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Sample records for high-energy plasma wakefield

  1. Magnetowave Induced Plasma Wakefield Acceleration for Ultra High Energy Cosmic Rays

    SciTech Connect

    Chang, Feng-Yin; Chen, Pisin; Lin, Guey-Lin; Noble, Robert; Sydora, Richard; /Alberta U.

    2009-10-17

    Magnetowave induced plasma wakefield acceleration (MPWA) in a relativistic astrophysical outflow has been proposed as a viable mechanism for the acceleration of cosmic particles to ultrahigh energies. Here we present simulation results that clearly demonstrate the viability of this mechanism for the first time. We invoke the high frequency and high speed whistler mode for the driving pulse. The plasma wakefield obtained in the simulations compares favorably with our newly developed relativistic theory of the MPWA. We show that, under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over hundreds of plasma skin depths. Invoking active galactic nuclei as the site, we show that MPWA production of ultrahigh energy cosmic rays beyond ZeV (10{sup 21} eV) is possible.

  2. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

    PubMed Central

    Zhang, C. J.; Hua, J. F.; Xu, X. L.; Li, F.; Pai, C.-H.; Wan, Y.; Wu, Y. P.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; Lu, W.

    2016-01-01

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method. PMID:27403561

  3. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

    DOE PAGESBeta

    Zhang, C. J.; Hua, J. F.; Xu, X. L.; Li, F.; Pai, C. -H.; Wan, Y.; Wu, Y. P.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; et al

    2016-07-11

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of themore » wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. As a result, the capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.« less

  4. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe.

    PubMed

    Zhang, C J; Hua, J F; Xu, X L; Li, F; Pai, C-H; Wan, Y; Wu, Y P; Gu, Y Q; Mori, W B; Joshi, C; Lu, W

    2016-01-01

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method. PMID:27403561

  5. Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

    NASA Astrophysics Data System (ADS)

    Zhang, C. J.; Hua, J. F.; Xu, X. L.; Li, F.; Pai, C.-H.; Wan, Y.; Wu, Y. P.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; Lu, W.

    2016-07-01

    A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

  6. High energy photon emission from wakefields

    NASA Astrophysics Data System (ADS)

    Farinella, D. M.; Lau, C. K.; Zhang, X. M.; Koga, J. K.; Taimourzadeh, S.; Hwang, Y.; Abazajian, K.; Canac, N.; Ebisuzaki, T.; Taborek, P.; Tajima, T.

    2016-07-01

    Experimental evidence has accumulated to indicate that wakefield acceleration (WFA) accompanies intense and sometimes coherent emission of radiation such as from betatron radiation. The investigation of this issue has additional impetus nowadays because we are learning (1) there is an additional acceleration process of the ponderomotive acceleration; (2) WFA may become relevant in much higher density regimes; (3) WFA has been proposed as the mechanism for extreme high energy cosmic ray acceleration and gamma ray bursts for active galactic nuclei. These require us to closely examine the radiative mechanisms in WFA anew. We report studies of radiation from wakefield (self-injected betatron) and ponderomotive (laser field) mechanisms in scalings of the frequency and intensity of the driver, as well as the plasma density.

  7. Positron driven plasma wakefields

    NASA Astrophysics Data System (ADS)

    Pinkerton, S.; Shi, Y.; Huang, C.; An, W.; Mori, W. B.; Muggli, P.

    2010-11-01

    The LHC is producing high-energy, high-charge proton bunches (1e11 protons at 1-7 TeV each) that could be used to accelerate ``witness'' electron bunches to TeV range eneregies via a plasma wakefield accelerator (PWFA). Simulations [1] suggest that a proton ``drive'' bunch is able to excite large wakefields if the bunch size is on the order of 100 μm; however, the LHC paramters are currently on the 1 cm scale. SLAC'S FACET is able to supply positorn bunchs with the ideal parameters for driving a PWFA. Although at lower energy (2e10 positrons at 23 GeV each), initial simiulations in QuickPIC show that the physics of a positron drive bunch is very similar to that of a proton drive bunch. Differences in the physics arise from the mass difference: slower dephasing but faster transverse bunch evolution. Other considerations include driver head erosion and purity of the wakefield ion column. The physics of positive drivers for PWFA and the viability of this scheme for future high-energy colliders will be investigated at SLAC's FACET.[4pt] [1] Caldwell, et al. Nature Physics 5, 363 (2009).[0pt] [2] C.H. Huang, et al., J. Comp. Phys., 217(2), 658, (2006).

  8. Cosmic Plasma Wakefield Acceleration

    NASA Astrophysics Data System (ADS)

    Chen, Pisin; Tajima, Toshiki; Takahashi, Yoshiyuki

    2002-10-01

    A cosmic acceleration mechanism is introduced which is based on the wakefields excited by the Alfven shocks in a relativistically flowing plasma. We show that there exists a threshold condition for transparency below which the accelerating particle is collision-free and suffers little energy loss in the plasma medium. The stochastic encounters of the random accelerating-decelerating phases results in a power-law energy spectrum: f([epsilon]) [is proportional to] 1/[epsilon]2. As an example, we discuss the possible production of super-GZK ultra high energy cosmic rays (UHECR) in the atmosphere of gamma ray bursts. The estimated event rate in our model agrees with that from UHECR observations. [copyright] 2002 American Institute of Physics

  9. Hybrid Laser-Plasma Wakefield Acceleration

    SciTech Connect

    Hidding, B.; Koenigstein, T.; Willi, O.; Pretzler, G.; Karsch, S.; Rosenzweig, J. B.

    2010-11-04

    The concept of driving a driver/witness-type plasma wakefield accelerator (PWFA) with quasimonoenergetic double electron bunches from a laser wakefield accelerator (LWFA) is studied. In the quasimonoenergetic LWFA/SMLWFA (self-modulated LWFA) regime, it is possible to generate multiple quasimonoenergetic electron bunches with durations of only a few fs and distances of only a few tens of fs with a comparably simple experimental setup. In a subsequent high-density plasma afterburner stage the witness bunch energy can be boosted in the plasma wakefield generated by the driver. Such a hybrid system can increase the maximum energy output of a laser wakefield accelerator and is well suited to study driver/witness plasma accelerator phenomena and can be used as a cost-effective test-bed for future high-energy plasma-based accelerators.

  10. Hybrid Laser-Plasma Wakefield Acceleration

    NASA Astrophysics Data System (ADS)

    Hidding, B.; Königstein, T.; Karsch, S.; Willi, O.; Pretzler, G.; Rosenzweig, J. B.

    2010-11-01

    The concept of driving a driver/witness-type plasma wakefield accelerator (PWFA) with quasimonoenergetic double electron bunches from a laser wakefield accelerator (LWFA) is studied. In the quasimonoenergetic LWFA/SMLWFA (self-modulated LWFA) regime, it is possible to generate multiple quasimonoenergetic electron bunches with durations of only a few fs and distances of only a few tens of fs with a comparably simple experimental setup. In a subsequent high-density plasma afterburner stage the witness bunch energy can be boosted in the plasma wakefield generated by the driver. Such a hybrid system can increase the maximum energy output of a laser wakefield accelerator and is well suited to study driver/witness plasma accelerator phenomena and can be used as a cost-effective test-bed for future high-energy plasma-based accelerators.

  11. Self-mode-transition from laser wakefield accelerator to plasma wakefield accelerator of laser-driven plasma-based electron acceleration

    SciTech Connect

    Pae, K. H.; Choi, I. W.; Lee, J.

    2010-12-15

    Via three-dimensional particle-in-cell simulations, the self-mode-transition of a laser-driven electron acceleration from laser wakefield to plasma-wakefield acceleration is studied. In laser wakefield accelerator (LWFA) mode, an intense laser pulse creates a large amplitude wakefield resulting in high-energy electrons. Along with the laser pulse depletion, the electron bunch accelerated in the LWFA mode drives a plasma wakefield. Then, after the plasma wakefield accelerator mode is established, electrons are trapped and accelerated in the plasma wakefield. The mode transition process and the characteristics of the accelerated electron beam are presented.

  12. Plasma Wakefield Acceleration of Positrons

    NASA Astrophysics Data System (ADS)

    Gessner, Spencer

    2016-03-01

    Recent particle beam and laser-driven plasma wakefield experiments have produced high-quality electron beams accelerated by a GeV or more in less than a meter. Efforts are underway to put these beams to work as sources for free-electron lasers. By contrast, little work has been done to demonstrate the tractability of plasma wakefield acceleration (PWFA) of positrons beams. The reasons for this are threefold: 1) positron beams are only useful for high-energy physics experiments, whereas electron beams are also useful as light sources, 2) there is a dearth of positron sources for PWFA experiments, and 3) the dynamics of accelerating positron beams in plasma is fundamentally different than that of electron beams. This talk will focus on the physics of accelerating positrons in plasma and contrast the dynamics of electron and positron beam-driven nonlinear plasma wakes. We describe recent experiments at the FACET test facility at SLAC National Accelerator Laboratory that for the first time demonstrate high-gradient acceleration of a positron beams in plasma. We also discuss an alternative acceleration technique called hollow channel acceleration that aims to symmetrize the dynamics of electron and positron beam-driven wakes.

  13. Results from Plasma Wakefield Experiments at FACET

    SciTech Connect

    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.; Muggli, P.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; Adli, E.; /U. Oslo

    2011-12-13

    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

  14. Giga-electronvolt electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

    SciTech Connect

    Masson-Laborde, P. E. Teychenné, D.; Mo, M. Z.; Ali, A.; Fedosejevs, R.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.; Rozmus, W.

    2014-12-15

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its own wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional particle-in-cell simulations support this analysis and confirm the scenario.

  15. Giga-electronvolt electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Masson-Laborde, P. E.; Mo, M. Z.; Ali, A.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.; Rozmus, W.; Teychenné, D.; Fedosejevs, R.

    2014-12-01

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its own wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional particle-in-cell simulations support this analysis and confirm the scenario.

  16. Argonne plasma wake-field acceleration experiments

    SciTech Connect

    Rosenzweig, J.B.; Cole, B.; Gai, W.; Konecny, R.; Norem, J.; Schoessow, P.; Simpson, J.

    1989-03-14

    Four years after the initial proposal of the Plasma Wake-field Accelerator (PWFA), it continues to be the object of much investigation, due to the promise of the ultra-high accelerating gradients that can exist in relativistic plasma waves driven in the wake of charged particle beams. These wake-fields are of interest both in the laboratory, for acceleration and focusing of electrons and positrons in future linear colliders, and in nature as a possible cosmic ray acceleration mechanism. The purpose of the present work is to review the recent experimental advances made in PWFA research at Argonne National Laboratory. Some of the topics discussed are: the Argonne Advanced Accelerator Test Facility; linear plasma wake-field theory; measurement of linear plasma wake-fields; review of nonlinear plasma wave theory; and experimental measurement of nonlinear plasma wake-fields. 25 refs., 11 figs.

  17. A New Type of Plasma Wakefield Accelerator Driven By Magnetowaves

    SciTech Connect

    Chen, Pisin; Chang, Feng-Yin; Lin, Guey-Lin; Noble, Robert J.; Sydora, Richard; /Alberta U.

    2011-09-12

    We present a new concept for a plasma wakefield accelerator driven by magnetowaves (MPWA). This concept was originally proposed as a viable mechanism for the 'cosmic accelerator' that would accelerate cosmic particles to ultra-high energies in the astrophysical setting. Unlike the more familiar plasma wakefield accelerator (PWFA) and the laser wakefield accelerator (LWFA) where the drivers, the charged-particle beam and the laser, are independently existing entities, MPWA invokes the high-frequency and high-speed whistler mode as the driver, which is a medium wave that cannot exist outside of the plasma. Aside from the difference in drivers, the underlying mechanism that excites the plasma wakefield via the ponderomotive potential is common. Our computer simulations show that under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over many plasma wavelengths. We suggest that in addition to its celestial application, the MPWA concept can also be of terrestrial utility. A proof-of-principle experiment on MPWA would benefit both terrestrial and celestial accelerator concepts.

  18. Plasma Wakefield Experiments at FACET

    SciTech Connect

    Hogan, M.J.; England, R.J.; Frederico, J.; Hast, C.; Li, S.Z.; Litos, M.; Walz, D.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; Muggli, P.; Pinkerton, S.; Shi, Y.; /Southern California U.

    2011-08-19

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to {approx}20{micro}m long and focused to {approx}10{micro}m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.

  19. Measurements of high-energy radiation generation from laser-wakefield accelerated electron beams

    SciTech Connect

    Schumaker, W. Vargas, M.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Maksimchuk, A.; Nees, J.; Yanovsky, V.; Thomas, A. G. R.; Krushelnick, K.; Sarri, G.; Dromey, B.; Zepf, M.

    2014-05-15

    Using high-energy (∼0.5 GeV) electron beams generated by laser wakefield acceleration (LWFA), bremsstrahlung radiation was created by interacting these beams with various solid targets. Secondary processes generate high-energy electrons, positrons, and neutrons, which can be measured shot-to-shot using magnetic spectrometers, short half-life activation, and Compton scattering. Presented here are proof-of-principle results from a high-resolution, high-energy gamma-ray spectrometer capable of single-shot operation, and high repetition rate activation diagnostics. We describe the techniques used in these measurements and their potential applications in diagnosing LWFA electron beams and measuring high-energy radiation from laser-plasma interactions.

  20. High energy plasma accelerators

    SciTech Connect

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ..omega../sub 0/, kappa/sub 0/ and ..omega../sub 1/, kappa/sub 1/ shone on a plasma with frequency separation equal to the electron plasma frequency ..omega../sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ..omega../sub pe//e of the order of 1GeV/cm for a plasma density of 10/sup 18/ cm/sup -3/ through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed.

  1. Energy Measurement in a Plasma Wakefield Accelerator

    SciTech Connect

    Ischebeck, R

    2007-07-06

    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.

  2. Plasma wakefield acceleration in self-ionized gas or plasmas.

    PubMed

    Deng, S; Barnes, C D; Clayton, C E; O'Connell, C; Decker, F J; Erdem, O; Fonseca, R A; Huang, C; Hogan, M J; Iverson, R; Johnson, D K; Joshi, C; Katsouleas, T; Krejcik, P; Lu, W; Marsh, K A; Mori, W B; Muggli, P; Tsung, F

    2003-10-01

    Tunnel ionizing neutral gas with the self-field of a charged particle beam is explored as a possible way of creating plasma sources for a plasma wakefield accelerator [Bruhwiler et al., Phys. Plasmas (to be published)]. The optimal gas density for maximizing the plasma wakefield without preionized plasma is studied using the PIC simulation code OSIRIS [R. Hemker et al., in Proceeding of the Fifth IEEE Particle Accelerator Conference (IEEE, 1999), pp. 3672-3674]. To obtain wakefields comparable to the optimal preionized case, the gas density needs to be seven times higher than the plasma density in a typical preionized case. A physical explanation is given. PMID:14683089

  3. Acceleration gradient of a plasma wakefield accelerator

    SciTech Connect

    Uhm, Han S.

    2008-02-25

    The phase velocity of the wakefield waves is identical to the electron beam velocity. A theoretical analysis indicates that the acceleration gradient of the wakefield accelerator normalized by the wave breaking amplitude is K{sub 0}({xi})/K{sub 1}({xi}), where K{sub 0}({xi}) and K{sub 1}({xi}) are the modified Bessel functions of the second kind of order zero and one, respectively and {xi} is the beam parameter representing the beam intensity. It is also shown that the beam density must be considerably higher than the diffuse plasma density for the large radial velocity of plasma electrons that are required for a high acceleration gradient.

  4. Staging optics considerations for a plasma wakefield acceleration linear collider

    NASA Astrophysics Data System (ADS)

    Lindstrøm, C. A.; Adli, E.; Allen, J. M.; Delahaye, J. P.; Hogan, M. J.; Joshi, C.; Muggli, P.; Raubenheimer, T. O.; Yakimenko, V.

    2016-09-01

    Plasma wakefield acceleration offers acceleration gradients of several GeV/m, ideal for a next-generation linear collider. The beam optics requirements between plasma cells include injection and extraction of drive beams, matching the main beam beta functions into the next cell, canceling dispersion as well as constraining bunch lengthening and chromaticity. To maintain a high effective acceleration gradient, this must be accomplished in the shortest distance possible. A working example is presented, using novel methods to correct chromaticity, as well as scaling laws for a high energy regime.

  5. Plasma channel guided laser wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Geddes, Cameron Guy Robinson

    2005-11-01

    ), electrons were trapped from the background plasma and accelerated. Tuning of the plasma density, laser power, and channel shape produced electron bunches with several 10 9 electrons within a few percent of a single high energy and with an emittance (focusability) competitive with state of the art conventional accelerators. Electron bunch energy was above 80 MeV using a 2 mm plasma channel, and energies as high as 150--170 MeV were observed. The presence of high energy electrons was highly correlated to well guided optical pulses. Measurements in pre-ionized plasmas with no channel structure confirmed that the enhancement was due to channeling not ionization. The experiments and simulations in this dissertation indicate that the guiding of intense laser pulses in pre-formed plasma channels is an important building block for laser plasma accelerators, facilitating scaling to higher energies and beam quality. (Abstract shortened by UMI.)

  6. Characteristics of a tapered capillary plasma waveguide for laser wakefield acceleration

    SciTech Connect

    Kim, M. S.; Jang, D. G.; Lee, T. H.; Nam, I. H.; Lee, I. W.; Suk, H.

    2013-05-20

    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.

  7. Blowout regimes of plasma wakefield acceleration.

    PubMed

    Lotov, K V

    2004-04-01

    A wide region of beam parameters is numerically scanned and the dependence of wakefield properties on the beam length and current is clarified for the blowout regime of beam-plasma interaction. The main regimes of the plasma response are found, which qualitatively differ in the plasma behavior. To characterize the efficiency of the energy exchange between the beam and the plasma, the energy flux through the comoving window is introduced. Scalings of the energy flux for the linear plasma response and the main blowout regimes are studied. The most efficient energy transfer occurs in the so-called "strong beam" regime of interaction. For this regime, analytical approximations for various aspects of the plasma response are obtained. PMID:15169104

  8. Plasma wakefield acceleration at CLARA facility in Daresbury Laboratory

    NASA Astrophysics Data System (ADS)

    Xia, G.; Nie, Y.; Mete, O.; Hanahoe, K.; Dover, M.; Wigram, M.; Wright, J.; Zhang, J.; Smith, J.; Pacey, T.; Li, Y.; Wei, Y.; Welsch, C.

    2016-09-01

    A plasma accelerator research station (PARS) has been proposed to study the key issues in electron driven plasma wakefield acceleration at CLARA facility in Daresbury Laboratory. In this paper, the quasi-nonlinear regime of beam driven plasma wakefield acceleration is analysed. The wakefield excited by various CLARA beam settings are simulated by using a 2D particle-in-cell (PIC) code. For a single drive beam, an accelerating gradient up to 3 GV/m can be achieved. For a two bunch acceleration scenario, simulation shows that a witness bunch can achieve a significant energy gain in a 10-50 cm long plasma cell.

  9. Optical plasma torch electron bunch generation in plasma wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Wittig, G.; Karger, O.; Knetsch, A.; Xi, Y.; Deng, A.; Rosenzweig, J. B.; Bruhwiler, D. L.; Smith, J.; Manahan, G. G.; Sheng, Z.-M.; Jaroszynski, D. A.; Hidding, B.

    2015-08-01

    A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

  10. Physics of beam self-modulation in plasma wakefield accelerators

    SciTech Connect

    Lotov, K. V.

    2015-10-15

    The self-modulation instability is a key effect that makes possible the usage of nowadays proton beams as drivers for plasma wakefield acceleration. Development of the instability in uniform plasmas and in plasmas with a small density up-step is numerically studied with the focus at nonlinear stages of beam evolution. The step parameters providing the strongest established wakefield are found, and the mechanism of stable bunch train formation is identified.

  11. Final Report: Experimental Investigation of Nonlinear Plasma Wake-Fields

    SciTech Connect

    Rosenzweig, J.

    1997-10-31

    We discuss the exploration of the newly proposed blowout regime of the plasma wakefield accelerator and advanced photoinjector technology for linear collider applications. The plasma wakefield experiment at ANL produced several ground-breaking results in the physics of the blowout regime. The photoinjector R and D effort produced breakthroughs in theoretical, computational, and experimental methods in high brightness beam physics. Results have been published.

  12. Multiple pulse resonantly enhanced laser plasma wakefield acceleration

    SciTech Connect

    Corner, L.; Walczak, R.; Nevay, L. J.; Dann, S.; Hooker, S. M.; Bourgeois, N.; Cowley, J.

    2012-12-21

    We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates.

  13. Plasma Dark Current in Self-Ionized Plasma Wakefield Accelerators

    SciTech Connect

    Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; Iverson, R.; Johnson, D.K.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA

    2006-01-30

    Evidence of particle trapping has been observed in a beam driven Plasma Wake Field Accelerator (PWFA) experiment, E164X, conducted at the Stanford Linear Accelerator Center by a collaboration which includes USC, UCLA and SLAC. Such trapping produces plasma dark current when the wakefield amplitude is above a threshold value and may place a limit on the maximum acceleration gradient in a PWFA. Trapping and dark current are enhanced when in an ionizing plasma, that is self-ionized by the beam. Here we present experimental results.

  14. Hot spots and dark current in advanced plasma wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Manahan, G. G.; Deng, A.; Karger, O.; Xi, Y.; Knetsch, A.; Litos, M.; Wittig, G.; Heinemann, T.; Smith, J.; Sheng, Z. M.; Jaroszynski, D. A.; Andonian, G.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

    2016-01-01

    Dark current can spoil witness bunch beam quality and acceleration efficiency in particle beam-driven plasma wakefield accelerators. In advanced schemes, hot spots generated by the drive beam or the wakefield can release electrons from higher ionization threshold levels in the plasma media. These electrons may be trapped inside the plasma wake and will then accumulate dark current, which is generally detrimental for a clear and unspoiled plasma acceleration process. Strategies for generating clean and robust, dark current free plasma wake cavities are devised and analyzed, and crucial aspects for experimental realization of such optimized scenarios are discussed.

  15. Nonlinear plasma and beam physics in plasma wake-fields

    SciTech Connect

    Rosenzweig, J.B.

    1990-02-12

    In experimental studies of the Plasma Wake-field Accelerator performed to date at the Argonne Advanced Accelerator Test Facility, significant nonlinearities in both plasma and beam behavior have been observed. The plasma waves driven in the wake of the intense driving beam in these experiments exhibit three-dimensional nonlinear behavior which has as yet no quantitative theoretical explanation. This nonlinearity is due in part to the self-pinching of the driving beam in the plasma, as the denser self-focused beam can excite larger amplitude plasma waves. The self-pinching is a process with interesting nonlinear aspects: the initial evolution of the beam envelope and the subsequent approach to Bennett equilibrium through phase mixing. 35 refs., 10 figs.

  16. Magnetowave induced plasma wakefield acceleration for ultrahigh energy cosmic rays.

    PubMed

    Chang, Feng-Yin; Chen, Pisin; Lin, Guey-Lin; Noble, Robert; Sydora, Richard

    2009-03-20

    Magnetowave induced plasma wakefield acceleration (MPWA) in a relativistic astrophysical outflow has been proposed as a viable mechanism for the acceleration of cosmic particles to ultrahigh energies. Here we present simulation results that clearly demonstrate the viability of this mechanism for the first time. We invoke the high frequency and high speed whistler mode for the driving pulse. The plasma wakefield obtained in the simulations compares favorably with our newly developed relativistic theory of the MPWA. We show that, under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over hundreds of plasma skin depths. Invoking active galactic nuclei as the site, we show that MPWA production of ultrahigh energy cosmic rays beyond ZeV (10{21} eV) is possible. PMID:19392185

  17. Progress of plasma wakefield self-modulation experiments at FACET

    NASA Astrophysics Data System (ADS)

    Adli, E.; Berglyd Olsen, V. K.; Lindstrøm, C. A.; Muggli, P.; Reimann, O.; Vieira, J. M.; Amorim, L. D.; Clarke, C. I.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; O`Shea, B. D.; Yakimenko, V.; Clayton, C.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Williams, O.

    2016-09-01

    Simulations and theory predict that long electron and positron beams may under favorable conditions self-modulate in plasmas. We report on the progress of experiments studying the self-modulation instability in plasma wakefield experiments at FACET. The experimental results obtained so far, while not being fully conclusive, appear to be consistent with the presence of the self-modulation instability.

  18. Transverse oscillations in plasma wakefield experiments at FACET

    NASA Astrophysics Data System (ADS)

    Adli, E.; Lindstrøm, C. A.; Allen, J.; Clarke, C. I.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; White, G. R.; Yakimenko, V.; An, W.; Clayton, C. E.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Corde, S.; Lu, W.

    2016-09-01

    We study transverse effects in a plasma wakefield accelerator. Experimental data from FACET with asymmetry in the beam-plasma system is presented. Energy dependent centroid oscillations are observed on the accelerated part of the charge. The experimental results are compared to PIC simulations and theoretical estimates.

  19. Plasma Wakefield Acceleration Simulations with Multiple Electron Bunches

    NASA Astrophysics Data System (ADS)

    Kallos, Efthymios; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl; Park, Jangho; Babzien, Marcus; Lichtl, Adam

    2008-11-01

    In the multibunch plasma wakefield accelerator, a train of electron bunches is utilized to excite a high gradient wakefield in a plasma which can be sampled by a trailing short witness bunch. We show that for five drive bunches with 150 pC total charge which can be generated in the Accelerator Test Facility of the Brookhaven National Lab, a wakefield of 140 MV/m can be generated if the plasma density is matched to the bunch train period. In addition, the possibility of ramping the charge per bunch in order to achieve high transformer ratios (>5) is examined, a scenario that is of great interest for a future afterburner collider. The work was supported by the US Department of Energy.

  20. Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam

    SciTech Connect

    Lotov, K. V.; Sosedkin, A. P.; Petrenko, A. V.; Amorim, L. D.; Vieira, J.; Fonseca, R. A.; Silva, L. O.; Gschwendtner, E.; Muggli, P.

    2014-12-15

    It is shown that co-linear injection of electrons or positrons into the wakefield of the self-modulating particle beam is possible and ensures high energy gain. The witness beam must co-propagate with the tail part of the driver, since the plasma wave phase velocity there can exceed the light velocity, which is necessary for efficient acceleration. If the witness beam is many wakefield periods long, then the trapped charge is limited by beam loading effects. The initial trapping is better for positrons, but at the acceleration stage a considerable fraction of positrons is lost from the wave. For efficient trapping of electrons, the plasma boundary must be sharp, with the density transition region shorter than several centimeters. Positrons are not susceptible to the initial plasma density gradient.

  1. Laser wakefield acceleration of electrons with ionization injection in a pure N{sup 5+} plasma waveguide

    SciTech Connect

    Goers, A. J.; Yoon, S. J.; Elle, J. A.; Hine, G. A.; Milchberg, H. M.

    2014-05-26

    Ionization injection-assisted laser wakefield acceleration of electrons up to 120 MeV is demonstrated in a 1.5 mm long pure helium-like nitrogen plasma waveguide. The guiding structure stabilizes the high energy electron beam pointing and reduces the beam divergence. Our results are confirmed by 3D particle-in-cell simulations.

  2. High Energy Plasma Space Propulsion

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    In order to meet NASA's challenge on advanced concept activity in the propulsion area, we initiated a new program entitled "High Energy Plasma Space Propulsion Studies" within the current cooperative agreement in 1998. The goals of this work are to gain further understanding of the engine of the AIMStar spacecraft, a concept which was developed at Penn State University, and to develop a prototype concept for the engine. The AIMStar engine concept was developed at Penn State University several years ago as a hybrid between antimatter and fusion technologies. Because of limited amounts of antimatter available, and concurrently the demonstrated ability for antiprotons to efficiently ignite nuclear fusion reactions, it was felt that this was a very good match. Investigations have been made concerning the performance of the reaction trap. This is a small Penning-like electromagnetic trap, which is used to simultaneously confine antiprotons and fusion fuels. Small DHe3 or DT droplets, containing a few percent molar of a fissile material, are injected into the trap, filled with antiprotons. We have found that it is important to separate the antiprotons into two adjacent wells, to inject he droplet between them and to simultaneously bring the antiprotons to the center of the trap, surrounding the droplet. Our previous concept had the droplet falling onto one cloud of antiprotons. This proved to be inefficient, as the droplet tended to evaporate away from the cloud as it interacted on its surface.

  3. Emission of strong Terahertz pulses from laser wakefields in weakly coupled plasma

    NASA Astrophysics Data System (ADS)

    Singh, Divya; Malik, Hitendra K.

    2016-09-01

    The present paper discusses the laser plasma interaction for the wakefield excitation and the role of external magnetic field for the emission of Terahertz radiation in a collisional plasma. Flat top lasers are shown to be more appropriate than the conventional Gaussian lasers for the effective excitation of wakefields and hence, the generation of strong Terahertz radiation through the transverse component of wakefield.

  4. Wakefield generation and GeV acceleration in tapered plasma channels

    NASA Astrophysics Data System (ADS)

    Sprangle, P.; Hafizi, B.; Peñano, J. R.; Hubbard, R. F.; Ting, A.; Moore, C. I.; Gordon, D. F.; Zigler, A.; Kaganovich, D.; Antonsen, T. M.

    2001-05-01

    To achieve multi-GeV electron energies in the laser wakefield accelerator (LWFA), it is necessary to propagate an intense laser pulse long distances in a plasma without disruption. One of the purposes of this paper is to evaluate the stability properties of intense laser pulses propagating extended distances (many tens of Rayleigh ranges) in plasma channels. A three-dimensional envelope equation for the laser field is derived that includes nonparaxial effects such as group velocity dispersion, as well as wakefield and relativistic nonlinearities. It is shown that in the broad beam, short pulse limit the nonlinear terms in the wave equation that lead to Raman and modulation instabilities cancel. This cancellation can result in pulse propagation over extended distances, limited only by dispersion. Since relativistic focusing is not effective for short pulses, the plasma channel provides the guiding necessary for long distance propagation. Long pulses (greater than several plasma wavelengths), on the other hand, experience substantial modification due to Raman and modulation instabilities. For both short and long pulses the seed for instability growth is inherently determined by the pulse shape and not by background noise. These results would indicate that the self-modulated LWFA is not the optimal configuration for achieving high energies. The standard LWFA, although having smaller accelerating fields, can provide acceleration for longer distances. It is shown that by increasing the plasma density as a function of distance, the phase velocity of the accelerating field behind the laser pulse can be made equal to the speed of light. Thus electron dephasing in the accelerating wakefield can be avoided and energy gain increased by spatially tapering the plasma channel. Depending on the tapering gradient, this luminous wakefield phase velocity is obtained several plasma wavelengths behind the laser pulse. Simulations of laser pulses propagating in a tapered plasma channel

  5. Mitigation of Ion Motion in future Plasma Wakefield Accelerators

    NASA Astrophysics Data System (ADS)

    Gholizadeh, Reza; Katsouleas, Tom; Muggli, Patric; Mori, Warren

    2007-11-01

    Simulation and analysis of the ion motion in a plasma wakefield accelerator is presented for the parameters required for a future ILC afterburner. We Show that although ion motion leads to substantial emittance growth for extreme parameters of future colliders in the sub-micron transverse beam Size regime, several factors that can mitigate the effect are explored. These include synchrotron radiation damping, plasma density gradients and hot plasmas.

  6. Transverse effects in plasma wakefield acceleration at FACET - Simulation studies

    SciTech Connect

    Adli, E.; Hogan, M.; Frederico, J.; Litos, M. D.; An, W.; Mori, W.

    2012-12-21

    We investigate transverse effects in the plasma-wakefield acceleration experiments planned and ongoing at FACET. We use PIC simulation tools, mainly QuickPIC, to simulate the interaction of the drive electron beam and the plasma. In FACET a number of beam dynamics knobs, including dispersion and bunch length knobs, can be used to vary the beam transverse characteristics in the plasma. We present simulation results and the status of the FACET experimental searches.

  7. Energy Measurements of Trapped Electrons from a Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, Neal; Auerbach, David; Berry, Melissa; Blumenfeld, Ian; Clayton, Christopher E.; Decer, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Johnson, Devon; Joshi, Chadrashekhar; Katsouleas, Thomas; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.

    2007-01-03

    Recent electron beam driven plasma wakefield accelerator experiments carried out at SLAC indicate trapping of plasma electrons. More charge came out of than went into the plasma. Most of this extra charge had energies at or below the 10 MeV level. In addition, there were trapped electron streaks that extended from a few GeV to tens of GeV, and there were mono-energetic trapped electron bunches with tens of GeV in energy.

  8. Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, Neil; /SLAC

    2009-10-30

    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

  9. Experimental studies of plasma wake-field acceleration and focusing

    SciTech Connect

    Rosenzweig, J.B.; Cole, B.; Ho, C.; Gai, W.; Konecny, R.; Mtingwa, S.; Norem, J.; Rosing, M.; Schoessow, P.; Simpson, J.

    1989-07-18

    More than four years after the initial proposal of the Plasma Wake-field Accelerator (PWFA), it continues to be the object of much investigation, due to the promise of the ultra-high accelerating gradients that can exist in relativistic plasma waves driven in the wake of charged particle beams. These large amplitude plasma wake-fields are of interest in the laboratory, both for the wealth of basic nonlinear plasma wave phenomena which can be studied, as well as for the applications of acceleration of focusing of electrons and positrons in future linear colliders. Plasma wake-field waves are also of importance in nature, due to their possible role in direct cosmic ray acceleration. The purpose of the present work is to review the recent experimental advances made in PWFA research at Argonne National Laboratory, in which many interesting beam and plasma phenomena have been observed. Emphasis is given to discussion of the nonlinear aspects of the PWFA beam-plasma interaction. 29 refs., 13 figs.

  10. Efficient accelerator afterburner design based on plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Huang, Chengkun; Blumenfeld, I.; Clayton, C. E.; Decker, F.-J.; Hogan, M. J.; Iverson, R.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, W.; Marsh, K. A.; Mori, W. B.; Muggli, P.; Siemann, R.; Walz, D.; Ischebeck, R.; Tzoufras, M.

    2008-11-01

    Recent plasma wakefield acceleration (PWFA) experiment using short (˜100fs), high peak current (>10KA) electron beam as wakefield driver has demonstrated sustained acceleration gradient of ˜50GeV/m over 85 cm. The rapid progress of PWFA experiments has attracted interests regarding the possibility of making an ``afterburner'' for a linear collider. In the ``afterburner'' concept, electron acceleration is achieved by placing a trailing electron beam into the wakefield (either by beam splitting or external injection) to extract energy deposited in the plasma wave wake. Several important aspects of the ``afterburner'' design in the blow-out regime, such as wakefield generation, efficient beam loading and hosing instability have been investigated theoretically. These relevant physics will have great impact on the beam quality of a possible ``afterburner'' design. A multi-stage ``afterburner'' design with 25GeV energy gain in each stage is explored numerically with a 3D quasi-static code QuickPIC. Parameters are suggested for a 0.5 TeV PWFA afterburner with this design and simulation result will be presented.

  11. First results of the plasma wakefield acceleration experiment at PITZ

    NASA Astrophysics Data System (ADS)

    Lishilin, O.; Gross, M.; Brinkmann, R.; Engel, J.; Grüner, F.; Koss, G.; Krasilnikov, M.; Martinez de la Ossa, A.; Mehrling, T.; Osterhoff, J.; Pathak, G.; Philipp, S.; Renier, Y.; Richter, D.; Schroeder, C.; Schütze, R.; Stephan, F.

    2016-09-01

    The self-modulation instability of long particle beams was proposed as a new mechanism to produce driver beams for proton driven plasma wakefield acceleration (PWFA). The PWFA experiment at the Photo Injector Test facility at DESY, Zeuthen site (PITZ) was launched to experimentally demonstrate and study the self-modulation of long electron beams in plasma. Key aspects for the experiment are the very flexible photocathode laser system, a plasma cell and well-developed beam diagnostics. In this contribution we report about the plasma cell design, preparatory experiments and the results of the first PWFA experiment at PITZ.

  12. High-efficiency acceleration of an electron beam in a plasma wakefield accelerator.

    PubMed

    Litos, M; Adli, E; An, W; Clarke, C I; Clayton, C E; Corde, S; Delahaye, J P; England, R J; Fisher, A S; Frederico, J; Gessner, S; Green, S Z; Hogan, M J; Joshi, C; Lu, W; Marsh, K A; Mori, W B; Muggli, P; Vafaei-Najafabadi, N; Walz, D; White, G; Wu, Z; Yakimenko, V; Yocky, G

    2014-11-01

    High-efficiency acceleration of charged particle beams at high gradients of energy gain per unit length is necessary to achieve an affordable and compact high-energy collider. The plasma wakefield accelerator is one concept being developed for this purpose. In plasma wakefield acceleration, a charge-density wake with high accelerating fields is driven by the passage of an ultra-relativistic bunch of charged particles (the drive bunch) through a plasma. If a second bunch of relativistic electrons (the trailing bunch) with sufficient charge follows in the wake of the drive bunch at an appropriate distance, it can be efficiently accelerated to high energy. Previous experiments using just a single 42-gigaelectronvolt drive bunch have accelerated electrons with a continuous energy spectrum and a maximum energy of up to 85 gigaelectronvolts from the tail of the same bunch in less than a metre of plasma. However, the total charge of these accelerated electrons was insufficient to extract a substantial amount of energy from the wake. Here we report high-efficiency acceleration of a discrete trailing bunch of electrons that contains sufficient charge to extract a substantial amount of energy from the high-gradient, nonlinear plasma wakefield accelerator. Specifically, we show the acceleration of about 74 picocoulombs of charge contained in the core of the trailing bunch in an accelerating gradient of about 4.4 gigavolts per metre. These core particles gain about 1.6 gigaelectronvolts of energy per particle, with a final energy spread as low as 0.7 per cent (2.0 per cent on average), and an energy-transfer efficiency from the wake to the bunch that can exceed 30 per cent (17.7 per cent on average). This acceleration of a distinct bunch of electrons containing a substantial charge and having a small energy spread with both a high accelerating gradient and a high energy-transfer efficiency represents a milestone in the development of plasma wakefield acceleration into a

  13. Parameter sensitivity of plasma wakefields driven by self-modulating proton beams

    SciTech Connect

    Lotov, K. V.; Minakov, V. A.; Sosedkin, A. P.

    2014-08-15

    The dependence of wakefield amplitude and phase on beam and plasma parameters is studied in the parameter area of interest for self-modulating proton beam-driven plasma wakefield acceleration. The wakefield phase is shown to be extremely sensitive to small variations of the plasma density, while sensitivity to small variations of other parameters is reasonably low. The study of large parameter variations clarifies the effects that limit the achievable accelerating field in different parts of the parameter space: nonlinear elongation of the wakefield period, insufficient charge of the drive beam, emittance-driven beam divergence, and motion of plasma ions.

  14. Measurement of the Decelerating Wake in a Plasma Wakefield Accelerator

    SciTech Connect

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

    2009-01-22

    Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch lengths were varied systematically at constant charge. The effort to extract a measurement of the decelerating wake from the maximum energy loss of the electron beam is discussed.

  15. Summary Report of Working Group 4: Plasma Wakefield Acceleration

    SciTech Connect

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

    2012-06-11

    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.

  16. Summary Report of Working Group 4: Plasma Wakefield Acceleration

    SciTech Connect

    Rosenzweig, J. B.; Seryi, A.

    2010-11-04

    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.

  17. The status and evolution of plasma Wakefield particle accelerators.

    PubMed

    Joshi, C; Mori, W B

    2006-03-15

    The status and evolution of the electron beam-driven Plasma Wakefield Acceleration scheme is described. In particular, the effects of the radial electric field of the wake on the drive beam such as multiple envelope oscillations, hosing instability and emission of betatron radiation are described. Using ultra-short electron bunches, high-density plasmas can be produced by field ionization by the electric field of the bunch itself. Wakes excited in such plasmas have accelerated electrons in the back of the drive beam to greater that 4 G eV in just 10 cm in experiments carried out at the Stanford Linear Accelerator Centre. PMID:16483949

  18. Controlled injection and acceleration of electrons in plasma wakefields by colliding laser pulses.

    PubMed

    Faure, J; Rechatin, C; Norlin, A; Lifschitz, A; Glinec, Y; Malka, V

    2006-12-01

    In laser-plasma-based accelerators, an intense laser pulse drives a large electric field (the wakefield) which accelerates particles to high energies in distances much shorter than in conventional accelerators. These high acceleration gradients, of a few hundreds of gigavolts per metre, hold the promise of compact high-energy particle accelerators. Recently, several experiments have shown that laser-plasma accelerators can produce high-quality electron beams, with quasi-monoenergetic energy distributions at the 100 MeV level. However, these beams do not have the stability and reproducibility that are required for applications. This is because the mechanism responsible for injecting electrons into the wakefield is based on highly nonlinear phenomena, and is therefore hard to control. Here we demonstrate that the injection and subsequent acceleration of electrons can be controlled by using a second laser pulse. The collision of the two laser pulses provides a pre-acceleration stage which provokes the injection of electrons into the wakefield. The experimental results show that the electron beams obtained in this manner are collimated (5 mrad divergence), monoenergetic (with energy spread <10 per cent), tuneable (between 15 and 250 MeV) and, most importantly, stable. In addition, the experimental observations are compatible with electron bunch durations shorter than 10 fs. We anticipate that this stable and compact electron source will have a strong impact on applications requiring short bunches, such as the femtolysis of water, or high stability, such as radiotherapy with high-energy electrons or radiography for materials science. PMID:17151663

  19. Optical Frequency Domain Visualization of Electron Beam Driven Plasma Wakefields

    NASA Astrophysics Data System (ADS)

    Zgadzaj, Rafal; Downer, M. C.; Muggli, Patric; Yakimenko, Vitaly; Babzien, Marcus; Kusche, Karl; Fedurin, Mikhail

    2010-11-01

    Beam-driven plasma wakefield accelerators (PWFA), such as the ``plasma afterburner,'' are a promising approach for significantly increasing the particle energies of conventional accelerators. The study and optimization of PWFA would benefit from an experimental correlation between the parameters of the drive bunch, the accelerated bunch and the corresponding, accelerating plasma wave structure. However, the plasma wave structure has not yet been observed directly in PWFA. We will report our current work on noninvasive optical Frequency Domain Interferometric (FDI) and Holographic (FDH) visualization of beam-driven plasma waves. Both techniques employ two laser pulses (probe and reference) co-propagating with the particle drive-beam and its plasma wake. The reference pulse precedes the drive bunch, while the probe overlaps the plasma wave and maps its longitudinal and transverse structure. The experiment is being developed at the BNL/ATF Linac to visualize wakes generated by two and multi-bunch drive beams.

  20. Beam head erosion in self-ionized plasma wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Zhou, Miaomiao; Clayton, Chris; Huang, Chengkun; Joshi, Chan; Lu, Wei; Marsh, Ken; Mori, Warren; Katsouleas, Tom; Muggli, Patric; Oz, Erdem; Berry, Melissa; Blumenfeld, Ian; Decker, Franz-Josef; Hogan, Mark; Ischebeck, Rasmus; Iverson, Richard; Kirby, Neil; Siemman, Robert; Walz, Dieter

    2007-11-01

    In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon -- beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by beta*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. Beam/plasma parameter scan in a large range using simulations shows that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A theoretical analysis on the erosion rate dependence on beam/plasma parameters and its implications on future afterburner relevant experiments will be provided. [1] I. Blumenfeld et al., Nature 445, 741(2007) [2] J. B. Rosenzweig et al., Phys. Rev. A 44, R6189 (1991)

  1. Plasma wakefield acceleration with a modulated proton bunch

    SciTech Connect

    Caldwell, A.; Lotov, K. V.

    2011-10-15

    The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.

  2. Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators

    SciTech Connect

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

    2008-01-28

    In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.

  3. Long-term evolution of broken wakefields in finite-radius plasmas.

    PubMed

    Lotov, K V; Sosedkin, A P; Petrenko, A V

    2014-05-16

    A novel effect of fast heating and charging a finite-radius plasma is discovered in the context of plasma wakefield acceleration. As the plasma wave breaks, most of its energy is transferred to plasma electrons. The electrons gain substantial transverse momentum and escape the plasma radially, which gives rise to a strong charge-separation electric field and azimuthal magnetic field around the plasma. The slowly varying field structure is preserved for hundreds of wakefield periods and contains (together with hot electrons) up to 80% of the initial wakefield energy. PMID:24877943

  4. Wakefield generation and GeV acceleration in tapered plasma channels.

    PubMed

    Sprangle, P; Hafizi, B; Peñano, J R; Hubbard, R F; Ting, A; Moore, C I; Gordon, D F; Zigler, A; Kaganovich, D; Antonsen, T M

    2001-05-01

    To achieve multi-GeV electron energies in the laser wakefield accelerator (LWFA), it is necessary to propagate an intense laser pulse long distances in a plasma without disruption. One of the purposes of this paper is to evaluate the stability properties of intense laser pulses propagating extended distances (many tens of Rayleigh ranges) in plasma channels. A three-dimensional envelope equation for the laser field is derived that includes nonparaxial effects such as group velocity dispersion, as well as wakefield and relativistic nonlinearities. It is shown that in the broad beam, short pulse limit the nonlinear terms in the wave equation that lead to Raman and modulation instabilities cancel. This cancellation can result in pulse propagation over extended distances, limited only by dispersion. Since relativistic focusing is not effective for short pulses, the plasma channel provides the guiding necessary for long distance propagation. Long pulses (greater than several plasma wavelengths), on the other hand, experience substantial modification due to Raman and modulation instabilities. For both short and long pulses the seed for instability growth is inherently determined by the pulse shape and not by background noise. These results would indicate that the self-modulated LWFA is not the optimal configuration for achieving high energies. The standard LWFA, although having smaller accelerating fields, can provide acceleration for longer distances. It is shown that by increasing the plasma density as a function of distance, the phase velocity of the accelerating field behind the laser pulse can be made equal to the speed of light. Thus electron dephasing in the accelerating wakefield can be avoided and energy gain increased by spatially tapering the plasma channel. Depending on the tapering gradient, this luminous wakefield phase velocity is obtained several plasma wavelengths behind the laser pulse. Simulations of laser pulses propagating in a tapered plasma channel

  5. Wakefield structure of plasma hollow channels self-driven by tightly focused beams

    NASA Astrophysics Data System (ADS)

    Amorim, Ligia D.; Vieira, Jorge; Fonseca, Ricardo A.; Silva, Luis O.

    2015-11-01

    Plasma based wakefield accelerators (PWFA) are promising alternatives to conventional configurations due to the high accelerating gradients they can sustain. For future linear colliders, however, PWFAs need to overcome the challenge of efficiently accelerating positrons. PWFAs regimes with high acceleration gradients typically defocus positron bunches. Several techniques have tried to solve this challenge. Here we explore how tightly focused positron bunches sent through homogeneous plasmas can radially expel the plasma ions generating a hollow channel with high accelerating and focusing fields. We modeled the hollow channel accelerating and focusing wakefields structures analytically, and found good agreement with 3D numerical simulations performed with the PIC code OSIRS. We demonstrated that this scheme could accelerate positrons to high energies. Furthermore, we analyzed the impact of the key drive bunch properties on the formation of the hollow channel, finding that bunches with short fall times (compared to electron bubble radius) and small transverse sizes (compared to plasma skin depth) maximize both accelerating and focusing fields. We also studied hollow channels driven by laser beams. Work supported by FCT grant SFRH/BD/84851/2012. We acknowledge PRACE for access to resources on SuperMUC (Leibniz Research Center).

  6. Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

    SciTech Connect

    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.

    2012-12-21

    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.

  7. Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Hidding, B.; Rosenzweig, J. B.; Xi, Y.; O'Shea, B.; Andonian, G.; Schiller, D.; Barber, S.; Williams, O.; Pretzler, G.; Königstein, T.; Kleeschulte, F.; Hogan, M. J.; Litos, M.; Corde, S.; White, W. W.; Muggli, P.; Bruhwiler, D. L.; Lotov, K.

    2012-12-01

    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.

  8. Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator

    SciTech Connect

    Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Joshi, Chandrashekhar; Katsouleas, Thomas; Kirby, Neil; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.

    2007-03-14

    The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively doubles their energy, producing the energy gain of the 3-km-long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-energy physics applications.

  9. Preservation of Ultra Low Emittances Using Adiabatic Matching in Future Plasma Wakefield-based Colliders

    SciTech Connect

    Gholizadeh, Reza; Muggli, Patric; Katsouleas, Tom; Mori, Warren

    2009-01-22

    The Plasma Wakefield Accelerator is a promising technique to lower the cost of the future high energy colliders by offering orders of magnitude higher gradients than the conventional accelerators. It has been shown that ion motion is an important issue to account for in the extreme regime of ultra high energies and ultra low emittances, characteristics of future high energy collider beams. In this regime, the transverse electric field of the beam is so high that in simulations, the plasma ions cannot be considered immobile at the time scale of electron plasma oscillation, thereby leading to a nonlinear focusing force. Therefore, the transverse emittance of a beam will not be preserved under these circumstances. However, we show that matched profile in case of a nonlinear focusing force still exists and can be derived from Vlasov equation. Furthermore, we introduce a plasma section that can reduce the emittance growth by adiabatically reducing the ion mass and hence increasing the nonlinear term in the focusing force. Simulation results are presented.

  10. GEANT4 simulations for beam emittance in a linear collider based on plasma wakefield acceleration

    SciTech Connect

    Mete, O. Xia, G.; Hanahoe, K.; Labiche, M.

    2015-08-15

    Alternative acceleration technologies are currently under development for cost-effective, robust, compact, and efficient solutions. One such technology is plasma wakefield acceleration, driven by either a charged particle or laser beam. However, the potential issues must be studied in detail. In this paper, the emittance evolution of a witness beam through elastic scattering from gaseous media and under transverse focusing wakefields is studied.

  11. Effect of plasma inhomogeneity on plasma wakefield acceleration driven by long bunches

    SciTech Connect

    Lotov, K. V.; Pukhov, A.; Caldwell, A.

    2013-01-15

    Effects of plasma inhomogeneity on self-modulating proton bunches and accelerated electrons were studied numerically. The main effect is the change of the wakefield wavelength which results in phase shifts and loss of accelerated particles. This effect imposes severe constraints on density uniformity in plasma wakefield accelerators driven by long particle bunches. The transverse two stream instability that transforms the long bunch into a train of micro-bunches is less sensitive to density inhomogeneity than are the accelerated particles. The bunch freely passes through increased density regions and interacts with reduced density regions.

  12. Optical Frequency Domain Visualization of Electron Beam Driven Plasma Wakefields

    NASA Astrophysics Data System (ADS)

    Zgadzaj, Rafal; Downer, Michael C.; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl; Fedurin, Michhail; Babzien, Marcus

    2010-11-01

    Bunch driven plasma wakefield accelerators (PWFA), such as the "plasma afterburner," are a promising emerging method for significantly increasing the energy output of conventional particle accelerators [1]. The study and optimization of this method would benefit from an experimental correlation of the drive bunch parameters and the accelerated particle parameters with the corresponding plasma wave structure. However, the plasma wave structure has not been observed directly so far. We will report ongoing development of a noninvasive optical Frequency Domain Interferometric (FDI) [2] and Holographic (FDH) [3] diagnostics of bunch driven plasma wakes. Both FDI and FDH have been previously demonstrated in the case of laser driven wakes. These techniques employ two laser pulses co-propagating with the drive particle bunch and the trailing plasma wave. One pulse propagates ahead of the drive bunch and serves as a reference, while the second is overlapped with the plasma wave and probes its structure. The multi-shot FDI and single-shot FDH diagnostics permit direct noninvasive observation of longitudinal and transverse structure of the plasma wakes. The experiment is being developed at the 70 MeV Linac in the Accelerator Test Facility at Brookhaven National Laboratory to visualize wakes generated by two [4] and multi-bunch [5] drive beams.

  13. Optical Frequency Domain Visualization of Electron Beam Driven Plasma Wakefields

    SciTech Connect

    Zgadzaj, Rafal; Downer, Michael C.; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl; Fedurin, Michhail; Babzien, Marcus

    2010-11-04

    Bunch driven plasma wakefield accelerators (PWFA), such as the 'plasma afterburner', are a promising emerging method for significantly increasing the energy output of conventional particle accelerators. The study and optimization of this method would benefit from an experimental correlation of the drive bunch parameters and the accelerated particle parameters with the corresponding plasma wave structure. However, the plasma wave structure has not been observed directly so far. We will report ongoing development of a noninvasive optical Frequency Domain Interferometric (FDI) and Holographic (FDH) diagnostics of bunch driven plasma wakes. Both FDI and FDH have been previously demonstrated in the case of laser driven wakes. These techniques employ two laser pulses co-propagating with the drive particle bunch and the trailing plasma wave. One pulse propagates ahead of the drive bunch and serves as a reference, while the second is overlapped with the plasma wave and probes its structure. The multi-shot FDI and single-shot FDH diagnostics permit direct noninvasive observation of longitudinal and transverse structure of the plasma wakes. The experiment is being developed at the 70 MeV Linac in the Accelerator Test Facility at Brookhaven National Laboratory to visualize wakes generated by two and multi-bunch drive beams.

  14. Simulations of a meter-long plasma wakefield accelerator

    SciTech Connect

    Lee, S.; Katsouleas, T.; Hemker, R.; Mori, W. B.

    2000-06-01

    Full-scale particle-in-cell simulations of a meter-long plasma wakefield accelerator (PWFA) are presented in two dimensions. The results support the design of a current PWFA experiment in the nonlinear blowout regime where analytic solutions are intractable. A relativistic electron bunch excites a plasma wake that accelerates trailing particles at rates of several hundred MeV/m. A comparison is made of various simulation codes, and a parallel object-oriented code OSIRIS is used to model a full meter of acceleration. Excellent agreement is obtained between the simulations and analytic expressions for the transverse betatron oscillations of the beam. The simulations are used to develop scaling laws for designing future multi-GeV accelerator experiments. (c) 2000 The American Physical Society.

