R.D.; Li, Y.; Mahajan, S.M.; Oakes, M.E.; Ross, D.W.; Wang, X.; Watkins, J.G.

1984-10-29T23:59:59.000Z

418

Plasma channel optical-pumping device and method  

DOE Patents (OSTI)

A device and method are described for optically pumping a gaseous laser using blackbody radiation produced by a plasma channel which is formed from an electrical discharge between two electrodes spaced at opposite longitudinal ends of the laser. A preionization device which can comprise a laser or electron beam accelerator produces a preionization beam which is sufficient to cause an elctrical discharge between the electrodes to initiate the plasma channel along the preionization path. The optical pumping energy is supplied by a high voltage power supply rather than by the preionization beam. High output optical intensities are produced by the laser due to the high temperature black-body radiation produced by the plasma channel, in the same manner as an exploding wire type laser. However, unlike the exploding wire type laser, the disclosed invention can be operated in a repetitive manner by utilizing a repetitive pulsed preionization device.

Judd, O.P.

1981-07-17T23:59:59.000Z

419

Generation of Picosecond Electron-Bunch Trains with Variable Spacing Using a Multi-Pulse Photocathode Laser  

SciTech Connect

We demonstrate the generation of a train of electron bunches with variable spacing at the Argonne Wakefield Accelerator. The photocathode ultraviolet laser pulse consists of a train of four pulses produced via polarization splitting using two alpha-BBO crystals. The photoemitted electron bunches are then manipulated in a horizontally-bending dogleg with variable longitudinal dispersion. A downstream vertically-deflecting cavity is then used to diagnose the temporal profile of the electron beam. The generation of a train composed of four bunches with tunable spacing is demonstrated. Such a train of bunch could have application to, e.g., the resonant excitation of wakefield in dielectric-lined structures. We have presented preliminary measurements on a simple technique to generate a train of electron bunches with variable separation. In the initial experiment appreciable density modulation down to wavelengths of {approx}1.8 mm (corresponding to a temporal separation of {approx}6 ps) were achieved for a total charge of 0.5 nC. Finding ways to reach smaller separations is being explored with the help of numerical simulations and will be presented elsewhere.

Conde, M.; Gai, W.; /Argonne; Jing, C.; /Euclid TechLabs /Argonne; Konecny, R.; Liu, W.; /Argonne; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Northern Illinois U. /Fermilab; Power, J.G.; /Argonne; Rihaoui, M.; /Northern Illinois U.; Yusof, Z.; /Argonne

2012-07-08T23:59:59.000Z

420

Transversal plasma resonance in a nonmagnetized plasma and possibilities of practical employment of it  

E-Print Network (OSTI)

It is shown that in a nonmagnetized plasma, beside the longitudinal Langmuir resonance, there may also exist the transversal resonance. Both these resonance kinds are degenerated. Employment of the transversal resonance makes it possible to design resonators and filters, as well as powerful single-frequency lasers operating on the basis of collective oscillations of plasma.

F. F. Mende

2005-06-09T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Research activities of the Institute of Plasma Physics. Annual report, 1972  

SciTech Connect

A survey of scientific work carried out during the year 1972 is presented. The research program was narrowed down to some main problem areas, such as plasma waves, plasma focusing, transient diagnostics, and laser applications. (GRA)

1973-01-01T23:59:59.000Z

422

Laser breakdown in air at ultrahigh laser pulse repetition rates  

SciTech Connect

Some specific features of interaction of intense femtosecond laser pulses with air at ultrahigh pulse repetition rates have been experimentally studied. Data on the dynamics of plasma cloud expansion and the plasma electron density on time intervals no longer than 10 ns are obtained by femtosecond interferometry. These data are interpreted in terms of the most likely mechanisms of ionised gas recombination. The effect of ultrahigh-frequency laser radiation on a medium was modelled by double-pulse irradiation with a short delay {Delta}t between the pulses: from 1 ps to 11 ns. A nonmonotonic dependence of the degree of air ionisation by the second pulse on the delay time {Delta}t is found; possible mechanisms of these dependences are discussed in terms of the processes of femtosecond radiation absorption in the residual plasma. (extreme light fields and their applications)

Kononenko, Vitalii V; Kononenko, Taras V; Pashinin, V P; Gololobov, V M; Konov, Vitalii I [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2013-04-30T23:59:59.000Z

423

Laser Spectro.  

Science Conference Proceedings (OSTI)

For more information about my work on laser spectroscopy, consult the following papers: Sansonetti, CJ, Gillaspy, JD, and ...