  15. Neutrino-driven wakefield plasma accelerator

    NASA Astrophysics Data System (ADS)

    Rios, L. A.; Serbeto, A.

    2003-08-01

    Processos envolvendo neutrinos são importantes em uma grande variedade de fenômenos astrofísicos, como as explosões de supernovas. Estes objetos, assim como os pulsares e as galáxias starburst, têm sido propostos como aceleradores cósmicos de partículas de altas energias. Neste trabalho, um modelo clássico de fluidos é utilizado para estudar a interação não-linear entre um feixe de neutrinos e um plasma não-colisional relativístico de pósitrons e elétrons na presença de um campo magnético. Durante a interação, uma onda híbrida superior de grande amplitude é excitada. Para parâmetros típicos de supernovas, verificamos que partículas carregadas "capturadas" por essa onda podem ser aceleradas a altas energias. Este resultado pode ser importante no estudo de mecanismos aceleradores de partículas em ambientes astrofísicos.

  16. Design of a plasma discharge circuit for particle wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Anania, M. P.; Chiadroni, E.; Cianchi, A.; Di Giovenale, D.; Ferrario, M.; Flora, F.; Gallerano, G. P.; Ghigo, A.; Marocchino, A.; Massimo, F.; Mostacci, A.; Mezi, L.; Musumeci, P.; Serio, M.

    2014-03-01

    Plasma wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV m-1), enabling acceleration of electrons to GeV energy in few centimetres. However, the quality of the electron bunches accelerated with this technique is still not comparable with that of conventional accelerators; radiofrequency-based accelerators, in fact, are limited in the accelerating field (10-100 MV m-1) requiring therefore kilometric distances to reach the GeV energies, but can provide very bright electron bunches. Combining high brightness electron bunches from conventional accelerators and high accelerating fields reachable with plasmas could be a good compromise allowing to further accelerate high brightness electron bunches coming from LINAC while preserving electron beam quality. Following the idea of plasma wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of plasma for SPARC-LAB [1,2]. In particular, here we focus on the ionization process; we show a simplified model to study the evolution of plasma induced by discharge, very useful to design the discharge circuit able to fully ionize the gas and bring the plasma at the needed temperature and density.

  17. Simulation of High Energy Density Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce

    2004-05-01

    High Energy Density plasmas are found in astrophysical environments, have been generated in past underground nuclear tests, and can be created in the laboratory by, e.g. laser or pulsed power experiments. These experiments can be used to validate simulation capabilities that are being developed to advance our understanding of plasma physics, and to develop predictive capabilities for HED plasma applications such as fusion energy. In this talk we will briefly introduce the subject of simulating HED plasmas using radiation hydrodynamics codes. We will give examples of simple test problems, showing how a problem is approached, including geometry specifications, simplifying assumptions, zoning, initial and boundary conditions, basic data on opacities and EOS, and illustrate sensitivities of results to variations. We will also show highlights of work at Los Alamos to validate codes, provide basic data, and develop applications, for example: 1) studying phenomena such as Rayleigh-Taylor and Richtmeyer-Meshkov instabilities, ablation, and supersonic jets at the Omega laser in Rochester and the Sandia Z Machine; 2) quantum molecular dynamics simulations which have recently led to a semi-classical, particle-particle particle-mesh code that allows ultra-fast simulations involving tens of thousands of particles to calculate properties of hot dense plasmas; 3) efforts to experimentally demonstrate the physics basis for magnetized target fusion (MTF), a potentially low cost path to fusion, intermediate in plasma regime between magnetic and inertial fusion energy.

  18. Narrow spread electron beams from a laser-plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Wiggins, S. M.; Anania, M. P.; Brunetti, E.; Cipiccia, S.; Ersfeld, B.; Islam, M. R.; Issac, R. C.; Raj, G.; Shanks, R. P.; Vieux, G.; Welsh, G. H.; Gillespie, W. A.; MacLeod, A. M.; Jaroszynski, D. A.

    2009-05-01

    The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme is developing laserplasma accelerators for the production of ultra-short electron bunches with subsequent generation of incoherent radiation pulses from plasma and coherent short-wavelength radiation pulses from a free-electron laser (FEL). The first quantitative measurements of the electron energy spectra have been made on the University of Strathclyde ALPHA-X wakefield acceleration beam line. A high peak power laser pulse (energy 900 mJ, duration 35 fs) is focused into a gas jet (nozzle length 2 mm) using an F/16 spherical mirror. Electrons from the laser-induced plasma are self-injected into the accelerating potential of the plasma density wake behind the laser pulse. Electron beams emitted from the plasma have been imaged downstream using a series of Lanex screens positioned along the beam line axis and the divergence of the electron beam has been measured to be typically in the range 1-3 mrad. Measurements of the electron energy spectrum, obtained using the ALPHA-X high resolution magnetic dipole spectrometer, are presented. The maximum central energy of the monoenergetic beam is 90 MeV and r.m.s. relative energy spreads as low as 0.8% are measured. The mean central energy is 82 MeV and mean relative energy spread is 1.1%. A theoretical analysis of this unexpectedly high electron beam quality is presented and the potential impact on the viability of FELs driven by electron beams from laser wakefield accelerators is examined.

  19. Application of Plasma Waveguides to High Energy Accelerators

    SciTech Connect

    Milchberg, Howard M

    2013-03-30

    The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We

  20. Excitation of two-dimensional plasma wakefields by trains of equidistant particle bunches

    SciTech Connect

    Lotov, K. V.

    2013-08-15

    Nonlinear effects responsible for elongation of the plasma wave period are numerically studied with the emphasis on two-dimensionality of the wave. The limitation on the wakefield amplitude imposed by detuning of the wave and the driver is found.

  1. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  2. Influence of emittance on transverse dynamics of accelerated bunches in the plasma-dielectric wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Kniaziev, R. R.; Sotnikov, G. V.

    2016-09-01

    We study theoretically transverse dynamics of the bunch of charged particles with the finite emittance in the plasma-dielectric wakefield accelerator. Parameters of bunches are chosen the same as available from the 15 MeV Argonne Wakefield Accelerator beamline. The goal of the paper is to study the behavior of bunches of charged particles with different emittances while accelerating these bunches by wakefields in plasma-dielectric structures. Obtained results allow us to determine the limits of the emittance of the bunch where dynamics of the accelerated particles remains stable.

  3. Proposed method for high-speed plasma density measurement in proton-driven plasma wakefield acceleration

    SciTech Connect

    Tarkeshian, R.; Reimann, O.; Muggli, P.

    2012-12-21

    Recently a proton-bunch-driven plasma wakefield acceleration experiment using the CERN-SPS beam was proposed. Different types of plasma cells are under study, especially laser ionization, plasma discharge, and helicon sources. One of the key parameters is the spatial uniformity of the plasma density profile along the cell that has to be within < 1% of the nominal density (6 Multiplication-Sign 10{sup 14} cm{sup -3}). Here a setup based on a photomixing concept is proposed to measure the plasma cut-off frequency and determine the plasma density.

  4. Magnetically Controlled Plasma Waveguide For Laser Wakefield Acceleration

    SciTech Connect

    Froula, D H; Divol, L; Davis, P; Palastro, J; Michel, P; Leurent, V; Glenzer, S H; Pollock, B; Tynan, G

    2008-05-14

    An external magnetic field applied to a laser plasma is shown produce a plasma channel at densities relevant to creating GeV monoenergetic electrons through laser wakefield acceleration. Furthermore, the magnetic field also provides a pressure to help shape the channel to match the guiding conditions of an incident laser beam. Measured density channels suitable for guiding relativistic short-pulse laser beams are presented with a minimum density of 5 x 10{sup 17} cm{sup -3} which corresponds to a linear dephasing length of several centimeters suitable for multi-GeV electron acceleration. The experimental setup at the Jupiter Laser Facility, Lawrence Livermore National Laboratory, where a 1-ns, 150 J 1054 nm laser will produce a magnetically controlled channel to guide a < 75 fs, 10 J short-pulse laser beam through 5-cm of 5 x 10{sup 17} cm{sup -3} plasma is presented. Calculations presented show that electrons can be accelerated to 3 GeV with this system. Three-dimensional resistive magneto-hydrodynamic simulations are used to design the laser and plasma parameters and quasi-static kinetic simulations indicate that the channel will guide a 200 TW laser beam over 5-cm.

  5. High-gradient plasma-wakefield acceleration with two subpicosecond electron bunches.

    PubMed

    Kallos, Efthymios; Katsouleas, Tom; Kimura, Wayne D; Kusche, Karl; Muggli, Patric; Pavlishin, Igor; Pogorelsky, Igor; Stolyarov, Daniil; Yakimenko, Vitaly

    2008-02-22

    A plasma-wakefield experiment is presented where two 60 MeV subpicosecond electron bunches are sent into a plasma produced by a capillary discharge. Both bunches are shorter than the plasma wavelength, and the phase of the second bunch relative to the plasma wave is adjusted by tuning the plasma density. It is shown that the second bunch experiences a 150 MeV/m loaded accelerating gradient in the wakefield driven by the first bunch. This is the first experiment to directly demonstrate high-gradient, controlled acceleration of a short-pulse trailing electron bunch in a high-density plasma. PMID:18352561

  6. Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes

    SciTech Connect

    Geddes, C.G.R.; Cormier-Michel, E.; Esarey, E.; Schroeder, C.B.; Mullowney, P.; Paul, K.; Cary, J.R.; Leemans, W.P.

    2010-06-01

    Laser-plasma collider designs point to staging of multiple accelerator stages at the 10 GeV level, which are to be developed on the upcoming BELLA laser, while Thomson Gamma source designs use GeV stages, both requiring efficiency and low emittance. Design and scaling of stages operating in the quasi-linear regime to address these needs are presented using simulations in the VORPAL framework. In addition to allowing symmetric acceleration of electrons and positrons, which is important for colliders, this regime has the property that the plasma wakefield is proportional to the transverse gradient of the laser intensity profile. We demonstrate use of higher order laser modes to tailor the laser pulse and hence the transverse focusing forces in the plasma. In particular, we show that by using higher order laser modes, we can reduce the focusing fields and hence increase the matched electron beam radius, which is important to increased charge and efficiency, while keeping the low bunch emittance required for applications.

  7. Laser-Plasma Wakefield Acceleration with Higher Order Laser Modes

    SciTech Connect

    Geddes, C. G. R.; Schroeder, C. B.; Cormier-Michel, E.; Mullowney, P.; Paul, K.; Esarey, E.; Cary, J. R.; Leemans, W. P.

    2010-11-04

    Laser-plasma collider designs point to staging of multiple accelerator stages at the 10 GeV level, which are to be developed on the upcoming BELLA laser, while Thomson Gamma source designs use GeV stages, both requiring efficiency and low emittance. Design and scaling of stages operating in the quasi-linear regime to address these needs are presented using simulations in the VORPAL framework. In addition to allowing symmetric acceleration of electrons and positrons, which is important for colliders, this regime has the property that the plasma wakefield is proportional to the transverse gradient of the laser intensity profile. We demonstrate use of higher order laser modes to tailor the laser pulse and hence the transverse focusing forces in the plasma. In particular, we show that by using higher order laser modes, we can reduce the focusing fields and hence increase the matched electron beam radius, which is important to increased charge and efficiency, while keeping the low bunch emittance required for applications.

  8. Simulations of a High-Transformer-Ratio Plasma Wakefield Accelerator Using Multiple Electron Bunches

    SciTech Connect

    Kallos, Efthymios; Muggli, Patric; Katsouleas, Thomas; Yakimenko, Vitaly; Park, Jangho

    2009-01-22

    Particle-in-cell simulations of a plasma wakefield accelerator in the linear regime are presented, consisting of four electron bunches that are fed into a high-density plasma. It is found that a high transformer ratio can be maintained over 43 cm of plasma if the charge in each bunch is increased linearly, the bunches are placed 1.5 plasma wavelengths apart and the bunch emmitances are adjusted to compensate for the nonlinear focusing forces. The generated wakefield is sampled by a test witness bunch whose energy gain after the plasma is six times the energy loss of the drive bunches.

  9. Enhanced betatron X-rays from axially modulated plasma wakefields

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-01

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  10. Enhanced betatron X-rays from axially modulated plasma wakefields

    SciTech Connect

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-15

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  11. Wakefields generated by collisional neutrinos in neutral-electron-positron plasma

    SciTech Connect

    Tinakiche, Nouara

    2013-02-15

    A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in this plasma.

  12. Demonstration of a positron beam-driven hollow channel plasma wakefield accelerator.

    PubMed

    Gessner, Spencer; Adli, Erik; Allen, James M; An, Weiming; Clarke, Christine I; Clayton, Chris E; Corde, Sebastien; Delahaye, J P; Frederico, Joel; Green, Selina Z; Hast, Carsten; Hogan, Mark J; Joshi, Chan; Lindstrøm, Carl A; Lipkowitz, Nate; Litos, Michael; Lu, Wei; Marsh, Kenneth A; Mori, Warren B; O'Shea, Brendan; Vafaei-Najafabadi, Navid; Walz, Dieter; Yakimenko, Vitaly; Yocky, Gerald

    2016-01-01

    Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition to being accelerated by the plasma wakefield, the beam particles also experience strong transverse forces that may disrupt the beam quality. Hollow plasma channels have been proposed as a technique for generating accelerating fields without transverse forces. Here we demonstrate a method for creating an extended hollow plasma channel and measure the wakefields created by an ultrarelativistic positron beam as it propagates through the channel. The plasma channel is created by directing a high-intensity laser pulse with a spatially modulated profile into lithium vapour, which results in an annular region of ionization. A peak decelerating field of 230 MeV m(-1) is inferred from changes in the beam energy spectrum, in good agreement with theory and particle-in-cell simulations. PMID:27250570

  13. Demonstration of a positron beam-driven hollow channel plasma wakefield accelerator

    PubMed Central

    Gessner, Spencer; Adli, Erik; Allen, James M.; An, Weiming; Clarke, Christine I.; Clayton, Chris E.; Corde, Sebastien; Delahaye, J. P.; Frederico, Joel; Green, Selina Z.; Hast, Carsten; Hogan, Mark J.; Joshi, Chan; Lindstrøm, Carl A.; Lipkowitz, Nate; Litos, Michael; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; O'Shea, Brendan; Vafaei-Najafabadi, Navid; Walz, Dieter; Yakimenko, Vitaly; Yocky, Gerald

    2016-01-01

    Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition to being accelerated by the plasma wakefield, the beam particles also experience strong transverse forces that may disrupt the beam quality. Hollow plasma channels have been proposed as a technique for generating accelerating fields without transverse forces. Here we demonstrate a method for creating an extended hollow plasma channel and measure the wakefields created by an ultrarelativistic positron beam as it propagates through the channel. The plasma channel is created by directing a high-intensity laser pulse with a spatially modulated profile into lithium vapour, which results in an annular region of ionization. A peak decelerating field of 230 MeV m−1 is inferred from changes in the beam energy spectrum, in good agreement with theory and particle-in-cell simulations. PMID:27250570

  14. Demonstration of a positron beam-driven hollow channel plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Gessner, Spencer; Adli, Erik; Allen, James M.; An, Weiming; Clarke, Christine I.; Clayton, Chris E.; Corde, Sebastien; Delahaye, J. P.; Frederico, Joel; Green, Selina Z.; Hast, Carsten; Hogan, Mark J.; Joshi, Chan; Lindstrøm, Carl A.; Lipkowitz, Nate; Litos, Michael; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; O'Shea, Brendan; Vafaei-Najafabadi, Navid; Walz, Dieter; Yakimenko, Vitaly; Yocky, Gerald

    2016-06-01

    Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition to being accelerated by the plasma wakefield, the beam particles also experience strong transverse forces that may disrupt the beam quality. Hollow plasma channels have been proposed as a technique for generating accelerating fields without transverse forces. Here we demonstrate a method for creating an extended hollow plasma channel and measure the wakefields created by an ultrarelativistic positron beam as it propagates through the channel. The plasma channel is created by directing a high-intensity laser pulse with a spatially modulated profile into lithium vapour, which results in an annular region of ionization. A peak decelerating field of 230 MeV m-1 is inferred from changes in the beam energy spectrum, in good agreement with theory and particle-in-cell simulations.

  15. Demonstration of a positron beam-driven hollow channel plasma wakefield accelerator

    DOE PAGESBeta

    Gessner, Spencer; Adli, Erik; Allen, James M.; An, Weiming; Clarke, Christine I.; Clayton, Chris E.; Corde, Sebastien; Delahaye, J. P.; Frederico, Joel; Green, Selina Z.; et al

    2016-06-02

    Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition to being accelerated by the plasma wakefield, the beam particles also experience strong transverse forces that may disrupt the beam quality. Hollow plasma channels have been proposed as a technique for generating accelerating fields without transverse forces. In this study, we demonstrate a method for creating an extended hollow plasma channel and measure the wakefields created by an ultrarelativistic positron beam as it propagates through the channel. The plasma channel ismore » created by directing a high-intensity laser pulse with a spatially modulated profile into lithium vapour, which results in an annular region of ionization. A peak decelerating field of 230 MeV m-1 is inferred from changes in the beam energy spectrum, in good agreement with theory and particle-in-cell simulations.« less

  16. Plasma Density Tapering for Laser Wakefield Acceleration of Electrons and Protons

    SciTech Connect

    Ting, A.; Gordon, D.; Kaganovich, D.; Sprangle, P.; Helle, M.; Hafizi, B.

    2010-11-04

    Extended acceleration in a Laser Wakefield Accelerator can be achieved by tailoring the phase velocity of the accelerating plasma wave, either through profiling of the density of the plasma or direct manipulation of the phase velocity. Laser wakefield acceleration has also reached a maturity that proton acceleration by wakefield could be entertained provided we begin with protons that are substantially relativistic, {approx}1 GeV. Several plasma density tapering schemes are discussed. The first scheme is called ''bucket jumping'' where the plasma density is abruptly returned to the original density after a conventional tapering to move the accelerating particles to a neighboring wakefield period (bucket). The second scheme is designed to specifically accelerate low energy protons by generating a nonlinear wakefield in a plasma region with close to critical density. The third scheme creates a periodic variation in the phase velocity by beating two intense laser beams with laser frequency difference equal to the plasma frequency. Discussions and case examples with simulations are presented where substantial acceleration of electrons or protons could be obtained.

  17. High-brightness, high-energy radiation generation from non-linear Thomson scattering of laser wakefield accelerated electrons

    NASA Astrophysics Data System (ADS)

    Schumaker, W.; Zhao, Z.; Thomas, A. G. R.; Krushelnick, K.; Sarri, G.; Corvan, D.; Zepf, M.; Cole, J.; Mangles, S. P. D.; Najmudin, Z.

    2014-10-01

    To date, all-optical sources of high-energy (>MeV) photons have only been reported in the linear (a0 < 1) regime of Thomson scattering using laser wakefield acceleration (LWFA). We present novel results of high-brightness, high-energy photons generated via non-linear Thomson scattering using the two-beam Astra-Gemini laser facility. With one 300 TW beam, electrons were first accelerated to 500 MeV energies inside gas cells through the process of LWFA. A second 300 TW laser pulse focused to a0 = 2 was subsequently scattered off these electrons, resulting in a highly directional, small source size, and short pulse beam of photons with >10 MeV energies. The photon beam was propagated through a low- Z converter and produced Compton-scattered electrons that were spectrally measured by magnetic deflection and correlated with the incident photons. The measured photon yield at 15 MeV was 2 ×106 photons/MeV and, when coupled with the small source size, divergence, and pulse duration, results in a record peak brightness of 2 ×1019 photons/s/mm2/mrad2/0.1%bandwidth at 15 MeV photon energy. Current Affiliation: Stanford University/SLAC National Accelerator Laboratory.

  18. Laser Wakefield Structures and Electron Acceleration in Gas Jet and Capillary Discharge Plasmas

    NASA Astrophysics Data System (ADS)

    Maksimchuk, Anatoly

    2007-11-01

    Laser-driven plasma wakefield accelerators have the potential to become the next generation of particle accelerators because of the very high acceleration gradients. The beam quality from such accelerators depends critically on the details plasma wave spatial structures. In experiments at the University of Michigan it was possible in a single shot by frequency domain holography (FDH) to visualize individual plasma waves produced by the 40 TW, 30 fs Hercules laser focused to the intensity of 10^19 W/cm^2 onto a supersonic He gas jet [1]. These holographic ``snapshots'' capture the evolution of multiple wake periods, and resolve wavefront curvature seen previously only in simulations. High-energy quasi-monoenergetic electron beams for plasma density in the specific range 1.5x10^19<=ne<=3.5x10^19 cm-3 were generated [2]. The experiments show that the energy, charge, divergence and pointing stability of the beam can be controlled by changing ne, and that higher electron energies and more stable beams are produced for lower densities. An optimized quasi-monoenergetic beam of over 300 MeV and 10 mrad angular divergence is demonstrated at a plasma density of ne=1.5x10^19 cm-3. The resulted relativistic electron beams have been used to perform gamma-neutron activation of ^12C and ^63Cu and photo-fission of ^238U with a record high reaction yields of ˜5x10^5/Joule [3]. Experiments performed with ablative capillary discharge plasma demonstrate stable guiding for laser power up to 10 TW with the transmission of 50% and guided intensity of ˜10^17 W/cm^2. Study of the staged electron acceleration have been performed which uses ablated plasma in front of the capillary to inject electrons into the wakefield structures. [1] N. H. Matlis et. al., Nature Physics 2, 749 (2006). [2] A. Maksimchuk et. al., Journal de Physique IV 133, 1123 (2006). [3] S. A. Reed et. al., Appl. Phys. Lett. 89, 231107 (2006).

  19. Probing the laser wakefield in underdense plasmas by induced terahertz emission

    SciTech Connect

    Hu, Z. D.; Wang, W. M.; Chen, L. M.; Li, Y. T.; Sheng, Z. M.; Zhang, J.; Key Laboratory for Laser Plasmas and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240

    2013-08-15

    Terahertz (THz) radiation can be produced from a laser wakefield driven in underdense plasmas in the presence of a transverse DC magnetic field. It is shown that the radiation usually contains a component at the electron plasma frequency and its harmonics when the wakefield is excited at high amplitudes. In the highly nonlinear bubble/blowout regime, the radiation contains a smooth component peaked at the reduced electron plasma frequency and an irregular spectrum extending to tens of the electron plasma frequency. The latter is due to the broken-wave structure behind the bubble. A theoretical model is presented and validated via two-dimensional particle-in-cell simulations. The measurement of such THz emission may provide a diagnostic of the laser wakefield structure.

  20. Simulation study of wakefield generation by two color laser pulses propagating in homogeneous plasma

    SciTech Connect

    Kumar Mishra, Rohit; Saroch, Akanksha; Jha, Pallavi

    2013-09-15

    This paper deals with a two-dimensional simulation of electric wakefields generated by two color laser pulses propagating in homogeneous plasma, using VORPAL simulation code. The laser pulses are assumed to have a frequency difference equal to the plasma frequency. Simulation studies are performed for two similarly as well as oppositely polarized laser pulses and the respective amplitudes of the generated longitudinal wakefields for the two cases are compared. Enhancement of wake amplitude for the latter case is reported. This simulation study validates the analytical results presented by Jha et al.[Phys. Plasmas 20, 053102 (2013)].

  1. Coherent seeding of self-modulated plasma wakefield accelerators

    SciTech Connect

    Schroeder, C. B.; Benedetti, C.; Esarey, E.; Leemans, W. P.; Grüner, F. J.

    2013-05-15

    The growth of the beam self-modulation and hosing instabilities initiated by a seed wakefield is examined. Although the growth rates for the self-modulation and hosing instabilities are comparable, it is shown that an externally excited wakefield can be effective in selectively seeding the beam radial self-modulation, enabling the beam to fully modulate before strong beam hosing develops. Methods for coherent seeding are discussed.

  2. Coherent seeding of self-modulated plasma wakefield accelerators

    SciTech Connect

    Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; Gruener, Florian; Leemans, Wim

    2013-04-30

    The growth of the beam self-modulation and hosing instabilities initiated by a seed wakefield is examined. Although the growth rates for the self-modulation and hosing instabilities are comparable, it is shown that an externally excited wakefield can be effective in selectively seeding the beam radial self-modulation, enabling the beam to fully modulate before strong beam hosing develops. Methods for coherent seeding are discussed.

  3. Meter scale plasma source for plasma wakefield experiments

    NASA Astrophysics Data System (ADS)

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-01

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 1017 cm-3 has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  4. Meter scale plasma source for plasma wakefield experiments

    SciTech Connect

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-21

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  5. Plasma Undulator Based on Laser Excitation of Wakefields in a Plasma Channel

    NASA Astrophysics Data System (ADS)

    Rykovanov, S. G.; Schroeder, C. B.; Esarey, E.; Geddes, C. G. R.; Leemans, W. P.

    2015-04-01

    An undulator is proposed based on the plasma wakefields excited by a laser pulse in a plasma channel. Generation of the undulator fields is achieved by inducing centroid oscillations of the laser pulse in the channel. The period of such an undulator is proportional to the Rayleigh length of the laser pulse and can be submillimeter, while preserving high undulator strength. The electron trajectories in the undulator are examined, expressions for the undulator strength are presented, and the spontaneous radiation is calculated. Multimode and multicolor laser pulses are considered for greater tunability of the undulator period and strength.

  6. Plasma undulator based on laser excitation of wakefields in a plasma channel.

    PubMed

    Rykovanov, S G; Schroeder, C B; Esarey, E; Geddes, C G R; Leemans, W P

    2015-04-10

    An undulator is proposed based on the plasma wakefields excited by a laser pulse in a plasma channel. Generation of the undulator fields is achieved by inducing centroid oscillations of the laser pulse in the channel. The period of such an undulator is proportional to the Rayleigh length of the laser pulse and can be submillimeter, while preserving high undulator strength. The electron trajectories in the undulator are examined, expressions for the undulator strength are presented, and the spontaneous radiation is calculated. Multimode and multicolor laser pulses are considered for greater tunability of the undulator period and strength. PMID:25910131

  7. Electron beam manipulation, injection and acceleration in plasma wakefield accelerators by optically generated plasma density spikes

    NASA Astrophysics Data System (ADS)

    Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B.; Bruhwiler, David L.; Smith, Jonathan; Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G.; Hidding, Bernhard

    2016-09-01

    We discuss considerations regarding a novel and robust scheme for optically triggered electron bunch generation in plasma wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary plasma column before the arrival of the plasma wake. This localized plasma density enhancement or optical "plasma torch" distorts the blowout during the arrival of the electron drive bunch and modifies the electron trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the plasma torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.

  8. Plasma undulator based on laser excitation of wakefields in a plasma channel

    NASA Astrophysics Data System (ADS)

    Schroeder, Carl; Rykovanov, Sergey; Esarey, Eric; Geddes, Cameron; Leemans, Wim

    2015-11-01

    A novel plasma undulator based on the wakefields excited by a laser pulse in a plasma channel is described. Generation of the undulator fields is achieved by inducing centroid oscillations of the laser pulse in the channel. The period of such a plasma undulator is proportional to the Rayleigh length of the laser pulse and can be sub-millimeter, with an effective undulator strength parameter of order unity. The undulator period can further be controlled and reduced by beating laser modes or using multiple colors. Analytic expressions for the electron trajectories in the plasma undulator and the synchrotron radiation are compared to numerical modeling. Examples of short-period laser-driven plasma undulators are presented based on available laser and plasma channel parameters. Work supported by the U.S. DOE under Contract No. DE-AC02-05CH11231.

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

    SciTech Connect

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

    2008-01-28

    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.

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

    SciTech Connect

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

    2000-06-01

    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.

  11. Effect of beam emittance on self-modulation of long beams in plasma wakefield accelerators

    SciTech Connect

    Lotov, K. V.

    2015-12-15

    The initial beam emittance determines the maximum wakefield amplitude that can be reached as a result of beam self-modulation in the plasma. The wakefield excited by the fully self-modulated beam decreases linearly with the increase in the beam emittance. There is a value of initial emittance beyond which the self-modulation does not develop even if the instability is initiated by a strong seed perturbation. The emittance scale at which the wakefield is suppressed by a factor of two with respect to the zero-emittance case (the so called critical emittance) is determined by inability of the excited wave to confine beam particles radially and is related to beam and plasma parameters by a simple formula. The effect of beam emittance can be observed in several discussed self-modulation experiments.

  12. Stable Electron Beams With Low Absolute Energy Spread From a LaserWakefield Accelerator With Plasma Density Ramp Controlled Injection

    SciTech Connect

    Geddes, Cameron G.R.; Cormier-Michel, E.; Esarey, E.; Leemans,W.P.; Nakamura, K.; Panasenko, D.; Plateau, Guillaume R.; Schroeder, CarlB.; Toth, Csaba; Cary, J.R.

    2007-06-25

    Laser wakefield accelerators produce accelerating gradientsup to hundreds of GeV/m, and recently demonstrated 1-10 MeV energy spreadat energies up to 1 GeV using electrons self-trapped from the plasma.Controlled injection and staging may further improve beam quality bycircumventing tradeoffs between energy, stability, and energyspread/emittance. We present experiments demonstrating production of astable electron beam near 1 MeV with hundred-keV level energy spread andcentral energy stability by using the plasma density profile to controlselfinjection, and supporting simulations. Simulations indicate that suchbeams can be post accelerated to high energies,potentially reducingmomentum spread in laser acceleratorsby 100-fold or more.

  13. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema

    Andrei Seryi

    2010-01-08

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  14. Wakefields generated by collisional neutrinos in neutral-electron-positron-ion plasma

    SciTech Connect

    Tinakiche, Nouara

    2015-12-15

    A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron-ion plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in presence of a fraction of ions in a neutral-electron-positron plasma. The results obtained in the present work are interpreted and compared with previous studies.

  15. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    SciTech Connect

    Andrei Seryi

    2009-09-09

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

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

    SciTech Connect

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

    2012-06-12

    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.

  17. 3-D Simulations of Plasma Wakefield Acceleration with Non-Idealized Plasmas and Beams

    SciTech Connect

    Deng, S.; Katsouleas, T.; Lee, S.; Muggli, P.; Mori, W.B.; Hemker, R.; Ren, C.; Huang, C.; Dodd, E.; Blue, B.E.; Clayton, C.E.; Joshi, C.; Wang, S.; Decker, F.J.; Hogan, M.J.; Iverson, R.H.; O'Connell, C.; Raimondi, P.; Walz, D.; /SLAC

    2005-09-27

    3-D Particle-in-cell OSIRIS simulations of the current E-162 Plasma Wakefield Accelerator Experiment are presented in which a number of non-ideal conditions are modeled simultaneously. These include tilts on the beam in both planes, asymmetric beam emittance, beam energy spread and plasma inhomogeneities both longitudinally and transverse to the beam axis. The relative importance of the non-ideal conditions is discussed and a worst case estimate of the effect of these on energy gain is obtained. The simulation output is then propagated through the downstream optics, drift spaces and apertures leading to the experimental diagnostics to provide insight into the differences between actual beam conditions and what is measured. The work represents a milestone in the level of detail of simulation comparisons to plasma experiments.

  18. HIGH ENERGY GASEOUS PLASMA CONTAINMENT DEVICE

    DOEpatents

    Josephson, V.; Hammel, J.E.

    1959-01-13

    An apparatus is presenied for producing neutrons as a result of collisions between ions in high temperature plasmas. The invention resides in the particular arrangement of ihe device whereby ihe magneiic and electric fields are made to cross at substantially right angles in several places along a torus shaped containment vessel. A plasma of deuterium gas is generated in the vessel under the electric fields and is "trapped" in any one of the "crossed field" regions to produce a release of energy.

  19. Emittance and Current of Electrons Trapped in a Plasma Wakefield Accelerator

    SciTech Connect

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

    2009-01-22

    In recent experiments plasma electrons became trapped in a plasma wakefield accelerator (PWFA). The transverse size of these trapped electrons on a downstream diagnostic yields an upper limit measurement of transverse normalized emittance divided by peak current, {epsilon}{sub N,{sub x}}/I. The lowest upper limit for {epsilon}{sub N,{sub x}}/I measured in the experiment is 1.3{center_dot}10{sup -10} m/A.

  20. Emittance and Current of Electrons Trapped in a Plasma Wakefield Accelerator

    SciTech Connect

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

    2008-09-24

    In recent experiments plasma electrons became trapped in a plasma wakefield accelerator (PWFA). The transverse size of these trapped electrons on a downstream diagnostic yields an upper limit measurement of transverse normalized emittance divided by peak current, {var_epsilon}{sub N,x}/I. The lowest upper limit for {var_epsilon}{sub N,x}/I measured in the experiment is 1.3 {center_dot} 10{sup -10} m/A.

  1. Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

    SciTech Connect

    Afhami, Saeedeh; Eslami, Esmaeil

    2014-06-15

    An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

  2. Synergistic laser-wakefield and direct-laser acceleration in the plasma-bubble regime.

    PubMed

    Zhang, Xi; Khudik, Vladimir N; Shvets, Gennady

    2015-05-01

    The concept of a hybrid laser plasma accelerator is proposed. Relativistic electrons undergoing resonant betatron oscillations inside the plasma bubble created by a laser pulse are accelerated by gaining energy directly from the laser pulse and from its plasma wake. The resulting phase space of self-injected plasma electrons is split into two, containing a subpopulation that experiences wakefield acceleration beyond the standard dephasing limit because of the multidimensional nature of its motion that reduces the phase slippage between the electrons and the wake. PMID:26001005

  3. Collective effects on the wakefield and stopping power of an ion beam pulse in plasmas

    SciTech Connect

    Zhang, Ling-yu; Zhao, Xiao-ying; Qi, Xin E-mail: duanws@nwnu.edu.cn Duan, Wen-shan E-mail: duanws@nwnu.edu.cn Xiao, Guo-qing; Yang, Lei E-mail: duanws@nwnu.edu.cn

    2015-05-15

    A two-dimensional (2D) particle-in-cell simulation is carried out to study the collective effects on the wakefield and stopping power for a hydrogen ion beam pulse propagation in hydrogen plasmas. The dependence of collective effects on the beam velocity and density is obtained and discussed. For the beam velocity, it is found that the collective effects have the strongest impact on the wakefield as well as the stopping power in the case of the intermediate beam velocities, in which the stopping power is also the largest. For the beam density, it is found that at low beam densities, the collective contribution to the stopping power increase linearly with the increase of the beam density, which corresponds well to the results calculated using the dielectric theory. However, at high beam densities, our results show that after reaching a maximum value, the collective contribution to the stopping power starts to decrease significantly with the increase of the beam density. Besides, at high beam densities, the wakefield loses typical V-shaped cone structures, and the wavelength of the oscillation wakefield increases as the beam density increases.

  4. Summary of Working Group 1: Laser Plasma Wakefield Accelerators

    SciTech Connect

    Krushelnick, Karl; Kaganovich, Dmitri; Gonsalves, Anthony

    2009-01-22

    There have been many significant experimental and theoretical advances recently with regard to the production of relativistic electron beams using laser wakefield accelerators (LWFA) driven by high power short pulse lasers. In particular, there has been an explosion of interest in this field following the discovery of methods to generate such beams with low energy spread. In recent work by many groups around the world the energy and quality of these beams has been improved and a more complete understanding of the 'bubble' regime of electron acceleration has been obtained, enabling a significant improvement in the output electron beam stability. The 2008 Advanced Accelerator Concepts workshop in Santa Cruz CA brought together the leading groups engaged in this research from around the world. This paper will summarize the major results presented at the conference. Further details on the work described here can be found in the other related papers in these proceedings.

  5. Monoenergetic energy doubling in a hybrid laser-plasma wakefield accelerator.

    PubMed

    Hidding, B; Königstein, T; Osterholz, J; Karsch, S; Willi, O; Pretzler, G

    2010-05-14

    An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields E(r)∼100  GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems. PMID:20866970

  6. Monoenergetic Energy Doubling in a Hybrid Laser-Plasma Wakefield Accelerator

    SciTech Connect

    Hidding, B.; Koenigstein, T.; Osterholz, J.; Willi, O.; Pretzler, G.; Karsch, S.

    2010-05-14

    An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields E{sub r{approx}}100 GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems.

  7. Monoenergetic Energy Doubling in a Hybrid Laser-Plasma Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Hidding, B.; Königstein, T.; Osterholz, J.; Karsch, S.; Willi, O.; Pretzler, G.

    2010-05-01

    An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields Er˜100GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems.

  8. Plasma wakefield acceleration studies using the quasi-static code WAKE

    SciTech Connect

    Jain, Neeraj; Palastro, John; Antonsen, T. M.; Mori, Warren B.; An, Weiming

    2015-02-15

    The quasi-static code WAKE [P. Mora and T. Antonsen, Phys. Plasmas 4, 217 (1997)] is upgraded to model the propagation of an ultra-relativistic charged particle beam through a warm background plasma in plasma wakefield acceleration. The upgraded code is benchmarked against the full particle-in-cell code OSIRIS [Hemker et al., Phys. Rev. Spec. Top. Accel. Beams 3, 061301 (2000)] and the quasi-static code QuickPIC [Huang et al., J. Comput. Phys. 217, 658 (2006)]. The effect of non-zero plasma temperature on the peak accelerating electric field is studied for a two bunch electron beam driver with parameters corresponding to the plasma wakefield acceleration experiments at Facilities for Accelerator Science and Experimental Test Beams. It is shown that plasma temperature does not affect the energy gain and spread of the accelerated particles despite suppressing the peak accelerating electric field. The role of plasma temperature in improving the numerical convergence of the electric field with the grid resolution is discussed.

  9. High-efficiency acceleration in the laser wakefield by a linearly increasing plasma density

    SciTech Connect

    Dong, Kegong; Wu, Yuchi; Zhu, Bin; Zhang, Zhimeng; Zhao, Zongqing; Zhou, Weimin; Hong, Wei; Cao, Leifeng; Gu, Yuqiu

    2014-12-15

    The acceleration length and the peak energy of the electron beam are limited by the dephasing effect in the laser wakefield acceleration with uniform plasma density. Based on 2D-3V particle in cell simulations, the effects of a linearly increasing plasma density on the electron acceleration are investigated broadly. Comparing with the uniform plasma density, because of the prolongation of the acceleration length and the gradually increasing accelerating field due to the increasing plasma density, the electron beam energy is twice higher in moderate nonlinear wakefield regime. Because of the lower plasma density, the linearly increasing plasma density can also avoid the dark current caused by additional injection. At the optimal acceleration length, the electron energy can be increased from 350 MeV (uniform) to 760 MeV (linearly increasing) with the energy spread of 1.8%, the beam duration is 5 fs and the beam waist is 1.25 μm. This linearly increasing plasma density distribution can be achieved by a capillary with special gas-filled structure, and is much more suitable for experiment.

  10. Beam dynamics in resonant plasma wakefield acceleration at SPARC_LAB

    NASA Astrophysics Data System (ADS)

    Romeo, S.; Anania, M. P.; Chiadroni, E.; Croia, M.; Ferrario, M.; Marocchino, A.; Pompili, R.; Vaccarezza, C.

    2016-09-01

    Strategies to mitigate the increase of witness emittance and energy spread in beam driven plasma wakefield acceleration are investigated. Starting from the proposed resonant wakefield acceleration scheme in quasi-non-linear regime that is going to be carried out at SPARC_LAB, we performed systematic scans of the parameters to be used for drivers. The analysis will show that one of the main requirements to preserve witness quality during the acceleration is to have accelerating and focusing fields that are very stable during all the accelerating length. The difference between the dynamics of the leading bunch and the trailing bunch is pointed out. The classical condition on bunch length kpσz =√{ 2 } seems to be an ideal condition for the first driver within long accelerating lengths. The other drivers show to follow different longitudinal matching conditions. In the end a new method for the investigation of the matching for the first driver is introduced.

  11. Wakefield-induced ionization injection in beam-driven plasma accelerators

    NASA Astrophysics Data System (ADS)

    Martinez de la Ossa, A.; Mehrling, T. J.; Schaper, L.; Streeter, M. J. V.; Osterhoff, J.

    2015-09-01

    We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches [Martinez de la Ossa et al., Phys. Rev. Lett. 111, 245003 (2013)]. The electron-beam drivers must feature high-peak currents ( Ib 0 ≳ 8.5 kA ) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ( k p σ z ˜ k p ɛ n ˜ 0.1 ). In addition, we show that the amount of injected charge can be adjusted by tuning the concentration of the dopant gas species, which allows for controlled beam loading and leads to a reduction of the total energy spread of the witness beams. Electron bunches, produced in this way, fulfil the requirements to drive blowout regime plasma wakes at a higher density and to trigger WII injection in a second stage. This suggests a promising new concept of self-similar staging of WII injection in steps with increasing plasma density, giving rise to the potential of producing electron beams with unprecedented energy and brilliance from plasma-wakefield accelerators.

  12. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    SciTech Connect

    Aslanyan, V.; Tallents, G. J.

    2014-06-15

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.

  13. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    NASA Astrophysics Data System (ADS)

    Aslanyan, V.; Tallents, G. J.

    2014-06-01

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.

  14. Laser red shifting based characterization of wakefield excitation in a laser-plasma accelerator

    SciTech Connect

    Shiraishi, S.; Benedetti, C.; Gonsalves, A. J.; Nakamura, K.; Shaw, B. H.; Sokollik, T.; Tilborg, J. van; Geddes, C. G. R.; Schroeder, C. B.; Tóth, Cs.; Esarey, E.; Leemans, W. P.

    2013-06-15

    Optical spectra of a drive laser exiting a channel guided laser-plasma accelerator (LPA) are analyzed through experiments and simulations to infer the magnitude of the excited wakefields. The experiments are performed at sufficiently low intensity levels and plasma densities to avoid electron beam generation via self-trapping. Spectral redshifting of the laser light is studied as an indicator of the efficiency of laser energy transfer into the plasma through the generation of coherent plasma wakefields. Influences of input laser energy, plasma density, temporal and spatial laser profiles, and laser focal location in a plasma channel are analyzed. Energy transfer is found to be sensitive to details of laser pulse shape and focal location. The experimental conditions for these critical parameters are modeled and included in particle-in-cell simulations. Simulations reproduce the redshift of the laser within uncertainties of the experiments and produce an estimate of the wake amplitudes in the experiments as a function of amount of redshift. The results support the practical use of laser redshifting to quantify the longitudinally averaged accelerating field that a particle would experience in an LPA powered below the self-trapping limit.

  15. Transverse stability of the primary beam in the plasma wake-field accelerator

    SciTech Connect

    Krall, J.; Joyce, G.

    1995-06-01

    The stability of the primary electron beam in the plasma wakefield accelerator is studied using a three-dimensional particle code, for cases in which a shaped electron beam, with length {ital L}{approx_gt}{lambda}{sub {ital p}} is used, where {lambda}{sub {ital p}} is the plasma wavelength. The electron-hose and the transverse two-stream instabilities are observed to cause transverse deflections of the beam, with the transverse two-stream instability having a lower growth rate. Operation in the electron-hose regime can be avoided by reducing the beam density. {copyright} 1995 {ital American Institute of Physics}.

  16. Positron acceleration in plasma bubble wakefield driven by an ultraintense laser

    NASA Astrophysics Data System (ADS)

    Hou, Ya-Juan; Wan, Feng; Sang, Hai-Bo; Xie, Bai-Song

    2016-01-01

    The dynamics of positrons accelerating in electron-positron-ion plasma bubble fields driven by an ultraintense laser is investigated. The bubble wakefield is obtained theoretically when laser pulses are propagating in the electron-positron-ion plasma. To restrict the positrons transversely, an electron beam is injected. Acceleration regions and non-acceleration ones of positrons are obtained by the numerical simulation. It is found that the ponderomotive force causes the fluctuation of the positrons momenta, which results in the trapping of them at a lower ion density. The energy gaining of the accelerated positrons is demonstrated, which is helpful for practical applications.

  17. Simulation of ionization effects for high-density positron drivers in future plasma wakefield experiments

    SciTech Connect

    Bruhwiler, D.L.; Dimitrov, D.A.; Cary, J.R.; Esarey, E.; Leemans, W.P.

    2003-05-12

    The plasma wakefield accelerator (PWFA) concept has been proposed as a potential energy doubler for present or future electron-positron colliders. Recent particle-in-cell (PIC) simulations have shown that the self-fields of the required electron beam driver can tunnel ionize neutral Li, leading to plasma wake dynamics differing significantly from that of a preionized plasma. It has also been shown, for the case of a preionized plasma, that the plasma wake of a positron driver differs strongly from that of an electron driver. We will present new PIC simulations, using the OOPIC code, showing the effects of tunneling ionization on the plasma wake generated by high-density positron drivers. The results will be compared to previous work on electron drivers with tunneling ionization and positron drivers without ionization. Parameters relevant to the energy doubler and the upcoming E-164x experiment at the Stanford Linear Accelerator Center will be considered.

  18. Electron self-injection in the proton-driven-plasma-wakefield acceleration

    SciTech Connect

    Hu, Zhang-Hu; Wang, You-Nian

    2013-12-15

    The self-injection process of plasma electrons in the proton-driven-plasma-wakefield acceleration scheme is investigated using a two-dimensional, electromagnetic particle-in-cell method. Plasma electrons are self-injected into the back of the first acceleration bucket during the initial bubble formation period, where the wake phase velocity is low enough to trap sufficient electrons. Most of the self-injected electrons are initially located within a distance of the skin depth c/ω{sub pe} to the beam axis. A decrease (or increase) in the beam radius (or length) leads to a significant reduction in the total charges of self-injected electron bunch. Compared to the uniform plasma, the energy spread, emittance and total charges of the self-injected bunch are reduced in the plasma channel case, due to a reduced injection of plasma electrons that initially located further away from the beam axis.

  19. Positron self-driven hollow channel in non-linear plasma wakefields

    NASA Astrophysics Data System (ADS)

    Amorim, Ligia Diana; Vieira, Jorge; Fonseca, Ricardo A.; Silva, Luis O.; GoLP/Instituto de Plasmas e Fusão Nuclear Team

    2014-10-01

    Plasma based accelerators are capable of sustaining very high acceleration gradients when compared to conventional accelerators. In particular plasma based accelerators operating in non-linear regimes reached the 100GV/m. One of the challenges for a future plasma based collider is to accelerate positrons in non-linear regimes. Although novel techniques have been investigated to this end, it is still important to propose and explore other new configurations for positron acceleration in non-linear regimes. In this context we suggest a novel process for positron acceleration in non-linear plasma wakefields, where a tightly focused positron drive beam expels the plasma ions forming a hollow channel with large accelerating and focusing wakefields suitable for positron acceleration. We introduce the setup of the proposed scheme and illustrate it with analytical and numerical results of a 3D numerical simulations performed with the PIC code OSIRS. Moreover, we discuss the optimal conditions for the positron drive beam stability. This work was partially supported by FCT grant SFRH / BD / 84851 / 2012. We acknowledge PRACE for access to resources on SuperMUC (Leibniz Research Center).

  20. Control of laser-wakefield acceleration by the plasma-density profile.

    PubMed

    Pukhov, A; Kostyukov, I

    2008-02-01

    We show that both the maximum energy gain and the accelerated beam quality can be efficiently controlled by the plasma-density profile. Choosing a proper density gradient one can uplift the dephasing limitation and keep the phase synchronism between the bunch of relativistic particles and the plasma wave over extended distances. Putting electrons into the n th wake period behind the driving laser pulse, the maximum energy gain is increased by the factor, which is proportional to n, over that in the case of uniform plasma. Layered plasma is suggested to keep the resonant condition for laser-wakefield excitation. The acceleration is limited then by laser depletion rather than by dephasing. Further, we show that the natural energy spread of the particle bunch acquired at the acceleration stage can be effectively removed by a matched deceleration stage, where a larger plasma density is used. PMID:18352081

  1. PROTOPLASMA - Proton-driven plasma-wakefield experiment at Fermilab: Stages and approach

    SciTech Connect

    Thangaraj, J. C. T.; Park, C. S.; Lewis, J. D.; Spentzouris, P.; An, W.; Mori, W.; Joshi, C.

    2012-12-21

    Generation of TeV-scale electron beams using conventional RF technology appears expensive for building the next generation of colliders. Proton-driven plasma-wakefield acceleration of electrons promises an alternative route to generate TeV-scale electron beams using existing proton machines. PROTOPLASMA is the proposed R and D project at Fermilab that plans to use a proton beam driven plasma-wakefield to accelerate electrons. The project is planned in stages with the project's path guided by simulations. First, a 60-120 GeV proton beam will be injected into 1-2 meters of plasma to observe selfmodulation instability in the proton beam. Next, an injected 5 MeV electron beam will be accelerated by the plasma. In this paper, we report on the basic project plan and outline our staged approach. We report on first simulation results that show self-modulation of a proton bunch and discuss beam optics requirements and other limits.

  2. Laser-wakefield acceleration of monoenergetic electron beams in the first plasma-wave period.

    PubMed

    Mangles, S P D; Thomas, A G R; Kaluza, M C; Lundh, O; Lindau, F; Persson, A; Tsung, F S; Najmudin, Z; Mori, W B; Wahlström, C-G; Krushelnick, K

    2006-06-01

    Beam profile measurements of laser-wakefield accelerated electron bunches reveal that in the monoenergetic regime the electrons are injected and accelerated at the back of the first period of the plasma wave. With pulse durations ctau >or= lambda(p), we observe an elliptical beam profile with the axis of the ellipse parallel to the axis of the laser polarization. This increase in divergence in the laser polarization direction indicates that the electrons are accelerated within the laser pulse. Reducing the plasma density (decreasing ctau/lambda(p)) leads to a beam profile with less ellipticity, implying that the self-injection occurs at the rear of the first period of the plasma wave. This also demonstrates that the electron bunches are less than a plasma wavelength long, i.e., have a duration <25 fs. This interpretation is supported by 3D particle-in-cell simulations. PMID:16803242

  3. Laser-seeded modulation instability in a proton driver plasma wakefield accelerator

    SciTech Connect

    Siemon, Carl; Khudik, Vladimir; Austin Yi, S.; Shvets, Gennady; Pukhov, Alexander

    2013-10-15

    A new method for initiating the modulation instability (MI) of a proton beam in a proton driver plasma wakefield accelerator using a short laser pulse preceding the beam is presented. A diffracting laser pulse is used to produce a plasma wave that provides a seeding modulation of the proton bunch with the period equal to that of the plasma wave. Using the envelope description of the proton beam, this method of seeding the MI is analytically compared with the earlier suggested seeding technique that involves an abrupt truncation of the proton bunch. The full kinetic simulation of a realistic proton bunch is used to validate the analytic results. It is further used to demonstrate that a plasma density ramp placed in the early stages of the laser-seeded MI leads to its stabilization, resulting in sustained accelerating electric fields (of order several hundred MV/m) over long propagation distances (∼100–1000 m)

  4. High energy density Z-pinch plasmas using flow stabilization

    SciTech Connect

    Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.

    2014-12-15

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

  5. High energy density Z-pinch plasmas using flow stabilization

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Golingo, R. P.; Nelson, B. A.; Bowers, C. A.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Knecht, S. D.; Lambert, K. K.; Lowrie, W.; Ross, M. P.; Weed, J. R.

    2014-12-01

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes - Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and scaling

  6. Power Spectrum of Cerenkov Radiation from Laser Wakefield in Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Gao, Hong; Higashiguchi, Takeshi; Yugami, Noboru; Ito, Hiroaki; Nishida, Yasushi

    2000-10-01

    An angle and radiation frequecy distribution of the output power of the electromagnetic wave radiation from the laser wakefield in a magnetized plasma (Cerenkov wakes radiaiton) have been calculated. The magnetic field here is applied for the far field electromagnetic wave radiation = requirement. The radiation frequency is confined from ωp to = ω_h. The electromagnetic wave generation originates from the coupling between the DC perpendicular magnetic field and the plasma electron longitudinal = disturbance caused by the laser ponderomotive force. Under Coulomb gauge condition, the wave equation can be completely partitioned for the scale potential = and the vector field, so it can be easily obtained from the near zone static = field and far zone radiation field. The former has well been studied as the = static wakefield acceleration. Here we wish to present the detailed study on = the feature of the radiated electromagnetic field for the later case. The radiation = power spectrum which depends on the magnetic field, the laser pulse length, = the radiation frequency and the corresponding refraction index have been = given. The analysis shows that at the direction of \\cos θ= c=3D1/β n, where n is the refraction index of the magnetized plasma, the output = power has the maximum which satisfies the Cerenkov radiation angle condition, = so that the output power for the radiation frequency of ωp = is mainly located at the forward direction.

  7. Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield

    SciTech Connect

    Corde, Sebastien; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Delahaye, J. P.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Lipkowitz, N.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Schmeltz, M.; Vafaei-Najafabadi, N.; Walz, D.; Yakimenko, V.; Yocky, G.; Clayton, C. E.

    2015-08-26

    New accelerator concepts must be developed to make future particle colliders more compact and affordable. The Plasma Wakefield Accelerator (PWFA) is one such concept, where the electric field of a plasma wake excited by a charged-particle bunch is used to accelerate a trailing bunch of particles. To apply plasma acceleration to particle colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas1. While substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch 2, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFA where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered – self-loaded – so that about a billion positrons gain five gigaelectronvolts (GeV) of energy with a narrow energy spread in a distance of just 1.3 meters. They extract about 30% of the wake’s energy and form a spectrally distinct bunch with as low as a 1.8% r.m.s. energy spread. This demonstrated ability of positron-driven plasma wakes to efficiently accelerate a significant number of positrons with a small energy spread may overcome the long-standing challenge of positron acceleration in plasma-based accelerators.