424

Overview of R&D Work on Laser Materials Processing at SMU  

Science Conference Proceedings (OSTI)

SMU's I/UCRC for Lasers and Plasmas site has built an R&D infrastructure that consists of the most advanced research equipment and well trained research ...

425

High efficiency cholesteric liquid crystal lasers with an external stable resonator  

E-Print Network (OSTI)

Shirvani-Mahdavi,1,2 Shima Fardad,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research

Richardson, Martin C.

426

Circularly polarized high-efficiency cholesteric liquid crystal lasers with a tunable  

E-Print Network (OSTI)

retarder Hamidreza Shirvani-Mahdavi,1,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research

Wu, Shin-Tson

427

Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays  

E-Print Network (OSTI)

of coherent transition radiation generated at a plasma-and G. Fubiani, “Terahertz radiation from laser acceleratedW. P. Leemans, “Synchrotron radiation from electron beams in

2004-01-01T23:59:59.000Z

428

SciTech Connect: "smart grid"  

Office of Scientific and Technical Information (OSTI)

Beam Matching to a Plasma Wakefield Accelerator Using a Ramped Density Profile at the Plasma Boundary Citation Details In-Document Search Title: Beam Matching to a Plasma Wakefield...

429

The athermal Laser  

E-Print Network (OSTI)

A new laser concept is presented, called the athermal laser, unifying all the hitherto known implementations of radiative laser cooling.

Muys, Peter

2009-01-01T23:59:59.000Z

430

High-Energy Laser Ponderomotive Acceleration  

SciTech Connect

A new concept of TeV-range laser ponderomotive acceleration in a plasma is proposed. Particles are accelerated in the point-like scattering by the leading front of the laser pulse, propagating at the group velocity less than the vacuum speed of light. In this scheme, the gain in particle energy is determined by the group velocity and does not depend on laser intensity, which determines the quantum probability of acceleration. The quantum and classical analysis of the scheme proposed is presented. Estimates show that the concept proposed is a promising technique for compact laser acceleration of TeV energy range.

Smetanin, I.V.; /Lebedev Inst.; Barnes, C.; /SLAC; Nakajima, K.; /KEK, Tsukuba

2006-03-10T23:59:59.000Z

431

Laser device  

DOE Patents (OSTI)

A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

2007-07-10T23:59:59.000Z

432

High-Energy-Density Plasmas, Fluids  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Energy-Density Plasmas, Fluids High-Energy-Density Plasmas, Fluids /science-innovation/_assets/images/icon-science.jpg High-Energy-Density Plasmas, Fluids National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. TRIDENT target chamber Sasi Palaniyappan, right, and Rahul Shah left inside a target chamber where the TRIDENT short pulse laser is aimed at a very thin diamond- foil target, a fraction of a micrometer thick. The laser delivers a power on target of 150 Terawatts focused into a 7 micrometer spot, yielding laser brilliance over 100 times more intense than needed to make the target electrons fully relativistic. These experiments test novel methods of producing intense

433

Three-Body Recombination and Rydberg Atoms in Ultracold Plasmas.  

E-Print Network (OSTI)

??Ultracold neutral plasmas, created by photoionizing samples of laser-cooled atoms, have well-controlled initial density and temperature parameters. With initial particle peak densities of ~1015 m-3,… (more)

Fletcher, Robert S

2008-01-01T23:59:59.000Z

434

Ultrashort pulse laser deposition of thin films  

DOE Patents (OSTI)

Short pulse PLD is a viable technique of producing high quality films with properties very close to that of crystalline diamond. The plasma generated using femtosecond lasers is composed of single atom ions with no clusters producing films with high Sp.sup.3 /Sp.sup.2 ratios. Using a high average power femtosecond laser system, the present invention dramatically increases deposition rates to up to 25 .mu.m/hr (which exceeds many CVD processes) while growing particulate-free films. In the present invention, deposition rates is a function of laser wavelength, laser fluence, laser spot size, and target/substrate separation. The relevant laser parameters are shown to ensure particulate-free growth, and characterizations of the films grown are made using several diagnostic techniques including electron energy loss spectroscopy (EELS) and Raman spectroscopy.

Perry, Michael D. (Livermore, CA); Banks, Paul S. (Livermore, CA); Stuart, Brent C. (Fremont, CA)

2002-01-01T23:59:59.000Z

435

Plasma valve  

DOE Patents (OSTI)

A plasma valve includes a confinement channel and primary anode and cathode disposed therein. An ignition cathode is disposed adjacent the primary cathode. Power supplies are joined to the cathodes and anode for rapidly igniting and maintaining a plasma in the channel for preventing leakage of atmospheric pressure through the channel.

Hershcovitch, Ady (Mount Sinai, NY); Sharma, Sushil (Hinsdale, IL); Noonan, John (Naperville, IL); Rotela, Elbio (Clarendon Hills, IL); Khounsary, Ali (Hinsdale, IL)

2003-01-01T23:59:59.000Z

436

Laser Catalyst  

INL’s Laser Catalyst is a method for removing contaminant matter from a porous material. A polymer material is applied to a contaminated surface and ...

437

System for the production of plasma  

DOE Patents (OSTI)

The present invention provides a system for the production of a plasma by concentrating and focusing a laser beam on the plasma-forming material with a lightfocusing member which comprises a parabolic axicon in conjunction with a coaxial conical mirror. The apex of the conical mirror faces away from the focus of the parabolic axicon such that the conical mirror serves to produce a virtual line source along the axis of the cone. Consequently, irradiation from a laser parallel to the axis toward the apex of the conical mirror will be concentrated at the focus of the parabolic axicon, impinging upon the plasma-forming material there introduced to produce a plasma. The system is adaptable to irradiation of a target pellet introduced at the focus of the parabolic axicon and offers an advantage in that the target pellet can be irradiated with a high degree of radial and spherical symmetry.

Bakken, George S. (Ann Arbor, MI)

1978-01-01T23:59:59.000Z

438

Nonlinear laser energy depletion in laser-plasma accelerators  

E-Print Network (OSTI)

k p ? ?) 2 . a ? p t 2000 BAS-ML-0525 (a) Copyright © 2005,reserved. 0 a ? ? p t 1000 BAS-ML-0527 (e) Copyright © 2005,reserved. 0 a ? ? p t 2000 BAS-ML-0525 ? p t 1000 BAS-ML-

Shadwick, B.A.

2009-01-01T23:59:59.000Z

439

PLASMA ENERGIZATION  

DOE Patents (OSTI)

BS>A method is given for ion cyclotron resonance heatthg of a magnetically confined plasma by an applied radio-frequency field. In accordance with the invention, the radiofrequency energy is transferred to the plasma without the usual attendent self-shielding effect of plasma polarlzatlon, whereby the energy transfer is accomplished with superior efficiency. More explicitly, the invention includes means for applying a radio-frequency electric field radially to an end of a plasma column confined in a magnetic mirror field configuration. The radio-frequency field propagates hydromagnetic waves axially through the column with the waves diminishing in an intermediate region of the column at ion cyclotron resonance with the fleld frequency. In such region the wave energy is converted by viscous damping to rotational energy of the plasma ions. (AEC)

Furth, H.P.; Chambers, E.S.

1962-03-01T23:59:59.000Z

440

PLASMA DEVICE  

DOE Patents (OSTI)

A device is described for establishing and maintaining a high-energy, rotational plasma for use as a fast discharge capacitor. A disc-shaped, current- conducting plasma is formed in an axinl magnetic field and a crossed electric field, thereby creating rotational kinetic enengy in the plasma. Such energy stored in the rotation of the plasma disc is substantial and is convertible tc electrical energy by generator action in an output line electrically coupled to the plasma volume. Means are then provided for discharging the electrical energy into an external circuit coupled to the output line to produce a very large pulse having an extremely rapid rise time in the waveform thereof. (AE C)

Baker, W.R.

1961-08-22T23:59:59.000Z

Note: This page contains sample records for the topic "laser plasma wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Laser machining of explosives  

DOE Patents (OSTI)

The invention consists of a method for machining (cutting, drilling, sculpting) of explosives (e.g., TNT, TATB, PETN, RDX, etc.). By using pulses of a duration in the range of 5 femtoseconds to 50 picoseconds, extremely precise and rapid machining can be achieved with essentially no heat or shock affected zone. In this method, material is removed by a nonthermal mechanism. A combination of multiphoton and collisional ionization creates a critical density plasma in a time scale much shorter than electron kinetic energy is transferred to the lattice. The resulting plasma is far from thermal equilibrium. The material is in essence converted from its initial solid-state directly into a fully ionized plasma on a time scale too short for thermal equilibrium to be established with the lattice. As a result, there is negligible heat conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond a few microns from the laser machined surface. Hydrodynamic expansion of