  8. Modeling laser-plasma acceleration in the wakefield frame

    SciTech Connect

    2011-01-01

    A simulation of laser-plasma acceleration in the boosted frame of the wake, moving at near lightspeed. Space has contracted and time has stretched, separating events in time. Relatively few time steps are needed to model them, requiring less computer time.

  9. Generation of wakefields by whistlers in spin quantum magnetoplasmas

    NASA Astrophysics Data System (ADS)

    Misra, A. P.; Brodin, G.; Marklund, M.; Shukla, P. K.

    2010-12-01

    The excitation of electrostatic wakefields in a magnetized spin quantum plasma by the classical and the spin-induced ponderomotive force (CPF and SPF, respectively) due to whistler waves is reported. The nonlinear dynamics of the whistlers and the wakefields is shown to be governed by a coupled set of nonlinear Schrödinger and driven Boussinesq-like equations. It is found that the quantum force associated with the Bohm potential introduces two characteristic length scales, which lead to the excitation of multiple wakefields in a strongly magnetized dense plasma (with a typical magnetic field strength B0≳109 T and particle density n0≳1036 m-3), where the SPF strongly dominates over the CPF. In other regimes, namely, B0≲108 T and n0≲1035 m-3, where the SPF is comparable to the CPF, a plasma wakefield can also be excited self-consistently with one characteristic length scale. Numerical results reveal that the wakefield amplitude is enhanced by the quantum tunneling effect; however, it is lowered by the external magnetic field. Under appropriate conditions, the wakefields can maintain high coherence over multiple plasma wavelengths and thereby accelerate electrons to extremely high energies. The results could be useful for particle acceleration at short scales, i.e., at nanometer and micrometer scales, in magnetized dense plasmas where the driver is the whistler wave instead of a laser or a particle beam.

  10. LCODE: A parallel quasistatic code for computationally heavy problems of plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Sosedkin, A. P.; Lotov, K. V.

    2016-09-01

    LCODE is a freely distributed quasistatic 2D3V code for simulating plasma wakefield acceleration, mainly specialized at resource-efficient studies of long-term propagation of ultrarelativistic particle beams in plasmas. The beam is modeled with fully relativistic macro-particles in a simulation window copropagating with the light velocity; the plasma can be simulated with either kinetic or fluid model. Several techniques are used to obtain exceptional numerical stability and precision while maintaining high resource efficiency, enabling LCODE to simulate the evolution of long particle beams over long propagation distances even on a laptop. A recent upgrade enabled LCODE to perform the calculations in parallel. A pipeline of several LCODE processes communicating via MPI (Message-Passing Interface) is capable of executing multiple consecutive time steps of the simulation in a single pass. This approach can speed up the calculations by hundreds of times.

  11. Investigation of a Gas Jet-Produced Hollow Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, N; Blumenfeld, I.; Hogan, M.J.; Siemann, R.H.; Walz, D.R.; Davidson, A.W.; Huang, C.; /UCLA

    2009-05-21

    The effect of ion motion and the need for practical positron propagation in a plasma wakefield accelerator (PWFA) have incited interest in hollow plasma channels. These channels are typically assumed to be cylindrically symmetric; however, a different geometry might be easier to achieve. The introduction of an obstruction into the outlet of a high Mach number gas jet can produce two parallel slabs of gas separated by a density depression. Here, there is a detailed simulation study of the density depression created in such a system. This investigation reveals that the density depression is insufficient at the desired plasma density. However, insights from the simulations suggest another avenue for the creation of the hollow slab geometry.

  12. Simulation of ultrashort electron pulse generation from optical injection into wake-field plasma waves.

    PubMed

    Dodd, E S; Kim, J K; Umstadter, D

    2004-11-01

    A laser-plasma-based source of relativistic electrons is described in detail, and analyzed in two dimensions using theoretical and numeric techniques. Two laser beams are focused in a plasma, one exciting a wake-field electron plasma wave while another locally alters some electron trajectories in such a way that they can be trapped and accelerated by the wave. Previous analyses dealt only with one-dimensional models. In this paper two-dimensional particle-in-cell simulations and analysis of single particle trajectories show that the radial wake field plays an important role. The simulation results are interpreted to evaluate the accelerated electron beam's properties and compared with existing devices. PMID:15600768

  13. Symbolic transfer entropy analysis of the dust interaction in the presence of wakefields in dusty plasmas

    NASA Astrophysics Data System (ADS)

    Melzer, André; Schella, André

    2014-04-01

    The method of symbolic transfer entropy has been applied to analyze the behavior of charged-particle systems under the influence of an ion focus (wakefield) in a dusty plasma. Using long-run experiments under various plasma and trapping conditions, it is revealed from the transfer entropy that information is transported from the upper particle in an ion flow to the lower. The information transfer increases with smaller interparticle distance and with reduced height in the sheath. This can be consistently explained by the formation of the ion focus by an ion flow in the sheath. From the analysis of two-particle and many-particle systems, the symbolic entropy transfer can be judged as a reliable measure for information asymmetry, and hence interaction asymmetry, in dusty plasma systems.

  14. Symbolic transfer entropy analysis of the dust interaction in the presence of wakefields in dusty plasmas.

    PubMed

    Melzer, André; Schella, André

    2014-04-01

    The method of symbolic transfer entropy has been applied to analyze the behavior of charged-particle systems under the influence of an ion focus (wakefield) in a dusty plasma. Using long-run experiments under various plasma and trapping conditions, it is revealed from the transfer entropy that information is transported from the upper particle in an ion flow to the lower. The information transfer increases with smaller interparticle distance and with reduced height in the sheath. This can be consistently explained by the formation of the ion focus by an ion flow in the sheath. From the analysis of two-particle and many-particle systems, the symbolic entropy transfer can be judged as a reliable measure for information asymmetry, and hence interaction asymmetry, in dusty plasma systems. PMID:24827184

  15. Simulation of ultrashort electron pulse generation from optical injection into wake-field plasma waves

    SciTech Connect

    Dodd, E.S.; Kim, J.K.; Umstadter, D.

    2004-11-01

    A laser-plasma-based source of relativistic electrons is described in detail, and analyzed in two dimensions using theoretical and numeric techniques. Two laser beams are focused in a plasma, one exciting a wake-field electron plasma wave while another locally alters some electron trajectories in such a way that they can be trapped and accelerated by the wave. Previous analyses dealt only with one-dimensional models. In this paper two-dimensional particle-in-cell simulations and analysis of single particle trajectories show that the radial wake field plays an important role. The simulation results are interpreted to evaluate the accelerated electron beam's properties and compared with existing devices.

  16. Frontiers in plasma science: a high energy density perspective

    NASA Astrophysics Data System (ADS)

    Remington, Bruce

    2015-11-01

    The potential for ground-breaking research in plasma physics in high energy density (HED) regimes is compelling. The combination of HED facilities around the world spanning microjoules to megajoules, with time scales ranging from femtoseconds to microseconds enables new regimes of plasma science to be experimentally probed. The ability to shock and ramp compress samples and simultaneously probe them allows dense, strongly coupled, Fermi degenerate plasmas relevant to planetary interiors to be studied. Shock driven hydrodynamic instabilities evolving into turbulent flows relevant to the dynamics of exploding stars are being probed. The physics and dynamics of magnetized plasmas relevant to astrophysics and inertial confinement fusion are also starting to be studied. High temperature, high velocity interacting flows are being probed for evidence of astrophysical collisionless shock formation. Turbulent, high magnetic Reynolds number flows are being experimentally generated to look for evidence of the turbulent magnetic dynamo effect. And new results from thermonuclear reactions in dense hot plasmas relevant to stellar interiors are starting to emerge. A selection of examples providing a compelling vision for frontier plasma science in the coming decade will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield.

    PubMed

    Corde, S; Adli, E; Allen, J M; An, W; Clarke, C I; Clayton, C E; Delahaye, J P; Frederico, J; Gessner, S; Green, S Z; Hogan, M J; Joshi, C; Lipkowitz, N; Litos, M; Lu, W; Marsh, K A; Mori, W B; Schmeltz, M; Vafaei-Najafabadi, N; Walz, D; Yakimenko, V; Yocky, G

    2015-08-27

    Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron-positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered--'self-loaded'--so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 metres. They extract about 30 per cent of the wake's energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron-positron collider. PMID:26310764

  18. Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield

    NASA Astrophysics Data System (ADS)

    Corde, S.; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Clayton, C. E.; Delahaye, J. P.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Lipkowitz, N.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Schmeltz, M.; Vafaei-Najafabadi, N.; Walz, D.; Yakimenko, V.; Yocky, G.

    2015-08-01

    Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron-positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered--`self-loaded'--so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 metres. They extract about 30 per cent of the wake's energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron-positron collider.

  19. High energy components and collective modes in thermonuclear plasmas

    SciTech Connect

    Coppi, B.; Cowley, S.; Detragiache, P.; Kulsrud, R.; Pegoraro, F.

    1986-02-01

    The theory of a class of collective modes of a thermonuclear magnetically confined plasma, with frequencies in the range of the ion cyclotron frequency and of its harmonics, is presented. These modes can be excited by their resonant cyclotron interaction with a plasma component of relatively high energy particles characterized by a strongly anisotropic distribution in velocity space. Normal modes that are spatially localized by the inhomogeneity of the plasma density are found. This ensures that the energy gained by their resonant interaction is not convected away. The mode spatial localization can be significantly altered by the magnetic field inhomogeneity for a given class of plasma density profiles. Special attention is devoted to the case of a spin polarized plasma, where the charged products of fusion reactions are anisotropically distributed. We show that for the mode of polarization that enhances nuclear reaction rates the tritium will be rapidly depolarized to toroidal configurations with relatively mild gradients of the confining magnetic field. 18 refs., 9 figs.

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

    SciTech Connect

    Yi, S. A.; Khudik, V.; Siemon, C.; Shvets, G.

    2012-12-21

    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.

  1. Positron Acceleration by Plasma Wakefields Driven by a Hollow Electron Beam.

    PubMed

    Jain, Neeraj; Antonsen, T M; Palastro, J P

    2015-11-01

    A scheme for positron plasma wakefield acceleration using hollow or donut-shaped electron driver beams is studied. An annular-shaped, electron-free region forms around the hollow driver beam, creating a favorable region (longitudinal field is accelerating and transverse field is focusing) for positron acceleration. For Facility for Advanced Accelerator Experimental Tests (FACET)-like parameters, the hollow beam driver produces accelerating gradients on the order of 10  GV/m. The accelerating gradient increases linearly with the total charge in the driver beam. Simulations show acceleration of a 23-GeV positron beam to 35.4 GeV with a maximum energy spread of 0.4% and very small emittance over a plasma length of 140 cm is possible. PMID:26588391

  2. Characterization of the equilibrium configuration for modulated beams in a plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Martorelli, Roberto; Pukhov, Alexander

    2016-05-01

    We analyze the equilibrium configuration for a modulated beam with sharp boundaries exposed to the fields self-generated by the interaction with a plasma. Through a semi-analytical approach, we show the presence of multiple equilibrium configurations and we determine the one more suitable for wakefield excitation. Once pointed out the absence of confinement for the front of the beam and the consequently divergence driven by the emittance, we study the evolution of the equilibrium configuration while propagating in the plasma, discarding all the other time-dependencies. We show the onset of a rigid backward drift of the equilibrium configuration, and we provide an explanation in the increasing length of the first bunch.

  3. High-quality electron beam from laser wake-field acceleration in laser produced plasma plumes

    SciTech Connect

    Sanyasi Rao, Bobbili; Moorti, Anand; Rathore, Ranjana; Ali Chakera, Juzer; Anant Naik, Prasad; Dass Gupta, Parshotam

    2013-06-10

    Generation of highly collimated ({theta}{sub div}{approx}10 mrad), quasi-monoenergetic electron beam with peak energy 12 MeV and charge {approx}50 pC has been experimentally demonstrated from self-guided laser wake-field acceleration (LWFA) in a plasma plume produced by laser ablation of solid nylon (C{sub 12}H{sub 22}N{sub 2}O{sub 2}){sub n} target. A 7 TW, 45 fs Ti:sapphire laser system was used for LWFA, and the plasma plume forming pulse was derived from the Nd:YAG pump laser of the same system. The results show that a reproducible, high quality electron beam could be produced from this scheme which is simple, low cost and has the capability for high repetition rate operation.

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

    SciTech Connect

    Rosenzweig, J. B.; Andonian, G.; Barber, S.; Ferrario, M.; Muggli, P.; O'Shea, B.; Sakai, Y.; Valloni, A.; Williams, O.; Xi, Y.; Yakimenko, V.

    2012-12-21

    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.

  5. Enhanced high field terahertz emission from plasma wakefields via pulse sharpening by a foil shutter

    NASA Astrophysics Data System (ADS)

    Chen, Zi-Yu

    2016-06-01

    A dual-stage scheme is proposed to generate terahertz (THz) pulses with an extremely high field strength that is in the GV/cm regime from laser-driven plasma wakefields. A thin foil target is employed to act as an optical shutter to sharpen the laser pulse front based on the mechanism of relativistic transparency. The shaped laser pulse then interacts with gaseous density plasmas to generate THz pulses via excitation of net residual transverse currents. Compared to the case of without the foil shutter, THz field strength can be notably enhanced by one order of magnitude. The scheme is numerically demonstrated through one and two dimensional particle-in-cell simulations.

  6. Transverse Emittance and Current of Multi-GeV Trapped Electrons in a Plasma Wakefield Accelerator

    SciTech Connect

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

    2009-10-17

    Multi-GeV trapped electron bunches in a plasma wakefield accelerator (PWFA) 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 emittance scales inversely with the square root of the plasma density in the nonlinear '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.

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

    SciTech Connect

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2001-01-01

    A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.

  8. A method of determining narrow energy spread electron beams from a laser plasma wakefield accelerator using undulator radiation

    SciTech Connect

    Gallacher, J. G.; Anania, M. P.; Brunetti, E.; Ersfeld, B.; Islam, M. R.; Reitsma, A. J. W.; Shanks, R. P.; Wiggins, S. M.; Jaroszynski, D. A.; Budde, F.; Debus, A.; Haupt, K.; Schwoerer, H.; Jaeckel, O.; Pfotenhauer, S.; Rohwer, E.; Schlenvoigt, H.-P.

    2009-09-15

    In this paper a new method of determining the energy spread of a relativistic electron beam from a laser-driven plasma wakefield accelerator by measuring radiation from an undulator is presented. This could be used to determine the beam characteristics of multi-GeV accelerators where conventional spectrometers are very large and cumbersome. Simultaneous measurement of the energy spectra of electrons from the wakefield accelerator in the 55-70 MeV range and the radiation spectra in the wavelength range of 700-900 nm of synchrotron radiation emitted from a 50 period undulator confirm a narrow energy spread for electrons accelerated over the dephasing distance where beam loading leads to energy compression. Measured energy spreads of less than 1% indicates the potential of using a wakefield accelerator as a driver of future compact and brilliant ultrashort pulse synchrotron sources and free-electron lasers that require high peak brightness beams.

  9. Colliding ionization injection in a plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Wan, Y.; Zhang, C. J.; Li, F.; Wu, Y. P.; Hua, J. F.; Pai, C.-H.; Lu, W.; Gu, Y. Q.; Xu, X. L.; Joshi, C.; Mori, W. B.

    2016-03-01

    A new scheme of generating high quality electron bunches via ionization injection triggered by an counter propagating laser pulse inside a beam driven plasma wake is proposed and examined via two-dimensional particle-in-cell (PIC) simulations. This scheme has two major advantages: first, the injection distance is easily tunable by varying the launching time or the focal position of the laser pulse; second, the electrons in each injected slice are released at nearly the same time. Both factors can significantly reduce the phase space mixing during the ionization injection process (Xu et al 2014 Phys. Rev. Lett. 112 035003, Xu et al 2014 Phys. Rev. Spec. Top.: Accel. Beams 17 061301, Li et al 2013 Phys. Rev. Lett. 111 015003), leading to very small energy spreads (˜10 keV for slice,˜100 keV for the whole bunch) and very small normalized emittance (˜few nm). As an example, a 4.5 fs 0.4 pC electron bunch with normalized emittance of 3.3 nm, slice energy spread of 13 keV, absolute energy spread of 80 keV, and a brightness of 7.2× {{10}18} A m-2rad-2 is obtained under realistic conditions. This scheme may have potential applications for future compact coherent light sources.

  10. Demonstration of passive plasma lensing of a laser wakefield accelerated electron bunch

    NASA Astrophysics Data System (ADS)

    Kuschel, S.; Hollatz, D.; Heinemann, T.; Karger, O.; Schwab, M. B.; Ullmann, D.; Knetsch, A.; Seidel, A.; Rödel, C.; Yeung, M.; Leier, M.; Blinne, A.; Ding, H.; Kurz, T.; Corvan, D. J.; Sävert, A.; Karsch, S.; Kaluza, M. C.; Hidding, B.; Zepf, M.

    2016-07-01

    We report on the first demonstration of passive all-optical plasma lensing using a two-stage setup. An intense femtosecond laser accelerates electrons in a laser wakefield accelerator (LWFA) to 100 MeV over millimeter length scales. By adding a second gas target behind the initial LWFA stage we introduce a robust and independently tunable plasma lens. We observe a density dependent reduction of the LWFA electron beam divergence from an initial value of 2.3 mrad, down to 1.4 mrad (rms), when the plasma lens is in operation. Such a plasma lens provides a simple and compact approach for divergence reduction well matched to the mm-scale length of the LWFA accelerator. The focusing forces are provided solely by the plasma and driven by the bunch itself only, making this a highly useful and conceptually new approach to electron beam focusing. Possible applications of this lens are not limited to laser plasma accelerators. Since no active driver is needed the passive plasma lens is also suited for high repetition rate focusing of electron bunches. Its understanding is also required for modeling the evolution of the driving particle bunch in particle driven wake field acceleration.

  11. Demonstration of passive plasma lensing of a laser wakefield accelerated electron bunch

    DOE PAGESBeta

    Kuschel, S.; Hollatz, D.; Heinemann, T.; Karger, O.; Schwab, M. B.; Ullmann, D.; Knetsch, A.; Seidel, A.; Rodel, C.; Yeung, M.; et al

    2016-07-20

    We report on the first demonstration of passive all-optical plasma lensing using a two-stage setup. An intense femtosecond laser accelerates electrons in a laser wakefield accelerator (LWFA) to 100 MeV over millimeter length scales. By adding a second gas target behind the initial LWFA stage we introduce a robust and independently tunable plasma lens. We observe a density dependent reduction of the LWFA electron beam divergence from an initial value of 2.3 mrad, down to 1.4 mrad (rms), when the plasma lens is in operation. Such a plasma lens provides a simple and compact approach for divergence reduction well matchedmore » to the mm-scale length of the LWFA accelerator. The focusing forces are provided solely by the plasma and driven by the bunch itself only, making this a highly useful and conceptually new approach to electron beam focusing. Possible applications of this lens are not limited to laser plasma accelerators. Since no active driver is needed the passive plasma lens is also suited for high repetition rate focusing of electron bunches. As a result, its understanding is also required for modeling the evolution of the driving particle bunch in particle driven wake field acceleration.« less

  12. Density profile of a line plasma generated by laser ablation for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Kim, J.; Hwangbo, Y.; Ryu, W.-J.; Kim, K. N.; Park, S. H.

    2016-03-01

    An elongated line plasma generated by a laser ablation of an aluminum target was investigated, which can be used in the laser wakefield acceleration (LWFA) by employing ultra-intense laser pulse through the longitudinal direction of the plasma. To generate a uniform and long plasma channel along the propagation of ultra-intense laser pulse (main pulse), a cylindrical lens combined with a biprism was used to shape the intensity of a ns Nd:YAG laser (pre-pulse) on the Al target. A uniformity of laser intensity can be manipulated by changing the distance between the biprism and the target. The density profile of the plasma generated by laser ablation was measured using two interferometers, indicating that a 3-mm long uniform line plasma with a density of 6 × 1017 cm-3 could be generated. The density with main pulse was also measured and the results indicated that the density would increase further due to additional ionization of the plasma by the main ultra-intense laser pulse. The resulting plasma density, which is a crucial parameter for the LWFA, can be controlled by the intensity of the pre-pulse, the time delay between the pre- and main pulse, and the distance of the main pulse from the target surface.

  13. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

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

  14. Ultra-bright XUV emission from laser wakefields in underdense plasma

    SciTech Connect

    Liu Yue; Sheng, Z. M.; Zheng, J.; Li, F. Y.; Xu, X. L.; Lu, W.; Mori, W. B.; Liu, C. S.; Zhang, J.

    2012-12-21

    By use of particle-in-cell (PIC) simulation, we observe ultra-bright XUV radiation pulses emerging from a laser wakefield driven above the wave-breaking threshold in underdense plasma, which is as short as a few hundred attoseconds in one-dimentsional simulations and a few femtoseconds in two-dimensional simulations. It is concerned with the formation of a transverse narrow current layer co-moving with the intense laser pulse. This current layer is formed by an electron density spike with trapped electrons in the wakefield with certain transverse kinetic momentum of electrons left behind the laser pulse. This net momentum appears when the driving laser pulse undergoes strong selfmodulation and subsequent pulse steepening at the front. In the multi-dimensional simulations, the XUV emission is found only near the laser axis with a much smaller spot size than the laser pulse due to the transverse dynamics of the trapped electrons. The present scheme provides an alternative method to produce ultra-bright XUV pulses for ultrafast applications.

  15. Efficient modeling of plasma wakefield acceleration in quasi-non-linear-regimes with the hybrid code Architect

    NASA Astrophysics Data System (ADS)

    Marocchino, A.; Massimo, F.; Rossi, A. R.; Chiadroni, E.; Ferrario, M.

    2016-09-01

    In this paper we present a hybrid approach aiming to assess feasible plasma wakefield acceleration working points with reduced computation resources. The growing interest for plasma wakefield acceleration and especially the need to control with increasing precision the quality of the accelerated bunch demands for more accurate and faster simulations. Particle in cell codes are the state of the art technique to simulate the underlying physics, however the run-time represents the major drawback. Architect is a hybrid code that treats the bunch kinetically and the background electron plasma as a fluid, initialising bunches in vacuum so to take into account for the transition from vacuum to plasma. Architect solves directly the Maxwell's equations on a Yee lattice. Such an approach allows us to drastically reduce run time without loss of generality or accuracy up to the weakly non linear regime.

  16. Plasma polymerized high energy density dielectric films for capacitors

    NASA Technical Reports Server (NTRS)

    Yamagishi, F. G.

    1983-01-01

    High energy density polymeric dielectric films were prepared by plasma polymerization of a variety of gaseous monomers. This technique gives thin, reproducible, pinhole free, conformable, adherent, and insoluble coatings and overcomes the processing problems found in the preparation of thin films with bulk polymers. Thus, devices are prepared completely in a vacuum environment. The plasma polymerized films prepared all showed dielectric strengths of greater than 1000 kV/cm and in some cases values of greater than 4000 kV/cm were observed. The dielectric loss of all films was generally less than 1% at frequencies below 10 kHz, but this value increased at higher frequencies. All films were self healing. The dielectric strength was a function of the polymerization technique, whereas the dielectric constant varied with the structure of the starting material. Because of the thin films used (thickness in the submicron range) surface smoothness of the metal electrodes was found to be critical in obtaining high dielectric strengths. High dielectric strength graft copolymers were also prepared. Plasma polymerized ethane was found to be thermally stable up to 150 C in the presence of air and 250 C in the absence of air. No glass transitions were observed for this material.

  17. Efficient numerical modelling of the emittance evolution of beams with finite energy spread in plasma wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Mehrling, T. J.; Robson, R. E.; Erbe, J.-H.; Osterhoff, J.

    2016-09-01

    This paper introduces a semi-analytic numerical approach (SANA) for the rapid computation of the transverse emittance of beams with finite energy spread in plasma wakefield accelerators in the blowout regime. The SANA method is used to model the beam emittance evolution when injected into and extracted from realistic plasma profiles. Results are compared to particle-in-cell simulations, establishing the accuracy and efficiency of the procedure. In addition, it is demonstrated that the tapering of vacuum-to-plasma and plasma-to-vacuum transitions is a viable method for the mitigation of emittance growth of beams during their injection and extraction from and into plasma cells.

  18. High-Energy Two-Stage Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Markusic, Tom

    2003-01-01

    A high-energy (28 kJ per pulse) two-stage pulsed plasma thruster (MSFC PPT-1) has been constructed and tested. The motivation of this project is to develop a high power (approximately 500 kW), high specific impulse (approximately 10000 s), highly efficient (greater than 50%) thruster for use as primary propulsion in a high power nuclear electric propulsion system. PPT-1 was designed to overcome four negative characteristics which have detracted from the utility of pulsed plasma thrusters: poor electrical efficiency, poor propellant utilization efficiency, electrode erosion, and reliability issues associated with the use of high speed gas valves and high current switches. Traditional PPTs have been plagued with poor efficiency because they have not been operated in a plasma regime that fully exploits the potential benefits of pulsed plasma acceleration by electromagnetic forces. PPTs have generally been used to accelerate low-density plasmas with long current pulses. Operation of thrusters in this plasma regime allows for the development of certain undesirable particle-kinetic effects, such as Hall effect-induced current sheet canting. PPT-1 was designed to propel a highly collisional, dense plasma that has more fluid-like properties and, hence, is more effectively pushed by a magnetic field. The high-density plasma loading into the second stage of the accelerator is achieved through the use of a dense plasma injector (first stage). The injector produces a thermal plasma, derived from a molten lithium propellant feed system, which is subsequently accelerated by the second stage using mega-amp level currents, which eject the plasma at a speed on the order of 100 kilometers per second. Traditional PPTs also suffer from dynamic efficiency losses associated with snowplow loading of distributed neutral propellant. The twostage scheme used in PPT-I allows the propellant to be loaded in a manner which more closely approximates the optimal slug loading. Lithium propellant

  19. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    SciTech Connect

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18

    This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.

  20. Time-resolved measurements with streaked diffraction patterns from electrons generated in laser plasma wakefield

    NASA Astrophysics Data System (ADS)

    He, Zhaohan; Nees, John; Hou, Bixue; Krushelnick, Karl; Thomas, Alec; Beaurepaire, Benoît; Malka, Victor; Faure, Jérôme

    2013-10-01

    Femtosecond bunches of electrons with relativistic to ultra-relativistic energies can be robustly produced in laser plasma wakefield accelerators (LWFA). Scaling the electron energy down to sub-relativistic and MeV level using a millijoule laser system will make such electron source a promising candidate for ultrafast electron diffraction (UED) applications due to the intrinsic short bunch duration and perfect synchronization with the optical pump. Recent results of electron diffraction from a single crystal gold foil, using LWFA electrons driven by 8-mJ, 35-fs laser pulses at 500 Hz, will be presented. The accelerated electrons were collimated with a solenoid magnetic lens. By applying a small-angle tilt to the magnetic lens, the diffraction pattern can be streaked such that the temporal evolution is separated spatially on the detector screen after propagation. The observable time window and achievable temporal resolution are studied in pump-probe measurements of photo-induced heating on the gold foil.

  1. An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

    SciTech Connect

    Anania, M. P.; Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A.; Geer, S. B. van der; Loos, M. J. de; Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A.; Gillespie, W. A.; MacLeod, A. M.

    2014-06-30

    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1 × 10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.

  2. Hosing instability in the blow-out regime for plasma-wakefield acceleration.

    PubMed

    Huang, C; Lu, W; Zhou, M; Clayton, C E; Joshi, C; Mori, W B; Muggli, P; Deng, S; Oz, E; Katsouleas, T; Hogan, M J; Blumenfeld, I; Decker, F J; Ischebeck, R; Iverson, R H; Kirby, N A; Walz, D

    2007-12-21

    The electron hosing instability in the blow-out regime of plasma-wakefield acceleration is investigated using a linear perturbation theory about the electron blow-out trajectory in Lu et al. [in Phys. Rev. Lett. 96, 165002 (2006)10.1103/PhysRevLett.96.165002]. The growth of the instability is found to be affected by the beam parameters unlike in the standard theory Whittum et al. [Phys. Rev. Lett. 67, 991 (1991)10.1103/PhysRevLett.67.991] which is strictly valid for preformed channels. Particle-in-cell simulations agree with this new theory, which predicts less hosing growth than found by the hosing theory of Whittum et al. PMID:18233526

  3. Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons

    SciTech Connect

    Toth, Carl B.; Esarey, Eric H.; Geddes, Cameron G.R.; Leemans,Wim P.; Nakamura, Kei; Panasenko, Dmitriy; Schroeder, Carl B.; Bruhwiler,D.; Cary, J.R.

    2007-06-25

    An optical injection scheme for a laser-plasma basedaccelerator which employs a non-collinear counter-propagating laser beamto push background electrons in the focusing and acceleration phase viaponderomotive beat with the trailing part of the wakefield driver pulseis discussed. Preliminary experiments were performed using a drive beamof a_0 = 2.6 and colliding beam of a_1 = 0.8 both focused on the middleof a 200 mu m slit jet backed with 20 bar, which provided ~; 260 mu mlong gas plume. The enhancement in the total charge by the collidingpulse was observed with sharp dependence on the delay time of thecolliding beam. Enhancement of the neutron yield was also measured, whichsuggests a generation of electrons above 10 MeV.

  4. Nonlinear laser-seeded modulation instability in a proton driver plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Siemon, Carl; Khudik, Vladimir; Yi, S. Austin; Pukhov, Alexander; Shvets, Gennady

    2013-10-01

    A new method for seeding the modulation instability (MI) in a proton driver plasma wakefield accelerator (PDPWA) using a CO2 laser pulse is presented. The proton beam's envelope equation is used to analytically compare the laser seed with previously suggested seeding methods. Simulations demonstrate that a laser pulse placed ahead of a proton beam with a realistic longitudinal density profile leads to peak accelerating gradients that are comparable to those produced by other seeding methods. The nonlinear BNS damping of the MI is analytically shown to lead to instability saturation. The envelope equation is Fourier expanded into a set of coupled, nonlinear equations that describe the evolution of the beam's Fourier components. Peak beam density and peak accelerating gradient during the beam's evolution are estimated.

  5. Enhancing Plasma Wakefield and E-cloud Simulation Performance Using a Pipelining Algorithm

    NASA Astrophysics Data System (ADS)

    Feng, B.; Huang, C.; Decyk, V.; Mori, W. B.; Katsouleas, T.; Muggli, P.

    2006-11-01

    Modeling long timescale propagation of beams in plasma wakefield accelerators at the energy frontier and in electron clouds in circular accelerators such as CERN-LHC requires faster and more efficient simulation codes. Simply increasing the number of processors does not scale beyond one-fifth of the number of cells in the decomposition direction. A pipelining algorithm applied on fully parallelized code QuickPIC is suggested to overcome this limit. The pipelining algorithm uses many groups of processors and optimizes the job allocation on the processors in parallel computing. With the new algorithm, it is possible to use on the order of 102 groups of processors, expanding the scale and speed of simulations with QuickPIC by a similar factor.

  6. Enhancing plasma wakefield and e-cloud simulation performance using a pipelining algorithm

    NASA Astrophysics Data System (ADS)

    Feng, Bing; Katsouleas, Tom; Huang, Chengkun; Decyk, Viktor; Mori, Warren B.

    2006-10-01

    Modeling long timescale propagation of beams in plasma wakefield accelerators at the energy frontier and in electron clouds in circular accelerators such as CERN-LHC require a faster and more efficient simulation code. Simply increasing the number of processors does not scale beyond one-fifth of the number of cells in the decomposition direction. A pipelining algorithm applied on fully parallel code QUICKPIC is suggested to overcome this limit. The pipelining algorithm uses many groups of processors and optimizes the job allocation on the processors in parallel computing. With the new algorithm, it is possible to use on the order of 100 groups of processors, expanding the scale and speed of simulations with QuickPIC by a similar factor.

  7. Observations of shear flows in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, Eric C.

    The research discussed in this thesis represents work toward the demonstration of experimental designs for creating a Kelvin-Helmholtz (KH) unstable shear layer in a high-energy-density (HED) plasma. Such plasmas are formed by irradiating materials with several kilo-Joules of laser light over a few nanoseconds, and are defined as having an internal pressure greater than one-million atmospheres. Similar plasmas exist in laboratory fusion experiments and in the astrophysical environment. The KH instability is a fundamental fluid instability that arises when strong velocity gradients exist at the interface between two fluids. The KH instability is important because it drives the mixing of fluids and initiates the transition to turbulence in the flow. Until now, the evolution of the KH instability has remained relatively unexplored in the HED regime This thesis presents the observations and analysis of two novel experiments carried out using two separate laser facilities. The first experiment used 1.4 kJ from the Nike laser to generate a supersonic flow of Al plasma over a low-density, rippled foam surface. The Al flow interacted with the foam and created distinct features that resulted from compressible effects. In this experiment there is little evidence of the KH instability. Nevertheless, this experimental design has perhaps pioneered a new method for generating a supersonic shear flow that has the potential to produce the KH instability if more laser energy is applied. The second experiment was performed on the Omega laser. In this case 4.3 kJ of laser energy drove a blast wave along a rippled foam/plastic interface. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vorticies characteristic of the KH instability. The Omega experiment was the first HED experiment to capture the evolution of the KH instability.

  8. THE IRON OPACITY PROJECT: High-Energy-Density Plasma Opacities

    NASA Astrophysics Data System (ADS)

    Palay, E.; Orban, C.; Nahar, S.; Pradhan, A.; Pinnsonoault, M.; Bailey, J.

    2013-05-01

    Opacity governs radiation flow in plasma sources. Accurate opacities are needed to model unobservable laboratory and astrophysical conditions. High-energy-density (HED) plasma conditions prevalent in stellar interiors can now be recreated in the laboratory. The Z-pinch fusion device at the Sandia National Lab can reproduce temperatures and densities near the boundary where radiation transport changes from diffusion to convection inside the Sun. To benchmark theoretical opacities experiments are essential to resolve the outstanding discrepancy in solar abundances. The most common volatile elements C, N, O, Ne, etc. have been spectroscopically measured to be up to 50% lower than the standard abundances. This introduces conflict in the derived values of basic solar parameters such as the radiation/convection boundary, sound speed, and the primordial He abundance with precisely measured oscillations of the Sun through Helioseismology. A potential solution is increment of stellar opacities, which has inverse but complex relation with abundacnes, at least 30%. New iron opacity calculations include hitherto neglected atomic physics of fine structure and resonances which are largely treated as lines in existing opacities calculations. Preliminary results on radiative transitions in Ne Partial support: DOE,NSF.

  9. QUICKPIC: A highly efficient particle-in-cell code for modeling wakefield acceleration in plasmas

    SciTech Connect

    Huang, C. . E-mail: huangck@ee.ucla.edu; Decyk, V.K.; Ren, C.; Zhou, M.; Lu, W.; Mori, W.B.; Cooley, J.H.; Antonsen, T.M.; Katsouleas, T.

    2006-09-20

    A highly efficient, fully parallelized, fully relativistic, three-dimensional particle-in-cell model for simulating plasma and laser wakefield acceleration is described. The model is based on the quasi-static or frozen field approximation, which reduces a fully three-dimensional electromagnetic field solve and particle push to a two-dimensional field solve and particle push. This is done by calculating the plasma wake assuming that the drive beam and/or laser does not evolve during the time it takes for it to pass a plasma particle. The complete electromagnetic fields of the plasma wake and its associated index of refraction are then used to evolve the drive beam and/or laser using very large time steps. This algorithm reduces the computational time by 2-3 orders of magnitude. Comparison between the new algorithm and conventional fully explicit models (OSIRIS) is presented. The agreement is excellent for problems of interest. Direction for future work is also presented.

  10. Fluid simulation of relativistic electron beam driven wakefield in a cold plasma

    SciTech Connect

    Bera, Ratan Kumar; Sengupta, Sudip; Das, Amita

    2015-07-15

    Excitation of wakefield in a cold homogeneous plasma, driven by an ultra-relativistic electron beam is studied in one dimension using fluid simulation techniques. For a homogeneous rigid beam having density (n{sub b}) less than or equal to half the plasma density (n{sub 0}), simulation results are found to be in good agreement with the analytical work of Rosenzweig [Phys. Rev. Lett. 58, 555 (1987)]. Here, Rosenzweig's work has been analytically extended to regimes where the ratio of beam density to plasma density is greater than half and results have been verified using simulation. Further in contrast to Rosenzweig's work, if the beam is allowed to evolve in a self-consistent manner, several interesting features are observed in simulation viz. splitting of the beam into beam-lets (for l{sub b} > λ{sub p}) and compression of the beam (for l{sub b} < λ{sub p}), l{sub b} and λ{sub p}, respectively, being the initial beam length and plasma wavelength.

  11. High energy density plasma science with an ultrarelativistic electron beam

    NASA Astrophysics Data System (ADS)

    Joshi, C.; Blue, B.; Clayton, C. E.; Dodd, E.; Huang, C.; Marsh, K. A.; Mori, W. B.; Wang, S.; Hogan, M. J.; O'Connell, C.; Siemann, R.; Watz, D.; Muggli, P.; Katsouleas, T.; Lee, S.

    2002-05-01

    An intense, high-energy electron or positron beam can have focused intensities rivaling those of today's most powerful laser beams. For example, the 5 ps (full-width, half-maximum), 50 GeV beam at the Stanford Linear Accelerator Center (SLAC) at 1 kA and focused to a 3 micron rms spot size gives intensities of >1020 W/cm-2 at a repetition rate of >10 Hz. Unlike a ps or fs laser pulse which interacts with the surface of a solid target, the particle beam can readily tunnel through tens of cm of steel. However, the same particle beam can be manipulated quite effectively by a plasma that is a million times less dense than air! This is because of the incredibly strong collective fields induced in the plasma by the Coulomb force of the beam. The collective fields in turn react back onto the beam leading to many clearly observable phenomena. The beam paraticles can be: (1) Deflected leading to focusing, defocusing, or even steering of the beam; (2) undulated causing the emission of spontaneous betatron x-ray radiation and; (3) accelerated or decelerated by the plasma fields. Using the 28.5 GeV electron beam from the SLAC linac a series of experiments have been carried out that demonstrate clearly many of the above mentioned effects. The results can be compared with theoretical predictions and with two-dimensional and three-dimensional, one-to-one, particle-in-cell code simulations. These phenomena may have practical applications in future technologies including optical elements in particle beam lines, synchrotron light sources, and ultrahigh gradient accelerators.

  12. An accurate Rb density measurement method for a plasma wakefield accelerator experiment using a novel Rb reservoir

    NASA Astrophysics Data System (ADS)

    Öz, E.; Batsch, F.; Muggli, P.

    2016-09-01

    A method to accurately measure the density of Rb vapor is described. We plan on using this method for the Advanced Wakefield (AWAKE) (Assmann et al., 2014 [1]) project at CERN , which will be the world's first proton driven plasma wakefield experiment. The method is similar to the hook (Marlow, 1967 [2]) method and has been described in great detail in the work by Hill et al. (1986) [3]. In this method a cosine fit is applied to the interferogram to obtain a relative accuracy on the order of 1% for the vapor density-length product. A single-mode, fiber-based, Mach-Zenhder interferometer will be built and used near the ends of the 10 meter-long AWAKE plasma source to be able to make accurate relative density measurement between these two locations. This can then be used to infer the vapor density gradient along the AWAKE plasma source and also change it to the value desired for the plasma wakefield experiment. Here we describe the plan in detail and show preliminary results obtained using a prototype 8 cm long novel Rb vapor cell.

  13. Modeling Self-Ionized Plasma Wakefield Acceleration for Afterburner Parameters Using QuickPIC

    SciTech Connect

    Zhou, M.; Clayton, C.E.; Decyk, V.K.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu, W.; Mori, W.B.; Tsung, F.S.; Deng, S.; Katsouleas, T.; Muggli, P.; Oz, E.; Decker, F.-J.; Iverson, R.; O'Connel, C.; Walz, D.; /SLAC

    2006-01-25

    For the parameters envisaged in possible afterburner stages[1] of a plasma wakefield accelerator (PWFA), the self-fields of the particle beam can be intense enough to tunnel ionize some neutral gases. Tunnel ionization has been investigated as a way for the beam itself to create the plasma, and the wakes generated may differ from those generated in pre-ionized plasmas[2],[3]. However, it is not practical to model the whole stage of PWFA with afterburner parameters using the models described in [2] and [3]. Here we describe the addition of a tunnel ionization package using the ADK model into QuickPIC, a highly efficient quasi-static particle in cell (PIC) code which can model a PWFA with afterburner parameters. Comparison between results from OSIRIS (a full PIC code with ionization) and from QuickPIC with the ionization package shows good agreement. Preliminary results using parameters relevant to the E164X experiment and the upcoming E167 experiment at SLAC are shown.

  14. Analysis of Ion Motion and Scattering in the Extreme Regime of High Intensity Electron Beams in Plasma Wakefield Accelerators

    SciTech Connect

    Gholizadeh, Reza; Katsouleas, Tom; Muggli, Patric; Mori, Warren

    2006-11-27

    Plasma wakefield accelerator is examined in the extreme regime of nanometer transverse beam sizes, typical of designs in the multi-TeV range. We find that ion motion, synchrotron radiation, nuclear scattering and particle trapping constrain the design parameters in which high beam quality and efficiency can be maintained. For a particular example relevant to an ILC Afterburner, the analysis suggests that an intermediate mass ion such as Argon may best satisfy the constraints.

  15. Analysis of Ion Motion and Scattering in the Extreme Regime of High Intensity Electron Beams in Plasma Wakefield Accelerators

    NASA Astrophysics Data System (ADS)

    Gholizadeh, Reza; Katsouleas, Tom; Muggli, Patric; Mori, Warren

    2006-11-01

    Plasma wakefield accelerator is examined in the extreme regime of nanometer transverse beam sizes, typical of designs in the multi-TeV range. We find that ion motion, synchrotron radiation, nuclear scattering and particle trapping constrain the design parameters in which high beam quality and efficiency can be maintained. For a particular example relevant to an ILC Afterburner, the analysis suggests that an intermediate mass ion such as Argon may best satisfy the constraints.

  16. The effect of the vacuum-plasma transition and an injection angle on electron-bunch injection into a laser wakefield

    SciTech Connect

    Luttikhof, M. J. H.; Khachatryan, A. G.; Goor, F. A. van; Boller, K.-J.

    2007-08-15

    External injection of an electron bunch in the laser wakefield can result in femtosecond accelerated bunches with relatively low energy spread. In this paper it is shown that the density transition from vacuum to plasma can play an important role in the trapping process. The plasma wavelength in this transition region changes continuously, which means that the injected electrons see an altering wakefield. This can result in strong defocusing of the injected bunch. It is found that the effect becomes stronger for stronger wakefields, longer transition lengths, and lower injection energies. The transition region can be avoided if the bunch is injected into the wakefield at an angle. Injecting the bunch at an angle allows the bunch to be wider and results in more charge being trapped. The dynamics of the bunch in this case are similar to the dynamics of a bunch injected in front of the laser pulse.

  17. Plasma wakefields driven by an incoherent combination of laser pulses: a path towards high-average power laser-plasma accelerators

    SciTech Connect

    Benedetti, C.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

    2014-05-01

    he wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e.,without constraining the pulse phases) is studied analytically and by means of fully-self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structure in the laser energy density produced by the combined pulses exists on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators and associated applications.

  18. Plasma wakefields driven by an incoherent combination of laser pulses: A path towards high-average power laser-plasma accelerators

    SciTech Connect

    Benedetti, C.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2014-05-15

    The wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e., without constraining the pulse phases) is studied analytically and by means of fully self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region, the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structures in the laser energy density produced by the combined pulses exist on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators, and associated applications.

  19. Near-threshold electron injection in the laser-plasma wakefield accelerator leading to femtosecond bunches

    NASA Astrophysics Data System (ADS)

    Islam, M. R.; Brunetti, E.; Shanks, R. P.; Ersfeld, B.; Issac, R. C.; Cipiccia, S.; Anania, M. P.; Welsh, G. H.; Wiggins, S. M.; Noble, A.; Cairns, R. A.; Raj, G.; Jaroszynski, D. A.

    2015-09-01

    The laser-plasma wakefield accelerator is a compact source of high brightness, ultra-short duration electron bunches. Self-injection occurs when electrons from the background plasma gain sufficient momentum at the back of the bubble-shaped accelerating structure to experience sustained acceleration. The shortest duration and highest brightness electron bunches result from self-injection close to the threshold for injection. Here we show that in this case injection is due to the localized charge density build-up in the sheath crossing region at the rear of the bubble, which has the effect of increasing the accelerating potential to above a critical value. Bunch duration is determined by the dwell time above this critical value, which explains why single or multiple ultra-short electron bunches with little dark current are formed in the first bubble. We confirm experimentally, using coherent optical transition radiation measurements, that single or multiple bunches with femtosecond duration and peak currents of several kiloAmpere, and femtosecond intervals between bunches, emerge from the accelerator.

  20. 9 GeV energy gain in a beam-driven plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Litos, M.; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Corde, S.; Clayton, C. E.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Schmeltz, M.; Vafaei-Najafabadi, N.; Yakimenko, V.

    2016-03-01

    An electron beam has gained a maximum energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square energy spread was 5.0%. The mean accelerated charge and energy gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV m-1at the spectral peak. The mean energy spread of the data set was 5.1%. These results are consistent with the extrapolation of the previously reported energy gain results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.

  1. 9 GeV energy gain in a beam-driven plasma wakefield accelerator

    DOE PAGESBeta

    Litos, M.; Adli, E.; Allen, J. M.; An, W.; Clarke, C. I.; Corde, S.; Clayton, C. E.; Frederico, J.; Gessner, S. J.; Green, S. Z.; et al

    2016-02-15

    An electron beam has gained a maximum energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square energy spread was 5.0%. The mean accelerated charge and energy gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV m-1 at the spectral peak. Moreover, the mean energy spread of the data set was 5.1%. Our results are consistent with the extrapolation of the previously reported energy gainmore » results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.« less

  2. High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding.

    PubMed

    Geddes, C G R; Toth, C S; Van Tilborg, J; Esarey, E; Schroeder, C B; Bruhwiler, D; Nieter, C; Cary, J; Leemans, W P

    2004-09-30

    Laser-driven accelerators, in which particles are accelerated by the electric field of a plasma wave (the wakefield) driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV m(-1) (refs 1-3). These fields are thousands of times greater than those achievable in conventional radio-frequency accelerators, spurring interest in laser accelerators as compact next-generation sources of energetic electrons and radiation. To date, however, acceleration distances have been severely limited by the lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance results in low-energy beams with 100 per cent electron energy spread, which limits potential applications. Here we demonstrate a laser accelerator that produces electron beams with an energy spread of a few per cent, low emittance and increased energy (more than 10(9) electrons above 80 MeV). Our technique involves the use of a preformed plasma density channel to guide a relativistically intense laser, resulting in a longer propagation distance. The results open the way for compact and tunable high-brightness sources of electrons and radiation. PMID:15457252

  3. Laser guiding at relativistic intensities and wakefield particle acceleration in plasma channels

    SciTech Connect

    Geddes, C.G.R.; Toth, Cs.; van Tilborg, J.; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Cary, J.; Leemans, W.P.

    2004-08-01

    Electron beams with hundreds of picoCoulombs of charge in percent energy spread at above 80 MeV, and with few milliradian divergence, have been produced for the first time in a high gradient laser wakefield accelerator by guiding the drive laser pulse. Channels formed by hydrodynamic shock were used to guide acceleration relevant laser intensities of at least 1E18W/cm2 at the guide output over more than 10 Rayleigh lengths at LBNL's l'OASIS facility (10TW, 2E19W/cm2). The pondermotive force of the laser pulse drove an intense plasma wave, producing acceleration gradients on the order of 100 GV/m. Electrons were trapped from the background plasma and accelerated. By extending the acceleration length using the guiding channel, the energy of the electron beam was greatly increased, and bunches of small energy spread and low emittance were formed. Experiments varying gas jet length as well assimilations indicate that the high quality beams were formed when beam loading turned off injection after an initial load, producing an isolated bunch, and when that bunch was subsequently accelerated to the dephasing length at which point it rotated in phase space to produce low energy spread.

  4. Measurement of the Charge Reduction and Asymmetrical Interaction Force Created by the Ion Wakefield in a Dusty Plasma

    NASA Astrophysics Data System (ADS)

    Chen, Mudi; Yousefi, Razieh; Kong, Jie; Qiao, Ke; Carmona-Reyes, Jorge; Matthews, Lorin; Hyde, Truell

    2014-10-01

    The manner in which the ion wakefield forms has strong implications on the structure, stability and dynamics of a complex plasma. The majority of vertically aligned, ordered dust particle structures observed in a complex plasma result from a combination of the ion wakefield and the external confinement. The ion wakefield is also responsible for other interesting phenomena, such as the reduction in charge seen for a down-stream particle in a vertically aligned dust particle chain and the asymmetrical interaction force between the up-stream and down-stream particles. Unfortunately, few experimental measurements of these phenomena are available. In this experiment, one dimensional (1-D) dust particle structures (i.e., particle chains) are formed in a GEC RF reference cell within a glass box sitting on the powered, lower electrode. The charge reduction on the downstream particle and the asymmetric interaction force are examined using an externally produced DC bias applied to the lower electrode and a diode pumped solid state laser (Coherent VERDI) for perturbation.

  5. Laser Wakefield experiments at LULI

    NASA Astrophysics Data System (ADS)

    Marquès, J. R.

    1997-11-01

    In the context of Laser Plasma Particle Acceleration, the Laser Wakefield(T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)) is a very promising scheme for the excitation of a high amplitude Electron Plasma Waves (EPW). In this scheme, the electrons of the plasma are pushed by the radiation pressure associated with the spatio-temporal profile of an ultra-short (< 1 ps), ultra-intense (> 10^16 W/cm^2) laser pulse. In the wake of this pulse, the electrons oscillate (EPW) around their initial positions. The associated electron-ion charge separation generates electric fields that can be over 100 GV/m. These fields can be longitudinal and of relativistic phase velocity, making them very attractive for high energy particle acceleration. We have studied(J. R. Marquès et al, Phys. Rev. Lett. 79 (18) 3463, 1996; J. R. Marquès et al, Phys. Rev. Lett. 76 (19) 3566, 1996.) the transverse electron oscillations excited by laser wakefield. The amplitude, the frequency, and the lifetime of the oscillation have been measured. The quasi-resonant behavior of the oscillation amplitude with the electron density and the increase of the plasma frequency for oscillations in the non-linear regime have been observed. A comparison of our results with 2-D simulations has allowed us to identify a new damping mechanism linked to a transverse gradient of the electron density. At the moment, we are experimentally studying the longitudinal electron oscillations excited by laser wakefield. Two kind of experiments are in progress. The first one is centered on the acceleration of electrons injected in an EPW, while the second one will characterize the EPW. We will present the results of these experiments.

  6. Betatron radiation based diagnostics for plasma wakefield accelerated electron beams at the SPARC_LAB test facility

    NASA Astrophysics Data System (ADS)

    Shpakov, V.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Dabagov, S.; Ferrario, M.; Filippi, F.; Marocchino, A.; Paroli, B.; Pompili, R.; Rossi, A. R.; Zigler, A.

    2016-09-01

    Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC_LAB for such diagnostics tool, along with expected parameters of betatron radiation.

  7. Controlled laser plasma wakefield acceleration of electrons via colliding pulse injection in non-collinear geometry

    NASA Astrophysics Data System (ADS)

    Toth, Csaba; Nakamura, Kei; Geddes, Cameron; Panasenko, Dmitriy; Plateau, Guillaume; Matlis, Nicholas; Schroeder, Carl; Esarey, Eric; Leemans, Wim

    2007-11-01

    Colliding laser pulses [1] have been proposed as a method for controlling injection of electrons into a laser wakefield accelerator (LWFA) and hence producing high quality electron beams with energy spread below 1% and normalized emittances < 1 micron. The. One pulse excites a plasma wake, and a collinear pulse following behind it collides with a counterpropagating pulse forming a beat pattern that boosts background electrons into accelerating phase. A variation of the original method uses only two laser pulses [2] which may be non-collinear. The first pulse drives the wake, and beating of the trailing edge of this pulse with the colliding pulse injects electrons. Non-collinear injection avoids optical elements on the electron beam path (avoiding emittance growth). We report on progress of non-collinear experiments at LBNL, using the Ti:Sapphire laser at the LOASIS facility of LBNL. New results indicate that the electron beam properties are affected by the presence of the second beam. [1] E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997) [2] G. Fubiani, Phys. Rev. E 70, 016402 (2004)

  8. Compact tunable Compton x-ray source from laser wakefield accelerator and plasma mirror

    NASA Astrophysics Data System (ADS)

    Tsai, Hai-En; Wang, Xiaoming; Shaw, Joseph; Li, Zhengyan; Zgadzaj, Rafal; Arefiev, Alex; Downer, Mike; InstituteFusion Studies, University of Texas at Austin Team

    2014-10-01

    Compton backscatter (CBS) x-rays have been generated from laser wakefield accelerator (LWFA) electron beams by retro-reflecting the LWFA drive pulse with a plasma mirror (PM) and by backscattering a secondary pulse split from the driver pulse. However, tunable quasi-monoenergetic CBS x-rays have been produced only by the latter method, which requires challenging alignment. Here we demonstrate quasi-monoenergetic (~50% FWHM), bright (5 × 106 photon per shot) CBS x-rays with central energy tunability from 75 KeV to 200 KeV by combining a PM with a tunable LWFA. 30 TW, 30-fs (FWHM), laser pulses from the UT3 laser system were focused (f/12) to spot diameter 11 micron, intensity ~6 × 1018 W/cm2 (a = 1.5) at a 1-mm long Helium gas jet, yielding quasi-monoenergetic relativistic electrons. A thin plastic film near the gas jet exit efficiently retro-reflected the LWFA driving pulse into oncoming electrons to produce CBS x-rays without detecting bremsstrahlung background. By changing gas jet backing pressure, electron energy was tuned from 60 to 90 MeV, thereby tuning the CBS x-ray energy, which was determined by measuring transmission through a metal filter pack. The x-ray beam profiles recorded on an image plate had 5-10-mrad divergence.

  9. Laser Guiding at Relativistic Intensities and Wakefield ParticleAcceleration in Plasma Channels

    SciTech Connect

    Geddes, C.G.R.; Toth, Cs.; van Tilborg, J.; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

    2005-05-01

    High quality electron beams with hundreds of picoCoulombs ofcharge inpercent energy spread above 80 MeV were produced for the firsttime in high gradient laser wakefield accelerators by guiding the drivelaser pulse.

  10. Exploration of Plasma Jets Approach to High Energy Density Physics. Final report

    SciTech Connect

    Chen, Chiping

    2013-08-26

    High-energy-density laboratory plasma (HEDLP) physics is an emerging, important area of research in plasma physics, nuclear physics, astrophysics, and particle acceleration. While the HEDLP regime occurs at extreme conditions which are often found naturally in space but not on the earth, it may be accessible by colliding high intensity plasmas such as high-energy-density plasma jets, plasmoids or compact toroids from plasma guns. The physics of plasma jets is investigated in the context of high energy density laboratory plasma research. This report summarizes results of theoretical and computational investigation of a plasma jet undergoing adiabatic compression and adiabatic expansion. A root-mean-squared (rms) envelope theory of plasma jets is developed. Comparison between theory and experiment is made. Good agreement between theory and experiment is found.

  11. Generation of wakefields by whistlers in spin quantum magnetoplasmas

    SciTech Connect

    Misra, A. P.; Brodin, G.; Marklund, M.; Shukla, P. K.

    2010-12-15

    The excitation of electrostatic wakefields in a magnetized spin quantum plasma by the classical and the spin-induced ponderomotive force (CPF and SPF, respectively) due to whistler waves is reported. The nonlinear dynamics of the whistlers and the wakefields is shown to be governed by a coupled set of nonlinear Schroedinger and driven Boussinesq-like equations. It is found that the quantum force associated with the Bohm potential introduces two characteristic length scales, which lead to the excitation of multiple wakefields in a strongly magnetized dense plasma (with a typical magnetic field strength B{sub 0} or approx. 10{sup 9} T and particle density n{sub 0} > or approx. 10{sup 36} m{sup -3}), where the SPF strongly dominates over the CPF. In other regimes, namely, B{sub 0} < or approx. 10{sup 8} T and n{sub 0} < or approx. 10{sup 35} m{sup -3}, where the SPF is comparable to the CPF, a plasma wakefield can also be excited self-consistently with one characteristic length scale. Numerical results reveal that the wakefield amplitude is enhanced by the quantum tunneling effect; however, it is lowered by the external magnetic field. Under appropriate conditions, the wakefields can maintain high coherence over multiple plasma wavelengths and thereby accelerate electrons to extremely high energies. The results could be useful for particle acceleration at short scales, i.e., at nanometer and micrometer scales, in magnetized dense plasmas where the driver is the whistler wave instead of a laser or a particle beam.

  12. Shielding effect and wakefield pattern of a moving test charge in a non-Maxwellian dusty plasma

    SciTech Connect

    Ali, S.; Khan, S.

    2013-07-15

    By using the Vlasov-Poisson equations, we calculate an expression for the electrostatic potential caused by a test charge in an unmagnetized non-Maxwellian dusty plasma, whose constituents are the superthermal hot-electrons, the mobile cold-electrons with a neutralizing background of cold ions, and charge fluctuating isolated dust grains. The superthermality effects due to hot electrons not only modify the dielectric constant of the electron-acoustic waves but also significantly affect the electrostatic potential. The latter can be decomposed into the Debye-Hückel and oscillatory wake potentials. Analytical and numerical results reveal that the Debye-Hückel and wakefield potentials converge to the Maxwellian case for large values of superthermality parameter. Furthermore, the plasma parameters play a vital role in the formation of shielding and wakefield pattern in a two-electron temperature plasma. The present results should be important for laboratory and space dusty plasmas, where hot-electrons can be assumed to follow the non-Maxwellian distribution function.

  13. High-quality electron beams from beam-driven plasma accelerators by wakefield-induced ionization injection.

    PubMed

    Martinez de la Ossa, A; Grebenyuk, J; Mehrling, T; Schaper, L; Osterhoff, J

    2013-12-13

    We propose a new and simple strategy for controlled ionization-induced trapping of electrons in a beam-driven plasma accelerator. The presented method directly exploits electric wakefields to ionize electrons from a dopant gas and capture them into a well-defined volume of the accelerating and focusing wake phase, leading to high-quality witness bunches. This injection principle is explained by example of three-dimensional particle-in-cell calculations using the code OSIRIS. In these simulations a high-current-density electron-beam driver excites plasma waves in the blowout regime inside a fully ionized hydrogen plasma of density 5×10(17)cm-3. Within an embedded 100  μm long plasma column contaminated with neutral helium gas, the wakefields trigger ionization, trapping of a defined fraction of the released electrons, and subsequent acceleration. The hereby generated electron beam features a 1.5 kA peak current, 1.5  μm transverse normalized emittance, an uncorrelated energy spread of 0.3% on a GeV-energy scale, and few femtosecond bunch length. PMID:24483670

  14. Development of high energy pulsed plasma simulator for plasma-lithium trench experiment

    NASA Astrophysics Data System (ADS)

    Jung, Soonwook

    To simulate detrimental events in a tokamak and provide a test-stand for a liquid lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat flux level in a major fusion device) in ~ 100 mus (≤ 0.1 MJ/m2) for a liquid lithium plasma facing component research. The existing theta pinch device, DEVeX, was built and operated for study on lithium vapor shielding effect. However, a typical plasma energy of 3 - 4 kJ/m2 is too low to study an interaction of plasma and plasma facing components in fusion devices. No or little preionized plasma, ringing of magnetic field, collisions of high energy particles with background gas have been reported as the main issues. Therefore, DEVeX is reconfigured to mitigate these issues. The new device is mainly composed of a plasma gun for a preionization source, a theta pinch for heating, and guiding magnets for a better plasma transportation. Each component will be driven by capacitor banks and controlled by high voltage / current switches. Several diagnostics including triple Langmuir probe, calorimeter, optical emission measurement, Rogowski coil, flux loop, and fast ionization gauge are used to characterize the new device. A coaxial plasma gun is manufactured and installed in the previous theta pinch chamber. The plasma gun is equipped with 500 uF capacitor and a gas puff valve. The increase of the plasma velocity with the plasma gun capacitor voltage is consistent with the theoretical predictions and the velocity is located between the snowplow model and the weak - coupling limit. Plasma energies measured with the calorimeter ranges from 0.02 - 0.065 MJ/m2 and increases with the voltage at the capacitor bank. A cross-check between the plasma energy measured with the calorimeter and the triple probe

  15. Laser wake-field acceleration in pre-formed plasma channel created by pre-pulse pedestal of terawatt laser pulse

    SciTech Connect

    Sanyasi Rao, Bobbili; Chakera, Juzer Ali; Naik, Prasad Anant; Kumar, Mukund; Gupta, Parshotam Dass

    2011-09-15

    The role of nanosecond duration pre-pulse pedestal (Amplified Spontaneous Emission (ASE) pre-pulse) in the propagation of 45 fs, 4 TW Ti:Sapphire laser pulse through a helium gas jet target has been investigated. We observed that the pre-pulse pedestal of about 1 ns duration and intensity 3 x 10{sup 12} W/cm{sup 2} creates pre-formed plasma with optical guiding channel like structure in the gas-jet at density around 3 x 10{sup 19} cm{sup -3}. Guiding of the 45 fs laser pulse (I{sub L} = 3 x 10{sup 18} W/cm{sup 2}) in the pre-formed plasma channel, over a distance much longer than the Rayleigh length was also observed. The guiding of the laser pulse resulted in the generation of high energy electron beam by laser wake-field acceleration of self-injected electrons. The accelerated electron beam was quasi-monoenergetic with peak energy up to 50 MeV, low divergence in the range of 3-6 mrad, and bunch charge up to 100 pC.

  16. Colliding pulse injection experiments in non-collinear geometry for controlled laser plasma wakefield acceleration of electrons

    NASA Astrophysics Data System (ADS)

    Toth, Csaba; Nakamura, K.; Geddes, C.; Michel, P.; Schroeder, C.; Esarey, E.; Leemans, W.

    2006-10-01

    A method for controlled injection of electrons into a plasma wakefield relying on colliding laser pulses [1] has been proposed a decade ago to produce high quality relativistic electron beams with energy spread below 1% and normalized emittances < 1 micron from a laser wakefield accelerator (LWFA). The original idea uses three pulses in which one pulse excites the plasma wake and a trailing laser pulse collides with a counterpropagating one to form a beat pattern that boosts background electrons to catch the plasma wave. Another, two-beam off-axis injection method [2] with crossing angles varying from 180 to 90 degrees avoids having optical elements on the path of the electron beam and has been studied at the LOASIS facility of LBNL as a viable method for laser triggered injection. It allows low dark current operation with controllable final beam energy and low energy spread. Here, we report on progress of electron optical injection via the two-beam non-collinear colliding pulse scheme using multi-terawatt Ti:Sapphire laser beams (45 fs, 100s of mJ) focused onto a Hydrogen gas plume. Experimental results indicate that electron beam properties are affected by the second beam. *This work is supported by DoE under contract DE-AC02-05CH11231. [1] E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997) [2] G. Fubiani, Phys. Rev. E 70, 016402 (2004)

  17. High Energy-Density Plasma Production from Plasma-Filled Rod-Pinch Diodes

    NASA Astrophysics Data System (ADS)

    Schumer, J. W.; Weber, B. V.; Mosher, D.; Apruzese, J. P.

    2008-04-01

    The Plasma-Filled Rod-Pinch diode (PFRP) concentrates a 100-ns, 500-kA, >MeV electron-beam onto the tip of a tapered tungsten rod, generating a High Energy Density Plasma (HEDP). The HEDP (warm dense plasma) is created by deposition of a high-power-density (40 TW/cm^2) electron-beam into solid-density tungsten. The diode current and voltage has been shown to be controllably modified between 260 kA and 1.8 MV to 770 kA and 0.45 MV by increasing the initial plasma-fill density. At the time of peak energy density, analytic estimates using a 0-d self-similar MHD model predict a solid-density (20 g/cm^3) tungsten plasma with 25 eV temperature, 16 Mbar pressure, and 2.4 MJ/cm^3 thermal energy density prior to rapid plasma expansion (after about 10 ns). Temperature and ionization state increase after this time as the rod-tip rapidly expands. This PFRP approach may have advantages for HEDP research. Various applications include high-fluence flash radiography and the study of equation-of-state of materials. Current research results will be presented.

  18. First measurement of laser Wakefield oscillations by longitudinal interferometry

    SciTech Connect

    Siders, C.W.; Le Blanc, S.P.; Rau, B.; Fisher, D.; Tajima, T.; Downer, M.C.; Babine, A.; Stepanov, A.; Sergeev, A.

    1996-12-31

    Because the electrostatic fields present in plasma waves can exceed those achievable in conventional accelerators and approach atomic scale values (E{sub a} {approximately} 500 GV/m), plasma based accelerators have received considerable attention as compact sources of high-energy electron pulses. Although stimulated Raman scattering or terahertz radiation at {ital w{sub p}} provided spatially averaged optical signatures of the plasma wave`s existence, new diagnostic techniques are required to map the the temporal and spatial structure of the plasma wave directly since such information is vital for addressing fundamental issues of wakefield generation and propagation. In this paper, we report femtosecond time resolved measurements of the longitudinal and radial structure of laser wakefield oscillations using an all optical technique known as interferometric ``photon acceleration`` or Longitudinal Interferometry.

  19. Analysis of radial and longitudinal force of plasma wakefield generated by a chirped pulse laser

    SciTech Connect

    Ghasemi, Leila; Afhami, Saeedeh; Eslami, Esmaeil

    2015-08-15

    In present paper, the chirp effect of an electromagnetic pulse via an analytical model of wakefield generation is studied. Different types of chirps are employed in this study. Our results show that by the use of nonlinear chirped pulse the longitudinal wakefield and focusing force is stronger than that of linear chirped pulse. It is indicated that quadratic nonlinear chirped pulses are globally much efficient than periodic nonlinear chirped pulses. Our calculations also predict that in nonlinear chirped pulse case, the overlap of focusing and accelerating regions is broader than that achieved in linear chirped pulse.

  20. Counter-facing plasma focus system as a repetitive and/or long-pulse high energy density plasma source

    NASA Astrophysics Data System (ADS)

    Aoyama, Yutaka; Nakajima, Mitsuo; Horioka, Kazuhiko

    2009-11-01

    A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and/or repetitive high energy density plasma source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrodes. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time durations in at least ten microseconds.

  1. Accelerating piston action and plasma heating in high-energy density laser plasma interactions

    NASA Astrophysics Data System (ADS)

    Levy, M. C.; Wilks, S. C.; Baring, M. G.

    2013-03-01

    In the field of high-energy density physics (HEDP), lasers in both the nanosecond and picosecond regimes can drive conditions in the laboratory relevant to a broad range of astrophysical phenomena, including gamma-ray burst afterglows and supernova remnants. In the short-pulse regime, the strong light pressure (>Gbar) associated ultraintense lasers of intensity I > 1018 W/cm2 plays a central role in many HEDP applications. Yet, the behavior of this nonlinear pressure mechanism is not well-understood at late time in the laser-plasma interaction. In this paper, a more realistic treatment of the laser pressure 'hole boring' process is developed through analytical modeling and particle-in-cell simulations. A simple Liouville code capturing the phase space evolution of ponderomotively-driven ions is employed to distill effects related to plasma heating and ion bulk acceleration. Taking into account these effects, our results show that the evolution of the laser-target system encompasses ponderomotive expansion, equipartition, and quasi-isothermal expansion epochs. These results have implications for light piston-driven ion acceleration scenarios, and astrophysical applications where the efficiencies of converting incident Poynting flux into bulk plasma flow and plasma heat are key unknown parameters.

  2. Enhancement of injection and acceleration of electrons in a laser wakefield accelerator by using an argon-doped hydrogen gas jet and optically preformed plasma waveguide

    SciTech Connect

    Ho, Y.-C.; Hung, T.-S.; Chen, S.-Y.; Chou, M.-C.; Yen, C.-P.; Wang, J.; Chu, H.-H.; Lin, J.-Y.

    2011-06-15

    A systematic experimental study on injection of electrons in a gas-jet-based laser wakefield accelerator via ionization of dopant was conducted. The pump-pulse threshold energy for producing a quasi-monoenergetic electron beam was significantly reduced by doping the hydrogen gas jet with argon atoms, resulting in a much better spatial contrast of the electron beam. Furthermore, laser wakefield electron acceleration in an optically preformed plasma waveguide based on the axicon-ignitor-heater scheme was achieved. It was found that doping with argon atoms can also lower the pump-pulse threshold energy in this experimental configuration.

  3. Studies of laser wakefield structures and electron acceleration in underdense plasmas

    SciTech Connect

    Maksimchuk, A.; Reed, S.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Matsuoka, T.; McGuffey, C.; Mourou, G.; Naumova, N.; Nees, J.; Rousseau, P.; Yanovsky, V.; Krushelnick, K.; Matlis, N. H.; Kalmykov, S.; Shvets, G.; Downer, M. C.; Vane, C. R.; Beene, J. R.; Stracener, D.

    2008-05-15

    Experiments on electron acceleration and optical diagnostics of laser wakes were performed on the HERCULES facility in a wide range of laser and plasma parameters. Using frequency domain holography we demonstrated single shot visualization of individual plasma waves, produced by 40 TW, 30 fs laser pulses focused to the intensity of 10{sup 19} W/cm{sup 2} onto a supersonic He gas jet with plasma densities n{sub e}<10{sup 19} cm{sup -3}. These holographic 'snapshots' capture the variation in shape of the plasma wave with distance behind the driver, and resolve wave front curvature seen previously only in simulations. High-energy quasimonoenergetic electron beams were generated using plasma density in the range 1.5x10{sup 19}{<=}n{sub e}{<=}3.5x10{sup 19} cm{sup -3}. These experiments demonstrated that the energy, charge, divergence, and pointing stability of the beam can be controlled by changing n{sub e}, and that higher electron energies and more stable beams are produced for lower densities. An optimized quasimonoenergetic beam of over 300 MeV and 10 mrad angular divergence is demonstrated at a plasma density of n{sub e}{approx_equal}1.5x10{sup 19} cm{sup -3}. The resultant relativistic electron beams have been used to perform photo-fission of {sup 238}U with a record high reaction yields of {approx}3x10{sup 5}/J. The results of initial experiments on electron acceleration at 70 TW are discussed.

  4. Electron acceleration by laser wakefield and x-ray emission at moderate intensity and density in long plasmas

    SciTech Connect

    Ferrari, H. E.; Lifschitz, A. F.; Maynard, G.; Cros, B.

    2011-08-15

    The dynamics of electron acceleration by laser wakefield and the associated x-rays emission in long plasmas are numerically investigated for parameters close to the threshold of laser self-focusing. The plasma length is set by the use of dielectric capillary tubes that confine the gas and the laser energy. Electrons self-injection and acceleration to the 170 MeVs are obtained for densities as low as 5 x 10{sup 18} cm{sup -3} and a moderate input intensity (0.77 x 10{sup 18} W/cm{sup 2}). The associated x-ray emission at the exit of the capillary tube is shown to be an accurate diagnostic of the electrons self-injection and acceleration process.

  5. Plasma simulations of emission line regions in high energy environments

    NASA Astrophysics Data System (ADS)

    Richardson, Chris T.

    This dissertation focuses on understanding two different, but in each case extreme, astrophysical environments: the Crab Nebula and emission line galaxies. These relatively local objects are well constrained by observations and are test cases of phenomena seen at high-z where detailed observations are rare. The tool used to study these objects is the plasma simulation code known as Cloudy. The introduction provides a brief summary of relevant physical concepts in nebular astrophysics and presents the basic features and assumptions of Cloudy. The first object investigated with Cloudy, the Crab Nebula, is a nearby supernova remnant that previously has been subject to photoionization modeling to reproduce the ionized emission seen in the nebula's filamentary structure. However, there are still several unanswered questions: (1) What excites the H2 emitting gas? (2) How much mass is in the molecular component? (3) How did the H2 form? (4) What is nature of the dust grains? A large suite of observations including long slit optical and NIR spectra over ionized, neutral and molecular gas in addition to HST and NIR ground based images constrain a particularly bright region of H2 emission, Knot 51, which exhibits a high excitation temperature of ˜3000 K. Simulations of K51 revealed that only a trace amount of H2 is needed to reproduce the observed emission and that H2 forms through an uncommon nebular process known as associative detachment. The final chapters of this dissertation focus on interpreting the narrow line region (NLR) in low-z emission line galaxies selected by a novel technique known as mean field independent component analysis (MFICA). A mixture of starlight and radiation from an AGN excites the gas present in galaxies. MFICA separates galaxies over a wide range of ionization into subsets of pure AGN and pure star forming galaxies allowing simulations to reveal the properties responsible for their observed variation in ionization. Emission line ratios can

  6. Phase-space moment-equation model of highly relativistic electron-beams in plasma-wakefield accelerators

    SciTech Connect

    Robson, R.E.; Mehrling, T.; Osterhoff, J.

    2015-05-15

    We formulate a new procedure for modelling the transverse dynamics of relativistic electron beams with significant energy spread when injected into plasma-based accelerators operated in the blow-out regime. Quantities of physical interest, such as the emittance, are furnished directly from solution of phase space moment equations formed from the relativistic Vlasov equation. The moment equations are closed by an Ansatz, and solved analytically for prescribed wakefields. The accuracy of the analytic formulas is established by benchmarking against the results of a semi-analytic/numerical procedure which is described within the scope of this work, and results from a simulation with the 3D quasi-static PIC code HiPACE.

  7. Simulation of electron post-acceleration in a two-stage laser Wakefield accelerator

    SciTech Connect

    Reitsma, A.J.W.; Leemans, W.P.; Esarey, E.; Kamp, L.P.J.; Schep, T.J.

    2002-04-01

    Electron bunches produced in self-modulated laser wakefield experiments usually have a broad energy spectrum, with most electrons at low energy (1-3 MeV) and only a small fraction at high energy. We propose and investigate further acceleration of such bunches in a channel-guided resonant laser wakefield accelerator. Two-dimensional simulations with and without the effects of self-consistent beam loading are performed and compared. These results indicate that it is possible to trap about 40 percent of the injected bunch charge and accelerate this fraction to an average energy of about 50 MeV in a plasma channel of a few mn.

  8. Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

    NASA Astrophysics Data System (ADS)

    Rawat, R. S.

    2015-03-01

    The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

  9. Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    An, W.; Zhou, M.; Vafaei-Najafabadi, N.; Marsh, K. A.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Lu, W.; Adli, E.; Corde, S.; Litos, M.; Li, S.; Gessner, S.; Frederico, J.; Hogan, M. J.; Walz, D.; England, J.; Delahaye, J. P.; Muggli, P.

    2013-10-01

    Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA) are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head) of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame) of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided) causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy) and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs) for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

  10. Shaping of pulses in optical grating-based laser systems for optimal control of electrons in laser plasma wake-field accelerator

    SciTech Connect

    Toth, Cs.; Faure, J.; Geddes, C.G.R.; van Tilborg, J.; Leemans, W.P.

    2003-05-01

    In typical chirped pulse amplification (CPA) laser systems, scanning the grating separation in the optical compressor causes the well know generation of linear chirp of frequency vs. time in a laser pulse, as well as a modification of all the higher order phase terms. By setting the compressor angle slightly different from the optimum value to generate the shortest pulse, a typical scan around this value will produce significant changes to the pulse shape. Such pulse shape changes can lead to significant differences in the interaction with plasmas such as used in laser wake-field accelerators. Strong electron yield dependence on laser pulse shape in laser plasma wake-field electron acceleration experiments have been observed in the L'OASIS Lab of LBNL [1]. These experiments show the importance of pulse skewness parameter, S, defined here on the basis of the ratio of the ''head-width-half-max'' (HWHM) and the ''tail-width-halfmax'' (TWHM), respectively.

  11. Quasi-phase-matched laser wakefield acceleration.

    PubMed

    Yoon, S J; Palastro, J P; Milchberg, H M

    2014-04-01

    The energy gain in laser wakefield acceleration is ultimately limited by dephasing, occurring when accelerated electrons outrun the accelerating phase of the wakefield. We apply quasi-phase-matching, enabled by axially modulated plasma channels, to overcome this limitation. Theory and simulations are presented showing that weakly relativistic laser intensities can drive significant electron energy gains. PMID:24745430

  12. Low-energy-spread laser wakefield acceleration using ionization injection with a tightly focused laser in a mismatched plasma channel

    NASA Astrophysics Data System (ADS)

    Li, F.; Zhang, C. J.; Wan, Y.; Wu, Y. P.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Gu, Y. Q.; Mori, W. B.; Joshi, C.

    2016-03-01

    An improved ionization injection scheme for laser wakefield acceleration using a tightly focused laser pulse, with intensity near the ionization threshold to trigger the injection in a mismatched plasma channel, has been proposed and examined via 3D particle-in-cell (PIC) simulations. In this scheme, the key to achieving a very low energy spread is shortening the injection distance through the fast diffraction of the tightly focused laser. Furthermore, the oscillation of the laser envelope in the mismatched plasma channel can induce multiple low-energy-spread injections with an even distribution in both space and energy. The envelope oscillation can also significantly enhance the energy gain of the injected beams compared to the standard non-evolving wake scenario due to the rephasing between the electron beam and the laser wake. A theoretical model has been derived to precisely predict the injection distance, the ionization degree of injection atoms/ions, the electron yield as well as the ionized charge for given laser-plasma parameters, and such expressions can be directly utilized for optimizing the quality of the injected beam. Through 3D PIC simulations, we show that an injection distance as short as tens of microns can be achieved, which leads to ultrashort fs, few pC electron bunches with a narrow absolute energy spread around 2 MeV (rms). Simulations also show that the initial absolute energy spread remains nearly constant during the subsequent acceleration due to the very short bunch length, and this indicates that further acceleration of the electron bunches up to the GeV level may lead to an electron beam with an energy spread well below 0.5%. Such low-energy-spread electron beams may have potential applications for future coherent light sources driven by laser-plasma accelerators.

  13. Experimental design to generate strong shear layers in a high-energy-density plasma

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Gillespie, R. S.; Grosskopf, M. J.; Weaver, J. L.; Velikovich, A. L.; Visco, A.; Ditmar, J. R.

    2010-06-01

    The development of a new experimental system for generating a strong shear flow in a high-energy-density plasma is described in detail. The targets were designed with the goal of producing a diagnosable Kelvin-Helmholtz (KH) instability, which plays an important role in the transition turbulence but remains relatively unexplored in the high-energy-density regime. To generate the shear flow the Nike laser was used to drive a flow of Al plasma over a low-density foam surface with an initial perturbation. The interaction of the Al and foam was captured with a spherical crystal imager using 1.86 keV X-rays. The selection of the individual targets components is discussed and results are presented.

  14. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect

    Rahman, H. U.; Wessel, F. J.; Ney, P.; Presura, R.; Ellahi, Rahmat; Shukla, P. K.

    2012-12-15

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  15. High-Energy Ions from Near-Critical Density Plasmas via Magnetic Vortex Acceleration

    SciTech Connect

    Nakamura, Tatsufumi; Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki

    2010-09-24

    Ultraintense laser pulses propagating in near-critical density plasmas generate magnetic dipole vortex structures. In the region of decreasing plasma density, the vortex expands both in forward and lateral directions. The magnetic field pressure pushes electrons and ions to form a density jump along the vortex axis and induces a longitudinal electric field. This structure moves together with the expanding dipole vortex. The background ions located ahead of the electric field are accelerated to high energies. The energy scaling of ions generated by this magnetic vortex acceleration mechanism is derived and corroborated using particle-in-cell simulations.

  16. Electron-beam manipulation techniques in the SINBAD Linac for external injection in plasma wake-field acceleration

    NASA Astrophysics Data System (ADS)

    Marchetti, B.; Assmann, R.; Behrens, C.; Brinkmann, R.; Dorda, U.; Floettmann, K.; Hartl, I.; Huening, M.; Nie, Y.; Schlarb, H.; Zhu, J.

    2016-09-01

    The SINBAD facility (Short and INnovative Bunches and Accelerators at Desy) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration techniques. Besides studying novel acceleration techniques aiming to produce high brightness short electron bunches, the ARD group at DESY is working on the design of a conventional RF accelerator that will allow the production of low charge (0.5 pC - few pC) ultra-short electron bunches (having full width half maximum, FWHM, length ≤ 1 fs - few fs). The setup will allow the direct experimental comparison of the performance achievable by using different compression techniques (velocity bunching, magnetic compression, hybrid compression schemes). At a later stage the SINBAD linac will be used to inject such electron bunches into a laser driven Plasma Wakefield Accelerator, which imposes strong requirements on parameters such as the arrival time jitter and the pointing stability of the beam. In this paper we review the compression techniques that are foreseen at SINBAD and we underline the differences in terms of peak current, beam quality and arrival time stability.

  17. Dynamics of magnetic fields in high-energy-density plasmas for fusion and astrophysics

    NASA Astrophysics Data System (ADS)

    Gao, Lan; Ji, H.; Fox, W.; Hill, K.; Efthimion, P.; Nilson, P.; Igumenshchev, I.; Froula, D.; Betti, R.; Meyerhofer, D.; Fiksel, G.; Blackman, E.; Schneider, M.; Chen, H.; Smalyuk, V.; Li, H.; Casner, A.

    2015-11-01

    An overview of our recent experimental and theoretical work on the dynamics of magnetic fields in high-energy-density plasmas will be presented. This includes: (1) precision mapping of the self-generated magnetic fields in the coronal plasma and the Nernst effect on their evolution, (2) characterizing the strong magnetic field generated by a laser-driven capacitor-coil target using ultrafast proton radiography, and (3) creating MHD turbulence in Rayleigh-Taylor unstable plasmas. The experimental results are compared with resistive MHD simulations providing a stringent test for their predictions. Applications in relevance to ignition target designs in inertial confinement fusion, material strength studies in high-energy-density physics, and astrophysical systems such as plasma dynamos and magnetic reconnection will be discussed. Future experiments proposed on the National Ignition Facility will be described. This material is supported in part by the Department of Energy National Nuclear Security Administration under Award No. DE-NA0001944, and the National Laser Users Facility under Grant No. DE-NA0002205.

  18. ZaP-HD: High Energy Density Z-Pinch Plasmas using Sheared Flow Stabilization

    NASA Astrophysics Data System (ADS)

    Golingo, R. P.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Ross, M. P.; Weed, J. R.

    2015-11-01

    The ZaP-HD flow Z-pinch project investigates scaling the flow Z-pinch to High Energy Density Plasma, HEDP, conditions by using sheared flow stabilization. ZaP used a single power supply to produce 100 cm long Z-pinches that were quiescent for many radial Alfven times and axial flow-through times. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are dimensionally large and persist for extended durations. The ZaP-HD device replaces the single power supply from ZaP with two separate power supplies to independently control the plasma flow and current in the Z-pinch. Equilibrium is determined by diagnostic measurements of the density with interferometry and digital holography, the plasma flow and temperature with passive spectroscopy, the magnetic field with surface magnetic probes, and plasma emission with optical imaging. The diagnostics fully characterize the plasma from its initiation in the coaxial accelerator, through the pinch, and exhaust from the assembly region. The plasma evolution is modeled with high resolution codes: Mach2, WARPX, and NIMROD. Experimental results and scaling analyses are presented. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.

  19. Strongly Driven Magnetic Reconnection in a Magnetized High-Energy-Density Plasma

    NASA Astrophysics Data System (ADS)

    Fiksel, G.; Barnak, D. H.; Chang, P.-Y.; Haberberger, D.; Hu, S. X.; Ivancic, S.; Nilson, P. M.; Fox, W.; Deng, W.; Bhattacharjee, A.; Germaschewski, K.

    2014-10-01

    Magnetic reconnection in a magnetized high-energy-density plasma is characterized by measuring the dynamics of the plasma density and magnetic field between two counter-propagating and colliding plasma flows. The density and magnetic field were profiled using the 4 ω angular filter refractometry and fast proton deflectometry diagnostics, respectively. The plasma flows are created by irradiating oppositely placed plastic targets with 1.8-kJ, 2-ns laser beams on the OMEGA EP Laser System. The two plumes are magnetized by an externally controlled magnetic field with an x-type null point geometry with B = 0 at the midplane and B = 8 T at the targets. The interaction region is pre-filled with a low-density background plasma. The counterflowing super-Alfvénic plasma plumes sweep up and compress the magnetic field and the background plasma into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing for the first detailed observation of a stretched current sheet in laser-driven reconnection experiments. The measurements are in good agreement with first-principles particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and NLUF Grant DE-SC0008655.

  20. Wave guided laser wake-field acceleration in splash plasma channels

    NASA Astrophysics Data System (ADS)

    MIZUTA, Yoshio; HOSOKAI, Tomonao; MASUDA, Shinichi; ZHIDKOV, Alexei; NAKANII, Nobuhiko; JIN, Zhan; NAKAHARA, Hiroki; KOHARA, Tomohiro; IWASA, Kenta; KANDO, Masaki; BULANOV, Sergei; KODAMA, Ryosuke

    2016-03-01

    A transient plasma micro optics (plasma channel and focusing plasma optics- TPMO) in the LWFA provides controllable electron self-injections that result in production of higher quality bunches. In recent study of the TPMO, the deep, straight and short-lived plasma channels [splash plasma channel] were produced by picosecond and sub-picosecond laser pulses in the ponderomotive force dominant regime. Various techniques were used to characterize those channels in argon gas jets irradiated by moderate intensity, ∼1015-16 W/cm2, laser pulses with their durations from sub-picoseconds.

  1. High-energy 4{omega} probe laser for laser-plasma experiments at nova

    SciTech Connect

    Glenzer, S. H., LLNL

    1998-06-02

    For the characterization of inertial confinement fusion plasmas we implemented a high-energy 4{omega} probe laser at the Nova laser facility. A total energy of > 50 Joules at 4{omega}, a focal spot size of order 100 {micro}m, and a pointing accuracy of 100 {micro}m was demonstrated for target shots. This laser provides intensities of up to 3 x 10{sup 14}W cm{sup -2} and therefore fulfills high-power requirements for laser-plasma interaction experiments. The 4{omega} probe laser is now routinely used for Thomson scattering. Successful experiments were performed in gas-filled hohlraums at electron densities of n{sub e} > 2 X 10{sup 21}cm{sup -3} which represents the highest density plasma so far being diagnosed with Thomson scattering.

  2. Generation and analysis of quasimonoenergetic electron beams by laser-plasma interaction in transitional region from the self-modulated laser wakefield to bubble acceleration regime

    SciTech Connect

    Masuda, S.; Miura, E.

    2009-09-15

    Generation of quasimonoenergetic electron beams in a transitional region from the self-modulated laser wakefield to bubble acceleration regime is reported. Quasimonoenergetic electron beams containing more than 3x10{sup 8} electrons in the monoenergetic peak with energies of 40-60 MeV have been obtained from a plasma with an electron density of 1.6x10{sup 19} cm{sup -3} produced by an 8 TW, 50 fs laser pulse. The generation of quasimonoenergetic electron beams is investigated by two-dimensional particle-in-cell simulations. Few periods of the plasma wave are located inside the laser pulse, because the laser pulse duration is longer than the wavelength of the plasma wave. Electrons trapped in the first period of the plasma wave can form the monoenergetic bunch, even though the trapped electrons interact directly with the laser field. The quasimonoenergetic electron beam can be obtained due to the small contribution of the direct acceleration by the laser field. This type of monoenergetic electron acceleration is different from that of both the self-modulated laser wakefield and bubble acceleration regimes, in which the trapped electrons in the plasma wave are located behind the laser pulse due to the pulse compression or fragmentation and free from the laser electric field. This result suggests a new regime for the quasimonoenergetic electron acceleration in the region between the self-modulation and bubble regime.

  3. Induction of electron injection and betatron oscillation in a plasma-waveguide-based laser wakefield accelerator by modification of waveguide structure

    SciTech Connect

    Ho, Y.-C.; Hung, T.-S.; Chen, W.-H.; Jhou, J.-G.; Qayyum, H.; Chen, S.-Y.; Chu, H.-H.; Lin, J.-Y.; Wang, J.

    2013-08-15

    By adding a transverse heater pulse into the axicon ignitor-heater scheme for producing a plasma waveguide, a variable three-dimensionally structured plasma waveguide can be fabricated. With this technique, electron injection in a plasma-waveguide-based laser wakefield accelerator was achieved and resulted in production of a quasi-monoenergetic electron beam. The injection was correlated with a section of expanding cross-section in the plasma waveguide. Moreover, the intensity of the X-ray beam produced by the electron bunch in betatron oscillation was greatly enhanced with a transversely shifted section in the plasma waveguide. The technique opens a route to a compact hard-X-ray pulse source.

  4. The formation of reverse shocks in magnetized high energy density supersonic plasma flows

    SciTech Connect

    Lebedev, S. V. E-mail: l.suttle10@imperial.ac.uk; Suttle, L.; Swadling, G. F.; Bennett, M.; Bland, S. N.; Burdiak, G. C.; Chittenden, J. P.; Grouchy, P. de; Hall, G. N.; Hare, J. D.; Kalmoni, N.; Niasse, N.; Patankar, S.; Smith, R. A.; Suzuki-Vidal, F.; Burgess, D.; Clemens, A.; Ciardi, A.; Sheng, L.; Yuan, J.; and others

    2014-05-15

    A new experimental platform was developed, based on the use of supersonic plasma flow from the ablation stage of an inverse wire array z-pinch, for studies of shocks in magnetized high energy density physics plasmas in a well-defined and diagnosable 1-D interaction geometry. The mechanism of flow generation ensures that the plasma flow (Re{sub M} ∼ 50, M{sub S} ∼ 5, M{sub A} ∼ 8, V{sub flow} ≈ 100 km/s) has a frozen-in magnetic field at a level sufficient to affect shocks formed by its interaction with obstacles. It is found that in addition to the expected accumulation of stagnated plasma in a thin layer at the surface of a planar obstacle, the presence of the magnetic field leads to the formation of an additional detached density jump in the upstream plasma, at a distance of ∼c/ω{sub pi} from the obstacle. Analysis of the data obtained with Thomson scattering, interferometry, and local magnetic probes suggests that the sub-shock develops due to the pile-up of the magnetic flux advected by the plasma flow.

  5. Design of a High-Energy, Two-Stage Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Markusic, T. E.; Thio, Y. C. F.; Cassibry, J. T.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    Design details of a proposed high-energy (approx. 50 kJ/pulse), two-stage pulsed plasma thruster are presented. The long-term goal of this project is to develop a high-power (approx. 500 kW), high specific impulse (approx. 7500 s), highly efficient (approx. 50%),and mechanically simple thruster for use as primary propulsion in a high-power nuclear electric propulsion system. The proposed thruster (PRC-PPT1) utilizes a valveless, liquid lithium-fed thermal plasma injector (first stage) followed by a high-energy pulsed electromagnetic accelerator (second stage). A numerical circuit model coupled with one-dimensional current sheet dynamics, as well as a numerical MHD simulation, are used to qualitatively predict the thermal plasma injection and current sheet dynamics, as well as to estimate the projected performance of the thruster. A set of further modelling efforts, and the experimental testing of a prototype thruster, is suggested to determine the feasibility of demonstrating a full scale high-power thruster.

  6. Solar High-energy Astrophysical Plasmas Explorer (SHAPE). Volume 1: Proposed concept, statement of work and cost plan

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Martin, Franklin D.; Prince, T.; Lin, R.; Bruner, M.; Culhane, L.; Ramaty, R.; Doschek, G.; Emslie, G.; Lingenfelter, R.

    1986-01-01

    The concept of the Solar High-Energy Astrophysical Plasmas Explorer (SHAPE) is studied. The primary goal is to understand the impulsive release of energy, efficient acceleration of particles to high energies, and rapid transport of energy. Solar flare studies are the centerpieces of the investigation because in flares these high energy processes can be studied in unmatched detail at most wavelenth regions of the electromagnetic spectrum as well as in energetic charged particles and neutrons.

  7. Numerical Modeling and Testing of an Inductively-Driven and High-Energy Pulsed Plasma Thrusters

    NASA Technical Reports Server (NTRS)

    Parma, Brian

    2004-01-01

    Pulsed Plasma Thrusters (PPTs) are advanced electric space propulsion devices that are characterized by simplicity and robustness. They suffer, however, from low thrust efficiencies. This summer, two approaches to improve the thrust efficiency of PPTs will be investigated through both numerical modeling and experimental testing. The first approach, an inductively-driven PPT, uses a double-ignition circuit to fire two PPTs in succession. This effectively changes the PPTs configuration from an LRC circuit to an LR circuit. The LR circuit is expected to provide better impedance matching and improving the efficiency of the energy transfer to the plasma. An added benefit of the LR circuit is an exponential decay of the current, whereas a traditional PPT s under damped LRC circuit experiences the characteristic "ringing" of its current. The exponential decay may provide improved lifetime and sustained electromagnetic acceleration. The second approach, a high-energy PPT, is a traditional PPT with a variable size capacitor bank. This PPT will be simulated and tested at energy levels between 100 and 450 joules in order to investigate the relationship between efficiency and energy level. Arbitrary Coordinate Hydromagnetic (MACH2) code is used. The MACH2 code, designed by the Center for Plasma Theory and Computation at the Air Force Research Laboratory, has been used to gain insight into a variety of plasma problems, including electric plasma thrusters. The goals for this summer include numerical predictions of performance for both the inductively-driven PPT and high-energy PFT, experimental validation of the numerical models, and numerical optimization of the designs. These goals will be met through numerical and experimental investigation of the PPTs current waveforms, mass loss (or ablation), and impulse bit characteristics.

  8. Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas

    NASA Astrophysics Data System (ADS)

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Séguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-01

    For the first time, quantitative measurements of ion stopping at energies around the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te ) and electron number density (ne ) in the range of 0.5-4.0 keV and 3 ×1022 to 3 ×1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne . The importance of including quantum diffraction is also demonstrated in the stopping-power modeling of high-energy-density plasmas.

  9. Pressure-driven, resistive magnetohydrodynamic interchange instabilities in laser-produced high-energy-density plasmas

    SciTech Connect

    Li, C. K.; Frenje, J. A.; Petrasso, R. D.; Seguin, F. H.; Amendt, P. A.; Landen, O. L.; Town, R. P. J.; Betti, R.; Knauer, J. P.; Meyerhofer, D. D.; Soures, J. M.

    2009-07-15

    Recent experiments using proton backlighting of laser-foil interactions provide unique opportunities for studying magnetized plasma instabilities in laser-produced high-energy-density plasmas. Time-gated proton radiograph images indicate that the outer structure of a magnetic field entrained in a hemispherical plasma bubble becomes distinctly asymmetric after the laser turns off. It is shown that this asymmetry is a consequence of pressure-driven, resistive magnetohydrodynamic (MHD) interchange instabilities. In contrast to the predictions made by ideal MHD theory, the increasing plasma resistivity after laser turn-off allows for greater low-mode destabilization (m>1) from reduced stabilization by field-line bending. For laser-generated plasmas presented herein, a mode-number cutoff for stabilization of perturbations with m>{approx}[8{pi}{beta}(1+D{sub m}k{sub perpendicular}{sup 2}{gamma}{sub max}{sup -1})]{sup 1/2} is found in the linear growth regime. The growth is measured and is found to be in reasonable agreement with model predictions.

  10. The impact of Hall physics on magnetized high energy density plasma jetsa)

    NASA Astrophysics Data System (ADS)

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.

    2014-05-01

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (ne ˜ 1019 cm-3). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (˜1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches).

  11. The impact of Hall physics on magnetized high energy density plasma jets

    SciTech Connect

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.

    2014-05-15

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e} ∼ 10{sup 19} cm{sup −3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (∼1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)

  12. Reduced entropic model for studies of multidimensional nonlocal transport in high-energy-density plasmas

    SciTech Connect

    Del Sorbo, D.; Feugeas, J.-L.; Nicolaï, Ph.; Olazabal-Loumé, M.; Dubroca, B.; Guisset, S.; Touati, M.; Tikhonchuk, V.

    2015-08-15

    Hydrodynamic simulations of high-energy-density plasmas require a detailed description of energy fluxes. For low and intermediate atomic number materials, the leading mechanism is the electron transport, which may be a nonlocal phenomenon requiring a kinetic modeling. In this paper, we present and test the results of a nonlocal model based on the first angular moments of a simplified Fokker-Planck equation. This multidimensional model is closed thanks to an entropic relation (the Boltzman H-theorem). It provides a better description of the electron distribution function, thus enabling studies of small scale kinetic effects within the hydrodynamic framework. Examples of instabilities of electron plasma and ion-acoustic waves, driven by the heat flux, are presented and compared with the classical formula.

  13. Subsonic and Supersonic shear flows in laser driven high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Kuranz, C. C.; Visco, A.; Ditmar, J. R.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Hurricane, O. A.; Hansen, J. F.; Remington, B. A.; Robey, H. F.; Bono, M. J.; Plewa, T.

    2009-05-01

    Shear flows arise in many high-energy-density (HED) and astrophysical systems, yet few laboratory experiments have been carried out to study their evolution in these extreme environments. Fundamentally, shear flows can initiate mixing via the Kelvin-Helmholtz (KH) instability and may eventually drive a transition to turbulence. We present two dedicated shear flow experiments that created subsonic and supersonic shear layers in HED plasmas. In the subsonic case the Omega laser was used to drive a shock wave along a rippled plastic interface, which subsequently rolled-upped into large KH vortices. In the supersonic shear experiment the Nike laser was used to drive Al plasma across a low-density foam surface also seeded with a ripple. Unlike the subsonic case, detached shocks developed around the ripples in response to the supersonic Al flow.

  14. Reduced entropic model for studies of multidimensional nonlocal transport in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Del Sorbo, D.; Feugeas, J.-L.; Nicolaï, Ph.; Olazabal-Loumé, M.; Dubroca, B.; Guisset, S.; Touati, M.; Tikhonchuk, V.

    2015-08-01

    Hydrodynamic simulations of high-energy-density plasmas require a detailed description of energy fluxes. For low and intermediate atomic number materials, the leading mechanism is the electron transport, which may be a nonlocal phenomenon requiring a kinetic modeling. In this paper, we present and test the results of a nonlocal model based on the first angular moments of a simplified Fokker-Planck equation. This multidimensional model is closed thanks to an entropic relation (the Boltzman H-theorem). It provides a better description of the electron distribution function, thus enabling studies of small scale kinetic effects within the hydrodynamic framework. Examples of instabilities of electron plasma and ion-acoustic waves, driven by the heat flux, are presented and compared with the classical formula.

  15. Enhanced Wakefields for the 1D Laser Wakefield Accelerator

    SciTech Connect

    Kingham, R.J.; Bell, A.R.

    1997-12-01

    The amplitudes of wakefields generated by the ponderomotive force of intense pulses much longer than {lambda}{sub p}/2 are determined using nonlinear, relativistic envelope equations and found to be significantly larger than predicted by linear theory. This is relevant to the self-modulated laser wakefield accelerator; under suitable experimental conditions enhanced wakefields should be large enough to act as the dominant source for seeding Raman forward scattering induced {open_quotes}beam breakup.{close_quotes} Consequently the use of other seeding mechanisms such as Raman backscattering, which is unpredictable, can be avoided. The enhancement mechanism is attributed to an effective bandwidth increase of the laser pulse due to nonlinearities in the response of the plasma to the ponderomotive force. {copyright} {ital 1997} {ital The American Physical Society}

  16. Supersonic shear flows in laser driven high-energy-density plasmas created by the Nike laser

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Ditmar, J. R.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Plewa, T.

    2008-11-01

    In high-energy-density (HED) plasmas the Kelvin-Helmholtz (KH) instability plays an important role in the evolution of Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) unstable interfaces, as well as material interfaces that experience the passage one or multiple oblique shocks. Despite the potentially important role of the KH instability few experiments have been carried out to explore its behavior in the high-energy-density regime. We report on the evolution of a supersonic shear flow that is generated by the release of a high velocity (>100 km/s) aluminum plasma onto a CRF foam (ρ = 0.1 g/cc) surface. In order to seed the Kelvin-Helmholtz (KH) instability various two-dimensional sinusoidal perturbations (λ = 100, 200, and 300 μm with peak-to-valley amplitudes of 10, 20, and 30 μm respectively) have been machined into the foam surface. This experiment was performed using the Nike laser at the Naval Research Laboratory.

  17. Laser-plasma accelerators-based high energy radiation femtochemistry and spatio-temporal radiation biomedicine

    NASA Astrophysics Data System (ADS)

    Gauduel, Y. A.; Lundh, O.; Martin, M. T.; Malka, V.

    2012-06-01

    The innovating advent of powerful TW laser sources (~1019 W cm-z) and laser-plasma interactions providing ultra-short relativistic particle beams (electron, proton) in the MeV domain open exciting opportunities for the simultaneous development of high energy radiation femtochemistry (HERF) and ultrafast radiation biomedicine. Femtolysis experiments (Femtosecond radiolysis) of aqueous targets performed with relativistic electron bunches of 2.5-15 MeV give new insights on transient physicochemical events that take place in the prethermal regime of confined ionization tracks. Femtolysis studies emphasize the pre-eminence of ultra-fast quantum effects in the temporal range 10-14 - 10-11 s. The most promising advances of HERF concern the quantification of ultrafast sub-nanometric biomolecular damages (bond weakening and bond breaking) in the radial direction of a relativistic particle beam. Combining ultra-short relativistic particle beams and near-infrared spectroscopic configurations, laser-plasma accelerators based high energy radiation femtochemistry foreshadows the development of real-time radiation chemistry in the prethermal regime of nascent ionisation clusters. These physico-chemical advances would be very useful for future developments in biochemically relevant environments (DNA, proteins) and in more complex biological systems such as living cells. The first investigation of single and multiple irradiation shots performed at high energy level (90 MeV) and very high dose rate, typically 1013 Gy s-1, demonstrates that measurable assessments of immediate and reversible DNA damage can be explored at single cell level. Ultrafast in vivo irradiations would permit the development of bio-nanodosimetry on the time scale of molecular motions, i.e. angstrom or sub-angstrom displacements and open new perspectives in the emerging domain of ultrafast radiation biomedicine such as pulsed radiotherapy.

  18. Dense Plasma Focus With High Energy Helium Beams for Radiological Source Replacement

    NASA Astrophysics Data System (ADS)

    Schmidt, Andrea; Ellsworth, Jennifer; Falabella, Steve; Link, Anthony; Rusnak, Brian; Sears, Jason; Tang, Vincent

    2014-10-01

    A dense plasma focus (DPF) is a compact accelerator that can produce intense high energy ion beams (multiple MeV). It could be used in place of americium-beryllium (AmBe) neutron sources in applications such as oil well logging if optimized to produce high energy helium beams. AmBe sources produce neutrons when 5.5 MeV alphas emitted from the Am interact with the Be. However, due to the very small alpha-Be cross section for alphas <2 MeV, an AmBe source replacement would have to accelerate ~0.15 μC of He to 2 + MeV in order to produce 107 neutrons per pulse. We are using our particle in cell (PIC) model in LSP of a 4 kJ dense plasma focus discharge to guide the optimization of a compact DPF for the production of high-energy helium beam. This model is fluid for the run-down phase, and then transitions to fully kinetic prior to the pinch in order to include kinetic effects such as ion beam formation and anomalous resistivity. An external pulsed-power driver circuit is used at the anode-cathode boundary. Simulations will be benchmarked to He beam measurements using filtered and time-of-flight Faraday cup diagnostics. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work supported by US DOE/NA-22 Office of Non-proliferation Research and Development. Computing support for this work came from the LLNL Institutional Computing Grand Challenge program.

  19. Magnetic Reconnection of an Externally Applied Magnetic Field in a High-Energy Density Plasma

    NASA Astrophysics Data System (ADS)

    Fiksel, G.; Barnak, D.; Chang, P.-Y.; Hu, S. X.; Nilson, P. M.; Betti, R.; Fox, W.; Germaschewski, K.; Bhattacharjee, A.

    2013-10-01

    An experiment on magnetic reconnection of an externally applied magnetic field in counter-propagating high-energy density plasmas was conducted on the OMEGA EP Laser System. Two counter-propagating plasma flows were created by irradiating oppositely placed plastic (CH) targets with 1.8-kJ, 2-ns laser beams. An external magnetic field was imposed perpendicular to the plasma flow by MIFEDS (magneto-inertial fusion electrical discharge system). The magnetic field has a null-x-point geometry with B = 5 T at the targets. The plasma interaction was imaged by laser-driven, fast-proton radiography. The radiography images demonstrate formation of a pair of counter-propagating magnetized ``ribbons'' that collide and reconnect at the midplane. The results will be compared with particle-in-cell simulations and interpreted with predictions from the DRACO code. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, and NLUF Grant DE-SC0008655.

  20. Modeling Nuclear Fusion in High Energy Density Plasmas Using a Strongly Magnetized Non-neutral Plasma

    NASA Astrophysics Data System (ADS)

    Dubin, D. H. E.

    2005-10-01

    In the hot dense interiors of stars and giant planets, nuclear reactions are predicted to occur at rates that are greatly enhanced compared to those at low densities. The enhancement is caused by plasma screening of the reacting pairs, increasing the probability of close collisions. However, strongly enhanced nuclear reaction rates have never been observed in the laboratory. This poster discusses a method for observing the enhancement using an analogy between nuclear energy and cyclotron energy in a non-neutral plasma in a strong magnetic field. In such a plasma, cyclotron energy is an adiabatic invariant, and is released only through close collisions that break this invariant. It is shown that the rate of release of cyclotron energy is enhanced by precisely the same factor as that for the release of nuclear energy, because both processes rely on close collisions that are enhanced by plasma screening.ootnotetextD. Dubin, Phys. Rev. Lett. 94, 025002 (2005). Simulations measuring the screening enhancement will be presented, and the possibility of exciting and studying burn fronts will be discussed.ootnotetextSee also adjacent poster by J. Bollinger.

  1. Experimental investigation of opacity models for stellar interiors, inertial fusion, and high energy density plasmas

    NASA Astrophysics Data System (ADS)

    Bailey, James

    2008-11-01

    Theoretical opacities are required for calculating energy transport in plasmas. In particular, understanding stellar interiors, inertial fusion, and Z-pinches depends on the opacities of mid-atomic-number elements in the 150-300 eV temperature range. These models are complex and experimental validation is crucial. For example, solar models presently disagree with helioseismology and one possible explanation is inadequate opacities. Testing these opacities requires a uniform plasma at temperatures high enough to produce the ion charge states that exist in the sun. Typical opacity experiments heat a sample using x-rays and measure the spectrally resolved transmission with a backlight. The difficulty grows as the temperature increases because the heating x-ray source must supply more energy and the backlighter source must be bright enough to overwhelm the plasma self emission. These problems were overcome using the dynamic hohlraum x-ray source at Sandia's Z facility to measure the transmission of a mixed Mg-Fe plasma heated above 150 eV. This capability will also advance opacity science for other high energy density plasmas. This tutorial describes opacity experiment challenges including accurate transmission measurements, plasma diagnostics, and quantitative model comparisons. The solar interior serves as a focal problem and Z facility experiments are used to illustrate the techniques. **In collaboration with C. Iglesias (LLNL), R. Mancini (U. Nevada), J.MacFarlane, I. Golovkin and P. Wang (Prism), C. Blancard, Ph. Cosse, G. Faussurier, F. Gilleron, and J.C. Pain (CEA), J. Abdallah Jr. (LANL), and G.A. Rochau and P.W. Lake (Sandia). ++Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  2. Experimental and Computational Studies of High Energy Density Plasma Streams Ablated from Fine Wires

    SciTech Connect

    Greenly, John B.; Seyler, Charles

    2014-03-30

    Experimental and computational studies of high energy density plasma streams ablated from fine wires. Laboratory of Plasma Studies, School of Electrical and Computer Engineering, Cornell University. Principal Investigators: Dr. John B. Greenly and Dr. Charles E. Seyler. This report summarizes progress during the final year of this project to study the physics of high energy density (HED) plasma streams of 10^17-10^20/cm3 density and high velocity (~100-500 km/s). Such streams are produced from 5-250 micrometer diameter wires heated and ionized by a 1 MA, 250 ns current pulse on the COBRA pulsed power facility at Cornell University. Plasma is ablated from the wires and is driven away to high velocity by unbalanced JxB force. A wire, or an array of wires, can persist as an essentially stationary, continuous source of this streaming plasma for >200 ns, even with driving magnetic fields of many Tesla and peak current densities in the plasma of many MA/cm2. At the heart of the ablation stream generation is the continuous transport of mass from the relatively cold, near-solid-density wire "core" into current-carrying plasma within 1 mm of the wire, followed by the magnetic acceleration of that plasma and its trapped flux to form a directed stream. In the first two years of this program, an advancing understanding of ablation physics led to the discovery of several novel wire ablation experimental regimes. In the final year, one of these new HED plasma regimes has been studied in quantitative detail. This regime studies highly reproducible magnetic reconnection in strongly radiating plasma with supersonic and superalfvenic flow, and shock structures in the outflow. The key discovery is that very heavy wires, e.g. 250 micrometer diameter Al or 150 micrometer Cu, behave in a qualitatively different way than the lighter wires typically used in wire-array Z-pinches. Such wires can be configured to produce a static magnetic X-point null geometry that stores magnetic and

  3. Studies of a hybrid Trojan Horse wakefield accelerator with high transformer ratio

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Bruhwiler, David; Hidding, Bernhard; Vay, Jean-Luc; Webb, Stephen

    2015-11-01

    Plasma wakefield acceleration uses relativistic high-charge electron bunches to generate a plasma blowout supporting intense electric fields for trapping and acceleration. Dramatic improvements in emittance, peak current and brightness are achievable through laser-controlled ionization in the plasma blowout, which is the premise of the Trojan Horse approach. The hybrid Trojan Horse concept extends this approach to use the output beam from a laser plasma accelerator to drive a Trojan Horse, resulting in a compact system that can produce higher brightness bunches with order-of-magnitude lower energy spread. We are exploring the use of multiple, shaped laser pulses to resonantly inject a shaped electron drive bunch. The resulting output bunch could generate wakes in PWFA or beam-driven dielectric structures with transformer ratios of 5 to 10 or larger. Hence, a hybrid Trojan Horse accelerator with bunch shaping may provide a compact source of nC bunches that can drive a variety of systems for studying high-gradient wakefields and lepton acceleration. Initial work will use previously simulated electron bunches from a laser plasma accelerator to drive the plasma wakefield stage. We present preliminary results from simulations using the parallel, particle-in-cell framework Warp. Work supported by the U.S. Department of Energy, Office of High Energy Physics, under Award Number DE-SC0013855.

  4. High field terahertz emission from relativistic laser-driven plasma wakefields

    SciTech Connect

    Chen, Zi-Yu; Pukhov, Alexander

    2015-10-15

    We propose a method to generate high field terahertz (THz) radiation with peak strength of GV/cm level in the THz frequency gap range of 1–10 THz using a relativistic laser interaction with a gaseous plasma target. Due to the effect of local pump depletion, an initially Gaussian laser pulse undergoes leading edge erosion and eventually evolves to a state with leading edge being step function. Interacting with such a pulse, electrons gain transverse residual momentum and excite net transverse currents modulated by the relativistic plasma frequency. These currents give rise to the low frequency THz emission. We demonstrate this process with one and two dimensional particle-in-cell simulations.

  5. High quality electron beams from a plasma channel guided laser wakefield accelerator

    SciTech Connect

    Geddes, C.G.R.; Toth, Cs.; van Tilborg, J.; Esarey, E.; Schroeder, C.B.; Bruhwiler, D.; Nieter, C.; Cary, J.; Leemans, W.P.

    2004-07-08

    Laser driven accelerators, in which particles are accelerated by the electric field of a plasma wave driven by an intense laser, have demonstrated accelerating electric fields of hundreds of GV/m. These fields are thousands of times those achievable in conventional radiofrequency (RF) accelerators, spurring interest in laser accelerators as compact next generation sources of energetic electrons and radiation. To date however, acceleration distances have been severely limited by lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance results in low energy beams with 100% electron energy spread, limiting applications. Here we demonstrate that a relativistically intense laser can be guided by a preformed plasma density channel and that the longer propagation distance can result in electron beams of percent energy spread with low emittance and increased energy, containing >10{sup 9} electrons above 80 MeV. The preformed plasma channel technique forms the basis of a new class of accelerators, combining beam quality comparable to RF accelerators with the high gradients of laser accelerators to produce compact tunable high brightness electron and radiation sources.

  6. Laser guiding due to transverse frequency chirp and plasma inhomogeneity: Relevance to laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Bandhu Pathak, Vishwa; Vieira, Jorge; Fonseca, Ricardo; Silva, Luis

    2012-10-01

    Multi-dimensional particle-in-cell (PIC) simulations using OSIRIS show that the transverse frequency chirp can induce pulse front tilt (PFT) in the laser as it propagates. The PFT leads to transverse inhomogeneity in the electron density at the laser front such that the laser drifts in the transverse direction followed by its wake and the injected/self-injected electron beam inside the blowout region. We further investigate the effect of the chirp and transverse plasma inhomogeneities (linear density gradient and parabolic plasma channel) on the transverse drift by developing an analytical model based on a variational principle approach. Theory and simulations predict a linear dependence of the frequency chirp on the transverse drift. In the presence of a linear density gradient the laser drifts towards the decreasing plasma density. We show that an appropriate transverse chirp can balance the drift, and can reduce/nullify the injected electron beam pointing angle. In extreme scenarios, dispersion effects due to transverse chirp can filament the laser generating multiple bubble in the same transverse plane.

  7. Measurements of Ion Stopping around the Bragg Peak in High-Energy-Density Plasmas

    NASA Astrophysics Data System (ADS)

    Frenje, Johan

    2015-11-01

    Over the last few decades, ion stopping in weakly- to strongly-coupled High-Energy-Density (HED) plasmas has been subject to extensive analytical and numerical studies, but only a limited set of experimental data exists to check the validity of these theories. Most of these experiments also did not probe the detailed characteristics of the Bragg peak (peak ion stopping) where the ion velocity is similar to the average thermal electron velocity. To the best of our knowledge, only one exploratory attempt to do this was conducted by Hicks et al., who were able to describe qualitatively the behavior of the Bragg peak for one plasma condition. The work described in this presentation makes significant advances over previous experimental efforts by quantitatively assessing the characteristics of the ion stopping, ranging from low-velocity stopping, through the Bragg peak, to high-velocity stopping for different HED plasma conditions. This was achieved by measuring the energy loss of DD-tritons, D3He-alphas, DD-protons and D3He-protons, with distinctly different velocities, and the results indicate that the stopping power varies strongly with Te and ne. This effort represents the first experimental test of state-of-art plasma-stopping-power theories around the Bragg peak, which is an important first step in our efforts of getting a fundamental understanding of DT-alpha stopping in HED plasmas, a prerequisite for understanding ignition margins in various implosion designs with varying hot spot areal density at the National Ignition Facility. The work described here was performed in part at the LLE National Laser User's Facility (NLUF), and was supported in part by US DOE (Grant No. DE-FG03- 03SF22691), LLNL (subcontract Grant No. B504974) and LLE (subcontract Grant No. 412160-001G).

  8. Observations of subsonic and supersonic shear flows in laser driven high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, E. C.

    2009-11-01

    Shear layers containing strong velocity gradients appear in many high-energy-density (HED) systems and play important roles in mixing and the transition to turbulence. Yet few laboratory experiments have been carried out to study their detailed evolution in this extreme environment where plasmas are compressible, actively ionizing, often involve strong shock waves and have complex material properties. Many shear flows produce the Kelvin-Helmholtz (KH) instability, which initiates the mixing at a fluid interface. We present results from two dedicated shear flow experiments that produced overall subsonic and supersonic flows using novel target designs. In the subsonic case, the Omega laser was used to drive a blast wave along a rippled interface between plastic and foam, shocking both the materials to produce two fluids separated by a sharp shear layer. The interface subsequently rolled-upped into large KH vortices that were accompanied by bubble-like structures of unknown origin. This was the first time the evolution of a well-resolved KH instability was observed in a HED plasma in the laboratory. We have analyzed the properties and dynamics of the plasma based on the data and fundamental models, without resorting to simulated values. In the second, supersonic experiment the Nike laser was used to drive a supersonic flow of Al plasma along a rippled, low-density foam surface. Here again the flowing plasma drove a shock into the second material, so that two fluids were separated by a shear layer. In contrast to the subsonic case, the flow developed shocks around the ripples in response to the supersonic flow of Al. Collaborators: R.P. Drake, O.A. Hurricane, J.F. Hansen, Y. Aglitskiy, T. Plewa, B.A. Remington, H.F. Robey, J.L. Weaver, A.L. Velikovich, R.S. Gillespie, M.J. Bono, M.J. Grosskopf, C.C. Kuranz, A. Visco.

  9. Megagauss field generation for high-energy-density plasma science experiments.

    SciTech Connect

    Rovang, Dean Curtis; Struve, Kenneth William; Porter, John Larry Jr.

    2008-10-01

    There is a need to generate magnetic fields both above and below 1 megagauss (100 T) with compact generators for laser-plasma experiments in the Beamlet and Petawatt test chambers for focused research on fundamental properties of high energy density magnetic plasmas. Some of the important topics that could be addressed with such a capability are magnetic field diffusion, particle confinement, plasma instabilities, spectroscopic diagnostic development, material properties, flux compression, and alternate confinement schemes, all of which could directly support experiments on Z. This report summarizes a two-month study to develop preliminary designs of magnetic field generators for three design regimes. These are, (1) a design for a relatively low-field (10 to 50 T), compact generator for modest volumes (1 to 10 cm3), (2) a high-field (50 to 200 T) design for smaller volumes (10 to 100 mm3), and (3) an extreme field (greater than 600 T) design that uses flux compression. These designs rely on existing Sandia pulsed-power expertise and equipment, and address issues of magnetic field scaling with capacitor bank design and field inductance, vacuum interface, and trade-offs between inductance and coil designs.

  10. Dependence of electron trapping on bubble geometry in laser-plasma wakefield acceleration

    SciTech Connect

    Li, X. F.; Yu, Q.; Huang, S.; Zhang, F.; Kong, Q.; Gu, Y. J.; Kawata, S.

    2014-07-15

    The effect of bubble shape in laser-plasma electron acceleration was investigated. We showed the general existence of an ellipsoid bubble. The electromagnetic field in this bubble and its dependence on bubble shape were determined through theory. The electron-trapping cross-section for different bubble aspect ratios was studied in detail. When the shape of the bubble was close to spherical, the trapping cross-section reached to the maximum. When the bubble deviated from a spherical shape, the cross-section decreased until electron injection no longer occurred. These results were confirmed by particle-in-cell simulation.

  11. Effect of high energy ion irradiation on silicon substrate in a pulsed plasma device

    NASA Astrophysics Data System (ADS)

    Bhuyan, H.; Favre, M.; Valderrama, E.; Avaria, G.; Guzman, F.; Chuaqui, H.; Mitchell, I.; Wyndham, E.; Saavedra, R.; Paulraj, M.

    2007-10-01

    We have performed an experimental analysis on the investigation of high energy ion beam irradiation on Si(1 0 0) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The surface modifications induced by the ion beams are characterized using standard surface science diagnostic tools, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), photothermal beam deflection, energy-dispersive X-ray (EDX) analysis and atomic force microscope (AFM) and the results are reported. In particular, it has been found that with silicon targets, the application of PF carbon ion beams results in the formation of a surface layer of hexagonal (6H) silicon carbide, with embedded self-organized step/terrace structures.

  12. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    SciTech Connect

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modeling of High-Energy-Density Plasmas.

  13. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    DOE PAGESBeta

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modelingmore » of High-Energy-Density Plasmas.« less

  14. Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas.

    PubMed

    Frenje, J A; Grabowski, P E; Li, C K; Séguin, F H; Zylstra, A B; Gatu Johnson, M; Petrasso, R D; Glebov, V Yu; Sangster, T C

    2015-11-13

    For the first time, quantitative measurements of ion stopping at energies around the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (T(e)) and electron number density (n(e)) in the range of 0.5-4.0 keV and 3×10(22) to 3×10(23) cm(-3) have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with T(e) with n(e). The importance of including quantum diffraction is also demonstrated in the stopping-power modeling of high-energy-density plasmas. PMID:26613448

  15. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility.

    PubMed

    Fiksel, G; Agliata, A; Barnak, D; Brent, G; Chang, P-Y; Folnsbee, L; Gates, G; Hasset, D; Lonobile, D; Magoon, J; Mastrosimone, D; Shoup, M J; Betti, R

    2015-01-01

    An upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energy storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology. PMID:25638132

  16. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility

    NASA Astrophysics Data System (ADS)

    Fiksel, G.; Agliata, A.; Barnak, D.; Brent, G.; Chang, P.-Y.; Folnsbee, L.; Gates, G.; Hasset, D.; Lonobile, D.; Magoon, J.; Mastrosimone, D.; Shoup, M. J.; Betti, R.

    2015-01-01

    An upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energy storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology.

  17. Large Enhancement in High-Energy Photoionization of Fe XVII and Missing Continuum Plasma Opacity

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.; Pradhan, Anil K.

    2016-06-01

    Aimed at solving the outstanding problem of solar opacity, and radiation transport plasma models in general, we report substantial photoabsorption in the high-energy regime due to atomic core photoexcitations not heretofore considered. In extensive R -matrix calculations of unprecedented complexity for an important iron ion Fe xvii (Fe16 + ), with a wave function expansion of 99 Fe xviii (Fe17 + ) LS core states from n ≤4 complexes (equivalent to 218 fine structure levels), we find (i) up to orders of magnitude enhancement in background photoionization cross sections, in addition to strongly peaked photo-excitation-of-core resonances not considered in current opacity models, and ii) demonstrate convergence with respect to successive core excitations. The resulting increase in the monochromatic continuum, and 35% in the Rosseland mean opacity, are compared with the "higher-than-predicted" iron opacity measured at the Sandia Z -pinch fusion device at solar interior conditions.

  18. Large Enhancement in High-Energy Photoionization of Fe XVII and Missing Continuum Plasma Opacity.

    PubMed

    Nahar, Sultana N; Pradhan, Anil K

    2016-06-10

    Aimed at solving the outstanding problem of solar opacity, and radiation transport plasma models in general, we report substantial photoabsorption in the high-energy regime due to atomic core photoexcitations not heretofore considered. In extensive R-matrix calculations of unprecedented complexity for an important iron ion Fe xvii (Fe^{16+}), with a wave function expansion of 99 Fe xviii (Fe^{17+}) LS core states from n≤4 complexes (equivalent to 218 fine structure levels), we find (i) up to orders of magnitude enhancement in background photoionization cross sections, in addition to strongly peaked photo-excitation-of-core resonances not considered in current opacity models, and ii) demonstrate convergence with respect to successive core excitations. The resulting increase in the monochromatic continuum, and 35% in the Rosseland mean opacity, are compared with the "higher-than-predicted" iron opacity measured at the Sandia Z-pinch fusion device at solar interior conditions. PMID:27341239

  19. Nuclear science research with dynamic high energy density plasmas at NIF

    NASA Astrophysics Data System (ADS)

    Shaughnessy, D. A.; Gharibyan, N.; Moody, K. J.; Despotopulos, J. D.; Grant, P. M.; Yeamans, C. B.; Berzak Hopkins, L.; Cerjan, C. J.; Schneider, D. H. G.; Faye, S.

    2016-05-01

    Nuclear reaction measurements are performed at the National Ignition Facility in a high energy density plasma environment by adding target materials to the outside of the hohlraum thermo-mechanical package on an indirect-drive exploding pusher shot. Materials are activated with 14.1-MeV neutrons and the post-shot debris is collected via the Solid Radiochemistry diagnostic, which consists of metal discs fielded 50 cm from target chamber center. The discs are removed post-shot and analyzed via radiation counting and mass spectrometry. Results from a shot using Nd and Tm foils as targets are presented, which indicate enhanced collection of the debris in the line of sight of a given collector. The capsule performance was not diminished due to the extra material. This provides a platform for future measurements of nuclear reaction data through the use of experimental packages mounted external to the hohlraum.

  20. Titanium carbonitride films on cemented carbide cutting tool prepared by pulsed high energy density plasma

    NASA Astrophysics Data System (ADS)

    Feng, Wenran; Liu, Chizi; Chen, Guangliang; Zhang, Guling; Gu, Weichao; Niu, Erwu; Yang, Si-Ze

    2007-03-01

    Hard films prepared by pulsed high energy density plasma (PHEDP) are characterized by high film/substrate adhesive strength, and high wear resistance. Titanium carbonitride (TiCN) films were deposited onto YG11C (ISO G20) cemented carbide cutting tool substrates by PHEDP at room temperature. XRD, XPS, SEM, AES, etc. were adopted to analyze the phases (elements) composition, microstructure and the interface of the films, respectively. The results show that, the uniform dense films are composed of grains ranging from 70 to 90 nm. According to the AES result, there is a broad transition layer between the film and the substrate, due to the ion implantation effect of the PHEDP. The transition layer is favorable for the film/substrate adhesion.

  1. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility

    DOE PAGESBeta

    Fiksel, G.; Agliata, A.; Barnak, D.; Brent, G.; Chang, P. -Y.; Folnsbee, L.; Gates, G.; Hasset, D.; Lonobile, D.; Magoon, J.; et al

    2015-01-12

    Here, an upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energymore » storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology.« less

  2. Note: Experimental platform for magnetized high-energy-density plasma studies at the omega laser facility

    SciTech Connect

    Fiksel, G.; Agliata, A.; Barnak, D.; Brent, G.; Chang, P. -Y.; Folnsbee, L.; Gates, G.; Hasset, D.; Lonobile, D.; Magoon, J.; Mastrosimone, D.; Shoup, III, M. J.; Betti, R.

    2015-01-12

    Here, an upgrade of the pulsed magnetic field generator magneto-inertial fusion electrical discharge system [O. Gotchev et al., Rev. Sci. Instrum. 80, 043504 (2009)] is described. The device is used to study magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of tens of tesla in a volume of a few cubic centimeters. The magnetic field is created by discharging a high-voltage capacitor through a small wire-wound coil. The coil current pulse has a duration of about 1 μs and a peak value of 40 kA. Compared to the original, the updated version has a larger energy storage and improved switching system. In addition, magnetic coils are fabricated using 3-D printing technology which allows for a greater variety of the magnetic field topology.

  3. Formation of reverse shocks in magnetized high energy density supersonic plasma flows

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergey

    2013-10-01

    There has been considerable effort in developing experiments for studies of both collisionless and radiative shocks in high energy density plasmas (HEDP), but there is still very limited experimental information the concerning properties of HEDP shocks in the presence of a magnetic field. A new experimental platform, based on the use of supersonic ablation plasma flows in inverse wire array z-pinches, was developed for studies of shocks in magnetized HEDP plasmas in a well-defined and diagnosable 1-D interaction geometry. The mechanism of flow generation ensures that the plasma flow (MA ~ 5 - 6 , Vflow 100 km/s, ni ~ 1017 cm-3) has a frozen-in magnetic field at a level sufficient to affect the shocks formed in the interaction with conducting obstacles. Experiments show that in addition to the formation of a ``standard'' reverse shock in a stagnated HEDP plasma, the presence of the magnetic field leads to the formation of an additional shock-like feature in the upstream plasma. This shock is triggered by the pile-up of magnetic flux diffusing into the upstream flow, despite a relatively small initial level of the frozen-in magnetic field (the flow ram pressure being much greater than the magnetic field pressure). The thickness of this shock is much smaller than the m.f.p. for the ion-ion collisions, the shock is formed at a distance of ~c/ωpi from the foil and remains stationary for the duration of the experiment (~100 ns). The plasma parameters in the flow and in the shock are measured using optical Thomson scattering, two-color laser interferometry, monochromatic X-ray radiography and miniature magnetic probes. The quantitative data from this experiment, especially the spatial profiles of the density and of the flow velocity measured simultaneously in the upstream and downstream of the shock, will allow detailed verification of MHD and PIC codes used by the HEDP community. Supported by EPSRC Grant EP/G001324/1 and by the OFES under DOE Cooperative Agreement DESC

  4. Computational studies and optimization of wakefield accelerators

    SciTech Connect

    Tsung, Frank S.; Bruhwiler, David L.; Cary, John R.; Esarey, Eric H.; Mori, Warren B.; Vay, Jean-Luc; Martins, Samuel F.; Katsouleas, Tom; Cormier-Michel, Estelle; Fawley, William M.; Huang, Chengkun; Wang, Xiadong; Cowan, Ben; Decyk, Victor K.; Fonseca, Ricardo A.; Lu, Wei; Messmer, Peter; Mullowney, Paul; Nakamura, Kei; Paul, Kevin; Plateau, Guillaume R.; Schroeder, Carl B.; Silva, Luis O.; Toth, Csaba; Geddes, C.G.R.; Tzoufras, Michael; Antonsen, Tom; Vieira, Jorge; Leemans, Wim P.

    2008-06-16

    Laser- and particle beam-driven plasma wakefield accelerators produce accelerating fields thousands of times higher than radio-frequency accelerators, offering compactness and ultrafast bunches to extend the frontiers of high energy physics and to enable laboratory-scale radiation sources. Large-scale kinetic simulations provide essential understanding of accelerator physics to advance beam performance and stability and show and predict the physics behind recent demonstration of narrow energy spread bunches. Benchmarking between codes is establishing validity of the models used and, by testing new reduced models, is extending the reach of simulations to cover upcoming meter-scale multi-GeV experiments. This includes new models that exploit Lorentz boosted simulation frames to speed calculations. Simulations of experiments showed that recently demonstrated plasma gradient injection of electrons can be used as an injector to increase beam quality by orders of magnitude. Simulations are now also modeling accelerator stages of tens of GeV, staging of modules, and new positron sources to design next-generation experiments and to use in applications in high energy physics and light sources.

  5. Beam loading by distributed injection of electrons in a plasma wakefield accelerator.

    PubMed

    Vafaei-Najafabadi, N; Marsh, K A; Clayton, C E; An, W; Mori, W B; Joshi, C; Lu, W; Adli, E; Corde, S; Litos, M; Li, S; Gessner, S; Frederico, J; Fisher, A S; Wu, Z; Walz, D; England, R J; Delahaye, J P; Clarke, C I; Hogan, M J; Muggli, P

    2014-01-17

    We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43  GV/m to a strongly loaded value of 26  GV/m. PMID:24484020

  6. Near-GeV-Energy Laser-Wakefield Acceleration of Self-Injected Electrons in a Centimeter-Scale Plasma Channel

    NASA Astrophysics Data System (ADS)

    Tsung, F. S.; Narang, Ritesh; Mori, W. B.; Joshi, C.; Fonseca, R. A.; Silva, L. O.

    2004-10-01

    The first three-dimensional, particle-in-cell (PIC) simulations of laser-wakefield acceleration of self-injected electrons in a 0.84cm long plasma channel are reported. The frequency evolution of the initially 50fs (FWHM) long laser pulse by photon interaction with the wake followed by plasma dispersion enhances the wake which eventually leads to self-injection of electrons from the channel wall. This first bunch of electrons remains spatially highly localized. Its phase space rotation due to slippage with respect to the wake leads to a monoenergetic bunch of electrons with a central energy of 0.26GeV after 0.55cm propagation. At later times, spatial bunching of the laser enhances the acceleration of a second bunch of electrons to energies up to 0.84GeV before the laser pulse intensity is significantly reduced.

  7. Near-GeV-energy laser-wakefield acceleration of self-injected electrons in a centimeter-scale plasma channel.

    PubMed

    Tsung, F S; Narang, Ritesh; Mori, W B; Joshi, C; Fonseca, R A; Silva, L O

    2004-10-29

    The first three-dimensional, particle-in-cell (PIC) simulations of laser-wakefield acceleration of self-injected electrons in a 0.84 cm long plasma channel are reported. The frequency evolution of the initially 50 fs (FWHM) long laser pulse by photon interaction with the wake followed by plasma dispersion enhances the wake which eventually leads to self-injection of electrons from the channel wall. This first bunch of electrons remains spatially highly localized. Its phase space rotation due to slippage with respect to the wake leads to a monoenergetic bunch of electrons with a central energy of 0.26 GeV after 0.55 cm propagation. At later times, spatial bunching of the laser enhances the acceleration of a second bunch of electrons to energies up to 0.84 GeV before the laser pulse intensity is significantly reduced. PMID:15525172

  8. Benchmarking multilevel, 2-D cylindrical radiation transport in a high energy density plasma environment

    NASA Astrophysics Data System (ADS)

    Apruzese, J. P.; Giuliani, J. L.; Hansen, S. B.

    2012-09-01

    In modeling optically thick, high energy density plasmas (HEDP), radiation transport is of comparable importance to atomic physics, hydrodynamics, and other transport processes. Radiation transport theory is the framework for calculating radiation output based on atomic kinetics, and is thus critical to designing and diagnosing experiments in which radiation production is significant. Starting in the 1960s, the astrophysics community established benchmarks for computational radiation transport, based on a parameterized two-level-atom, and mostly applicable to media with very high optical depths and low collisional quenching of radiative transitions. The purpose of the work reported here is to establish a similar computational radiation transport benchmark that is more relevant to a laboratory HEDP environment. Our model consists of 8 levels of mostly K-shell Al ions, ranging from the ground state of Li-like Al to its bare nucleus. Rates connecting the levels are given by well-known, readily reproducible analytic prescriptions. The results presented consist of level populations as a function of position within the cylindrical medium, and emitted line profiles. For the plasma conditions considered, the magnitudes and spatial variations of the populations are a sensitive indicator of the accuracy of the radiation transport model, and are critical in calculating experimentally relevant quantities such as radiative powers and line ratios.

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

    SciTech Connect

    Fox, W.; Bhattacharjee, A.; Germaschewski, K.

    2012-05-15

    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.

  10. Femtosecond probing around the K-edge of a laser heated plasma using X-rays from betatron oscillations in a laser wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Behm, Keegan; Zhao, Tony; Maksimchuk, Anatoly; Yanovsky, Victor; Nees, John; Mangles, Stuart; Krushelnick, Karl; Thomas, Alexander; CenterUltrafast Optical Science Team; Plasmas Group Team

    2015-11-01

    Presented here are data from a two-beam pump-probe experiment. We used synchrotron-like X-rays created by betatron oscillations to probe a thin metal foil that is pumped by the secondary laser beam. The Hercules Ti:Sapph laser facility was operated with a pulse duration of 34 fs and a power of 65 TW split to drive a laser wakefield accelerator and heat the secondary target. We observed opacity changes around the K-edge of thin foils as they were heated by an ultrafast pump laser. To understand how the opacity is changing with heating and expansion of the plasma, the delay between the two laser paths was adjusted on a fs and ps time scale. Experimental data for polyvinylidene chloride (PVDC) and aluminum show variations in opacity around the Cl and Al K-edges with changes in the probe delay. The transmitted synchrotron-like spectrum was measured using single photon counting on an X-ray CCD camera and was available on a shot-by-shot basis. The success of this work demonstrates a practical application for X-rays produced from betatron oscillations in a wakefield accelerator. The compact size of these ``table-top'' accelerators and the ultrashort nature of the generated X-ray pulses allows pump-probe experiments that can probe events that occur on the femtosecond time scale.

  11. Increasing energy coupling into plasma waves by tailoring the laser radial focal spot distribution in a laser wakefield accelerator

    SciTech Connect

    Genoud, G.; Burza, M.; Persson, A.; Svensson, K.; Wahlström, C.-G.; Bloom, M. S.; Najmudin, Z.; Mangles, S. P. D.; Vieira, J.; Silva, L. O.

    2013-06-15

    By controlling the focal spot quality with a deformable mirror, we are able to show that increasing the fraction of pulse energy contained within the central part of the focal spot, while keeping the total energy and central spot size constant, significantly increases the amount of energy transferred to the wakefield: Our measurements show that the laser loses significantly more laser energy and undergoes greater redshifting and that more charge is produced in the accelerated beam. Three dimensional particle in cell simulations performed with accurate representations of the measured focal spot intensity distribution confirm that energy in the wings of the focal spot is effectively wasted. Even though self-focusing occurs, energy in the wings of the focal spot distribution is not coupled into the wakefield, emphasising the vital importance of high quality focal spot profiles in experiments.

  12. Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

    SciTech Connect

    Blue, Brent Edward; /SLAC /UCLA

    2005-10-10

    In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.

  13. Interaction of high-energy trapped particles with ballooning modes in a tokamak with a high-. beta. plasma

    SciTech Connect

    Mikhailovskii, A. B.; Novakovaskii, S. V.; Smolyakov, A. I.

    1988-12-01

    A theory is derived for the interaction of high-energy trapped particleswith ballooning modes in a tokamak with a high-..beta.. plasma. A dispersionrelation is derived to describe the ballooning modes in the presence ofsuch particles; the effects of the high plasma ..beta.. are taken into account.The stability boundary for ballooning modes with zero and finite frequenciesis studied. The effects of finite bananas on the stability of ballooningmodes with zero frequencies are determined.

  14. BEAMING AND RAPID VARIABILITY OF HIGH-ENERGY RADIATION FROM RELATIVISTIC PAIR PLASMA RECONNECTION

    SciTech Connect

    Cerutti, B.; Werner, G. R.; Uzdensky, D. A.; Begelman, M. C. E-mail: greg.werner@colorado.edu E-mail: mitch@jila.colorado.edu

    2012-08-01

    We report on the first study of the angular distribution of energetic particles and radiation generated in relativistic collisionless electron-positron pair plasma reconnection using two-dimensional particle-in-cell simulations. We discover a strong anisotropy of the particles accelerated by reconnection and the associated strong beaming of their radiation. The focusing of particles and radiation increases with their energy; in this sense, this 'kinetic beaming' effect differs fundamentally from the relativistic Doppler beaming usually invoked in high-energy astrophysics, in which all photons are focused and boosted achromatically. We also present, for the first time, the modeling of the synchrotron emission as seen by an external observer during the reconnection process. The expected light curves comprise several bright symmetric sub-flares emitted by the energetic beam of particles sweeping across the line of sight intermittently, and exhibit super-fast time variability as short as about one-tenth of the system light-crossing time. The concentration of the energetic particles into compact regions inside magnetic islands and particle anisotropy explain the rapid variability. This radiative signature of reconnection can account for the brightness and variability of the gamma-ray flares in the Crab Nebula and in blazars.

  15. Jet Tomography of Quark Gluon Plasmas in High Energy Nuclear Collisions

    NASA Astrophysics Data System (ADS)

    Gyulassy, Miklos

    2015-04-01

    The attenuation pattern of high energy jet fragments in ultra-relativistic nuclear collisions provides information on the space-time evolution and dynamical properties of the Quark Gluon Plasma (QGP) phase of matter discovered at the Relativistic Heavy Ion Collider (RHIC) and observed at higher densities at the Large Hadron Collider (LHC). First I review our jet tomography theory of quark and gluon energy loss in a weakly coupled picture of the QGP. While the average attenuation pattern of light and heavy quark jets were well accounted for in that picture, the predicted azimuthal elliptic asymmetry of jets was underestimated when realistic bulk collective flow effects were taken into account. I then show that the elliptic asymmetry of jet fragments can also be quantitatively understood when nonperturbative lattice QCD constraints on the suppression of color electric fluctuations and the enhancement of color magnetic fluctuations near the critical QCD confinement temperature, Tc ~ 160 MeV, are incorporated into the theory. Our analysis provides a novel quantitative connection between the jet transport properties controlling the hard jet quenching observables and the bulk viscous transport properties controlling the remarkable ``perfect fluidity'' of QGP observed at RHIC and LHC.

  16. Talbot-Lau X-ray Moiré deflectometry Diagnostic for High Energy Density Plasmas

    NASA Astrophysics Data System (ADS)

    Valdivia Leiva, Maria Pia; Stutman, Dan; Finkenthal, Michael

    2013-10-01

    A Talbot-Lau (TL) x-ray interferometer measures beam angular deviations due to refraction index gradients within objects along its path. By tilting one of the gratings in the interferometer by small angles, Moiré patterns which enable the detection of density gradients in low-Z matter are obtained. In addition to the detection of both sharp and smooth density gradients this technique makes also possible the identification of micro structures within an object. The sensitivity and spatial resolution is adequate to characterize High Energy Density Laboratory Plasmas (HEDLP). The technique allows for the simultaneous acquisition of x-ray attenuation, refraction, and scatter information from a single x-ray image. Experimental and simulated results acquired show a clear advantage of the TL Moiré single image based phase-retrieval technique over the attenuation and propagation methods. Additionally, the method makes use of extended, polychromatic, incoherent, line and continuum x-ray sources, thus allowing for less demanding backlighters than those typically used in HEDLP radiography. Work supported by U.S. DOE/NNSA grant DENA0001835.

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

    SciTech Connect

    Kneip, S.; 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.; Bloom, M. S.; Najmudin, Z.; Palmer, C. A. J.; Schreiber, J.

    2011-08-29

    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.

  18. High-energy tail formation in an ion energy distribution function in the cylindrical Hall thruster plasma

    NASA Astrophysics Data System (ADS)

    Lim, Youbong; Kim, Holak; Park, Jaesun; Seon, Jongho; Choe, Wonho

    2014-10-01

    Ion energy distribution functions (IEDFs) of individual ion species having different charge states (i.e. Xe+, Xe2+, Xe3+, etc.) in the Hall thruster plasma are obtained from the measured E × B probe spectrum by a novel inversion technique using the iterative Tikhonov regularization method. The obtained IEDFs show the existence of a high-energy tail in the cylindrical Hall thruster plasmas that is mainly due to Xe+ ions despite the presence of Xe2+ and Xe3+ ions with a large fraction. Ion dynamics inside the plasma was numerically investigated to demonstrate that the high-energy tail is due to nonlinear ion acceleration in the plasma oscillating at typically 100 to 500 kHz. We found that this oscillation driven by transit-time instability is responsible for the shift of the IEDF of the Xe+ ions toward the high-energy side, showing the formation of high-energy tail in the overall IEDF. It was also found that the Xe flow rate raised from 4 to 10 sccm increases the oscillation strength at the same frequency of 360 kHz, which can be applied to control of the shape of the IEDF.

  19. Gigavolt-per-Meter Wakefields in Annular Dielectric Structures

    NASA Astrophysics Data System (ADS)

    O'Shea, Brendan Donald

    A wakefield accelerator uses a medium capable of sustaining appropriate electric fields to transfer energy from a drive beam to a witness beam. Examples of such systems include electron beam driven plasma wakefields, laser driven plasma wakefields and electron beam driven dielectric wakefield structures. Dielectrics and plasmas are of particular interest because they are capable of maintaining electric fields on the order of GV/m and in the case of plasmas upwards of TV/m. These systems provide a significant step beyond current radiofrequency accelerating structures capable of peak electric fields on the order of 100 MV/m and average effective electric fields of 20 MV/m. Furthermore, beam driven dielectric structures produce a wakefield which is phase synchronous with the beam, these structures do not suffer from transit time or dephasing effects. In the case of dielectric wakefield accelerators, the structures under study in this publication, the modes generated by the driving beam are in the terahertz (THz) regime. Thus development of dielectric wakefield accelerators is seen as a path to smaller, more compact accelerating systems and as a means to generate THz radiation. Here we demonstrate a beam-driven dielectric wakefield accelerating structure that produces sustained fields of 1.35 GV/m for many hundreds of thousands of drive beam pulses. In addition we show beam-driven dielectric structures have the potential to produce single mode, high spectral purity THZ radiation of unprecedented energy scale.

  20. Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

    SciTech Connect

    Bonatto, A.; Schroeder, C. B.; Vay, J. -L.; Geddes, C. R.; Benedetti, C.; Esarey and, E.; Leemans, W. P.

    2014-07-13

    A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

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

    SciTech Connect

    Grebenyuk, Julia; Mehrling, Timon; Tsung, Frank S.; Floettman, Klaus; Osterhoff, Jens

    2012-12-21

    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.

  2. A nonlinear particle dynamics map of wakefield acceleration in a linear collider

    SciTech Connect

    Tajima, T.; Cheshkov, S.; Horton, W.; Yokoya, K.

    1998-08-01

    The performance of a wakefield accelerator in a high energy collider application is analyzed. In order to carry out this task, it is necessary to construct a strawman design system (no matter how preliminary) and build a code of the systems approach. A nonlinear dynamics map built on a simple theoretical model of the wakefield generated by the laser pulse (or whatever other method) is obtained and they employ this as a base for building a system with multi-stages (and components) as a high energy collider. The crucial figures of merit for such a system other than the final energy include the emittance (that determines the luminosity). The more complex the system is, the more opportunities the system has to degrade the emittance (or entropy of the beam). Thus the map gu ides one to identify where the crucial elements lie that affect the emittance. They find that a strong focusing force of the wakefield coupled with a possible jitter of the axis (or laser aiming) of each stage and a spread in the betatron frequencies arising from different phase space positions for individual particles leads to a phase space mixing. This sensitively controls the emittance degradation. They show that in the case of a uniform plasma the effect of emittance growth is large and may cause serious problems. They discuss possibilities to avoid it and control the situation.

  3. Interaction of the high energy deuterons with the graphite target in the plasma focus devices based on Lee model

    SciTech Connect

    Akel, M. Alsheikh Salo, S.; Ismael, Sh.; Saw, S. H.; Lee, S.

    2014-07-15

    Numerical experiments are systematically carried out using the Lee model code extended to compute the ion beams on various plasma focus devices operated with Deuterium gas. The deuteron beam properties of the plasma focus are studied for low and high energy plasma focus device. The energy spectral distribution for deuteron ions ejected from the pinch plasma is calculated and the ion numbers with energy around 1 MeV is then determined. The deuteron–graphite target interaction is studied for different conditions. The yield of the reaction {sup 12}C(d,n){sup 13}N and the induced radioactivity for one and multi shots plasma focus devices in the graphite solid target is investigated. Our results present the optimized high energy repetitive plasma focus devices as an alternative to accelerators for the production of {sup 13}N short lived radioisotopes. However, technical challenges await solutions on two fronts: (a) operation of plasma focus machines at high rep rates for a sufficient period of time (b) design of durable targets that can take the thermal load.

  4. Wakefield generation via two color laser pulses

    SciTech Connect

    Jha, Pallavi; Saroch, Akanksha; Kumar Verma, Nirmal

    2013-05-15

    The analytical study for the evolution of longitudinal as well as transverse electric wakefields, generated via passage of two color laser pulses through uniform plasma, has been presented in the mildly relativistic regime. The frequency difference between the two laser pulses is assumed to be equal to the plasma frequency, in the present analysis. The relative angle between the directions of polarization of the two laser pulses is varied and the wakefield amplitudes are compared. Further, the amplitude of the excited wakes by two color pulses are compared with those generated by a single laser pulse.

  5. Current filamentation instability in laser wakefield accelerators.

    PubMed

    Huntington, C M; Thomas, A G R; McGuffey, C; Matsuoka, T; Chvykov, V; Kalintchenko, G; Kneip, S; Najmudin, Z; Palmer, C; Yanovsky, V; Maksimchuk, A; Drake, R P; Katsouleas, T; Krushelnick, K

    2011-03-11

    Experiments using an electron beam produced by laser-wakefield acceleration have shown that varying the overall beam-plasma interaction length results in current filamentation at lengths that exceed the laser depletion length in the plasma. Three-dimensional simulations show this to be a combination of hosing, beam erosion, and filamentation of the decelerated beam. This work suggests the ability to perform scaled experiments of astrophysical instabilities. Additionally, understanding the processes involved with electron beam propagation is essential to the development of wakefield accelerator applications. PMID:21469796

  6. Current Filamentation Instability in Laser Wakefield Accelerators

    SciTech Connect

    Huntington, C. M.; Drake, R. P.; Thomas, A. G. R.; McGuffey, C.; Matsuoka, T.; Chvykov, V.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Kneip, S.; Najmudin, Z.; Palmer, C.; Katsouleas, T.

    2011-03-11

    Experiments using an electron beam produced by laser-wakefield acceleration have shown that varying the overall beam-plasma interaction length results in current filamentation at lengths that exceed the laser depletion length in the plasma. Three-dimensional simulations show this to be a combination of hosing, beam erosion, and filamentation of the decelerated beam. This work suggests the ability to perform scaled experiments of astrophysical instabilities. Additionally, understanding the processes involved with electron beam propagation is essential to the development of wakefield accelerator applications.

  7. Argonne's new Wakefield Test Facility

    SciTech Connect

    Simpson, J.D.

    1992-07-20

    The first phase of a high current, short bunch length electron beam research facility, the AWA, is near completion at Argonne. At the heart of the facility is a photocathode based electron gun and accelerating sections designed to deliver 20 MeV pulses with up to 100 nC per pulse and with pulse lengths of approximately 15 ps (fw). Using a technique similar to that originated at Argonne's AATF facility, a separate weak probe pulse can be generated and used to diagnose wake effects produced by the intense pulses. Initial planned experiments include studies of plasma wakefields and dielectric wakefield devices, and expect to demonstrate large, useful accelerating gradients (> 100 MeV/m). Later phases of the facility will increase the drive bunch energy to more than 100 MeV to enable acceleration experiments up to the GeV range. Specifications, design details, and commissioning progress are presented.

  8. 26Al Production in the Early Solar Nebula by Neutral High-Energy Plasma Winds

    NASA Astrophysics Data System (ADS)

    Spergel, M. S.

    1995-09-01

    In the light of recent observations, I believe that the sources for the presence of ^26Al within the solar nebula must be reconsidered [2,3]. Recent low observational estimates of the probability of encounters between mass-losing evolved stars and molecular clouds [4] for the production of ^26Al and the observed low production [5] of 26 Al from AGB (Asymptotic Giant Branch stars) along with the predicted low abundance of cosmic ray induced local production [6] in the early solar nebula all support continued investigation for additional sources of the solar nebula ^26Al presence. It is suggested based on the presences of new cross section data [7], that an important source of this ^26Al presence might be from enhanced interactions from the collisions of the local "T. Tauri" like plasma winds with the atomic and molecular Early Solar Nebula (ESN). Interactions like ^26Mg (p,n) ^26Al in this "neutral" electrical setting may provide the needed selective production. The ESN provides an environment where plasma winds can lead to such nucleosynthesis. Stellar winds of 300-700 km/s (about 3x10^7 K) are seen to T. Tauri like stars, presumed precursor to solar like stars, and also within the Solar heliosphere [8.9]. These winds provide the source of Solar High Energy Particles which can interact with such in situ targets such as ^26Mg to produce the ^26Al. The presence of the atomic and molecular environments, will enhance [10] nucleosynthesis over that seen in scattering of protons off bare nuclei. Such enhancement has been recently observed in low energy scattering on electrically shield targets [7]. There it was also suggested that in stellar convective zones, electron clouds of the plasma shield may also shield bare target nuclei. Measured values of low energy proton scattered on atomic and molecular targets indicated [7] that fusion cross sections are enlarged and elastic cross sections are reduced, therefore simple extrapolation of accelerator data can lead to an

  9. High-energy negative ion beam obtained from pulsed inductively coupled plasma for charge-free etching process

    NASA Astrophysics Data System (ADS)

    Vozniy, O. V.; Yeom, G. Y.

    2009-06-01

    Negative ions in conventional inductively coupled plasma are often more chemically active than positive ions (for example, in CF4 or SF6 plasmas), but inconveniently they are trapped inside the sheath and cannot be used for high-energy surface etching in sources with a grid-type acceleration system. In this work we describe a method of positive and negative ion extraction that allows the energy and flux of oppositely charged particles to be varied independently. Then by scattering the ions off from a metal surface, it is possible to form a high-energy beam of neutrals from the negative ions by using the low-energy positive component of the beam current for better charge compensation.

  10. Observation of enhanced transformer ratio in collinear wakefield acceleration.

    PubMed

    Jing, C; Kanareykin, A; Power, J G; Conde, M; Yusof, Z; Schoessow, P; Gai, W

    2007-04-01

    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, R<2 for this configuration. A number of techniques have been proposed to overcome the transformer 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 1:2.5 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. PMID:17501280

  11. Numerical simulation of the interaction between two high-energy plasma bunches in the ionosphere

    NASA Astrophysics Data System (ADS)

    Motorin, A. A.; Stupitsky, E. L.; Kholodov, A. S.

    2016-07-01

    The 3D MHD algorithm developed by us has been adapted to modeling the interaction between two plasma bunches in the ionosphere, mainly in order to sufficiently correctly describe the physics of the interaction between two plasma regions with regard to the ionospheric inhomogeneity and the geomagnetic field action. Modeling has been performed for several versions of location of the plasma region centers.

  12. Relativistic quantum corrections to laser wakefield acceleration.

    PubMed

    Zhu, Jun; Ji, Peiyong

    2010-03-01

    The influence of quantum effects on the interaction of intense laser fields with plasmas is investigated by using a hydrodynamic model based on the framework of the relativistic quantum theory. Starting from the covariant Wigner function and Dirac equation, the hydrodynamic equations for relativistic quantum plasmas are derived. Based on the relativistic quantum hydrodynamic equations and Poisson equation, the perturbations of electron number densities and the electric field of the laser wakefield containing quantum effects are deduced. It is found that the corrections generated by the quantum effects to the perturbations of electron number densities and the accelerating field of the laser wakefield cannot be neglected. Quantum effects will suppress laser wakefields, which is a classical manifestation of quantum decoherence effects, however, the contribution of quantum effects for the laser wakefield correction will been partially counteracted by the relativistic effects. The analysis also reveals that quantum effects enlarge the effective frequencies of plasmas, and the quantum behavior appears a screening effect for plasma electrons. PMID:20365881

  13. Relativistic quantum corrections to laser wakefield acceleration

    SciTech Connect

    Zhu Jun; Ji Peiyong

    2010-03-15

    The influence of quantum effects on the interaction of intense laser fields with plasmas is investigated by using a hydrodynamic model based on the framework of the relativistic quantum theory. Starting from the covariant Wigner function and Dirac equation, the hydrodynamic equations for relativistic quantum plasmas are derived. Based on the relativistic quantum hydrodynamic equations and Poisson equation, the perturbations of electron number densities and the electric field of the laser wakefield containing quantum effects are deduced. It is found that the corrections generated by the quantum effects to the perturbations of electron number densities and the accelerating field of the laser wakefield cannot be neglected. Quantum effects will suppress laser wakefields, which is a classical manifestation of quantum decoherence effects, however, the contribution of quantum effects for the laser wakefield correction will been partially counteracted by the relativistic effects. The analysis also reveals that quantum effects enlarge the effective frequencies of plasmas, and the quantum behavior appears a screening effect for plasma electrons.

  14. Progress toward Kelvin-Helmholtz instabilities in a High-Energy-Density Plasma on the Nike laser

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Huntington, C. M.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Plewa, T.; Dwarkadas, V. V.

    2008-04-01

    In the realm of high-energy-density (HED) plasmas, there exist three primary hydrodynamic instabilities of concern: Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH). Although the RT and the RM instabilities have been readily observed and diagnosed in the laboratory, the KH instability remains relatively unexplored in HED plasmas. Unlike the RT and RM instabilities, the KH instability is driven by a lifting force generated by a strong velocity gradient in a stratified fluid. Understanding the KH instability mechanism in HED plasmas will provide essential insight into oblique shock systems, jets, mass stripping, and detailed RT-spike development. In addition, our KH experiment will help provide the groundwork for future transition to turbulence experiments. We present 2D FLASH simulations and experimental data from our initial attempts to create a pure KH system using the Nike laser at the Naval Research Laboratory.

  15. Plasma Diagnostic Calibration and Characterizations with High Energy X-rays

    SciTech Connect

    Zaheer Ali

    2009-06-05

    National Security Technologies’ High Energy X-ray (HEX) Facility is unique in the U.S. Department of Energy complex. The HEX provides fluorescent X-rays of 5 keV to 100 keV with fluence of 10^5–10^6 photons/cm^2/second at the desired line energy. Low energy lines can be filtered, and both filters and fluorescers can be changed rapidly. We present results of calibrating image plates (sensitivity and modulation transfer function), a Bremsstrahlung spectrometer (stacked filters and image plates), and the National Ignition Facility’s Filter- Fluorescer Experiment (FFLEX) high energy X-ray spectrometer. We also show results of a scintillator light yield and alignment study for a neutron imaging system.

  16. Study of electron acceleration and x-ray radiation as a function of plasma density in capillary-guided laser wakefield accelerators

    SciTech Connect

    Ju, J.; Döpp, A.; Cros, B.; Svensson, K.; Genoud, G.; Wojda, F.; Burza, M.; Persson, A.; Lundh, O.; Wahlström, C.-G.; Ferrari, H.

    2013-08-15

    Laser wakefield electron acceleration in the blow-out regime and the associated betatron X-ray radiation were investigated experimentally as a function of the plasma density in a configuration where the laser is guided. Dielectric capillary tubes were employed to assist the laser keeping self-focused over a long distance by collecting the laser energy around its central focal spot. With a 40 fs, 16 TW pulsed laser, electron bunches with tens of pC charge were measured to be accelerated to an energy up to 300 MeV, accompanied by X-ray emission with a peak brightness of the order of 10{sup 21} ph/s/mm{sup 2}/mrad{sup 2}/0.1%BW. Electron trapping and acceleration were studied using the emitted X-ray beam distribution to map the acceleration process; the number of betatron oscillations performed by the electrons was inferred from the correlation between measured X-ray fluence and beam charge. A study of the stability of electron and X-ray generation suggests that the fluctuation of X-ray emission can be reduced by stabilizing the beam charge. The experimental results are in good agreement with 3D particle-in-cell (PIC) simulation.

  17. High-energy x-ray microscopy of laser-fusion plasmas at the National Ignition Facility

    SciTech Connect

    Koch, J.A.; Landen, O.L.; Hammel, B.A.

    1997-08-26

    Multi-keV x-ray microscopy will be an important laser-produced plasma diagnostic at future megajoule facilities such as the National Ignition Facility (NIF).In preparation for the construction of this facility, we have investigated several instrumentation options in detail, and we conclude that near normal incidence single spherical or toroidal crystals may offer the best general solution for high-energy x-raymicroscopy at NIF and at similar large facilities. Kirkpatrick-Baez microscopes using multi-layer mirrors may also be good secondary options, particularly if apertures are used to increase the band-width limited field of view.

  18. Electron trapping and acceleration across a parabolic plasma density profile.

    PubMed

    Kim, J U; Hafz, N; Suk, H

    2004-02-01

    It is known that as a laser wakefield passes through a downward density transition in a plasma some portion of the background electrons are trapped in the laser wakefield and the trapped electrons are accelerated to relativistic high energies over a very short distance. In this study, by using a two-dimensional (2D) particle-in-cell (PIC) simulation, we suggest an experimental scheme that can manipulate electron trapping and acceleration across a parabolic plasma density channel, which is easier to produce and more feasible to apply to the laser wakefield acceleration experiments. In this study, 2D PIC simulation results for the physical characteristics of the electron bunches that are emitted from the parabolic density plasma channel are reported in great detail. PMID:14995568

  19. Novel high-energy physics studies using intense lasers and plasmas

    SciTech Connect

    Leemans, Wim P.; Bulanov, Stepan; Esarey, Eric; Schroeder, Carl

    2015-06-29

    In the framework of the project “Novel high-energy physics studies using intense lasers and plasmas” we conducted the study of ion acceleration and “flying mirrors” with high intensity lasers in order to develop sources of ion beams and high frequency radiation for different applications. Since some schemes of laser ion acceleration are also considered a good source of “flying mirrors”, we proposed to investigate the mechanisms of “mirror” formation. As a result we were able to study the laser ion acceleration from thin foils and near critical density targets. We identified several fundamental factors limiting the acceleration in the RPA regime and proposed the target design to compensate these limitations. In the case of near critical density targets, we developed a concept for the laser driven ion source for the hadron therapy. Also we studied the mechanism of “flying mirror” generation during the intense laser interaction with thin solid density targets. As for the laser-based positron creation and capture we initially proposed to study different regimes of positron beam generation and positron beam cooling. Since the for some of these schemes a good quality electron beam is required, we studied the generation of ultra-low emittance electron beams. In order to understand the fundamental physics of high energy electron beam interaction with high intensity laser pulses, which may affect the efficient generation of positron beams, we studied the radiation reaction effects.

  20. High Energy Plasmas, General Relativity and Collective Modes in the Vicinity of Black Holes*

    NASA Astrophysics Data System (ADS)

    Coppi, B.

    2009-05-01

    Plasmas around black holes can take different equilibrium configurations^1 from those known from fluid theory as the vertical Lorentz compression due to plasma currents can overtake that of the gravitational force. In a disk with a ``seed'' magnetic field, axisymmetric modes as well as tri-dimensional spirals can be excited by the combined effects of the radial gradient of the plasma rotation frequency and of the plasma pressure gradient^2. The spirals' properties depend strongly on their vertical structure^3. Axisymmetric modes can produce vertical counter-flows of thermal energy and particles and be candidates for the origin of the winds emanating from disks in Active Galactic Nuclei (AGN's)^2. The excitation of radially localized density spirals corotating with the plasma near a black hole can provide an explanation for^4 the observed Quasi Periodic Oscillations (QPO's) of the X-ray emission from compact objects. Convective spiral modes^3 that are purely oscillatory in time and not localized radially can acquire their amplitudes from coupling to unstable modes and provide transport^3 of angular momentum toward the outer region of the disk structure.*Sponsored in part by the U.S. DOE. ^1B. Coppi and F. Rousseau, Ap. J., 641, 458 (2006). ^2B. Coppi, Europhys. Letters 82, 19001 (2008). ^3B. Coppi, MIT/LNS Report 08/08, submitted to A&A (2008). ^4B. Coppi and P. Rebusco, Paper P5.154, E.P.S. Conf. Pl. Phys. (Crete, 2008).

  1. Talbot-Lau X-ray Deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments

    DOE PAGESBeta

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Mileham, C.; Begishev, I.; Theobald, W.; Bromage, J.; Regan, S. P.; Klein, S. R.; Munoz-Cordoves, G.; et al

    2016-04-21

    Talbot-Lau X-ray Deflectometry has been developed as an electron density diagnostic for High Energy Density plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping was demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moire pattern formation and grating survival was also observed using a copper x-pinch driven at 400 kA, ~1 kA/ns. Lastly, these results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

  2. Progress Toward Kelvin-Helmholtz instabilities in a High-Energy-Density Plasma on the Nike Laser

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Dwarkadas, V. V.; Gillespie, R. S.; Grosskopf, M. J.; Huntington, C. M.; Gjeci, N.; Campbell, D. A.; Marion, D. C.

    2007-11-01

    In the realm of high-energy-density (HED) plasmas, there exist three primary hydrodynamic instabilities: Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH). Although the RT and the RM instabilities have been observed in the laboratory, no experiment to our knowledge has cleanly diagnosed the KH instability. While the RT instability results from the acceleration of a more dense fluid into a less dense fluid and the RM instability is due to shock deposited vorticity onto an interface, the KH instability is driven by a lifting force generated by velocity shear at a perturbed fluid interface. Understanding the KH instability mechanism in HED plasmas will provide essential insight into detailed RT-spike development, mass stripping, many astrophysical processes, as well as laying the groundwork for future transition to turbulence experiments. We present 2D simulations and data from our initial attempts to create a pure KH system using the Nike laser at the Naval Research Laboratory.

  3. Modeling of strongly collimated jets produced by high energy density plasmas on COBRA

    NASA Astrophysics Data System (ADS)

    Gourdain, P.-A.; Seyler, C. E.

    2014-03-01

    Jet collimation in astrophysical plasmas and in the laboratory has recently received much attention. When the magnetohydrodynamics (MHD) model is used to represent both systems, scale invariance allows for the simple extension of the parameters encountered in laboratory experiments to much larger systems, like astrophysical outflows. However, the validation of such a model requires a precise comparison of numerical simulations with experimental data. Using radial foils as an experimental setup to generate strongly collimated plasma jets, we show that the Hall MHD model included in the PERSEUS code does well to capture the plasma dynamics of collimated jets, even with restrictive conditions such as a constant ionization number and the neglect of normally important transport processes. Very importantly, we show that jet collimation is not only the result of magnetic forces, but also converging radial flows.

  4. Spectroscopic Study of a Pulsed High-Energy Plasma Deflagration Accelerator

    NASA Astrophysics Data System (ADS)

    Loebner, Keith; Underwood, Thomas; Mouratidis, Theodore; Cappelli, Mark

    2015-11-01

    Observations of broadened Balmer lines emitted by a highly-ionized transient plasma jet are presented. A gated CCD camera coupled to a high-resolution spectrometer is used to obtain chord-averaged broadening data for a complete cross section of the plasma jet, and the data is Abel inverted to derive the radial plasma density distribution. This measurement is performed over narrow gate widths and at multiple axial positions to provide high spatial and temporal resolution. A streak camera coupled to a spectrometer is used to obtain continuous-time broadening data over the entire duration of the discharge event (10-50 microseconds). Analyses of discharge characteristics and comparisons with previous work are discussed. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program, as well as the National Defense Science Engineering Graduate Fellowship.

  5. Modeling of plasma flow switches at low, intermediate and high energies

    SciTech Connect

    Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.; Roderick, N.; Turchi, P.

    1992-01-01

    Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch's efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime.

  6. Modeling of plasma flow switches at low, intermediate and high energies

    SciTech Connect

    Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.; Roderick, N.; Turchi, P.

    1992-12-31

    Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch`s efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime.

  7. Electron acceleration by a nonlinear wakefield generated by ultrashort (23-fs) high-peak-power laser pulses in plasma.

    PubMed

    Kando, M; Masuda, S; Zhidkov, A; Yamazaki, A; Kotaki, H; Kondo, S; Homma, T; Kanazawa, S; Nakajima, K; Hayashi, Y; Mori, M; Kiriyama, H; Akahane, Y; Inoue, N; Ueda, H; Nakai, Y; Tsuji, K; Yamamoto, Y; Yamakawa, K; Koga, J; Hosokai, T; Uesaka, M; Tajima, T

    2005-01-01

    We study experimentally the interaction of the shortest at present (23-fs) , relativistically intense (20-TW), tightly focused laser pulses with underdense plasma. MeV electrons constitute a two-temperature distribution due to different plasma wave-breaking processes at a plasma density of 10(20) cm(-3). These two groups of electrons are shown numerically to constitute bunches with very distinctive time durations. PMID:15697651

  8. The extremely high-energy plasma/particle sensor for electron (XEP-e) of the ERG satellite

    NASA Astrophysics Data System (ADS)

    Higashio, N.; Matsumoto, H.

    2015-12-01

    It is well known that satellites are always in danger in space and especially high-energy radiation damages them. One of the sources that cause them is the radiation belt (the Van Allen belt). It was thought to be static, but in the 1990s it rediscovered the radiation belt fluctuates greatly. There are some reasons to occur this phenomenon, but we have not understood a clear reason of this yet. On the other hand, it is well known that the energetic particle flux vary during geomagnetic disturbances and the relativistic electrons in the other radiation belt change with solar wind speed. Now we are trying to develop the satellite (ERG) to reveal this mechanism. ERG (Energization and Radiation in Geospace) satellite is the small space science platform for rapid investigation and test satellite of JAXA/ISAS. This satellite will be lanched in 2016. Our group is developing the instrument (the XEP-e) to measure high-energy electrons (400keV~20MeV), that is one of many ERG satellite instruments. The XEP-e (eXtremely high Energy Plasma/ particle sensor for electron) is consists of the 5 SSDs (Solid-State Silicon Detectors) and a GSO single crystal scintillator. It has one-way conic sight and an electric part is unified with a part of sensor that is covered with aluminum to protect from contaminationand and an anti-scintillator to detect it. The front part of the SSDs discriminate a radiation enters into the sensor and the back part of the plastic scintillator get the value of its energy. We can get the data of high-energy electron by using this sensor and it will be useful to reveal the detail of the radiation belt's fluctuation.

  9. From a colored glass condensate to the gluon plasma: Equilibration in high energy heavy ion collisions

    SciTech Connect

    Bjoraker, Jefferson; Venugopalan, Raju

    2001-02-01

    The initial distribution of gluons at the very early times after a high-energy heavy ion collision is described by the bulk scale Q{sub s} of gluon saturation in the nuclear wave function. The subsequent evolution of the system towards kinetic equilibrium is described by a nonlinear Landau equation for the single particle distributions [A. H. Mueller, Nucl. Phys. B572, 227 (2000); Phys. Lett. B 475, 220 (2000)]. In this paper, we solve this equation numerically for the idealized initial conditions proposed by Mueller, and study the evolution of the system to equilibrium. We discuss the sensitivity of our results on the dynamical screening of collinear divergences. In a particular model of dynamical screening, the convergence to the hydrodynamic limit is seen to be rapid relative to hydrodynamic time scales. The equilibration time, the initial temperature, and the chemical potential are shown to have a strong functional dependence on the initial gluon saturation scale Q{sub s}.

  10. Demonstration of x-ray fluorescence imaging of a high-energy-density plasma

    SciTech Connect

    MacDonald, M. J. Gamboa, E. J.; Keiter, P. A.; Fein, J. R.; Klein, S. R.; Kuranz, C. C.; LeFevre, H. J.; Manuel, M. J.-E.; Wan, W. C.; Drake, R. P.; Montgomery, D. S.; Biener, M. M.; Fournier, K. B.; Streit, J.

    2014-11-15

    Experiments at the Trident Laser Facility have successfully demonstrated the use of x-ray fluorescence imaging (XRFI) to diagnose shocked carbonized resorcinol formaldehyde (CRF) foams doped with Ti. One laser beam created a shock wave in the doped foam. A second laser beam produced a flux of vanadium He-α x-rays, which in turn induced Ti K-shell fluorescence within the foam. Spectrally resolved 1D imaging of the x-ray fluorescence provided shock location and compression measurements. Additionally, experiments using a collimator demonstrated that one can probe specific regions within a target. These results show that XRFI is a capable alternative to path-integrated measurements for diagnosing hydrodynamic experiments at high energy density.

  11. Ringing After a High-Energy Collision: Ambipolar Oscillations During Impact Plasma Expansion

    NASA Technical Reports Server (NTRS)

    Zimmerman, M. I.; Farrell, W. M.; Stubbs, T. J.

    2012-01-01

    High-velocity impacts on the Moon and other airless bodies deliver energy and material to the lunar surface and exosphere. The target and i mpactor material may become vaporized and ionized to form a collision al plasma that expands outward and eventually becomes collisionless. In the present work, kinetic simulations of the later collision less stage of impact plasma expansion are performed. Attention is paid to characterizing "ambipolar oscillations" in which thermodynamic distur bances propagate outward to generate "ringing" within the expanding e lectron cloud, which could radiate an electromagnetic signature of lo cal plasma conditions. The process is not unlike a beam-plasma intera ction, with the perturbing electron population in the present case ac ting as a highly thermal "beam" that resonates along the expanding de nsity gradient. Understanding the electromagnetic aspects of impact p lasma expansion could provide insight into the lasting effects of nat ural, impact-generated currents on airless surfaces and charging haza rds to human exploration infrastructure and instrumentation.

  12. Experimental characterization of railgun-driven supersonic plasma jets motivated by high energy density physics applications

    SciTech Connect

    Hsu, S. C.; Moser, A. L.; Awe, T. J.; Davis, J. S.; Dunn, J. P.; Merritt, E. C.; Adams, C. S.; Brockington, S. J. E.; Case, A.; Messer, S. J.; Witherspoon, F. D.; Cassibry, J. T.; Gilmore, M. A.; Lynn, A. G.

    2012-12-15

    We report experimental results on the parameters, structure, and evolution of high-Mach-number (M) argon plasma jets formed and launched by a pulsed-power-driven railgun. The nominal initial average jet parameters in the data set analyzed are density Almost-Equal-To 2 Multiplication-Sign 10{sup 16} cm{sup -3}, electron temperature Almost-Equal-To 1.4 eV, velocity Almost-Equal-To 30 km/s, M Almost-Equal-To 14, ionization fraction Almost-Equal-To 0.96, diameter Almost-Equal-To 5 cm, and length Almost-Equal-To 20 cm. These values approach the range needed by the Plasma Liner Experiment, which is designed to use merging plasma jets to form imploding spherical plasma liners that can reach peak pressures of 0.1-1 Mbar at stagnation. As these jets propagate a distance of approximately 40 cm, the average density drops by one order of magnitude, which is at the very low end of the 8-160 times drop predicted by ideal hydrodynamic theory of a constant-M jet.

  13. Compton X-rays from Self-Generated Backscattered Radiation in a Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Ting, Antonio; Kaganovich, Dmitri; Helle, Michael; Chen, Yu-Hsin; Palastro, John; Hafizi, Bahman; Gordon, Daniel

    2015-11-01

    A unique Compton scattering configuration for generating monochromatic, short pulse, and potentially coherent x-rays in a Laser Wakefield Accelerator (LWFA) is being studied at the Naval Research Laboratory. Reflection mechanisms such as stimulated Raman scattering and shock-created density gradients in a plasma can generate the required backward-travelling laser pulse directly from the same laser pulse used in the LWFA, i.e., the high energy electron beam and the counter-propagating photon beam are both self-generated by an ultrashort laser pulse in plasma. Extended interaction distance and automatic alignment of electron beam and backscattered radiation could be beneficial to the amplification of the Doppler upshifted Compton X-rays. Preliminary experiments are ongoing with measurement of Raman backscattering and reflection off a plasma density gradient. Energy resolved X-ray results are also anticipated. This work is supported by NRL Base Program and DOE.

  14. Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Shalloo, R. J.; Corner, L.; Arran, C.; Cowley, J.; Cheung, G.; Thornton, C.; Walczak, R.; Hooker, S. M.

    2016-09-01

    In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150-170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

  15. Enhancement of wave growth for warm plasmas with a high-energy tail distribution

    NASA Technical Reports Server (NTRS)

    Thorne, Richard M.; Summers, Danny

    1991-01-01

    The classical linear theory of electromagnetic wave growth in a warm plasma is considered for waves propagating parallel to a uniform ambient magnetic field. Wave-growth rates are calculated for ion-driven right-hand mode waves for Kappa and Maxwellian particle distribution functions and for various values of the spectral index, the temperature anisotropy, and the ratio of plasma pressure to magnetic pressure appropriate to the solar wind. When the anisotropy is low the wave growth is limited to frequencies below the proton gyrofrequency and the growth rate increases dramatically as the spectral index is reduced. The growth rate for any Kappa distribution greatly exceeds that for a Maxwellian with the same bulk properties. For large thermal anisotropy the growth rate from either distribution is greatly enhanced. The growth rates from a Kappa distribution are generally larger than for a Maxwellian distribution, and significant wave growth occurs over a broader range of frequencies.

  16. Stimulated Raman side scattering in laser wakefield acceleration.

    PubMed

    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

    2010-07-16

    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. PMID:20867770

  17. Stimulated Raman Side Scattering in Laser Wakefield Acceleration

    SciTech Connect

    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.

    2010-07-16

    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.

  18. Basic concepts in plasma accelerators.

    PubMed

    Bingham, Robert

    2006-03-15

    In this article, we present the underlying physics and the present status of high gradient and high-energy plasma accelerators. With the development of compact short pulse high-brightness lasers and electron and positron beams, new areas of studies for laser/particle beam-matter interactions is opening up. A number of methods are being pursued vigorously to achieve ultra-high-acceleration gradients. These include the plasma beat wave accelerator (PBWA) mechanism which uses conventional long pulse ( approximately 100 ps) modest intensity lasers (I approximately 10(14)-10(16) W cm(-2)), the laser wakefield accelerator (LWFA) which uses the new breed of compact high-brightness lasers (<1 ps) and intensities >10(18) W cm(-2), self-modulated laser wakefield accelerator (SMLWFA) concept which combines elements of stimulated Raman forward scattering (SRFS) and electron acceleration by nonlinear plasma waves excited by relativistic electron and positron bunches the plasma wakefield accelerator. In the ultra-high intensity regime, laser/particle beam-plasma interactions are highly nonlinear and relativistic, leading to new phenomenon such as the plasma wakefield excitation for particle acceleration, relativistic self-focusing and guiding of laser beams, high-harmonic generation, acceleration of electrons, positrons, protons and photons. Fields greater than 1 GV cm(-1) have been generated with monoenergetic particle beams accelerated to about 100 MeV in millimetre distances recorded. Plasma wakefields driven by both electron and positron beams at the Stanford linear accelerator centre (SLAC) facility have accelerated the tail of the beams. PMID:16483948

  19. Radiation from Ag high energy density Z-pinch plasmas and applications to lasing

    SciTech Connect

    Weller, M. E. Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Shrestha, I.; Stafford, A.; Keim, S. F.; Shlyaptseva, V. V.; Osborne, G. C.; Petkov, E. E.; Apruzese, J. P.; Giuliani, J. L.; Chuvatin, A. S.

    2014-03-15

    Silver (Ag) wire arrays were recently introduced as efficient x-ray radiators and have been shown to create L-shell plasmas that have the highest electron temperature (>1.8 keV) observed on the Zebra generator so far and upwards of 30 kJ of energy output. In this paper, results of single planar wire arrays and double planar wire arrays of Ag and mixed Ag and Al that were tested on the UNR Zebra generator are presented and compared. To further understand how L-shell Ag plasma evolves in time, a time-gated x-ray spectrometer was designed and fielded, which has a spectral range of approximately 3.5–5.0 Å. With this, L-shell Ag as well as cold L{sub α} and L{sub β} Ag lines was captured and analyzed along with photoconducting diode (PCD) signals (>0.8 keV). Along with PCD signals, other signals, such as filtered XRD (>0.2 keV) and Si-diodes (SiD) (>9 keV), are analyzed covering a broad range of energies from a few eV to greater than 53 keV. The observation and analysis of cold L{sub α} and L{sub β} lines show possible correlations with electron beams and SiD signals. Recently, an interesting issue regarding these Ag plasmas is whether lasing occurs in the Ne-like soft x-ray range, and if so, at what gains? To help answer this question, a non-local thermodynamic equilibrium (LTE) kinetic model was utilized to calculate theoretical lasing gains. It is shown that the Ag L-shell plasma conditions produced on the Zebra generator at 1.7 maximum current may be adequate to produce gains as high as 6 cm{sup −1} for various 3p → 3s transitions. Other potential lasing transitions, including higher Rydberg states, are also included in detail. The overall importance of Ag wire arrays and plasmas is discussed.

  20. Radiation from Ag high energy density Z-pinch plasmas and applications to lasing

    NASA Astrophysics Data System (ADS)

    Weller, M. E.; Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Shrestha, I.; Apruzese, J. P.; Giuliani, J. L.; Chuvatin, A. S.; Stafford, A.; Keim, S. F.; Shlyaptseva, V. V.; Osborne, G. C.; Petkov, E. E.

    2014-03-01

    Silver (Ag) wire arrays were recently introduced as efficient x-ray radiators and have been shown to create L-shell plasmas that have the highest electron temperature (>1.8 keV) observed on the Zebra generator so far and upwards of 30 kJ of energy output. In this paper, results of single planar wire arrays and double planar wire arrays of Ag and mixed Ag and Al that were tested on the UNR Zebra generator are presented and compared. To further understand how L-shell Ag plasma evolves in time, a time-gated x-ray spectrometer was designed and fielded, which has a spectral range of approximately 3.5-5.0 Å. With this, L-shell Ag as well as cold Lα and Lβ Ag lines was captured and analyzed along with photoconducting diode (PCD) signals (>0.8 keV). Along with PCD signals, other signals, such as filtered XRD (>0.2 keV) and Si-diodes (SiD) (>9 keV), are analyzed covering a broad range of energies from a few eV to greater than 53 keV. The observation and analysis of cold Lα and Lβ lines show possible correlations with electron beams and SiD signals. Recently, an interesting issue regarding these Ag plasmas is whether lasing occurs in the Ne-like soft x-ray range, and if so, at what gains? To help answer this question, a non-local thermodynamic equilibrium (LTE) kinetic model was utilized to calculate theoretical lasing gains. It is shown that the Ag L-shell plasma conditions produced on the Zebra generator at 1.7 maximum current may be adequate to produce gains as high as 6 cm-1 for various 3p → 3s transitions. Other potential lasing transitions, including higher Rydberg states, are also included in detail. The overall importance of Ag wire arrays and plasmas is discussed.

  1. The phase-lock dynamics of the laser wakefield acceleration with an intensity-decaying laser pulse

    SciTech Connect

    Li, Wentao; Liu, Jiansheng Wang, Wentao; Zhang, Zhijun; Chen, Qiang; Tian, Ye; Qi, Rong; Yu, Changhai; Wang, Cheng; Li, Ruxin Xu, Zhizhan; Tajima, T.

    2014-03-03

    An electron beam with the maximum energy extending up to 1.8 GeV, much higher than the dephasing limit, is experimentally obtained in the laser wakefield acceleration with the plasma density of 3.5 × 10{sup 18} cm{sup −3}. With particle in cell simulations and theoretical analysis, we find that the laser intensity evolution plays a major role in the enhancement of the electron energy gain. While the bubble length decreases due to the intensity-decay of the laser pulse, the phase of the electron beam in the wakefield can be locked, which contributes to the overcoming of the dephasing. Moreover, the laser intensity evolution is described for the phase-lock acceleration of electrons in the uniform plasma, confirmed with our own simulation. Since the decaying of the intensity is unavoidable in the long distance propagation due to the pump depletion, the energy gain of the high energy laser wakefield accelerator can be greatly enhanced if the current process is exploited.

  2. Donut wakefields generated by intense laser pulses with orbital angular momentum

    SciTech Connect

    Mendonça, J. T.; Vieira, J.

    2014-03-15

    We study the wakefields produced in a plasma by intense laser pulses carrying a finite amount of orbital angular momentum. We show that these wakefields have new donut-like shapes, different from those usually considered in the literature, and could be used to accelerate hollow electron beams. Wakefields with a more general angular structure were also considered. The analytical solutions are corroborated by relativistic particle-in-cell simulations using OSIRIS.

  3. Laser-Foil Acceleration of High-Energy Protons in Small-Scale Plasma Gradients

    SciTech Connect

    Fuchs, J.; Audebert, P.; Cecchetti, C. A.; Borghesi, M.; Romagnani, L.; Grismayer, T.; Mora, P.; D'Humieres, E.; Sentoku, Y.; Antici, P.; Atzeni, S.; Schiavi, A.; Pipahl, A.; Toncian, T.; Willi, O.

    2007-07-06

    Proton beams laser accelerated from thin foils are studied for various plasma gradients on the foil rear surface. The beam maximum energy and spectral slope reduce with the gradient scale length, in good agreement with numerical simulations. The results also show that the jxB mechanism determines the temperature of the electrons driving the ion expansion. Future ion-driven fast ignition of fusion targets will use multikilojoule petawatt laser pulses, the leading part of which will induce target preheat. Estimates based on the data show that this modifies by less than 10% the ion beam parameters.

  4. Laser-foil acceleration of high-energy protons in small-scale plasma gradients.

    PubMed

    Fuchs, J; Cecchetti, C A; Borghesi, M; Grismayer, T; d'Humières, E; Antici, P; Atzeni, S; Mora, P; Pipahl, A; Romagnani, L; Schiavi, A; Sentoku, Y; Toncian, T; Audebert, P; Willi, O

    2007-07-01

    Proton beams laser accelerated from thin foils are studied for various plasma gradients on the foil rear surface. The beam maximum energy and spectral slope reduce with the gradient scale length, in good agreement with numerical simulations. The results also show that the jxB mechanism determines the temperature of the electrons driving the ion expansion. Future ion-driven fast ignition of fusion targets will use multikilojoule petawatt laser pulses, the leading part of which will induce target preheat. Estimates based on the data show that this modifies by less than 10% the ion beam parameters. PMID:17678159

  5. A high-resolution imaging x-ray crystal spectrometer for high energy density plasmas

    SciTech Connect

    Chen, Hui E-mail: bitter@pppl.gov; Magee, E.; Nagel, S. R.; Park, J.; Schneider, M. B.; Stone, G.; Williams, G. J.; Beiersdorfer, P.; Bitter, M. E-mail: bitter@pppl.gov; Hill, K. W.; Kerr, S.

    2014-11-15

    Adapting a concept developed for magnetic confinement fusion experiments, an imaging crystal spectrometer has been designed and tested for HED plasmas. The instrument uses a spherically bent quartz [211] crystal with radius of curvature of 490.8 mm. The instrument was tested at the Titan laser at Lawrence Livermore National Laboratory by irradiating titanium slabs with laser intensities of 10{sup 19}–10{sup 20} W/cm{sup 2}. He-like and Li-like Ti lines were recorded, from which the spectrometer performance was evaluated. This spectrometer provides very high spectral resolving power (E/dE > 7000) while acquiring a one-dimensional image of the source.

  6. Raman backscatter as a remote laser power sensor in high-energy-density plasmas.

    PubMed

    Moody, J D; Strozzi, D J; Divol, L; Michel, P; Robey, H F; LePape, S; Ralph, J; Ross, J S; Glenzer, S H; Kirkwood, R K; Landen, O L; MacGowan, B J; Nikroo, A; Williams, E A

    2013-07-12

    Stimulated Raman backscatter is used as a remote sensor to quantify the instantaneous laser power after transfer from outer to inner cones that cross in a National Ignition Facility (NIF) gas-filled hohlraum plasma. By matching stimulated Raman backscatter between a shot reducing outer versus a shot reducing inner power we infer that about half of the incident outer-cone power is transferred to inner cones, for the specific time and wavelength configuration studied. This is the first instantaneous nondisruptive measure of power transfer in an indirect drive NIF experiment using optical measurements. PMID:23889410

  7. Current Distribution Characterization and Circuit Analysis of a High Energy Pulsed Plasma Deflagration

    NASA Astrophysics Data System (ADS)

    Loebner, Keith; Poehlmann, Flavio; Cappelli, Mark

    2012-10-01

    Measurements and analysis of the transient current density within a coaxial electromagnetic plasma accelerator operating in a pulsed deflagration mode are presented. Current measurements are performed using an axial array of dual-Rogowksi coils in a balanced circuit configuration. An equivalent circuit model of the accelerator is formulated and compared with experimental data. Current distribution measurements were carried out over a wide range of operating conditions and compared with the equivalent circuit model in order to determine the governing physics of the discharge and verify the existence of a deflagration at all tested conditions.

  8. Measurements of turbulent mixing due to Kelvin-Helmholtz instability in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Smalyuk, V. A.; Hurricane, O. A.; Hansen, J. F.; Langstaff, G.; Martinez, D.; Park, H.-S.; Raman, K.; Remington, B. A.; Robey, H. F.; Schilling, O.; Wallace, R.; Elbaz, Y.; Shimony, A.; Shvarts, D.; Di Stefano, C.; Drake, R. P.; Marion, D.; Krauland, C. M.; Kuranz, C. C.

    2013-03-01

    Kelvin-Helmholtz (KH) turbulent mixing measurements were performed in experiments on the OMEGA Laser Facility [T.R. Boehly et al., Opt. Commun. 133 (1997) 495]. In these experiments, laser-driven shock waves propagated through low-density plastic foam placed on top of a higher-density plastic foil. Behind the shock front, lower-density foam plasma flowed over the higher-density plastic plasma. The interface between the foam and plastic was KH unstable. The experiments were performed with pre-imposed, sinusoidal 2D perturbations, and broadband 3D perturbations due to surface roughness at the interface between the plastic and foam. KH instability growth was measured using X-ray, point-projection radiography. The mixing layer caused by the KH instability with layer width up to ˜100 μm was observed at a location ˜1 mm behind the shock front. The measured mixing layer width was in good agreement with simulations using a K-L turbulent mixing model in the two-dimensional ARES hydrodynamics code. In the definition of the K-L model K stands for the specific turbulent kinetic (K) energy, and L for the scale length (L) of the turbulence.

  9. THE IRON PROJECT: High-Energy-Density (HED) Plasma Opacities and Diagnostics

    NASA Astrophysics Data System (ADS)

    Gokce, Yasin; Bostelmann, T.; Nahar, S.; Pradhan, A.; Bailey, J.

    2014-05-01

    The composition of the Sun, the benchmark for astronomical objects, has been a longstanding problem for the last few decades. The abundances of common elements in the Sun, such as, carbon, nitrogen, oxygen, supported by helioseismology are at discrepant by up to 50% higher from those derived from state-of-the-art spectroscopy and elaborate 3-D radiative transfer models. The uncertainty is compounded by recent experiments at the Sandia National Laboratory on the Z-pinch inertial confinement fusion device which is able to re-create the HED plasma conditions existing at the solar radiative-convection zone boundary. Measured monochromatic iron opacities disagree with all known theoretical opacities models. The abundance problem and potential solution are related to radiative opacities. Uur continued investigation of the problem will be presented. We will also present collision strengths of carbon-like silicon which shows new resonances in the low energy region introduced by relativistic effects in the Breit-Pauli R-matrix method. Line intensity ratios of this ion, obtained for optically allowed transitions as seen in astronomical spectra, are the diagnostics for the density and termperature of the plasmas will be reported. Partial support of NSF, DOE.

  10. High energy and density plasmas produced by UHI interaction and buried-layer targets

    NASA Astrophysics Data System (ADS)

    Baton, Sophie; Dervieux, Vincent; Loupias, Berenice; Blancard, Christophe; Bowen, Christopher; Gremillet, Laurent; Lecherbourg, Ludovic; Pain, Jean-Christophe; Reverdin, Charles; Renaudin, Patrick; Rousseaux, Christophe; Silvert, Virginie; Allan, Peter; Brown, Colin; Hill, Matthew; Hoarty, David

    2013-10-01

    The radiative properties of hot (hundreds of eV), dense (rho ~ rhosol) plasmas are of interest in several research fields including inertial confinement fusion and astrophysics. The achieved plasma conditions (temperature, density, LTE/NLTE) have to be well characterized to constrain equation of state and opacity models. Ongoing progresses in ultra-intense laser facilities have led to the experimental demonstration of laser-driven isochoric heating of solid-density, micrometer targets to high temperatures (>100 eV). Here, we report on a recent experiment carried out with the ELFIE at LULI. The ultra-fast heating of various targets (multi-layered and reduced-mass targets) by using different laser conditions (1w and 2w) was inferred from their thermal x-ray emission. Two main diagnostics were used: a time-integrated Von Hamos crystal spectrometer and a toroidal crystal spectrometer coupled to an x-ray streak camera. According to combined atomic physics and hydrodynamic calculations, the measurements are consistent with densities rho ~ rhosol and maximum temperatures T ~ 450 eV.

  11. Talbot-Lau based Moiré deflectometry with non-coherent sources as potential High Energy Density plasma diagnostic

    SciTech Connect

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2013-10-28

    X-ray phase-contrast radiography could better characterize highly localized density gradients expected in High Energy Density (HED) plasma experiments than conventional attenuation radiography. In particular, the Talbot-Lau (TL) grating interferometer, which works with extended and polychromatic x-ray sources, is a potentially attractive HED diagnostic due to its high sensitivity. For HED characterization the TL setup and imaging techniques must be changed from the recently studied medical system. The object magnification must be increased greatly in order to resolve μm scale gradients while the Talbot magnification must be increased in order to keep the gratings away from the plasma. Additionally, techniques for retrieving the density profile from a single plasma image must be developed. We thus study the performance of high magnification TL interferometers, in conjunction with Moiré fringe deflectometry for single image phase retrieval. The results show a very good interferometer contrast (≤30%) at high magnification. The Moiré technique enables measuring both sharp and mild density gradients with good accuracy and spatial resolution. Both the laboratory and simulation studies indicate that the TL based Moiré deflectometry is more sensitive than the propagation phase-contrast method when utilizing an extended x-ray source (∼80 μm). In HED experiments this would allow for less demanding X-ray backlighters than those used at present.

  12. Talbot-Lau based Moiré deflectometry with non-coherent sources as potential High Energy Density plasma diagnostic

    NASA Astrophysics Data System (ADS)

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2013-10-01

    X-ray phase-contrast radiography could better characterize highly localized density gradients expected in High Energy Density (HED) plasma experiments than conventional attenuation radiography. In particular, the Talbot-Lau (TL) grating interferometer, which works with extended and polychromatic x-ray sources, is a potentially attractive HED diagnostic due to its high sensitivity. For HED characterization the TL setup and imaging techniques must be changed from the recently studied medical system. The object magnification must be increased greatly in order to resolve μm scale gradients while the Talbot magnification must be increased in order to keep the gratings away from the plasma. Additionally, techniques for retrieving the density profile from a single plasma image must be developed. We thus study the performance of high magnification TL interferometers, in conjunction with Moiré fringe deflectometry for single image phase retrieval. The results show a very good interferometer contrast (≤30%) at high magnification. The Moiré technique enables measuring both sharp and mild density gradients with good accuracy and spatial resolution. Both the laboratory and simulation studies indicate that the TL based Moiré deflectometry is more sensitive than the propagation phase-contrast method when utilizing an extended x-ray source (˜80 μm). In HED experiments this would allow for less demanding X-ray backlighters than those used at present.

  13. Monoenergetic proton backlighter for measuring E and B fields and for radiographing implosions and high-energy density plasmas (invited)

    SciTech Connect

    Li, C. K.; Seguin, F. H.; Frenje, J. A.; Rygg, J. R.; Petrasso, R. D.; Town, R. P. J.; Amendt, P. A.; Hatchett, S. P.; Landen, O. L.; Mackinnon, A. J.; Patel, P. K.; Smalyuk, V. A.; Knauer, J. P.; Sangster, T. C.; Stoeckl, C.

    2006-10-15

    A novel monoenergetic proton backlighter source and matched imaging detector have been utilized on the OMEGA laser system to study electric (E) and magnetic (B) fields generated by laser-plasma interactions and will be utilized in the future to radiograph implosions and high-energy density (HED) plasmas. The backlighter consists of an imploding glass microballoon with D {sup 3}He fuel, producing 14.7 MeV D {sup 3}He protons and 3 MeV DD protons that are then passed through a mesh that divides the protons into beamlets. For quantitative study of E+B field structure, monoenergetic protons have several unique advantages compared to the broad energy spectrum used in previous experiments. Recent experiments have been performed with a single laser beam (intensity of {approx}10{sup 14} W/cm{sup 2}) interacting with a CH foil, and B fields of {approx}0.5 MG and E fields of {approx}1.5x10{sup 8} V/m have been measured using proton deflectometry. LASNEX simulations are being used to interpret these experiments. Additional information will also be presented on the application of this technique to measuring E and B fields associated with Hohlraums and directly driven implosions, to radiographically mapping the areal density ({rho}R) distribution in imploded capsules, and to radiographing HED plasmas.

  14. High Energy Plasmas in the Surroundings of Black Holes: Composite Disk Structures and Characteristic Modes*

    NASA Astrophysics Data System (ADS)

    Coppi, Bruno

    2009-11-01

    Theoretically finding of composite disk structures around compact objects (e.g. black holes) and recent experimental observations indicate that highly coherent and dynamically important magnetic field configurations exist in the core of these structures [1]. These coherent configurations provide a means to resolve the ``accretion paradox'' for a magnetized disk [2] while the formation of jets that are emitted in the close vicinity of the compact object is related to them. The absence of vigorous accretion activity in the presence of black holes in old galaxies can be attributed to the loss of the surrounding coherent magnetic configurations during their history. As for relevant dynamics, axisymmetric (ballooning) modes as well as tri-dimensional spirals can be excited from disks with a ``seed'' magnetic field, under the effects of differential rotation and of the vertical plasma pressure gradient. The properties of these spirals are strongly dependent on their vertical structure. Axisymmetric modes can produce vertical flows of thermal energy [3] and particles in opposing directions that can be connected to the winds emanating from disks in Active Galactic Nuclei (AGN's). A similarity with the effects of temperature gradient driven modes in magnetically confined laboratory plasmas is pointed out. Spiral modes that are oscillatory in time and in the radial direction can produce transport of angular momentum toward the outer region of the disk structure, a necessary process for the occurrence of accretion [3]. The excitation of radially localized density spirals co-rotating with the plasma, at a distance related to the Schwartzchild radius RS=2GM*/c^2 where M* is the black hole mass, is proposed [4] as the explanation for High Frequency Quasi Periodic Oscillations (HFQPOs) of non-thermal X-ray emission from compact objects. *Sponsored in part by the U.S. Department of Energy.[4pt] [1] B. Coppi and F. Rousseau Ap. J. 641 458 (2006)[0pt] [2] B. Coppi to be published in

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

    SciTech Connect

    Sohbatzadeh, F.; Akou, H.

    2013-04-15

    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.

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

    NASA Astrophysics Data System (ADS)

    Sohbatzadeh, F.; Akou, H.

    2013-04-01

    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 1018W/cm2, an intense laser pulse with initial positive chirp generates larger wake field compared to negatively and un-chirped pulses.

  17. High-energy-density electron jet generation from an opening gold cone filled with near-critical-density plasma

    SciTech Connect

    Yu, T. P. Shao, F. Q.; Zou, D. B.; Ge, Z. Y.; Zhang, G. B.; Wang, W. Q.; Li, X. H.; Liu, J. X.; Ouyang, J. M.; Yu, W.; Luan, S. X.; Wang, J. W.; Wong, A. Y.

    2015-01-14

    By using two-dimensional particle-in-cell simulations, we propose a scheme for strong coupling of a petawatt laser with an opening gold cone filled with near-critical-density plasmas. When relevant parameters are properly chosen, most laser energy can be fully deposited inside the cone with only 10% leaving the tip opening. Due to the asymmetric ponderomotive acceleration by the strongly decayed laser pulse, high-energy-density electrons with net laser energy gain are accumulated inside the cone, which then stream out of the tip opening continuously, like a jet. The jet electrons are fully relativistic, with speeds around 0.98−0.998 c and densities at 10{sup 20}/cm{sup 3} level. The jet can keep for a long time over 200 fs, which may have diverse applications in practice.

  18. Observation of a high-energy tail in ion energy distribution in the cylindrical Hall thruster plasma

    SciTech Connect

    Lim, Youbong; Kim, Holak; Choe, Wonho Lee, Seung Hun; Seon, Jongho; Lee, Hae June

    2014-10-15

    A novel method is presented to determine populations and ion energy distribution functions (IEDFs) of individual ion species having different charge states in an ion beam from the measured spectrum of an E × B probe. The inversion of the problem is performed by adopting the iterative Tikhonov regularization method with the characteristic matrices obtained from the calculated ion trajectories. In a cylindrical Hall thruster plasma, an excellent agreement is observed between the IEDFs by an E × B probe and those by a retarding potential analyzer. The existence of a high-energy tail in the IEDF is found to be mainly due to singly charged Xe ions, and is interpreted in terms of non-linear ion acceleration.

  19. Effects of high energy photon emissions in laser generated ultra-relativistic plasmas: Real-time synchrotron simulations

    SciTech Connect

    Wallin, Erik; Gonoskov, Arkady; Marklund, Mattias

    2015-03-15

    We model the emission of high energy photons due to relativistic charged particle motion in intense laser-plasma interactions. This is done within a particle-in-cell code, for which high frequency radiation normally cannot be resolved due to finite time steps and grid size. A simple expression for the synchrotron radiation spectra is used together with a Monte-Carlo method for the emittance. We extend previous work by allowing for arbitrary fields, considering the particles to be in instantaneous circular motion due to an effective magnetic field. Furthermore, we implement noise reduction techniques and present validity estimates of the method. Finally, we perform a rigorous comparison to the mechanism of radiation reaction, and find the emitted energy to be in excellent agreement with the losses calculated using radiation reaction.

  20. Observation of a high-energy tail in ion energy distribution in the cylindrical Hall thruster plasma

    NASA Astrophysics Data System (ADS)

    Lim, Youbong; Kim, Holak; Choe, Wonho; Lee, Seung Hun; Seon, Jongho; Lee, Hae June

    2014-10-01

    A novel method is presented to determine populations and ion energy distribution functions (IEDFs) of individual ion species having different charge states in an ion beam from the measured spectrum of an E × B probe. The inversion of the problem is performed by adopting the iterative Tikhonov regularization method with the characteristic matrices obtained from the calculated ion trajectories. In a cylindrical Hall thruster plasma, an excellent agreement is observed between the IEDFs by an E × B probe and those by a retarding potential analyzer. The existence of a high-energy tail in the IEDF is found to be mainly due to singly charged Xe ions, and is interpreted in terms of non-linear ion acceleration.

  1. High-energy-density electron beam from interaction of two successive laser pulses with subcritical-density plasma

    NASA Astrophysics Data System (ADS)

    Wang, J. W.; Yu, W.; Yu, M. Y.; Xu, H.; Ju, J. J.; Luan, S. X.; Murakami, M.; Zepf, M.; Rykovanov, S.

    2016-02-01

    It is shown by particle-in-cell simulations that a narrow electron beam with high energy and charge density can be generated in a subcritical-density plasma by two consecutive laser pulses. Although the first laser pulse dissipates rapidly, the second pulse can propagate for a long distance in the thin wake channel created by the first pulse and can further accelerate the preaccelerated electrons therein. Given that the second pulse also self-focuses, the resulting electron beam has a narrow waist and high charge and energy densities. Such beams are useful for enhancing the target-back space-charge field in target normal sheath acceleration of ions and bremsstrahlung sources, among others.

  2. EXPERIMENTS ON LASER AND E-BEAM TRANSPORT AND INTERACTION IN A PLASMA CHANNEL.

    SciTech Connect

    POGORELSKY,I.V.; PAVLISHIN,I.V.; BEN-ZVI,I.; ET AL.

    2004-09-15

    An ablative capillary discharge is installed into a linac beamline and serves as a plasma source for generating and characterizing wakefields. Simultaneously, the electron beam is used as a tool for plasma diagnostics. A high-energy picosecond CO{sub 2} laser channeled within the same capillary strongly affects a counterpropagating electron beam. These observations, supported with simulations, suggest the possibility of manipulating relativistic electron beams by steep plasma channels ponderomotively produced by a laser.

  3. Experiments on Laser and e-Beam Transport and Interaction in a Plasma Channel

    SciTech Connect

    Pogorelsky, I.V.; Pavlishin, I.V.; Ben-Zvi, I.; Yakimenko, V.; Kumita, T.; Kamiya, Y.; Zigler, A.; Diublov, A.; Andreev, N.; Bobrova, N.; Sasorov, P.

    2004-12-07

    An ablative capillary discharge is installed into a linac beamline and serves as a plasma source for generating and characterizing wakefields. Simultaneously, the electron beam is used as a tool for plasma diagnostics. A high-energy picosecond CO2 laser channeled within the same capillary strongly affects a counterpropagating electron beam. These observations, supported with simulations, suggest the possibility of manipulating relativistic electron beams by steep plasma channels ponderomotively produced by a laser.

  4. High energy density capacitors for vacuum operation with a pulsed plasma load

    NASA Technical Reports Server (NTRS)

    Guman, W. J.

    1976-01-01

    Results of the effort of designing, fabricating, and testing of a 40 joules/lb (88.2 joules/Kg) high voltage energy storage capacitor suitable for operating a pulsed plasma thruster in a vacuum environment for millions of pulses are presented. Using vacuum brazing and heli-arc welding techniques followed by vacuum and high pressure helium leak tests it was possible to produce a hermetically sealed relatively light weight enclosure for the dielectric system. An energy density of 40 joules/lb was realized with a KF-polyvinylidene fluoride dielectric system. One capacitor was D.C. life tested at 4 KV (107.8 joules/lb) for 2,000 hours before it failed. Another exceeded 2,670 hours without failure at 38.3 joules/lb. Pulse life testing in a vacuum exceeded 300,000 discharges with testing still in progress. The D.C. life test data shows a small decrease in capacitance and an increase in dissipation factor with time. Heat transfer from the load to the capacitor must also be considered besides the self-heat generated by the capacitor.

  5. Undulator radiation driven by laser-wakefield accelerator electron beams

    NASA Astrophysics Data System (ADS)

    Wiggins, S. M.; Anania, M. P.; Welsh, G. H.; Brunetti, E.; Cipiccia, S.; Grant, P. A.; Reboredo, D.; Manahan, G.; Grant, D. W.; Jaroszynski, D. A.

    2015-05-01

    The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme is developing laserplasma accelerators for the production of ultra-short electron bunches with subsequent generation of coherent, bright, short-wavelength radiation pulses. The new Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) will develop a wide range of applications utilising such light sources. Electron bunches can be propagated through a magnetic undulator with the aim of generating fully coherent free-electron laser (FEL) radiation in the ultra-violet and Xrays spectral ranges. Demonstration experiments producing spontaneous undulator radiation have been conducted at visible and extreme ultra-violet wavelengths but it is an on-going challenge to generate and maintain electron bunches of sufficient quality in order to stimulate FEL behaviour. In the ALPHA-X beam line experiments, a Ti:sapphire femtosecond laser system with peak power 20 TW has been used to generate electron bunches of energy 80-150 MeV in a 2 mm gas jet laser-plasma wakefield accelerator and these bunches have been transported through a 100 period planar undulator. High peak brilliance, narrow band spontaneous radiation pulses in the vacuum ultra-violet wavelength range have been generated. Analysis is provided with respect to the magnetic quadrupole beam transport system and subsequent effect on beam emittance and duration. Requirements for coherent spontaneous emission and FEL operation are presented.

  6. Laser wakefield accelerator based light sources: potential applications and requirements

    SciTech Connect

    Albert, F.; Thomas, A. G.; Mangles, S. P.D.; Banerjee, S.; Corde, S.; Flacco, A.; Litos, M.; Neely, D.; Viera, J.; Najmudin, Z.; Bingham, R.; Joshi, C.; Katsouleas, T.

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  7. A 1 GeV Laser Wakefield Accelerator: Experimental Progress at the l'OASIS Facility of LBNL

    NASA Astrophysics Data System (ADS)

    Leemans, W. P.; Geddes, C. G. R.; Toth, C. S.; van Tilborg, J.; Nagler, B.; Michel, P.; Nakamura, K.; Esarey, E.; Schroeder, C. B.; Gonsalves, A.; Spence, D. J.; Hooker, S. M.; Filip, C.; Cowan, T.

    2004-11-01

    Experimental progress towards a 1 GeV laser-driven plasma-based accelerator will be discussed. The design of the 1 GeV accelerator module consists of two components: (1) an all-optical electron injector and (2) a plasma channel for laser guiding and electron acceleration to high energy via the laser wakefield acceleration (LWFA) mechanism. Experimental results on the injector development include the demonstration of laser guiding at relativistic intensities in preformed plasmas and production of quasi-monochromatic electron beams with energy around 100 MeV. Progress on guiding 100 TW laser pulses in capillary-discharge-based plasma channels will be discussed and integration of these channels with the all-optical injector will be reported.

  8. Prospects of turbulence studies in high-energy density laser-generated plasma: Numerical investigations in two dimensions

    NASA Astrophysics Data System (ADS)

    Handy, Timothy; Plewa, Tomasz; Drake, R. Paul; Zhiglo, Andrey

    2014-06-01

    We investigate the possibility of generating and studying turbulence in plasma by means of high-energy density laser-driven experiments. Our focus is to create supersonic, self-magnetized turbulence with characteristics that resemble those found in the interstellar medium (ISM). We consider a target made of a spherical core surrounded by a shell made of denser material. The shell is irradiated by a sequence of laser pulses sending inward-propagating shocks that convert the inner core into plasma and create turbulence. In the context of the evolution of the ISM, the shocks play the role of supernova remnant shocks and the core represents the ionized interstellar medium. We consider the effects of both pre-existing and self-generating magnetic fields and study the evolution of the system by means of two-dimensional numerical simulations. We find that the evolution of the turbulent core is generally, subsonic with rms-Mach number Mrms ≈ 0.2. We observe an isotropic, turbulent velocity field with an inertial range power spectra of P(k) ∝ k-2.3. We account for the effects of self-magnetization and find that the resulting magnetic field has characteristic strength ≈3 × 104 G. The corresponding plasma β is about 1 × 104-1 × 105, indicating that the magnetic field does not play an important role in the dynamical evolution of the system. The natural extension of this work is to study the system evolution in three-dimensions, with various laser drive configurations, and targets with shells and cores of different masses. The latter modification may help to increase the turbulent intensity and possibly create transonic turbulence. One of the key challenges is to obtain transonic turbulent conditions in a quasi-steady state environment.

  9. Nonlinear dynamics of circularly polarized laser pulse propagating in a magnetized plasma with superthermal ions and mixed nonthermal high-energy tail electrons distributions

    NASA Astrophysics Data System (ADS)

    Etemadpour, R.; Sepehri Javan, N.; Dorranian, D.

    2016-05-01

    The nonlinear dynamics of a circularly polarized laser pulse propagating in the magnetized plasmas whose constituents are superthermal ions and mixed nonthermal high-energy tail electrons is studied theoretically. A nonlinear equation which describes the dynamics of the slowly varying amplitude is obtained using a relativistic two-fluid model. Based on this nonlinear equation and taking into account some nonlinear phenomena such as modulational instability, self-focusing and soliton formation are investigated. Effect of the magnetized plasma with superthermal ions and mixed nonthermal high-energy tail electrons on these phenomena is considered. It is shown that the nonthermality and superthermality of particles can substantially change the nonlinearity of medium.

  10. Observation of a Kelvin-Helmholtz Instability in a High-Energy-Density Plasma on the Omega Laser

    SciTech Connect

    Harding, E C; Hansen, J F; Hurricane, O A; Drake, R P; Robey, H F; Kuranz, C C; Remington, B A; Bono, M J; Grosskopf, M J; Gillespie, R S

    2009-02-12

    A laser initiated experiment is described in which an unstable plasma shear layer is produced by driving a blast wave along a plastic surface with sinusoidal perturbations. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vortices characteristic of the Kelvin-Helmholtz (KH) instability. The experiment used x ray radiography to capture the first well-resolved images of KH vortices in a high-energy-density plasma, and possibly the first images of transonic shocks generated by large-scale structures in a shear layer. The physical processes governing the evolution of a stratified fluid flow with a large velocity gradient (i.e., a shear flow) are of fundamental interest to a wide range of research areas including combustion, inertial confinement fusion (ICF), stellar supernovae, and geophysical fluid dynamics. Traditional experiments have used inclined tanks of fluid to initiate a flow, generally at low Reynolds numbers, or wind tunnels that combine two parallel gas flows at the end of a thin wedge, known as a splitter plate. The splitter plate experiments have explored flows with maximum shear velocities on the order of 10{sup 3} m/s and Reynolds numbers up to 10{sup 6}. Here we report the creation of a novel type of shear flow, achieved by confining a laser driven blast wave in a millimeter-sized shock tube, which produced shear velocities on the order of 10{sup 4} m/s and Reynolds numbers of 10{sup 6} in a plasma. This system enabled the first apparent observation of transonic shocklets, which are small, localized shocks believed to develop in response to a local supersonic flow occurring over a growing perturbation. These shocklets have been predicted previously in simulations, but have never to our knowledge been observed. These experiments are also the first to observe the growth of perturbations by the Kelvin-Helmholtz (KH) instability under high-energy-density (HED) conditions. In all

  11. ULTRA-SHORT X-RAY RADIATION COMING FROM A LASER WAKEFIELD ACCELERATOR

    SciTech Connect

    Leurent, V; Michel, P; Clayton, C E; Pollock, B; Doeppner, T; Wang, T L; Ralph, J; Pak, A; Joshi, C; Tynan, G; Divol, L; Palastro, J P; Glenzer, S H; Froula, D H

    2008-06-17

    A Laser Wakefield Accelerator (LWFA) is under development at Lawrence Livermore National Laboratory (LLNL) to produce electron bunches with GeV class energy and energy spreads of a few-percent. The ultimate goal is to provide a bright and compact photon source for high energy density physics. The interaction of a high power (200 TW), short pulse (50 fs) laser with neutral He gas can generate quasi-monoenergetic electrons beams at energies up to 1 GeV [1]. The laser pulse can be self-guided over a dephasing length of 1 cm (for a plasma density of 1.5 x 10{sup 18} cm{sup -3}) overcoming the limitation of vacuum diffraction. Betatron radiation is emitted while the accelerated electrons undergo oscillations in the wakefield electrostatic field. Here we present electron spectrum measurements with a two screen spectrometer allowing to fix the ambiguities due to unknown angle at the plasma exit. We have measured monoenergetic electron beams at energies around 110 MeV. Furthermore a forward directed x-ray beam is observed. The peak energy of the measured synchrotron spectrum is reconstructed based on the energy deposited after different sets of filters, assuming x-ray radiation described in the synchrotron asymptotic limit (SAL) and is found around 6 keV.

  12. Laser Wakefield Acceleration and Fundamental Physics

    SciTech Connect

    Tajima, Toshiki

    2011-06-20

    The laser wakefield acceleration (LWFA) along with the now available laser technology allows us to look at TeV physics both in leptons and hadrons. Near future proof-of-principle experiments for a collider as well as high energy frontier experiments without a collider paradigm are suggested. The intense laser can also contribute to other fundamental physics explorations such as those of dark matter and dark energy candidates. Finally the combination of intense laser and laser-accelerated particles (electrons, hadrons, gammas) provides a further avenue of fundamental research.

  13. Efficient Production of High-energy Nonthermal Particles during Magnetic Reconnection in a Magnetically Dominated Ion-Electron Plasma

    NASA Astrophysics Data System (ADS)

    Guo, Fan; Li, Xiaocan; Li, Hui; Daughton, William; Zhang, Bing; Lloyd-Ronning, Nicole; Liu, Yi-Hsin; Zhang, Haocheng; Deng, Wei

    2016-02-01

    Magnetic reconnection is a leading mechanism for dissipating magnetic energy and accelerating nonthermal particles in Poynting-flux-dominated flows. In this Letter, we investigate nonthermal particle acceleration during magnetic reconnection in a magnetically dominated ion-electron plasma using fully kinetic simulations. For an ion-electron plasma with a total magnetization of {σ }0={B}2/(4π n({m}i+{m}e){c}2), the magnetization for each species is {σ }i˜ {σ }0 and {σ }e˜ ({m}i/{m}e){σ }0, respectively. We have studied the magnetically dominated regime by varying σe = 103-105 with initial ion and electron temperatures {T}i={T}e=5-20{m}e{c}2 and mass ratio {m}i/{m}e=1-1836. The results demonstrate that reconnection quickly establishes power-law energy distributions for both electrons and ions within several (2-3) light-crossing times. For the cases with periodic boundary conditions, the power-law index is 1\\lt s\\lt 2 for both electrons and ions. The hard spectra limit the power-law energies for electrons and ions to be {γ }{be}˜ {σ }e and {γ }{bi}˜ {σ }i, respectively. The main acceleration mechanism is a Fermi-like acceleration through the drift motions of charged particles. When comparing the spectra for electrons and ions in momentum space, the spectral indices sp are identical as predicted in Fermi acceleration. We also find that the bulk flow can carry a significant amount of energy during the simulations. We discuss the implication of this study in the context of Poynting-flux dominated jets and pulsar winds, especially the applications for explaining nonthermal high-energy emissions.

  14. Direct photoetching of polymers using radiation of high energy density from a table-top extreme ultraviolet plasma source

    SciTech Connect

    Barkusky, Frank; Bayer, Armin; Peth, Christian; Mann, Klaus

    2009-01-01

    In order to perform material interaction studies with intense extreme ultraviolet (EUV) radiation, a Schwarzschild mirror objective coated with Mo/Si multilayers was adapted to a compact laser-driven EUV plasma source utilizing a solid Au target. By 10x demagnified imaging of the plasma a maximum pulse energy density of {approx}0.73 J/cm{sup 2} at a wavelength of 13.5 nm can be achieved in the image plane of the objective at a pulse duration of 8.8 ns. In this paper we present EUV photoetching rates measured for polymethyl methacrylate, polycarbonate, and polytetrafluoroethylene at various fluence levels. A linear dependence between etch depth and applied EUV pulse number could be observed without the necessity for any incubation pulses. By evaluating the slope of these data, etch rates were determined, revealing also a linear behavior for low fluences. A threshold energy density could not be observed. The slope of the linear etch regime as well as deviations from the linear trend at higher energy densities are discussed and compared to data known from deep UV laser ablation. Furthermore, the surface roughness of the structured polymers was measured by atomic force microscopy and compared to the nonirradiated polymer surface, indicating a rather smooth etch process (roughness increase of 20%-30%). The different shapes of the etch craters observed for the three polymers at high energy densities can be explained by the measured fluence dependence of the etch rates, having consequences for the proper use of polymer ablation for beam profiling of focused EUV radiation.

  15. A multi-dimensional Vlasov-Fokker-Planck code for arbitrarily anisotropic high-energy-density plasmas

    SciTech Connect

    Tzoufras, M.; Tableman, A.; Tsung, F. S.; Mori, W. B.; Bell, A. R.

    2013-05-15

    To study the kinetic physics of High-Energy-Density Laboratory Plasmas, we have developed the parallel relativistic 2D3P Vlasov-Fokker-Planck code Oshun. The numerical scheme uses a Cartesian mesh in configuration-space and incorporates a spherical harmonic expansion of the electron distribution function in momentum-space. The expansion is truncated such that the necessary angular resolution of the distribution function is retained for a given problem. Finite collisionality causes rapid decay of the high-order harmonics, thereby providing a natural truncation mechanism for the expansion. The code has both fully explicit and implicit field-solvers and employs a linearized Fokker-Planck collision operator. Oshun has been benchmarked against well-known problems, in the highly kinetic limit to model collisionless relativistic instabilities, and in the hydrodynamic limit to recover transport coefficients. The performance of the code, its applicability, and its limitations are discussed in the context of simple problems with relevance to inertial fusion energy.

  16. Argonne`s new Wakefield Test Facility

    SciTech Connect

    Simpson, J.D.

    1992-07-20

    The first phase of a high current, short bunch length electron beam research facility, the AWA, is near completion at Argonne. At the heart of the facility is a photocathode based electron gun and accelerating sections designed to deliver 20 MeV pulses with up to 100 nC per pulse and with pulse lengths of approximately 15 ps (fw). Using a technique similar to that originated at Argonne`s AATF facility, a separate weak probe pulse can be generated and used to diagnose wake effects produced by the intense pulses. Initial planned experiments include studies of plasma wakefields and dielectric wakefield devices, and expect to demonstrate large, useful accelerating gradients (> 100 MeV/m). Later phases of the facility will increase the drive bunch energy to more than 100 MeV to enable acceleration experiments up to the GeV range. Specifications, design details, and commissioning progress are presented.

  17. Plasma-Density-Gradient Injection of Low Absolute-Momentum-Spread Electron Bunches

    SciTech Connect

    Geddes, C. G. R.; Nakamura, K.; Plateau, G. R.; Toth, Cs.; Cormier-Michel, E.; Esarey, E.; Schroeder, C. B.; Leemans, W. P.; Cary, J. R.

    2008-05-30

    Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold in a laser wakefield accelerator, producing stable electron bunches with longitudinal and transverse momentum spreads more than 10 times lower than in previous experiments (0.17 and 0.02 MeV/c FWHM, respectively) and with central momenta of 0.76{+-}0.02 MeV/c. Transition radiation measurements combined with simulations indicated that the bunches can be used as a wakefield accelerator injector to produce stable beams with 0.2 MeV/c-class momentum spread at high energies.

  18. Plasma density gradient injection of low absolute momentum spread electron bunches

    SciTech Connect

    Geddes, C.G.R.; Nakamura, K.; Plateau, G.R.; Toth, Cs.; Cormier-Michel, E.; Esarey, E.; Schroeder, C.B.; Cary, J.R.; Leemans, W.P.

    2007-12-22

    Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold in a laser wakefield accelerator, producing stable electron bunches with longitudinal and transverse momentum spreads more than ten times lower than in previous experiments (0.17 and 0.02 MeV/c FWHM, respectively) and with central momenta of 0.76 +- 0.02 MeV/c. Transition radiation measurements combined with simulations indicated that the bunches can be used as a wakefield accelerator injector to produce stable beams with 0.2 MeV/c-class momentum spread at high energies.

  19. Control of focusing forces and emittances in plasma-based accelerators using near-hollow plasma channels

    SciTech Connect

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

    2013-08-06

    A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth due to Coulomb scattering for high energy physics applications.

  20. Control of focusing forces and emittances in plasma-based accelerators using near-hollow plasma channels

    SciTech Connect

    Schroeder, C. B.; Esarey, E.; Benedetti, C.; Leemans, W. P.

    2013-08-15

    A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth due to Coulomb scattering for high-energy physics applications.

  1. Ultra-high energy probes of classicalization

    SciTech Connect

    Dvali, Gia; Gomez, Cesar E-mail: cesar.gomez@uam.es

    2012-07-01

    Classicalizing theories are characterized by a rapid growth of the scattering cross section. This growth converts these sort of theories in interesting probes for ultra-high energy experiments even at relatively low luminosity, such as cosmic rays or Plasma Wakefield accelerators. The microscopic reason behind this growth is the production of N-particle states, classicalons, that represent self-sustained lumps of soft Bosons. For spin-2 theories this is the quantum portrait of what in the classical limit are known as black holes. We emphasize the importance of this quantum picture which liberates us from the artifacts of the classical geometric limit and allows to scan a much wider landscape of experimentally-interesting quantum theories. We identify a phenomenologically-viable class of spin-2 theories for which the growth of classicalon production cross section can be as efficient as to compete with QCD cross section already at 100TeV energy, signaling production of quantum black holes with graviton occupation number N ∼ 10{sup 4}.

  2. High Energy Density Plasmas (HEDP) for studies of basic nuclear science relevant to Stellar and Big Bang Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Frenje, Johan

    2014-06-01

    Thermonuclear reaction rates and nuclear processes have been explored traditionally by means of conventional accelerator experiments, which are difficult to execute at conditions relevant to stellar nucleosynthesis. Thus, nuclear reactions at stellar energies are often studied through extrapolations from higher-energy data or in low-background underground experiments. Even when measurements are possible using accelerators at relevant energies, thermonuclear reaction rates in stars are inherently different from those in accelerator experiments. The fusing nuclei are surrounded by bound electrons in accelerator experiments, whereas electrons occupy mainly continuum states in a stellar environment. Nuclear astrophysics research will therefore benefit from an enlarged toolkit for studies of nuclear reactions. In this presentation, we report on the first use of High Energy Density Plasmas for studies of nuclear reactions relevant to basic nuclear science, stellar and Big Bang nucleosynthesis. These experiments were carried out at the OMEGA laser facility at University of Rochester and the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, in which spherical capsules were irradiated with powerful lasers to compress and heat the fuel to high enough temperatures and densities for nuclear reactions to occur. Four experiments will be highlighted in this presentation. In the first experiment, the differential cross section for the elastic neutron-triton (n-T) scattering at 14.1 MeV was measured with significantly higher accuracy than achieved in accelerator experiments. In the second experiment, the T(t,2n)4He reaction, a mirror reaction to the 3He(3He,2p)4He reaction that plays an important role in the proton-proton chain that transforms hydrogen into ordinary 4He in stars like our Sun, was studied at energies in the range 15-40 keV. In the third experiment, the 3He+3He solar fusion reaction was studied directly, and in the fourth experiment, we

  3. Self-modulated wakefield acceleration in a centimetre self-guiding channel

    NASA Astrophysics Data System (ADS)

    Kamperidis, C.; Bellei, C.; Bourgeois, N.; Kaluza, M. C.; Krushelnick, K.; Mangles, S. P. D.; Marques, J. R.; Nagel, S. R.; Najmudin, Z.; Najmudin

    2012-08-01

    Self-modulated wakefield acceleration was investigated at densities down to ~4 × 1018 cm-3 by propagating the 50 TW 300 fs LULI laser in helium gas jets at lengths up to 1 cm. Long interaction lengths were achieved by closer matching of the initial focal spot size to the matched spot size for these densities. Electrons with energies extending to 180 MeV were observed in broad energy spectra which show some evidence for non-Maxwellian features at high energy. Two-dimensional PIC simulations indicate that the intial laser pulse breaks up into small pulselets that are eventually compressed and focused inside the first few plasma periods, leading to a `bubble-like' acceleration of electron bunches.

  4. Self-guided laser wakefield acceleration beyond 1 GeV using ionization-induced injection.

    PubMed

    Clayton, C E; Ralph, J E; Albert, F; Fonseca, R A; Glenzer, S H; Joshi, C; Lu, W; Marsh, K A; Martins, S F; Mori, W B; Pak, A; Tsung, F S; Pollock, B B; Ross, J S; Silva, L O; Froula, D H

    2010-09-01

    The concepts of matched-beam, self-guided laser propagation and ionization-induced injection have been combined to accelerate electrons up to 1.45 GeV energy in a laser wakefield accelerator. From the spatial and spectral content of the laser light exiting the plasma, we infer that the 60 fs, 110 TW laser pulse is guided and excites a wake over the entire 1.3 cm length of the gas cell at densities below 1.5 × 10(18) cm(-3). High-energy electrons are observed only when small (3%) amounts of CO2 gas are added to the He gas. Computer simulations confirm that it is the K-shell electrons of oxygen that are ionized and injected into the wake and accelerated to beyond 1 GeV energy. PMID:20867526

  5. Witness gun for the Argonne Wakefield Accelerator

    SciTech Connect

    Power, J.; Simpson, J.; Chojnacki, E.; Konecny, R.

    1995-06-01

    The witness gun for the Argonne Wakefield Accelerator (AWA) is a six-cell, copper, iris loaded, rf photocathode operating at 1.3 GHz in a {pi}/2 standing wave mode. An intense drive beam (up to 100 nC {at} 20 psec FWHM) used in the AWA project to excite (i.e. drive) wakefields in at least two separate test devices: a dielectric loaded cylindrical waveguide and a plasma cell. In both cases a low charge, low emittance witness beam (0.1 nC charge, 1 {pi}mm-mrad 90% physical emittance) is required to probe (i.e. witness) the wakefields left behind by the drive beam. This paper will primarily discuss the recent progress in the construction of the witness gun, while also briefly summarizing the central design issues of the gun. A brief status report on the dielectric witness gun option is also included. The authors conclude with a short statement on the near term future plans.

  6. A Compact Wakefield Measurement Facility

    NASA Astrophysics Data System (ADS)

    Power, J. G.; Gai, W.

    2015-10-01

    The conceptual design of a compact, photoinjector-based, facility for high precision measurements of wakefields is presented. This work is motivated by the need for a thorough understanding of beam induced wakefield effects for any future linear collider. We propose to use a high brightness photoinjector to generate (approximately) a 2 nC, 2 mm-mrad drive beam at 20 MeV to excite wakefields and a second photoinjector to generate a 5 MeV, variably delayed, trailing witness beam to probe both the longitudinal and transverse wakefields in the structure under test. Initial estimates show that we can detect a minimum measurable dipole transverse wake function of 0.1 V/pC/m/mm and a minimum measurable monopole longitudinal wake function of 2.5 V/pC/m. Simulations results for the high brightness photoinjector, calculations of the facility's wakefield measurement resolution, and the facility layout are presented.

  7. Quasimonoenergetic electron beams from laser wakefield acceleration in pure nitrogen

    SciTech Connect

    Mo, M. Z.; Ali, A.; Fedosejevs, R.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.

    2012-02-13

    Quasimonoenergetic electron beams with maximum energy >0.5 GeV and 2 mrad divergence have been generated in pure nitrogen gas via wakefield acceleration with 80 TW, 30 fs laser pulses. Long low energy tail features were typically observed due to continuous ionization injection. The measured peak electron energy decreased with the plasma density, agreeing with the predicted scaling for electrons. The experiments showed a threshold electron density of 3x10{sup 18}cm{sup -3} for self-trapping. Our experiments suggest that pure Nitrogen is a potential candidate gas to achieve GeV monoenergetic electrons using the ionization induced injection scheme for laser wakefield acceleration.

  8. Progress of Laser-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhisa

    2007-07-01

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world. Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called "dream beams on a table top", which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  9. Progress of Laser-Driven Plasma Accelerators

    SciTech Connect

    Nakajima, Kazuhisa

    2007-07-11

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world.Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called ''dream beams on a table top'', which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  10. Pulse propagation and electron acceleration in a corrugated plasma channel.

    PubMed

    Palastro, J P; Antonsen, T M; Morshed, S; York, A G; Milchberg, H M

    2008-03-01

    A preformed plasma channel provides a guiding structure for laser pulses unbound by the intensity thresholds of standard waveguides. The recently realized corrugated plasma channel [Layer, Phys. Rev. Lett. 99, 035001 (2007)] allows for the guiding of laser pulses with subluminal spatial harmonics. These spatial harmonics can be phase matched to high energy electrons, making the corrugated plasma channel ideal for the acceleration of electrons. We present a simple analytic model of pulse propagation in a corrugated plasma channel and examine the laser-electron beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes. PMID:18517531

  11. Generation of overdense and high-energy electron-positron-pair plasmas by irradiation of a thin foil with two ultraintense lasers.

    PubMed

    Chang, H X; Qiao, B; Xu, Z; Xu, X R; Zhou, C T; Yan, X Q; Wu, S Z; Borghesi, M; Zepf, M; He, X T

    2015-11-01

    A scheme for enhanced quantum electrodynamics (QED) production of electron-positron-pair plasmas is proposed that uses two ultraintense lasers irradiating a thin solid foil from opposite sides. In the scheme, under a proper matching condition, in addition to the skin-depth emission of γ-ray photons and Breit-Wheeler creation of pairs on each side of the foil, a large number of high-energy electrons and photons from one side can propagate through it and interact with the laser on the other side, leading to much enhanced γ-ray emission and pair production. More importantly, the created pairs can be collected later and confined to the center by opposite laser radiation pressures when the foil becomes transparent, resulting in the formation of unprecedentedly overdense and high-energy pair plasmas. Two-dimensional QED particle-in-cell simulations show that electron-positron-pair plasmas with overcritical density 10(22) cm(-3) and a high energy of 100s of MeV are obtained with 10 PW lasers at intensities 10(23) W/cm(2), which are of key significance for laboratory astrophysics studies. PMID:26651802

  12. Modeling laser wakefield accelerators in a Lorentz boosted frame

    SciTech Connect

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

    2010-09-15

    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.

  13. Modeling laser wakefield accelerators in a Lorentz boosted frame

    SciTech Connect

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

    2010-06-15

    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.

  14. Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators.

    PubMed

    O'Shea, B D; Andonian, G; Barber, S K; Fitzmorris, K L; Hakimi, S; Harrison, J; Hoang, P D; Hogan, M J; Naranjo, B; Williams, O B; Yakimenko, V; Rosenzweig, J B

    2016-01-01

    There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m(-1)) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m(-1) using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m(-1). Both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons. PMID:27624348

  15. Ion Acceleration by Ultra-intense Laser Pulse Interacting with Double-layer Near-critical Density Plasma

    NASA Astrophysics Data System (ADS)

    Gu, Y. J.; Kong, Q.; Kawata, S.; Izumiyama, T.; Nagashima, T.; Takano, M.; Li, X. F.; Yu, Q.; Barada, D.; Ma, Y. Y.; Wang, P. X.

    2016-03-01

    A collimated ion beam is generated through the interaction between ultra-intense laser pulse and a double layer plasma. The maximum energy is above 1GeV and the total charge of high energy protons is about several tens of nC/μm. The double layer plasma is combined with an underdense plasma and a thin overdense one. The wakefield traps and accelerates a bunch of electrons to high energy in the first underdense slab. When the well collimated electron beam accelerated by the wakefield penetrates through the second overdense slab, it enhances target normal sheath acceleration (TNSA) and breakout after-burner (BOA) regimes. The mechanism is simulated and analyzed by 2.5 dimensional Particle-in-cell code. Compared with single target TNSA or BOA, both the acceleration gradient and energy transfer efficiency are higher in the double layer regime.

  16. Investigation of the 2p_{32}-3d_{52} line emission of Au;{53+}-Au;{69+} for diagnosing high energy density plasmas.

    PubMed

    Brown, G V; Hansen, S B; Träbert, E; Beiersdorfer, P; Widmann, K; Chen, H; Chung, H K; Clementson, J H T; Gu, M F; Thorn, D B

    2008-06-01

    Measurements of the L -shell emission of highly charged gold ions were made under controlled laboratory conditions using the SuperEBIT electron beam ion trap, allowing detailed spectral observations of lines from Fe-like Au53+ through Ne-like Au69+ . Using atomic data from the Flexible Atomic Code, we have identified strong 3d_{52}-->2p_{32} emission features that can be used to diagnose the charge state distribution in high energy density plasmas, such as those found in the laser entrance hole of hot hohlraum radiation sources. We provide collisional-radiative calculations of the average ion charge Z as a function of temperature and density, which can be used to relate charge state distributions inferred from 3d_{52}-->2p_{32} emission features to plasma conditions, and investigate the effects of plasma density on calculated L -shell Au emission spectra. PMID:18643382

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

    SciTech Connect

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

    2012-05-01

    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.

  18. Inverse free electron lasers and laser wakefield acceleration driven by CO2 lasers.

    PubMed

    Kimura, W D; Andreev, N E; Babzien, M; Ben-Zvi, I; Cline, D B; Dilley, C E; Gottschalk, S C; Hooker, S M; Kusche, K P; Kuznetsov, S V; Pavlishin, I V; Pogorelsky, I V; Pogosova, A A; Steinhauer, L C; Ting, A; Yakimenko, V; Zigler, A; Zhou, F

    2006-03-15

    The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e-beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e-beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e-beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO(2) laser beam. PMID:16483952

  19. Effect of pulse profile and chirp on a laser wakefield generation

    SciTech Connect

    Zhang Xiaomei; Shen Baifei; Ji Liangliang; Wang Wenpeng; Xu Jiancai; Yu Yahong; Yi Longqing; Wang Xiaofeng; Hafz, Nasr A. M.; Kulagin, V.

    2012-05-15

    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.

  20. Trapping, compression, and acceleration of an electron bunch in the nonlinear laser wakefield.

    PubMed

    Khachatryan, Arsen G

    2002-04-01

    A scheme of laser wakefield acceleration, when a relatively rare and long bunch of nonrelativistic or weakly relativistic electrons is initially in front of the laser pulse, is suggested and considered. The motion of test electrons is studied both in the one-dimensional (1D) case (1D wakefield) and in the case of three-dimensional laser wakefield excited in a plasma channel. It is shown that for definite parameters of the problem the bunch can be trapped, effectively compressed both in longitudinal and transverse directions, and accelerated to ultra-relativistic energies in the region of first accelerating maximum of the wakefield. The accelerated bunch has sizes much less than the plasma wavelength and relatively small energy spread. PMID:12006039

  1. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration

    SciTech Connect

    Jing, C.; Kanareykin, A.; Power, J.; Conde, M.; Yusof, Z.; Gai, W.

    2006-11-27

    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.

  2. Supersonic jets of hydrogen and helium for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Svensson, K.; Hansson, M.; Wojda, F.; Senje, L.; Burza, M.; Aurand, B.; Genoud, G.; Persson, A.; Wahlström, C.-G.; Lundh, O.

    2016-05-01

    The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ˜30 % higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.

  3. Volumetric Heating of Ultra-High Energy Density Relativistic Plasmas by Ultrafast Laser Irradiation of Aligned Nanowire Arrays

    NASA Astrophysics Data System (ADS)

    Bargsten, Clayton; Hollinger, Reed; Shlyaptsev, Vyacheslav; Pukhov, Alexander; Keiss, David; Townsend, Amanda; Wang, Yong; Wang, Shoujun; Prieto, Amy; Rocca, Jorge

    2014-10-01

    We have demonstrated the volumetric heating of near-solid density plasmas to keV temperatures by ultra-high contrast femtosecond laser irradiation of arrays of vertically aligned nanowires with an average density up to 30% solid density. X-ray spectra show that irradiation of Ni and Au nanowire arrays with laser pulses of relativistic intensities ionizes plasma volumes several micrometers in depth to the He-like and Co-like (Au 52 +) stages respectively. The penetration depth of the heat into the nanowire array was measured monitoring He-like Co lines from irradiated arrays in which the nanowires are composed of a Co segment buried under a selected length of Ni. The measurement shows the ionization reaches He-like Co for depth of up to 5 μm within the target. This volumetric plasma heating approach creates a new laboratory plasma regime in which extreme plasma parameters can be accessed with table-top lasers. Scaling to higher laser intensities promises to create plasmas with temperatures and pressures approaching those in the center of the sun. Work supported by the U.S Department of Energy, Fusion Energy Sciences and the Defense Threat Reduction Agency grant HDTRA-1-10-1-0079. A.P was supported by of DFG-funded project TR18.

  4. Frequency-Domain Interferometry of Electron Bunch Driven Wakefields

    NASA Astrophysics Data System (ADS)

    Zgadzaj, Rafal; Downer, M. C.; Yi, Austin; Shvets, Gennady; Fang, Yun; Muggli, Patric; Yakimenko, Vitaly; Babzien, Marcus; Fedurin, Mikhail; Kusche, Karl

    2012-10-01

    Beam-driven plasma wakefield accelerators (PWFA), such as the ``plasma afterburner'' can potentially greatly increase the particle energies of conventional accelerators . Various schemes using single and multiple bunches of electrons, positrons and protons have been investigated. Appropriately delayed witness bunches have been the usual method to probe the fields of such wakes, and indirectly, the corresponding plasma wake structures. However, the wake structure has not been observed directly in the PWFA. We will report our progress in the development of direct, optical interferometric methods of measuring the plasma density modulation in electron beam driven wakefields. Frequency Domain Holography (FDH), employing two chirped laser pulses (probe and reference) co-propagating with the particle drive-beam and its plasma wake, permits single shot observation of an extended section of the wakefield behind a drive bunch. The chirped, temporally stretched, probe samples several periods of the wake, while the undisturbed reference pulse propagates ahead of the electron drive bunch. The technique is being developed in the Accelerator Test Facility at the Brookhaven National Laboratory as a probe for two and multibunch driven plasmawakefield experiments

  5. Photoionized plasmas induced in neon with extreme ultraviolet and soft X-ray pulses produced using low and high energy laser systems

    SciTech Connect

    Bartnik, A.; Wachulak, P.; Fok, T.; Węgrzyński, Ł.; Fiedorowicz, H.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Dudzak, R.; Dostal, J.; Krousky, E.; Skala, J.; Ullschmied, J.; Hrebicek, J.; Medrik, T.

    2015-04-15

    A comparative study of photoionized plasmas created by two soft X-ray and extreme ultraviolet (SXR/EUV) laser plasma sources with different parameters is presented. The two sources are based on double-stream Xe/He gas-puff targets irradiated with high (500 J/0.3 ns) and low energy (10 J/1 ns) laser pulses. In both cases, the SXR/EUV beam irradiated the gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Irradiation of gases resulted in formation of photoionized plasmas emitting radiation in the SXR/EUV range. The measured Ne plasma radiation spectra are dominated by emission lines corresponding to radiative transitions in singly charged ions. A significant difference concerns origin of the lines: K-shell or L-shell emissions occur in case of the high and low energy irradiating system, respectively. In high energy system, the electron density measurements were also performed by laser interferometry, employing a femtosecond laser system. A maximum electron density for Ne plasma reached the value of 2·10{sup 18 }cm{sup −3}. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.

  6. Plasma-induced spectral broadening of high-energy ultrashort laser pulses in a helium-filled multiple-pass cell

    SciTech Connect

    Nurhuda, Muhammad; Suda, Akira; Midorikawa, Katsumi

    2006-09-15

    We investigated the possibility of plasma-induced spectral broadening of high-energy ultrashort laser pulses in a helium-filled multipass cell (MPC) through a series of full numerical simulations of the extended nonlinear Schroedinger equation. It was found that the gas pressure must be set low so that the propagation dynamics can be controlled only by plasma defocusing. Simulations using 100 mJ, 40 fs laser pulses in the MPC, which is 6 m long and has a mirror of 3.1 m radius at each end, showed that if the gas pressure is set within the range of 40-130 Pa, then the relevant spectral broadening can be obtained after five passes, yielding compressed pulses of a 4.7-6.4 fs width. The ratio of the energy of the compressed pulse to the output pulse is found to be within 58-88%.

  7. Two-color beam generation based on wakefield excitation

    NASA Astrophysics Data System (ADS)

    Bettoni, S.; Prat, E.; Reiche, S.

    2016-05-01

    Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two subpulses with different energies and delayed in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach the power of the emitted radiation is not degraded compared to the monochromatic beam, and the setup in the machine is quite simple because the bunch is manipulated only in the high energy section, where it is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two subbunches.

  8. Dielectric Wakefield Accelerator to drive the future FEL Light Source.

    SciTech Connect

    Jing, C.; Power, J.; Zholents, A. )

    2011-04-20

    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.

  9. Direct Acceleration of Electrons in a Corrugated Plasma Channel

    SciTech Connect

    Palastro, J. P.; Antonsen, T. M.; Morshed, S.; York, A. G.; Layer, B.; Aubuchon, M.; Milchberg, H. M.; Froula, D. H.

    2009-01-22

    Direct laser acceleration of electrons provides a low power tabletop alternative to laser wakefield accelerators. Until recently, however, direct acceleration has been limited by diffraction, phase matching, and material damage thresholds. The development of the corrugated plasma channel [B. Layer et al., Phys. Rev. Lett. 99, 035001 (2007)] has removed all of these limitations and promises to allow direct acceleration of electrons over many centimeters at high gradients using femtosecond lasers [A. G. York et al., Phys Rev. Lett 100, 195001 (2008), J. P. Palastro et al., Phys. Rev. E 77, 036405 (2008)]. We present a simple analytic model of laser propagation in a corrugated plasma channel and examine the laser-electron beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes. In addition, the laser provides a transverse force that confines the high energy electrons on axis, while expelling low energy electrons.

  10. Laser-plasma experiments to study super high-energy phenomena during extreme compression of the Earth's magnetosphere by Coronal Mass Ejections*

    NASA Astrophysics Data System (ADS)

    Zakharov, Yu P.; Ponomarenko, A. G.; Antonov, V. M.; Boyarintsev, E. L.; Melekhov, A. V.; Posukh, V. G.; Shaikhislamov, I. F.

    2016-03-01

    Problem of the global and even catastrophic modification of the Earth's magnetosphere (into Artificial one) by impulsive and huge plasma ejecta, was proposed for the first time during our study of possible after-effects of high-energy explosions against asteroids at near-Earth space. Later, a similar problem of extreme compression of the Earth's magnetopause from its usual Rmp ≈ 10RE up to new stand-off distance Rm * ∼ 3RE, by plasma of giant Coronal Mass Ejections (CME, with effective energy E0 ∼1028 J), was considered for its simulations by Laser-Produced Plasma (LPP) at KI-1 facility of ILP, that were done initially without “Solar Wind” (in AMEX experiment). Here we present the first results of the “full” laboratory simulations of the CME-problem with the up-stream impact of LPP (with E0 ∼ 1 kJ) onto classical terrella-model of “stationary” magnetopause (with Rmp ≈ 17 cm), formed near compact dipole in a flow of background H+-plasma, imitated Solar Wind. As a result, we have observed for the first time a two-fold compression of magnetopause size, accompanied by very strong and near expected value of dipole magnetic field's compression up to the factor 7÷8 ≈ (Rmp/Rm *)3 inside of magnetopause. Our data allow to predict a global CME-effect at E0∼1029J.

  11. Load management strategy for Particle-In-Cell simulations in high energy particle acceleration

    NASA Astrophysics Data System (ADS)

    Beck, A.; Frederiksen, J. T.; Dérouillat, J.

    2016-09-01

    In the wake of the intense effort made for the experimental CILEX project, numerical simulation campaigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. In this paper, we compare the results given by different codes and point out algorithmic limitations both in terms of physical accuracy and computational performances. These limitations are illustrated in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-performance PIC code for high energy particle acceleration.

  12. Potential applications of the dielectric wakefield accelerators in the SINBAD facility at DESY

    NASA Astrophysics Data System (ADS)

    Nie, Y. C.; Assmann, R.; Dorda, U.; Marchetti, B.; Weikum, M.; Zhu, J.; Hüning, M.

    2016-09-01

    Short, high-brightness relativistic electron bunches can drive ultra-high wakefields in the dielectric wakefield accelerators (DWFAs). This effect can be used to generate high power THz coherent Cherenkov radiation, accelerate a witness bunch with gradient two or three orders of magnitude larger than that in the conventional RF linear accelerators, introduce energy modulation within the driving bunch itself, etc. The paper studies potential applications of the DWFAs in the SINBAD facility at DESY. The simulations show that the ultra-short relativistic bunches from the SINBAD injector ARES can excite accelerating wakefields with peak amplitudes as high as GV/m at THz frequencies in proper DWFA structures. In addition, it illustrates that the DWFA structure can serve as a dechirper to compensate the correlated energy spread of the bunches accelerated by the laser plasma wakefield accelerator.

  13. Temporal Evolution of Self-Modulated Laser Wakefields Measured by Coherent Thomson Scattering

    SciTech Connect

    Ting, A.; Krushelnick, K.; Moore, C.I.; Burris, H.R.; Esarey, E.; Krall, J.; Sprangle, P. |

    1996-12-01

    Coherent Thomson scattering of a picosecond probe laser was used to measure the time evolution of plasma wakefields produced by a high intensity laser pulse (7{times}10{sup 18} W/cm{sup 2}) in an underdense plasma ({ital n}{sub {ital e}}{approx_equal}10{sup 19} cm{sup {minus}3}) in the self-modulated laser wakefield accelerator configuration. Large amplitude plasma wakefields which lasted less than 5ps were observed to decay into ion acoustic waves. The time scales associated with these measurements were consistent with the effects of the modulational instability and the enhancement of scattered signal from plasma channel formation. {copyright} {ital 1996 The American Physical Society.}

  14. Overcomingthe Dephasing Limit in the Bubble Regime by Synergybetween Direct Laser Acceleration and Laser Wakefield Acceleration

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Khudik, Vladimir; Shvets, Gennady

    2014-10-01

    Direct Laser Acceleration (DLA) in the bubble regime is an acceleration mechanism that combines the traditional plasma wakefield acceleration inside the plasma bubble with energy gain directly from the laser pulse. Recent experiments demonstrated one of the signatures of the DLA: highly efficient gamma-rays from resonantly excited betatron oscillations of accelerated electrons inside the plasma bubble. Here we propose another potential benefit of DLA: the reduction of dephasing between the accelerated electrons and accelerating field of the bubble. A simple semi-analytic model is developed to investigate the synergy between DLA and LWA acceleration mechanisms. We propose to enhance the DLA by adding a second time-delayed weak laser pulse capable of interacting with bubble electrons right after self-injection. This scenario is validated by direct PIC modeling using the 2D VLPL code. The prospects for achieving high-energy electrons at the Texas Petawatt laser are discussed. This work is supported by the US DOE grant DE-SC0007889.

  15. Laser Wakefield Acceleration in the PetaWatt Regime

    NASA Astrophysics Data System (ADS)

    Katsouleas, Tom; Tsung, Frank; Mori, Warren

    2002-11-01

    Laser wakefield acceleration with multi-terawatt lasers has demonstrated impressive results in experiments around the world-- e.g., energy gains up to 200 MeV in mm-scale gas jets. With the prospects good for a number of petawatt class lasers in the near future, we examine with 2-D and 3-D PIC simulations the potential energy gain and new physics of laser wakefield acceleration in this regime. Prospects for producing GeV electron beams in underdense plasmas will be described. In addition, the differences in physics between terawatt and petawatt regimes will be explored. Preliminary results indicate that there are two acceleration stages in the petawatt regime -- with the early electrons dephasing due to elongation of the laser wake as the laser pump evolves. The later stage produces a long beam of electrons several times the initial plasma wake wavelength with a fairly defined energy in the GeV range.

  16. A table-top x-ray FEL based on a laser wakefield accelerator-undulator system

    SciTech Connect

    Nakajima, K.; Kawakubo, T.; Nakanishi, H.

    1995-12-31

    Ultrahigh-gradient electron acceleration has been confirmed owing to the laser wakefield acceleration mechanism driven by an intense short laser wakefield acceleration mechanism driven by an intense short laser pulse in an underdense plasma. The laser wakefield acceleration makes it possible to build a compact electron linac capable of producing an ultra-short bunched electron beam. While the accelerator is attributed to longitudinal wakefields, transverse wakefields simultaneously generated by a short laser pulse can serve as a plasma undulator with a very short wavelength equal to a half of the plasma wavelength. We propose a new FEL concept for X-rays based on a laser wakefield accelerator-undulator system driven by intense short laser pulses delivered from table-top terawatt lasers. The system is composed of the accelerator stage and the undulator stage in a table-top size. A low energy electron beam is accelerated an bunched into microbunches due to laser wakefields in the accelerator stage. A micro-bunched beam travelling to the opposite direction of driving laser pulses produces coherent X-ray radiation in the undulator stage. A practical configuration and its analyses are presented.

  17. Plasma-based generation and control of a single few-cycle high-energy ultrahigh-intensity laser pulse.

    PubMed

    Tamburini, M; Di Piazza, A; Liseykina, T V; Keitel, C H

    2014-07-11

    A laser-boosted relativistic solid-density paraboloidal foil is known to efficiently reflect and focus a counterpropagating laser pulse. Here we show that in the case of an ultrarelativistic counterpropagating pulse, a high-energy and ultrahigh-intensity reflected pulse can be more effectively generated by a relatively slow and heavy foil than by a fast and light one. This counterintuitive result is explained with the larger reflectivity of a heavy foil, which compensates for its lower relativistic Doppler factor. Moreover, since the counterpropagating pulse is ultrarelativistic, the foil is abruptly dispersed and only the first few cycles of the counterpropagating pulse are reflected. Our multidimensional particle-in-cell simulations show that even few-cycle counterpropagating laser pulses can be further shortened (both temporally and in the number of laser cycles) with pulse amplification. A single few-cycle, multipetawatt laser pulse with several joules of energy and with a peak intensity exceeding 10(23)  W/cm(2) can be generated already employing next-generation high-power laser systems. In addition, the carrier-envelope phase of the generated few-cycle pulse can be tuned provided that the carrier-envelope phase of the initial counterpropagating pulse is controlled. PMID:25062199

  18. Demonstration of a Narrow Energy Spread, ˜0.5GeV Electron Beam from a Two-Stage Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Pollock, B. B.; Clayton, C. E.; Ralph, J. E.; Albert, F.; Davidson, A.; Divol, L.; Filip, C.; Glenzer, S. H.; Herpoldt, K.; Lu, W.; Marsh, K. A.; Meinecke, J.; Mori, W. B.; Pak, A.; Rensink, T. C.; Ross, J. S.; Shaw, J.; Tynan, G. R.; Joshi, C.; Froula, D. H.

    2011-07-01

    Laser wakefield acceleration of electrons holds great promise for producing ultracompact stages of GeV scale, high-quality electron beams for applications such as x-ray free electron lasers and high-energy colliders. Ultrahigh intensity laser pulses can be self-guided by relativistic plasma waves (the wake) over tens of vacuum diffraction lengths, to give >1GeV energy in centimeter-scale low density plasmas using ionization-induced injection to inject charge into the wake even at low densities. By restricting electron injection to a distinct short region, the injector stage, energetic electron beams (of the order of 100 MeV) with a relatively large energy spread are generated. Some of these electrons are then further accelerated by a second, longer accelerator stage, which increases their energy to ˜0.5GeV while reducing the relative energy spread to <5% FWHM.

  19. Demonstration of a narrow energy spread, ∼0.5  GeV electron beam from a two-stage laser wakefield accelerator.

    PubMed

    Pollock, B B; Clayton, C E; Ralph, J E; Albert, F; Davidson, A; Divol, L; Filip, C; Glenzer, S H; Herpoldt, K; Lu, W; Marsh, K A; Meinecke, J; Mori, W B; Pak, A; Rensink, T C; Ross, J S; Shaw, J; Tynan, G R; Joshi, C; Froula, D H

    2011-07-22

    Laser wakefield acceleration of electrons holds great promise for producing ultracompact stages of GeV scale, high-quality electron beams for applications such as x-ray free electron lasers and high-energy colliders. Ultrahigh intensity laser pulses can be self-guided by relativistic plasma waves (the wake) over tens of vacuum diffraction lengths, to give >1  GeV energy in centimeter-scale low density plasmas using ionization-induced injection to inject charge into the wake even at low densities. By restricting electron injection to a distinct short region, the injector stage, energetic electron beams (of the order of 100 MeV) with a relatively large energy spread are generated. Some of these electrons are then further accelerated by a second, longer accelerator stage, which increases their energy to ∼0.5  GeV while reducing the relative energy spread to <5% FWHM. PMID:21867013

  20. Investigation of the 2p3/2-3d5/2 line emission of Au53+ -- Au69+ for diagnosing high energy density plasmas

    SciTech Connect

    Brown, G V; Hansen, S B; Trabert, E; Beiersdorfer, P; Widmann, K; Chen, H; Chung, H K; Clementson, J T; Gu, M F; Thorn, D B

    2008-01-29

    Measurements of the L-shell emission of highly charged gold ions were made under controlled laboratory conditions using the SuperEBIT electron beam ion trap, allowing detailed spectral observations of lines from ironlike Au{sup 53+} through neonlike Au{sup 69+}. Using atomic data from the Flexible Atomic Code, we have identified strong 3d{sub 5/2} {yields} 2p{sub 3/2} emission features that can be used to diagnose the charge state distribution in high energy density plasmas, such as those found in the laser entrance hole of hot hohlraum radiation sources. We provide collisional-radiative calculations of the average ion charge as a function of temperature and density, which can be used to relate charge state distributions inferred from 3d{sub 5/2} {yields} 2p{sub 3/2} emission features to plasma conditions, and investigate the effects of plasma density on calculated L-shell Au emission spectra.

  1. Precision Mapping of Laser-Driven Magnetic Fields and Their Evolution in High-Energy-Density Plasmas

    NASA Astrophysics Data System (ADS)

    Gao, L.; Nilson, P. M.; Igumenshchev, I. V.; Haines, M. G.; Froula, D. H.; Betti, R.; Meyerhofer, D. D.

    2015-05-01

    The magnetic fields generated at the surface of a laser-irradiated planar solid target are mapped using ultrafast proton radiography. Thick (50 μ m ) plastic foils are irradiated with 4-kJ, 2.5-ns laser pulses focused to an intensity of 4 ×1014 W /cm2 . The data show magnetic fields concentrated at the edge of the laser-focal region, well within the expanding coronal plasma. The magnetic-field spatial distribution is tracked and shows good agreement with 2D resistive magnetohydrodynamic simulations using the code draco when the Biermann battery source, fluid and Nernst advection, resistive magnetic diffusion, and Righi-Leduc heat flow are included.

  2. Precision mapping of laser-driven magnetic fields and their evolution in high-energy-density plasmas

    SciTech Connect

    Gao, L.; Nilson, P. M.; Igumenshchev, I. V.; Haines, M. G.; Froula, D. H.; Betti, R.; Meyerhofer, D. D.

    2015-05-29

    The magnetic fields generated at the surface of a laser-irradiated planar solid target are mapped using ultrafast proton radiography. Thick (50 μm) plastic foils are irradiated with 4-kJ, 2.5-ns laser pulses focused to an intensity of 4 x 10¹⁴ W/cm². The data show magnetic fields concentrated at the edge of the laser-focal region, well within the expanding coronal plasma. The magnetic-field spatial distribution is tracked and shows good agreement with 2D resistive magnetohydrodynamic simulations using the code DRACO when the Biermann battery source, fluid and Nernst advection, resistive magnetic diffusion, and Righi-Leduc heat flow are included.

  3. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

    SciTech Connect

    Li, C. K.; Seguin, F. H.; Frenje, J. A.; Manuel, M.; Casey, D.; Sinenian, N.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Rygg, J. R.; Town, R. P. J.; Betti, R.; Meyerhofer, D. D.; Delettrez, J.; Knauer, J. P.; Marshall, F.; Sangster, T. C.; Smalyuk, V. A.; Soures, J. M.; Shvarts, D.

    2009-05-15

    Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields produced in laser-foil interactions and during the implosion of inertial-confinement-fusion capsules. These experiments resulted in the first observations of several new and important features: (1) observations of the generation, decay dynamics, and instabilities of megagauss B fields in laser-driven planar plastic foils, (2) the observation of radial E fields inside an imploding capsule, which are initially directed inward, reverse direction during deceleration, and are likely related to the evolution of the electron pressure gradient, and (3) the observation of many radial filaments with complex electromagnetic field striations in the expanding coronal plasmas surrounding the capsule. The physics behind and implications of such observed fields are discussed.

  4. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

    SciTech Connect

    Li, C. K.; Séguin, F. H.; Frenje, J. A.; Manuel, M.; Casey, D.; Sinenian, N.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Rygg, J. R.; Town, R. P. J.; Betti, R.; Delettrez, J.; Knauer, J. P.; Marshall, F.; Meyerhofer, D. D.; Sangster, T. C.; Shvarts, D.; Smalyuk, V. A.; Soures, J. M.; Back, C. A.; Kilkenny, J. D.; Nikroo, A.

    2009-01-01

    Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields produced in laser-foil interactions and during the implosion of inertial-confinement-fusion capsules. These experiments resulted in the first observations of several new and important features: (1) observations of the generation, decay dynamics, and instabilities of megagauss B fields in laser-driven planar plastic foils, (2) the observation of radial E fields inside an imploding capsule, which are initially directed inward, reverse direction during deceleration, and are likely related to the evolution of the electron pressure gradient, and (3) the observation of many radial filaments with complex electromagnetic field striations in the expanding coronal plasmas surrounding the capsule. The physics behind and implications of such observed fields are discussed.

  5. A scalable high-energy diode-pumped solid state laser for laser-plasma interaction science and applications

    NASA Astrophysics Data System (ADS)

    De Vido, M.; Ertel, K.; Mason, P. D.; Banerjee, S.; Phillips, P. J.; Butcher, T. J.; Smith, J. M.; Shaikh, W.; Hernandez-Gomes, C.; Greenhalgh, R. J. S.; Collier, J. L.

    2016-05-01

    Laser systems efficiently generating nanosecond pules at kJ energy levels and at multi-Hz repetition rates are required in order to translate laser-plasma interactions into practical applications. We have developed a scalable, actively-cooled diode-pumped solid state laser amplifier design based on a multi-slab ceramic Yb:YAG architecture called DiPOLE (Diode-Pumped Optical Laser for Experiments) capable of meeting such requirements. We demonstrated 10.8 J, 10 Hz operation at 1030 nm using a scaled-down prototype, reaching an optical-to-optical efficiency of 22.5%. Preliminary results from a larger scale version, delivering 100 J pulse energy at 10 Hz, are also presented.

  6. Structure-Property Correlation in Fe-Al2O3 In Situ Nanocomposite Synthesized by High-Energy Ball Milling and Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Udhayabanu, V.; Ravi, K. R.; Murty, B. S.

    2016-07-01

    In the present study, Fe-10 vol pct Al2O3 in situ nanocomposite has been derived by high-energy ball milling of Fe2O3-Fe-Al powder mixture followed by the consolidation using spark plasma sintering (SPS). The consolidated nanocomposite has bimodal-grained structure consisting of nanometer- and submicron-sized Fe grains along with nanometer-sized Al2O3, and Fe3O4 particles. The mechanical property analysis reveals that compressive yield strength of Fe-10 vol pct Al2O3 nanocomposite is 2100 MPa which is nearly two times higher than that of monolithic Fe processed by Mechanical Milling and SPS. The strengthening contributions obtained from matrix, grain size, and particles in the synthesized nanocomposite have been calculated theoretically, and are found to be matching well with the experimental strength levels.

  7. Recent Advances in Plasma Acceleration

    SciTech Connect

    Hogan, Mark

    2007-03-19

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

  8. Optimization of laser wakefield accelerator parameters

    SciTech Connect

    Pogorelsky, I.V.

    1998-02-01

    The author reveals the dependencies of the laser wakefield accelerator (LWFA) performance upon such basic parameters as laser wavelength, power, and pulse duration and apply them for optimization of the plasma-channeled standard LWFA operating in a linear regime. The maximum energy gain over the dephasing distance scales proportionally to the laser peak power, while the allowed minimum laser pulse duration is proportional to the square root of the energy gain. Electron beam energy spread, emittance and luminosity tend to improve with the laser wavelength increase. These considerations, supported by quantitative examples for the S GeV LWFA stage, favor picosecond CO{sub 2} laser as the optimum choice for future advanced accelerator projects.

  9. High energy from space

    NASA Technical Reports Server (NTRS)

    Margon, Bruce; Canizares, Claude; Catura, Richard C.; Clark, George W.; Fichtel, Carl E.; Friedman, Herbert; Giacconi, Riccardo; Grindlay, Jonathan E.; Helfand, David J.; Holt, Stephen S.

    1991-01-01

    The following subject areas are covered: (1) important scientific problems for high energy astrophysics (stellar activity, the interstellar medium in galaxies, supernovae and endpoints of stellar evolution, nucleosynthesis, relativistic plasmas and matter under extreme conditions, nature of gamma-bursts, identification of black holes, active nuclei, accretion physics, large-scale structures, intracluster medium, nature of dark matter, and the X- and gamma-ray background); (2) the existing experimental programs (Advanced X-Ray Astrophysics Facility (AXAF), Gamma Ray Observatory (GRO), X-Ray Timing Explorer (XTE), High Energy Transient Experiment (HETE), U.S. participation in foreign missions, and attached Shuttle and Space Station Freedom payloads); (3) major missions for the 1990's; (4) a new program of moderate missions; (5) new opportunities for small missions; (6) technology development issues; and (7) policy issues.

  10. Radio-isotope production using laser Wakefield accelerators

    SciTech Connect

    Leemans, W.P.; Rodgers, D.; Catravas, P.E.; Geddes, C.G.R.; Fubiani, G.; Toth, C.; Esarey, E.; Shadwick, B.A.; Donahue, R.; Smith, A.; Reitsma, A.

    2001-07-27

    A 10 Hz, 10 TW solid state laser system has been used to produce electron beams suitable for radio-isotope production. The laser beam was focused using a 30 cm focal length f/6 off-axis parabola on a gas plume produced by a high pressure pulsed gas jet. Electrons were trapped and accelerated by high gradient wakefields excited in the ionized gas through the self-modulated laser wakefield instability. The electron beam was measured to contain excesses of 5 nC/bunch. A composite Pb/Cu target was used to convert the electron beam into gamma rays which subsequently produced radio-isotopes through (gamma, n) reactions. Isotope identification through gamma-ray spectroscopy and half-life time measurements demonstrated that Cu{sup 61} was produced which indicates that 20-25 MeV gamma rays were produced, and hence electrons with energies greater than 25-30 MeV. The production of high energy electrons was independently confirmed using a bending magnet spectrometer. The measured spectra had an exponential distribution with a 3 MeV width. The amount of activation was on the order of 2.5 uCi after 3 hours of operation at 1 Hz. Future experiments will aim at increasing this yield by post-accelerating the electron beam using a channel guided laser wakefield accelerator.

  11. Electron self-injection and trapping into an evolving plasma bubble.

    PubMed

    Kalmykov, S; Yi, S A; Khudik, V; Shvets, G

    2009-09-25

    The blowout (or bubble) regime of laser wakefield acceleration is promising for generating monochromatic high-energy electron beams out of low-density plasmas. It is shown analytically and by particle-in-cell simulations that self-injection of the background plasma electrons into the quasistatic plasma bubble can be caused by slow temporal expansion of the bubble. Sufficient criteria for the electron trapping and bubble's expansion rate are derived using a semianalytic nonstationary Hamiltonian theory. It is further shown that the combination of bubble's expansion and contraction results in monoenergetic electron beams. PMID:19905519

  12. Trapping of high-energy electrons into regime of surfatron acceleration by electromagnetic waves in space plasma

    SciTech Connect

    Erokhin, A. N.; Erokhin, N. S.; Milant'ev, V. P.

    2012-05-15

    The phenomenon of trapping of weakly relativistic charged particles (with kinetic energies on the order of mc{sup 2}) into a regime of surfatron acceleration by an electromagnetic wave that propagates in plasma across a weak external magnetic field has been studied using nonlinear numerical calculations based on a solution of the relativistic equations of motion. Analysis showed that, for the wave amplitude above a certain threshold value and the initial wave phase outside the interval favorable for the surfing regime, the trajectory of a charged particle initially corresponds to its cyclotron rotation in the external magnetic field. For the initial particle energies studied, the period of this rotation is relatively short. After a certain number (from several dozen to several thousand and above) of periods of rotation, the wave phase takes a value that is favorable for trapping of the charged particle on its trajectory by the electromagnetic wave, provided the Cherenkov resonance conditions are satisfied. As a result, the wave traps the charged particle and imparts it an ultrarelativistic acceleration. In momentum space, the region of trapping into the regime of surfing on an electromagnetic wave turns out to be rather large.

  13. Design of a 26 GHZ wakefield power extractor.

    SciTech Connect

    Konecny, R.; Gai, W.; Gao, F.; Jing, C.; Kanareykin, A.; Kazakov, S.; High Energy Physics; Euclid Techlabs, LLC; KEK

    2008-01-01

    High frequency, high output power, and high efficiency RF sources have compelling applications in accelerators for high energy physics. The 26 GHz RF power extractor proposed in this paper provides a practical approach for generating high power RF in this particular frequency range. The extractor is designed to couple out RF power generated from the high charge electron bunch train at the Argonne Wakefield Accelerator (AWA) facility traversing a dielectric loaded waveguide. Designs are presented including parameter optimization, electromagnetic modeling of structures and RF couplers, and analysis of beam dynamics.

  14. Experimental results of the quasi-monoenergetic electron beam generation from the self-modulated laser wakefield acceleration using a pinhole-like collimator

    NASA Astrophysics Data System (ADS)

    Suk, Hyyong

    2005-10-01

    We report recent results from the self-modulated laser wakefield acceleration experiment that has been carried out at KERI (Korea Electrotechnology Research Institute), For this experiment, we used a 3 TW Nd:glass/Ti:sapphire hybrid laser system that can deliver an energy of 2.1 J with a pulse duration of 700 fs. In the experiment, the high power laser beam is focused to a beam size of ˜ 10 microns in the supersonically ejected He gas jet (density˜1019°cm -3̂) by a parabolic mirror. The strong laser-plasma interaction led to production of MeV-level high energy electrons up to ˜10 MeV. We used a pinhole-like collimator with a diameter of 1 mm to select only high energy electrons that propagate along the axis. In this way, we could obtain quasi-monoenergetic high-energy electrons. Detailed beam and plasma parameters were measured by using several diagnostic tools including an ICT for charge measurement, dipole magnet/lanex film for energy and energy distribution, spectrometer for plasma density from the Raman scattered laser beam, etc. In this presentation, detailed experimental results are shown.

  15. Laser-plasma interactions from thin tapes for high-energy electron accelerators and seeding compact FELs

    NASA Astrophysics Data System (ADS)

    Shaw, Brian Henry

    This thesis comprises a detailed investigation of the physics of using a plasma mirror (PM) from a tape by reflecting ultrashort pulses from a laser-triggered surface plasma. The tapes used in the characterization of the PM are VHS and computer data storage tape. The tapes are 6.6 m (computer storage tape) and 15 m (VHS) thick. Each tape is 0.5 inches wide, and 10s of meters of tape are spooled using a tape drive; providing thousands of shots on a single reel of tape. The amount of reflected energy of the PM was studied for different input intensities. The fluence was varied by translating the focus of the laser upstream and downstream of the tape, which changed the spot size on the tape surface and hence changed the fluence. This study measured reflectances from both sides of the two tapes, and for input light of both s and p-polarizations. Lastly, an analytic model was developed to understand the reflectance as a function of fluence for each tape material and polarization. Another application that benefits from the advancements of LPA technology is an LPAbased FEL. By sending a high quality electron bunch through an undulator (a periodic structure of positive and negative magnetic poles), the electrons oscillate transversely to the propagation axis and produce radiation. The 1.5 m THUNDER undulator at the BELLA Center has been commissioned using electron beams of 400MeV beams with broad energy spread (35%). To produce a coherent LPA-based FEL, the beam quality would need to improve to sub-percent level energy spread. A seed source could be used to help induce bunching of the electron beam within the undulator. This thesis described the experimental investigation of the physics of using solid-based surface high-harmonic generation (SHHG) from a thin tape as a possible seed source for an FEL. A thin tape placed within centimeters of the undulator's entrance could act as a harmonic generating source, while simultaneously transmitting an electron beam. This removes

  16. Blood volume, plasma volume and circulation time in a high-energy-demand teleost, the yellowfin tuna (Thunnus albacares)

    PubMed

    Brill; Cousins; Jones; p

    1998-06-01

    We measured red cell space with 51Cr-labeled red blood cells, and dextran space with 500 kDa fluorescein-isothiocyanate-labeled dextran (FITC-dextran), in two groups of yellowfin tuna (Thunnus albacares). Red cell space was 13.8+/-0.7 ml kg-1 (mean +/- s.e.m.) Assuming a whole-body hematocrit equal to the hematocrit measured at the ventral aortic sampling site and no significant sequestering of 51Cr-labeled red blood cells by the spleen, blood volume was 46. 7+/-2.2 ml kg-1. This is within the range reported for most other teleosts (30-70 ml kg-1), but well below that previously reported for albacore (Thunnus alalunga, 82-197 ml kg-1). Plasma volume within the primary circulatory system (calculated from the 51Cr-labeled red blood cell data) was 32.9+/-2.3 ml kg-1. Dextran space was 37.0+/-3.7 ml kg-1. Because 500 kDa FITC-dextran appeared to remain within the vascular space, these data imply that the volume of the secondary circulatory system of yellowfin tuna is small, and its exact volume is not measurable by our methods. Although blood volume is not exceptional, circulation time (blood volume/cardiac output) is clearly shorter in yellowfin tuna than in other active teleosts. In a 1 kg yellowfin tuna, circulation time is approximately 0.4 min (47 ml kg-1/115 ml min-1 kg-1) compared with 1. 3 min (46 ml kg-1/35 ml min-1 kg-1) in yellowtail (Seriola quinqueradiata) and 1.9 min (35 ml kg-1/18 ml min-1 kg-1) in rainbow trout (Oncorhynchus mykiss). In air-breathing vertebrates, high metabolic rates are necessarily correlated with short circulation times. Our data are the first to imply that a similar relationship occurs in fishes. PMID:9450974

  17. Compton Backscattered X-rays from Self-Generated Laser Wiggler in a Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Ting, Antonio; Kaganovich, Dmitri; Hafizi, Bahman; Palastro, John; Helle, Michael; Gordon, Daniel; Chen, Yu-Hsin; Seely, John

    2014-10-01

    A unique Compton backscattering configuration for generating monochromatic, short pulse, and potentially coherent x-rays in a Laser Wakefield Accelerator (LWFA) is being studied at the Naval Research Laboratory. Reflection mechanisms such as stimulated Raman scattering and shock-created density gradients in a plasma can generate the required backward-travelling laser pulse directly from the same laser pulse used in the LWFA, i.e., the high energy electron beam and the counter-propagating photon beam are both self-generated by an ultrashort laser pulse in plasma. The automatic alignment of the counter-propagating electrons and photons together with the extended interaction distance and tightly guided beam sizes in a LWFA can lead to a high-gain situation for the Doppler upshifted forward propagating x-rays. Possibilities for exponential gain to achieve coherent generation of the x-rays are under investigation. Theoretical, numerical, and preliminary experimental results will be presented. This work is supported by DOE and NRL 6.1 funding.

  18. Development of High Gradient Laser Wakefield Accelerators Towards Nuclear Detection Applications at LBNL

    SciTech Connect

    Geddes, Cameron G. R.; Gonsalves, Anthony J.; Lin Chen; Cormier-Michel, Estelle; Matlis, Nicholas H.; Panasenko, Dmitriy; Plateau, Guillaume R.; Schroeder, Carl B.; Toth, Csaba; Bruhwiler, David L.; Cary, John R.; Esarey, Eric H.; Nakamura, Kei; Bakeman, Mike; Leemans, Wim P.

    2009-03-10

    Compact high-energy linacs are important to applications including monochromatic gamma sources for nuclear material security applications. Recent laser wakefield accelerator experiments at LBNL demonstrated narrow energy spread beams, now with energies of up to 1 GeV in 3 cm using a plasma channel at low density. This demonstrates the production of GeV beams from devices much smaller than conventional linacs, and confirms the anticipated scaling of laser driven accelerators to GeV energies. Stable performance at 0.5 GeV was demonstrated. Experiments and simulations are in progress to control injection of particles into the wake and hence to improve beam quality and stability. Using plasma density gradients to control injection, stable beams at 1 MeV over days of operation, and with an order of magnitude lower absolute momentum spread than previously observed, have been demonstrated. New experiments are post-accelerating the beams from controlled injection experiments to increase beam quality and stability. Thomson scattering from such beams is being developed to provide collimated multi-MeV monoenergetic gamma sources for security applications from compact devices. Such sources can reduce dose to target and increase accuracy for applications including photofission and nuclear resonance fluorescence.

  19. Development of high gradient laser wakefield accelerators towards nuclear detection applications at LBNL

    SciTech Connect

    Geddes, Cameron GR; Bruhwiler, David L.; Cary, John R.; Esarey, Eric H.; Gonsalves, Anthony J.; Lin, Chen; Cormier-Michel, Estelle; Matlis, Nicholas H.; Nakamura, Kei; Bakeman, Mike; Panasenko, Dmitriy; Plateau, Guillaume R.; Schroeder, Carl B.; Toth, Csaba; Leemans, Wim P.

    2008-09-08

    Compact high-energy linacs are important to applications including monochromatic gamma sources for nuclear material security applications. Recent laser wakefield accelerator experiments at LBNL demonstrated narrow energy spread beams, now with energies of up to 1 GeV in 3 cm using a plasma channel at low density. This demonstrates the production of GeV beams from devices much smaller than conventional linacs, and confirms the anticipated scaling of laser driven accelerators to GeV energies. Stable performance at 0.5 GeV was demonstrated. Experiments and simulations are in progress to control injection of particles into the wake and hence to improve beam quality and stability. Using plasma density gradients to control injection, stable beams at 1 MeV over days of operation, and with an order of magnitude lower absolute momentum spread than previously observed, have been demonstrated. New experiments are post-accelerating the beams from controlled injection experiments to increase beam quality and stability. Thomson scattering from such beams is being developed to provide collimated multi-MeV monoenergetic gamma sources for security applications from compact devices. Such sources can reduce dose to target and increase accuracy for applications including photofission and nuclear resonance fluorescence.

  20. High Transformer ratios in collinear wakefield accelerators.

    SciTech Connect

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

    2008-01-01

    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.

  1. High energy electron cooling

    SciTech Connect

    Parkhomchuk, V.

    1997-09-01

    High energy electron cooling requires a very cold electron beam. The questions of using electron cooling with and without a magnetic field are presented for discussion at this workshop. The electron cooling method was suggested by G. Budker in the middle sixties. The original idea of the electron cooling was published in 1966. The design activities for the NAP-M project was started in November 1971 and the first run using a proton beam occurred in September 1973. The first experiment with both electron and proton beams was started in May 1974. In this experiment good result was achieved very close to theoretical prediction for a usual two component plasma heat exchange.

  2. Emission of electromagnetic pulses from laser wakefields through linear mode conversion.

    PubMed

    Sheng, Zheng-Ming; Mima, Kunioki; Zhang, Jie; Sanuki, Heiji

    2005-03-11

    Powerful coherent emission around the plasma oscillation frequency can be produced from a laser wakefield through linear mode conversion. This occurs when the laser pulse is incident obliquely to the density gradient of inhomogeneous plasmas. The emission spectrum and conversion efficiency are obtained analytically, which are in agreement with particle-in-cell simulations. The emission can be tuned to be a radiation source in the terahertz region and with field strengths as large as a few GV/m, suitable for high-field applications. The emission also provides a simple way to measure the wakefield produced for particle acceleration. PMID:15783972

  3. Efficiency and energy spread in laser-wakefield acceleration.

    PubMed

    Reitsma, A J W; Cairns, R A; Bingham, R; Jaroszynski, D A

    2005-03-01

    The theoretical limits on efficiency and energy spread of the laser-wakefield accelerator are investigated using a one-dimensional model. Modifications, both of the wakefield due to the electron bunch, and of the laser pulse shape due to the varying permittivity of the plasma, are described self-consistently. It is found that a short laser pulse gives a higher efficiency than a long laser pulse with the same initial energy. Energy spread can be minimized by optimizing bunch length and bunch charge such that the variation of the accelerating force along the length of the bunch is minimized. An inherent trade-off between energy spread and efficiency exists. PMID:15783901

  4. Analyzing non-LTE Kr plasmas produced in high energy density experiments: from the Z machine to the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Dasgupta, Arati

    2015-11-01

    Designing high fluence photon sources above 10 keV are a challenge for High Energy Density plasmas. This has motivated radiation source development investigations of Kr with K-shell energies around 13 keV. Recent pulsed power driven gas-puff experiments on the refurbished Z machine at Sandia have produced intense X-rays in the multi-keV photon energy range. K-shell radiative yields and efficiencies are very high for Ar, but rapidly decrease for higher atomic number (ZA) elements such as Kr. It has been suggested that an optimum exists corresponding to a trade-off between the increase of photon energy for higher ZA elements and the corresponding fall off in radiative power. However the conversion efficiency on NIF, where the drive, energy deposition process, and target dynamics are different, does not fall off with higher ZA as rapidly as on Z. We have developed detailed atomic structure and collisional data for the full K-, L- and partial M-shell of Kr using the Flexible Atomic Code (FAC). Our non-LTE atomic model includes all collisional and recombination processes, including state-specific dielectronic recombination (DR), that significantly affect ionization balance and spectra of Kr plasmas at the temperatures and densities of concern. The model couples ionization physics, radiation production and transport, and magnetohydrodynamics. In this talk, I will give a detailed description of the model and discuss 1D Kr simulations employing a multifrequency radiation transport scheme. Synthetic K- and L-shell spectra will be compared with available experimental data. This talk will analyze experimental data indicative of the differences between Z and NIF experimental data and discuss how they affect the K-shell radiative output of Kr plasma. Work supported by DOE/NNSA.

  5. Observations of microwave continuum emission from air shower plasmas

    SciTech Connect

    Gorham, P. W.; Lehtinen, N. G.; Varner, G. S.; Hebert, C. L.; Miki, C.; Kowalski, J.; Ruckman, L.; Stokes, B. T.; Beatty, J. J.; Connolly, A.; Saltzberg, D.; Chen, P.; Hast, C.; Ng, J.; Reil, K.; Walz, D.; Conde, M. E.; Gai, W.; Konecny, R.; Power, J. G.

    2008-08-01

    We investigate a possible new technique for microwave detection of cosmic-ray extensive air showers which relies on detection of expected continuum radiation in the microwave range, caused by free-electron collisions with neutrals in the tenuous plasma left after the passage of the shower. We performed an initial experiment at the Argonne Wakefield Accelerator laboratory in 2003 and measured broadband microwave emission from air ionized via high-energy electrons and photons. A follow-up experiment at the Stanford Linear Accelerator Center in the summer of 2004 confirmed the major features of the previous Argonne Wakefield Accelerator observations with better precision. Prompted by these results we built a prototype detector using satellite television technology and have made measurements suggestive of the detection of cosmic-ray extensive air showers. The method, if confirmed by experiments now in progress, could provide a high-duty cycle complement to current nitrogen fluorescence observations.

  6. Applications of laser wakefield accelerators for biomedical imaging

    NASA Astrophysics Data System (ADS)

    Najmudin, Zulfikar

    2014-10-01

    Laser-wakefield accelerators driven by high-intensity short-pulse lasers are a proven compact source of high-energy electron beams, with energy gains of ~GeV energy in centimetres of plasma demonstrated. One of the main proposed applications for these accelerators is to drive synchrotron light sources, in particular for x-ray applications. It has also been shown that the same plasma accelerator can also act as a wigglers, capable of the production of high brightness and spatially coherent hard x-ray beams. In this latest work, we demonstrate the application of these unique light-sources for biological and medical applications. The experiments were performed with the Astra Gemini laser at the Rutherford Appleton Laboratory in the UK. Gemini produces laser pulses with energy exceeding 10 J in pulse lengths down to 40 fs. A long focal length parabola (f / 20) is used to focus the laser down to a spot of size approximately 25 μ m (fwhm) into a gas-cell of variable length. Electrons are accelerated to energies up to 1 GeV and a bright beam of x-rays is observed simultaneously with the accelerated beam. The length of the gas cell was optimised to produce high contrast x-ray images of radiographed test objects. This source was then used for imaging a number of interesting medical and biological samples. Full tomographic imaging of a human trabecular bone sample was made with resolution easily exceeding the ~100 μm level required for CT applications. Phase-contrast imaging of human prostrate and mouse neonates at the micron level was also demonstrated. These studies indicate the usefulness of these sources in research and clinical applications. They also show that full 3D imaging can be made possible with this source in a fraction of the time that it would take with a corresponding x-ray tube. The JAI is funded by STFC Grant ST/J002062/1.

  7. Laser Triggered Electron Injection into a Channel Guided Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Filip, C.

    2005-10-01

    Laser-plasma accelerators have demonstrated the generation of narrow energy spread (˜ few %) electron beams with considerable amount of charge (>100 pC). Stability of laser-plasma accelerators, as in the conventional accelerators, requires highly synchronized injection of electrons into the structured accelerating field. The Colliding Pulse Method[1] with pre-formed plasma channel guiding [2] can result in jitter-free injection in a dark-current-free accelerating structure. We report on experimental progress of laser triggered injection of electrons into a laser wakefield, where an intense laser pulse is guided by a pre-formed plasma channel. The experiments use the multi-beam, multi-terawatt Ti:Al2O3 laser at LOASIS facility of LBNL. The ignitor-heater method is used to first produce a pre-formed plasma channel in a hydrogen gas jet. Two counter propagating beams (wakefield driver:100-500mJ-50fs, injector:50-300mJ-50fs) then are focused onto the entrance of the channel. Preliminary results indicate that electron beam properties are affected by the second beam. Details of the experiment will be presented. [1]G.Fubiani, et al, Phys. Rev. E 70, 016402 (2004). [2]C.G.R. Geddes et al, Nature 431, 538 (2004). This work is supported by DoE under contract DE-AC02-05CH11231.

  8. Laser pulse propagation in inhomogeneous magnetoplasma channels and wakefield acceleration

    SciTech Connect

    Sharma, B. S. Jain, Archana; Jaiman, N. K.; Gupta, D. N.; Jang, D. G.; Suk, H.; Kulagin, V. V.

    2014-02-15

    Wakefield excitation in a preformed inhomogeneous parabolic plasma channel by an intense relativistic (≃10{sup 19} W/cm{sup 2}) circularly polarized Gaussian laser pulse is investigated analytically and numerically in the presence of an external longitudinal magnetic field. A three dimensional envelope equation for the evolution of the laser pulse is derived, which includes the effect of the nonparaxial and applied external magnetic field. A relation for the channel radius with the laser spot size is derived and examines numerically to see the external magnetic field effect. It is observed that the channel radius depends on the applied external magnetic field. An analytical expression for the wakefield is derived and validated with the help of a two dimensional particle in cell (2D PIC) simulation code. It is shown that the electromagnetic nature of the wakes in an inhomogeneous plasma channel makes their excitation nonlocal, which results in change of fields with time and external magnetic field due to phase mixing of the plasma oscillations with spatially varying frequencies. The magnetic field effect on perturbation of the plasma density and decreasing length is also analyzed numerically. In addition, it has been shown that the electron energy gain in the inhomogeneous parabolic magnetoplasma channel can be increased significantly compared with the homogeneous plasma channel.

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

    SciTech Connect

    Banerjee, S.; Powers, N. D.; Ramanathan, V.; Ghebregziabher, I.; Brown, K. J.; Maharjan, C. M.; Chen, S.; Umstadter, D. P.; Beck, A.; Lefebvre, E.; Kalmykov, S. Y.; Shadwick, B. A.

    2012-05-15

    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.

  10. Summary report: Working Group 2 on 'Plasma Based Acceleration Concepts'

    SciTech Connect

    Leemans, W. P.; Esarey, E.

    1999-07-12

    A summary of the talks, papers and discussion sessions presented in the Working Group on Plasma Based Acceleration Concepts is given within the context of the progress towards a 1 GeV laser driven accelerator module. The topics covered within the Working Group were self-modulated laser wakefield acceleration, standard laser wakefield acceleration, plasma beatwave acceleration, laser guiding and wake excitation in plasma channels, plasma wakefield acceleration, plasma lenses and optical injection techniques for laser wakefield accelerators. An overview will be given of the present status of experimental and theoretical progress as well as an outlook towards the future physics and technological challenges for the development of an optimized accelerator module.

  11. Positron generation using laser-wakefield electron sources

    SciTech Connect

    Williams, G. J. Park, J.; Pollock, B. B.; Albert, F.; Chen, Hui

    2015-09-15

    Positron generation, using wakefield-accelerated electrons driven into a converter target, was investigated experimentally and through Monte Carlo simulations. Using experimentally measured initial electron distributions from a 60 fs laser system, modeling shows that a collimated wakefield electron beam of moderate energy (50–200 MeV) produces a large number of positrons (∼10{sup 7}), which are emitted from the rear of a mm-scale, high-Z target with divergence angles between 50 and 150 mrad. The large perpendicular momentum of the positrons was found to be dominated by contributions from multiple small angle Coulomb scattering. Positrons were not observed above background noise for a range of targets where simulations indicate a 5–30× increase in the beam charge was necessary to exceed threshold detection. These results provide new understanding to the fundamental limitations of creating narrow-divergence, high-density positron beams from laser-wakefield platforms for use in future laboratory pair plasma experiments.

  12. Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for High Energy Density plasmas at energies below 10 keV

    SciTech Connect

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2014-07-15

    The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities. We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients.

  13. Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for High Energy Density plasmas at energies below 10 keV

    NASA Astrophysics Data System (ADS)

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2014-07-01

    The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities. We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients.

  14. Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for high energy density plasmas at energies below 10 keV.

    PubMed

    Valdivia, M P; Stutman, D; Finkenthal, M

    2014-07-01

    The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities. We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients. PMID:25085141

  15. Laser Wakefield Acceleration Experiments Using HERCULES Laser

    SciTech Connect

    Matsuoka, T.; McGuffey, C.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Horovitz, Y.

    2009-07-25

    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.

  16. Final report 'IONPACK: Ionization Package for Intense Lasers and Plasma Physics Codes'

    SciTech Connect

    Dimitre A Dimitorv; David L Bruhwiler

    2004-01-06

    OAK-B135 There is a need for accurate models of ionization processes in simulations on advanced concepts for next-generation high-energy accelerators. In this Phase I project, we studied the feasibility to develop of a generic, extendable, and interoperable software library for simulation of tunneling, impact, multiphoton, and barrier suppression ionization processes that can easily be used with existing Particle-In-Cell (PIC), hydrodynamic, and other plasma simulation codes. We developed a functional prototype of the package in and identified the complete library design to be implemented in the Phase II and tested on currently relevant research problems in laser and beam-plasma wakefield accelerators.

  17. Tomographic characterisation of gas-jet targets for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Couperus, J. P.; Köhler, A.; Wolterink, T. A. W.; Jochmann, A.; Zarini, O.; Bastiaens, H. M. J.; Boller, K. J.; Irman, A.; Schramm, U.

    2016-09-01

    Laser wakefield acceleration (LWFA) has emerged as a promising concept for the next generation of high energy electron accelerators. The acceleration medium is provided by a target that creates a local well-defined gas-density profile inside a vacuum vessel. Target development and analysis of the resulting gas-density profiles is an important aspect in the further development of LWFA. Gas-jet targets are widely used in regimes where relatively high electron densities over short interaction lengths are required (up to several millimetres interaction length, plasma densities down to ~1018cm-3). In this paper we report a precise characterisation of such gas-jet targets by a laser interferometry technique. We show that phase shifts down to 4 mrad can be resolved. Tomographic phase reconstruction enables detection of non-axisymmetrical gas-density profiles which indicates defects in cylindrical nozzles, analysis of slit-nozzles and nozzles with an induced shock-wave density step. In a direct comparison between argon and helium jets we show that it cannot automatically be assumed, as is often done, that a nozzle measured with argon will provide the same gas density with helium.

  18. Self-modulated laser wakefield acceleration as a X-ray source

    NASA Astrophysics Data System (ADS)

    Lemos, Nuno; Tsung, Frank; Shaw, Jessica; Marsh, Ken; Albert, Felicie; Pollock, Brad; Joshi, Chan

    2015-11-01

    Understanding material properties under extreme conditions of temperature and pressure is critical for different fields of physics such as astrophysics and high energy density (HED) science. The HED science facilities such as OMEGA and the National Ignition Facility are now uniquely able to recreate in the laboratory conditions of temperature and pressure that were thought to be only attainable in the interiors of stars and planets. To diagnose such extreme states of matter, the development of efficient, versatile and fast (sub-picosecond scale) x-ray probes with energies larger than 50 kilo-electronvolts has become essential for HED science experiments on these specific facilities. In this work we explore the betatron radiation generated in self-modulated laser-wakefield accelerators to probe HED plasmas with unprecedented time resolution. Through Osiris 2D particle-in-cell simulations we we will show that this acceleration scheme can produce radiation with energies exceeding 50keV. The work at UCLA was supported by DOE grant # DE/SC0010064 and NSF grant # PHY/1415386.

  19. High-resolution and ultrafast imaging using betatron x-rays from laser wakefield accelerators

    NASA Astrophysics Data System (ADS)

    Najmudin, Zulfikar

    2015-11-01

    Laser wakefield accelerators now routinely produce ~GeV energy gain in ~cm plasmas. and are simultaneously capable of producing high brightness and spatially coherent hard x-ray beams. This unique light-source has been used for medical applications, and also for ultrafast imaging in high energy density science. The experiments were performed with the Astra Gemini laser producing 10 J pulses with duration ~ 40 fs focussed to produce a spot of 25 μ m (fwhm) in a gas-cell of variable length to produce a low divergence beam of x-rays. The length of the gas cell was optimised to produce high contrast x-ray images of radiographed test objects. This source was used for full tomographic imaging of a human trabecular bone sample, with resolution exceeding the ~ 100 μ m level required for CT applications. Phase-contrast imaging of human prostate and mouse neonates at the micron level was also demonstrated. These studies indicate the usefulness of these sources in research and clinical applications. The ultrafast nature of the source was also demonstrated by performing time resolved imaging of a laser driven shock. The ultrashort duration of the x-ray source essentially freeze the motion of these fast moving transient phenomena.

  20. Role of stochastic heating in wakefield acceleration when optical injection is used

    SciTech Connect

    Rassou, S.; Bourdier, A.; Drouin, M.

    2014-08-15

    The dynamics of an electron in two counterpropagating waves is investigated. Conditions for stochastic acceleration are derived. The possibility of stochastic heating is confirmed when two waves interact with low density plasma by performing PIC (Particle In Cell) code simulations. It is shown that stochastic heating can play an important role in laser wakefield acceleration. When considering low density plasma interacting with a high intensity wave perturbed by a low intensity counterpropagating wave, stochastic heating can provide electrons with the right momentum for trapping in the wakefield. The influence of stochastic acceleration on the trapping of electrons is compared to the one of the beatwave force which is responsible for cold injection. To do so, several polarizations for the colliding pulses are considered. For some value of the plasma density and pulse duration, a transition from an injection due to stochastic acceleration to a cold injection dominated regime—regarding the trapped charge—has been observed from 2D and 3D PIC code simulations. This transition is ruled by the ratio of the interaction length of the pulses to the longitudinal size of the bubble. When the interaction length of the laser pulses reaches the radius of the accelerating cavity stochastic heating becomes dominant, and might be necessary to get electrons trapped into the wakefield, when wakefield inhibition grows with plasma density.

  1. Generation of electron beams from a laser wakefield acceleration in pure neon gas

    SciTech Connect

    Li, Song; Hafz, Nasr A. M. Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie; Tao, Mengze; Chen, Liming

    2014-08-15

    We report on the generation of quasimonoenergetic electron beams by the laser wakefield acceleration of 17–50 TW, 30 fs laser pulses in pure neon gas jet. The generated beams have energies in the range 40–120 MeV and up to ∼430 pC of charge. At a relatively high density, we observed multiple electron beamlets which has been interpreted by simulations to be the result of breakup of the laser pulse into multiple filaments in the plasma. Each filament drives its own wakefield and generates its own electron beamlet.

  2. First demonstration of a staged all-optical laser wakefield acceleration

    SciTech Connect

    Kaganovich, D.; Ting, A.; Gordon, D.F.; Hubbard, R.F.; Jones, T.G.; Zigler, A.; Sprangle, P.

    2005-10-01

    A proof-of-principle experiment on staged all-optical laser wakefield acceleration was performed at the Naval Research Laboratory. Electrons with <1 MeV energy created by the interaction of a 2 TW laser beam with a nitrogen gas jet were injected and accelerated to more than 20 MeV in a plasma wakefield generated by a 10 TW laser beam in a helium gas jet. The energy gain occurred in a narrow time window of 3 ps between the injection and acceleration laser beams, and within a tight spatial alignment of {approx}10 {mu}m.

  3. Overloading effect of energetic electrons in the bubble regime of laser wakefield acceleration

    SciTech Connect

    Xu Jiancai; Shen Baifei; Zhang Xiaomei; Wen Meng; Ji Liangliang; Wang Wenpeng; Yu Yahong; Li Yuelin

    2010-10-15

    The overloading effect of self-injected high-charge electron bunch in the bubble regime of laser wakefield acceleration is studied. When too many electrons are trapped by the bubble, the wakefield can be strongly modified, preventing further injection of the background electrons. This process is directly observed in two-dimensional particle-in-cell simulation and is explained using a one-dimensional wake model. For obtaining significantly more energetic electrons, the use of a decreasing plasma density profile is proposed.

  4. Tomography of injection and acceleration of monoenergetic electrons in a laser-wakefield accelerator.

    PubMed

    Hsieh, C-T; Huang, C-M; Chang, C-L; Ho, Y-C; Chen, Y-S; Lin, J-Y; Wang, J; Chen, S-Y

    2006-03-10

    A tomographic diagnosis method was developed to systematically resolve the injection and acceleration processes of a monoenergetic electron beam in a laser-wakefield accelerator. It was found that all the monoenergetic electrons are injected at the same location in the plasma column and accelerated from 5 to 55 MeV energy in 200 microm distance. This is a direct measurement of the real acceleration gradient in a laser-wakefield accelerator, and the experimental data are consistent with the model of transverse wave breaking and beam loading for monoenergetic electron injection. PMID:16606269

  5. Compton Scattering X-Ray Sources Driven by Laser Wakefield Acceleration

    SciTech Connect

    Hartemann, F V; Gibson, D J; Brown, W J; Rousse, A; Phuoc, K T; Pukhov, A

    2005-10-19

    Recent laser wakefield acceleration experiments have demonstrated the generation of femtosecond, nano-Coulomb, low emittance, nearly monokinetic relativistic electron bunches of sufficient quality to produce bright, tunable, ultrafast x-rays via Compton scattering. Design parameters for a proof-of-concept experiment are presented using a three-dimensional Compton scattering code and a laser-plasma interaction particle-in-cell code modeling the wakefield acceleration process; x-ray fluxes exceeding 10{sup 22} s{sup -1} are predicted, with a peak brightness > 10{sup 20} photons/(mm{sup 2} x mrad{sup 2} x s x 0.1% bandwidth).

  6. Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration.

    PubMed

    Hafz, N; Hur, M S; Kim, G H; Kim, C; Ko, I S; Suk, H

    2006-01-01

    A relativistic electron bunch with a large charge (>2 nC) was produced from a self-modulated laser wakefield acceleration configuration. For this experiment, an intense laser beam with a peak power of 2 TW and a duration of 700 fs was focused in a supersonic He gas jet, and relativistic high-energy electrons were observed from the strong laser-plasma interaction. By passing the electron bunch through a small pinholelike collimator, we could generate a quasimonoenergetic high-energy electron beam, in which electrons within a cone angle of 0.25 mrad (f/70) were selected. The beam clearly showed a narrow-energy-spread behavior with a central energy of 4.3 MeV and a charge of 200 pC. The acceleration gradient was estimated to be about 30 GeV/m. Particle-in-cell simulations were performed for comparison study and the result shows that both the experimental and simulation results are in good agreement and the electron trapping is initiated by the slow beat wave of the Raman backward wave and the incident laser pulse. PMID:16486286

  7. Dense attosecond electron sheets from laser wakefields using an up-ramp density transition.

    PubMed

    Li, F Y; Sheng, Z M; Liu, Y; Meyer-ter-Vehn, J; Mori, W B; Lu, W; Zhang, J

    2013-03-29

    Controlled electron injection into a laser-driven wakefield at a well defined space and time is reported based on particle-in-cell simulations. Key novel ingredients are an underdense plasma target with an up-ramp density profile followed by a plateau and a fairly large laser focus diameter that leads to an essentially one-dimensional (1D) regime of laser wakefield, which is different from the bubble (complete blowout) regime occurring for tightly focused drive beams. The up-ramp profile causes 1D wave breaking to occur sharply at the up-ramp-plateau transition. As a result, it generates an ultrathin (few nanometer, corresponding to attosecond duration), strongly overdense relativistic electron sheet that is injected and accelerated in the wakefield. A peaked electron energy spectrum and high charge (∼nC) distinguish the final sheet. PMID:23581329

  8. High transformer ratio drive beams for wakefield accelerator studies

    SciTech Connect

    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.

    2012-12-21

    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.

  9. Quasi-stable injection channels in a wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Wiltshire-Turkay, Mara; Farmer, John P.; Pukhov, Alexander

    2016-05-01

    The influence of initial position on the acceleration of externally injected electrons in a plasma wakefield is investigated. Test-particle simulations show previously unobserved complex structure in the parameter space, with quasi-stable injection channels forming for particles injected in narrow regions away from the wake centre. Particles injected into these channels remain in the wake for a considerable time after dephasing and as a result achieve significantly higher energy than their neighbours. The result is relevant to both the planning and optimisation of experiments making use of external injection.

  10. SCALED SIMULATION DESIGN OF HIGH QUALITY LASER WAKEFIELD ACCELERATOR STAGES

    SciTech Connect

    Geddes, C.G.R.; Cormier-Michel, E.; Esarey, E.; Schroeder, C.B.; Leemans, W.P.; Bruhwiler, D.L.; Cowan, B.; Nieter, C.; Paul, K.; Cary, J.R.

    2009-05-04

    Design of efficient, high gradient laser driven wakefield accelerator (LWFA) stages using explicit particle-incell simulations with physical parameters scaled by plasma density is presented. LWFAs produce few percent energy spread electron bunches at 0.1-1 GeV with high accelerating gradients. Design tools are now required to predict and improve performance and efficiency of future LWFA stages. Scaling physical parameters extends the reach of explicit simulations to address applications including 10 GeV stages and stages for radiation sources, and accurately resolves deep laser depletion to evaluate efficient stages.

  11. Transformer ratio saturation in a beam-driven wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Farmer, J. P.; Martorelli, R.; Pukhov, A.

    2015-12-01

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  12. Transformer ratio saturation in a beam-driven wakefield accelerator

    SciTech Connect

    Farmer, J. P.; Martorelli, R.; Pukhov, A.

    2015-12-15

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  13. The Argonne Wakefield Accelerator: Overview and status

    SciTech Connect

    Schoessow, P.; Chojnacki, E.; Gai, W.; Ho, C.; Konecny, R.; Power, J.; Rosing, M.; Simpson, J.

    1993-08-01

    The Argonne Wakefield Accelerator (AWA) is a new facility for advanced accelerator research, with a particular emphasis on studies of high gradient ({approximately}100 MeV/m) wakefield acceleration. A novel high current short pulse L-Band photocathode and preaccelerator will provide 100 nC electron bunches at 20 MeV to be used as a drive beam, while a second high brightness gun will be used to generate a 5 MeV witness beam for wakefield measurements. We will present an overview of the various AWA systems, the status of construction, and initial commissioning results.

  14. Wakefield effects in a linear collider

    SciTech Connect

    Bane, K.L.F.

    1986-12-01

    In this paper the wakefields for the Stanford Linear Accelerator Center (SLAC) accelerating structure are first discussed, and then some considerations dealing with the longitudinal wakefields are described. The main focus is on the effects of the transverse wakefield on the beam, including the case when there is an energy variation along the bunch. The use of an energy spread to inhibit emittance growth in a linac, indeed to damp the oscillations of the core of the bunch to below the unperturbed betatron oscillations, (in a process that is similar to Landau Damping) is qualitatively detailed. The example of the SLC, including errors, is also in detail.

  15. High Energy Density Microwaves

    SciTech Connect

    Phillips, R.M.

    1999-04-01

    These proceedings represent papers presented at the RF98 Workshop entitled `High Energy Density Microwaves` held in California in October, 1998. The topics discussed were predominantly accelerator{minus}related. The Workshop dealt, for the most part, with the generation and control of electron beams, the amplification of RF signals, the design of mode converters, and the effect of very high RF field gradients. This Workshop was designed to address the concerns of the microwave tube industry worldwide, the plasma physicists who deal with very high beam currents and gigawatts of RF power, and researchers in accelerator centers around the world. Papers were presented on multibeam klystrons, gyrotron development, plasmas in microwave tubes, RF breakdown, and alternatives to conventional linear coliders at 1 TeV and above. The Workshop was partially sponsored by the US Department of Energy. There were 46 papers presented at the conference,out of which 19 have been abstracted for the Energy,Science and Technology database.(AIP)

  16. Positron acceleration in doughnut wakefields in the blowout regime

    NASA Astrophysics Data System (ADS)

    Vieira, Jorge; Mendonca, Jose; Fonseca, Ricardo; Silva, Luis

    2014-10-01

    Most important plasma acceleration results were reached in the so called bubble or blowout regime. Although ideally suited for electron acceleration, it has been recognized that non-linear regimes are not adequate to accelerate positrons. New configurations enabling positron acceleration in non-linear regimes would therefore open new research paths for future plasma based collider configurations. In this work, we explore, analytically and through 3D OSIRIS simulations, a novel configuration for positron acceleration in strongly non-linear laser wakefield excitation regimes using Laguerre-Gaussian laser drivers to drive doughnut shaped wakefields with positron focusing and accelerating fields. We demonstrate that positron focusing-fields can be up to an order of magnitude larger than electron focusing in the spherical blowout regime. The amplitude of the accelerating fields is similar to the spherical blowout. Simulations demonstrate laser self-guiding and stable positron acceleration until the laser energy has been exhausted to the plasma. Other realisations of the scheme, using two Gaussian laser pulses, will also be explored. FCT Grant No EXPL/FIS-PLA/0834/2012 and European Research Council ERC-2010-AdG Grant No. 267841.

  17. On some theoretical problems of laser wake-field accelerators

    NASA Astrophysics Data System (ADS)

    Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kiriyama, H.; Koga, J. K.; Kotaki, H.; Mori, M.; Kando, M.

    2016-06-01

    Enhancement of the quality of laser wake-field accelerated (LWFA) electron beams implies the improvement and controllability of the properties of the wake waves generated by ultra-short pulse lasers in underdense plasmas. In this work we present a compendium of useful formulas giving relations between the laser and plasma target parameters allowing one to obtain basic dependences, e.g. the energy scaling of the electrons accelerated by the wake field excited in inhomogeneous media including multi-stage LWFA accelerators. Consideration of the effects of using the chirped laser pulse driver allows us to find the regimes where the chirp enhances the wake field amplitude. We present an analysis of the three-dimensional effects on the electron beam loading and on the unlimited LWFA acceleration in inhomogeneous plasmas. Using the conditions of electron trapping to the wake-field acceleration phase we analyse the multi-equal stage and multiuneven stage LWFA configurations. In the first configuration the energy of fast electrons is a linear function of the number of stages, and in the second case, the accelerated electron energy grows exponentially with the number of stages. The results of the two-dimensional particle-in-cell simulations presented here show the high quality electron acceleration in the triple stage injection-acceleration configuration.

  18. On some theoretical problems of laser wake-field accelerators

    NASA Astrophysics Data System (ADS)

    Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kiriyama, H.; Koga, J. K.; Kotaki, H.; Mori, M.; Kando, M.

    2016-06-01

    > Enhancement of the quality of laser wake-field accelerated (LWFA) electron beams implies the improvement and controllability of the properties of the wake waves generated by ultra-short pulse lasers in underdense plasmas. In this work we present a compendium of useful formulas giving relations between the laser and plasma target parameters allowing one to obtain basic dependences, e.g. the energy scaling of the electrons accelerated by the wake field excited in inhomogeneous media including multi-stage LWFA accelerators. Consideration of the effects of using the chirped laser pulse driver allows us to find the regimes where the chirp enhances the wake field amplitude. We present an analysis of the three-dimensional effects on the electron beam loading and on the unlimited LWFA acceleration in inhomogeneous plasmas. Using the conditions of electron trapping to the wake-field acceleration phase we analyse the multi-equal stage and multiuneven stage LWFA configurations. In the first configuration the energy of fast electrons is a linear function of the number of stages, and in the second case, the accelerated electron energy grows exponentially with the number of stages. The results of the two-dimensional particle-in-cell simulations presented here show the high quality electron acceleration in the triple stage injection-acceleration configuration.

  19. Plasma gradient controlled injection and postacceleration of high quality electron bunches

    SciTech Connect

    Geddes, C. G. R.; Cormier-Michel, E.; Nakamura, K.; Schroeder, C. B.; Toth, Cs.; Esarey, E.; Plateau, G. R.; Bruhwiler, D. L.; Cary, J. R.; Leemans, W. P.

    2009-01-22

    Plasma density gradient control of wake phase velocity and trapping threshold in a laser wakefield accelerator produced electron bunches with absolute longitudinal and transverse momentum spreads more than ten times lower than in previous experiments (0.17 and 0.02 MeV/c FWHM, respectively) and with central momenta of 0.76{+-}0.02 MeV/c, stable over a week of operation. Simulations validated against diagnostics show that use of such bunches as a wakefield accelerator injector can produce stable beams with 0.2 MeV/c-class momentum spread at high energies. Preservation of bunch momentum spread requires high simulation momentum accuracy, and related self-trapped simulations showed that high order particle weight effectively suppresses simulation momentum errors allowing design of low emittance stages.

  20. Laser wakefield and direct acceleration with ionization injection

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Khudik, Vladimir N.; Pukhov, Alexander; Shvets, Gennady

    2016-03-01

    We demonstrate using particle-in-cell simulations that electrons can be injected into a hybrid laser wakefield and direct laser accelerator via ionization injection. We propose an accelerator and injector scenario that utilizes two laser pulses. The first (pump) pulse produces the plasma ‘bubble’ by expelling the plasma electrons generated by its leading edge from the low-Z component of the gas mixture, and then injects electrons into the bubble by ionizing the high-Z component. The second time-delayed laser pulse resonantly interacts with these injected electrons undergoing betatron oscillations inside the bubble. We show that the electrons ionized off-axis and on-axis but off the peak ionization phase possess sufficient transverse energy to undergo efficient direct laser acceleration (DLA). When combined with their acceleration by the bubble’s longitudinal plasma wake, DLA can double the total energy gain and produce a monoenergetic beam.

  1. Wakefield Computations for the Injector (Part I)

    SciTech Connect

    Limborg-Deprey, C.

    2010-12-13

    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.

  2. Experimental study of self-trapping in capillary discharge guided laser wakefield acceleration

    SciTech Connect

    Panasenko, D.; Esarey, E.; Geddes, C. G. R.; Gonsalves, A. J.; Leemans, W. P.; Lin, C.; Nakamura, K.; Schroeder, C. B.; Toth, C.

    2009-05-04

    Laser wakefield acceleration experiments were carried out using hydrogen-filled capillary discharge waveguides. For a 33 mm long, 300 mu m capillary, parameter regimes with high energy electron beams (up to 1 GeV) and stable 0.5 GeV were found. In the high energy regime, the electron beam peak energy was correlated with the number of trapped electrons. For a 15 mm long, 200 mu m diameter capillary, quasi-monoenergetic e beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized.

  3. Summary report: working group 2 on 'Plasma Based AccelerationConcepts'

    SciTech Connect

    Esarey, E.; Leemans, Wim

    1998-09-01

    A summary of the talks, papers and discussion sessions presented in the Working Group on Plasma Based Acceleration Concepts is given within the context of the progress towards a 1 GeV laser driven accelerator module. The topics covered within the Working Group were self-modulated laser wakefield acceleration, standard laser wakefield acceleration, plasma beatwave acceleration, laser guiding and wake excitation in plasma channels, plasma wakefield acceleration, plasma lenses and optical injection techniques for laser wakefield accelerators. An overview will be given of the present status of experimental and theoretical progress as well as an outlook towards the future physics and technological challenges for the development of an optimized accelerator module.

  4. Multistage coupling of independent laser-plasma accelerators.

    PubMed

    Steinke, S; van Tilborg, J; Benedetti, C; Geddes, C G R; Schroeder, C B; Daniels, J; Swanson, K K; Gonsalves, A J; Nakamura, K; Matlis, N H; Shaw, B H; Esarey, E; Leemans, W P

    2016-02-11

    Laser-plasma accelerators (LPAs) are capable of accelerating charged particles to very high energies in very compact structures. In theory, therefore, they offer advantages over conventional, large-scale particle accelerators. However, the energy gain in a single-stage LPA can be limited by laser diffraction, dephasing, electron-beam loading and laser-energy depletion. The problem of laser diffraction can be addressed by using laser-pulse guiding and preformed plasma waveguides to maintain the required laser intensity over distances of many Rayleigh lengths; dephasing can be mitigated by longitudinal tailoring of the plasma density; and beam loading can be controlled by proper shaping of the electron beam. To increase the beam energy further, it is necessary to tackle the problem of the depletion of laser energy, by sequencing the accelerator into stages, each powered by a separate laser pulse. Here, we present results from an experiment that demonstrates such staging. Two LPA stages were coupled over a short distance (as is needed to preserve the average acceleration gradient) by a plasma mirror. Stable electron beams from a first LPA were focused to a twenty-micrometre radius--by a discharge capillary-based active plasma lens--into a second LPA, such that the beams interacted with the wakefield excited by a separate laser. Staged acceleration by the wakefield of the second stage is detected via an energy gain of 100 megaelectronvolts for a subset of the electron beam. Changing the arrival time of the electron beam with respect to the second-stage laser pulse allowed us to reconstruct the temporal wakefield structure and to determine the plasma density. Our results indicate that the fundamental limitation to energy gain presented by laser depletion can be overcome by using staged acceleration, suggesting a way of reaching the electron energies required for collider applications. PMID:26829223

  5. Laser Wakefield Acceleration in the PetaWatt Regime

    NASA Astrophysics Data System (ADS)

    Joshi, C.; Tsung, F. S.; Mori, W. B.; Katsouleas, T.; Fonseca, R. A.; Silva, L. O.

    2003-10-01

    Laser wakefield acceleration with multi-terawatt lasers has demonstrated impressive results in experiments around the world-- e.g., energy gains up to 700 MeV in mm-scale gas jets has recently been reported. With a number of petawatt class lasers planned for operation in the near future, we examine with 2-D and 3-D PIC simulations the potential energy gain and new physics of laser wakefield acceleration in this regime. These lasers will operated for a variety of pulse lengths. We consider both 35 fs and 600 fs pulses, but will emphasize the 35 fs results for this poster. Prospects for producing GeV electron beams in underdense plasmas will be described. In addition, the differences in physics between terawatt and petawatt regimes will be explored. Preliminary results for the 35 fs class lasers indicate that there are two acceleration stages in the petawatt regime -- with the early electrons dephasing due to elongation of the laser wake as the laser pump evolves. The later stage produces a long beam of electrons several times the initial plasma wake wavelength with a fairly defined energy in the GeV range. For the 600 fs class lasers, 2D simulations indicate that the acceleration process is much more complicated and it involves an interaction between the fields in the wake and the laser.

  6. Proof-of-principle experiments of laser Wakefield acceleration

    SciTech Connect

    Nakajima, K.; Kawakubo, T.; Nakanishi, H.

    1994-04-01

    Recently there has been a great interest in laser-plasma accelerators as possible next-generation particle accelerators because of their potential for ultra high accelerating gradients and compact size compared with conventional accelerators. It is known that the laser pulse is capable of exciting a plasma wave propagating at a phase velocity close to the velocity of light by means of beating two-frequency lasers or an ultra short laser pulse. These schemes came to be known as the Beat Wave Accelerator (BWA) for beating lasers or as the Laser Wakefield Accelerator (LWFA) for a short pulse laser. In this paper, the principle of laser wakefield particle acceleration has been tested by the Nd:glass laser system providing a short pulse with a power of 10 TW and a duration of 1 ps. Electrons accelerated up to 18 MeV/c have been observed by injecting 1 MeV/c electrons emitted from a solid target by an intense laser impact. The accelerating field gradient of 30 GeV/m is inferred.

  7. Model experiment of cosmic ray acceleration due to an incoherent wakefield induced by an intense laser pulse

    SciTech Connect

    Kuramitsu, Y.; Sakawa, Y.; Takeda, K.; Tampo, M.; Takabe, H.; Nakanii, N.; Kondo, K.; Tsuji, K.; Kimura, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Kodama, R.; Mima, K.; Tanaka, K. A.; Mori, Y.; Miura, E.; Kitagawa, Y.

    2011-01-15

    The first report on a model experiment of cosmic ray acceleration by using intense laser pulses is presented. Large amplitude light waves are considered to be excited in the upstream regions of relativistic astrophysical shocks and the wakefield acceleration of cosmic rays can take place. By substituting an intense laser pulse for the large amplitude light waves, such shock environments were modeled in a laboratory plasma. A plasma tube, which is created by imploding a hollow polystyrene cylinder, was irradiated by an intense laser pulse. Nonthermal electrons were generated by the wakefield acceleration and the energy distribution functions of the electrons have a power-law component with an index of {approx}2. The maximum attainable energy of the electrons in the experiment is discussed by a simple analytic model. In the incoherent wakefield the maximum energy can be much larger than one in the coherent field due to the momentum space diffusion or the energy diffusion of electrons.

  8. Wakefield accelerators in the blowout regime with mobile ions

    SciTech Connect

    Lee, S.; Katsouleas, T.

    1999-07-12

    In the Plasma Wakefield Accelerator a high current drive-beam excites a large wake that can accelerate trailing particles. The wake is created when the space charge of the drive beam displaces plasma electrons. The plasma ions provide the restoring force on the displaced electrons. For symmetric bunches, the peak accelerating gradient is proportional to the current over a pulse length. For example, for a Gaussian bunch with 6nC of charge and bunch length {sigma}{sub z}{approx_equal}0.6 mm, a gradient of 1GeV/m can be obtained. For the case of dense (beam density greater than plasma density), narrow (beam spot size {sigma}{sub r} smaller than c/{omega}{sub p}) beams the plasma response is non-linear and is dominated by the radial blow out of all the plasma electrons. However, such dense beams are strongly focused by the plasma lens effect. As a result they become so dense that ion motion should become important even on the electron plasma frequency time-scale. We will present analytic and 2-D particle-in-cell (PIC) models of wake excitation including mobile ions. The effect of the ion motion on the accelerating and focusing wake and the dynamics of the drive beam are discussed.

  9. Wakefield accelerators in the blowout regime with mobile ions

    SciTech Connect

    Lee, S.; Katsouleas, T.

    1999-07-01

    In the Plasma Wakefield Accelerator a high current drive-beam excites a large wake that can accelerate trailing particles. The wake is created when the space charge of the drive beam displaces plasma electrons. The plasma ions provide the restoring force on the displaced electrons. For symmetric bunches, the peak accelerating gradient is proportional to the current over a pulse length. For example, for a Gaussian bunch with 6nC of charge and bunch length {sigma}{sub z}{approx}0.6&hthinsp;mm, a gradient of 1GeV/m can be obtained. For the case of dense (beam density greater than plasma density), narrow (beam spot size {sigma}{sub r} smaller than c/{omega}{sub p}) beams the plasma response is non-linear and is dominated by the radial blow out of all the plasma electrons. However, such dense beams are strongly focused by the plasma lens effect. As a result they become so dense that ion motion should become important even on the electron plasma frequency time-scale. We will present analytic and 2-D particle-in-cell (PIC) models of wake excitation including mobile ions. The effect of the ion motion on the accelerating and focusing wake and the dynamics of the drive beam are discussed. {copyright} {ital 1999 American Institute of Physics.}

  10. Wakefield accelerators in the blowout regime with mobile ions

    NASA Astrophysics Data System (ADS)

    Lee, S.; Katsouleas, T.

    1999-07-01

    In the Plasma Wakefield Accelerator a high current drive-beam excites a large wake that can accelerate trailing particles. The wake is created when the space charge of the drive beam displaces plasma electrons. The plasma ions provide the restoring force on the displaced electrons. For symmetric bunches, the peak accelerating gradient is proportional to the current over a pulse length. For example, for a Gaussian bunch with 6nC of charge and bunch length σz≈0.6 mm, a gradient of 1GeV/m can be obtained. For the case of dense (beam density greater than plasma density), narrow (beam spot size σr smaller than c/ωp) beams the plasma response is non-linear and is dominated by the radial blow out of all the plasma electrons. However, such dense beams are strongly focused by the plasma lens effect. As a result they become so dense that ion motion should become important even on the electron plasma frequency time-scale. We will present analytic and 2-D particle-in-cell (PIC) models of wake excitation including mobile ions. The effect of the ion motion on the accelerating and focusing wake and the dynamics of the drive beam are discussed.

  11. High energy neutron radiography

    SciTech Connect

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-06-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos.

  12. Optimization of THz Radiation Generation from a Laser Wakefield Accelerator

    SciTech Connect

    Plateau, G. R.; Matlis, N. H.; Toth, C.; Geddes, C. G. R.; Schroeder, C. B.; Tilborg, J. van; Albert, O.; Esarey, E.; Leemans, W. P.

    2009-01-22

    Ultrashort terahertz pulses with energies in the {mu}J range can be generated with laser wakefield accelerators (LWFA), which are novel, compact accelerators that produce ultrashort electron bunches with energies up to 1 GeV and energy spreads of a few-percent. Laser pulses interacting with a plasma create accelerated electrons which upon exiting the plasma emit terahertz pulses via transition radiation. Because these electron bunches are ultrashort (<50 fs), they can radiate coherently (coherent transition radiation--CTR) in a wide bandwidth ({approx}1-10 THz) yielding high intensity terahertz pulses. In addition to providing a non-invasive bunch-length diagnostic and thus feedback for the LWFA, these high peak power THz pulses are suitable for high field (MV/cm) pump-probe experiments. Here we present energy-based measurements using a Golay cell and an electro-optic technique which were used to characterize these THz pulses.

  13. Laser wakefield acceleration: the injection issue. Overview and latest results.

    PubMed

    van der Wiel, M J; Luiten, O J; Brussaard, G J H; van der Geer, S B; Urbanus, W H; van Dijk, W; van Oudheusden, Th

    2006-03-15

    External injection of electron bunches into laser-driven plasma waves so far has not resulted in 'controlled' acceleration, i.e. production of bunches with well-defined energy spread. Recent simulations, however, predict that narrow distributions can be achieved, provided the conditions for properly trapping the injected electrons are met. Under these conditions, injected bunch lengths of one to several plasma wavelengths are acceptable. This paper first describes current efforts to demonstrate this experimentally, using state-of-the-art radio frequency technology. The expected charge accelerated, however, is still low for most applications. In the second part, the paper addresses a number of novel concepts for significant enhancement of photo-injector brightness. Simulations predict that, once these concepts are realized, external injection into a wakefield accelerator will lead to accelerated bunch specs comparable to those of recent 'laser-into-gasjet' experiments, without the present irreproducibility of charge and final energy of the latter. PMID:16483957

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

    SciTech Connect

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

    2011-08-19

    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.

  15. Direct Observation of the Injection Dynamics of a Laser Wakefield Accelerator Using Few-Femtosecond Shadowgraphy.

    PubMed

    Sävert, A; Mangles, S P D; Schnell, M; Siminos, E; Cole, J M; Leier, M; Reuter, M; Schwab, M B; Möller, M; Poder, K; Jäckel, O; Paulus, G G; Spielmann, C; Skupin, S; Najmudin, Z; Kaluza, M C

    2015-07-31

    We present few-femtosecond shadowgraphic snapshots taken during the nonlinear evolution of the plasma wave in a laser wakefield accelerator with transverse synchronized few-cycle probe pulses. These snapshots can be directly associated with the electron density distribution within the plasma wave and give quantitative information about its size and shape. Our results show that self-injection of electrons into the first plasma-wave period is induced by a lengthening of the first plasma period. Three-dimensional particle-in-cell simulations support our observations. PMID:26274425

  16. Plasma gradient controlled injection and postacceleration of high quality electron bunches

    SciTech Connect

    Geddes, Cameron G.R.; Nakamura, Kei; Plateau, Guillaume R.; Toth, Csaba; Cormier-Michel, Estelle; Esarey, Eric; Schroeder, Carl B.; Cary, John R.; Leemans, Wim P.; Bruhwiler, D.L.

    2008-10-15

    Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold in a laser wakefield accelerator, producing stable electron bunches with longitudinal and transverse momentum spreads more than 10 times lower than in previous experiments (0.17 and 0.02 MeV=c FWHM, respectively) and with central momenta of 0.76 +- 0.02 MeV=c. Transition radiation measurements combined with simulations indicated that the bunches can be used as a wakefieldaccelerator injector to produce stable beams with 0.2 MeV=c-class momentum spread at high energies.

  17. High gradient dielectric wakefield device measurements at the Argonne wakefield accelerator

    SciTech Connect

    Schoessow, P.; Conde, M.; Gai, W.; Konecny, R.; Power, J.; Simpson, J.

    1997-10-01

    The Argonne Wakefield Accelerator (AWA) is a facility designed to investigate high gradient wakefield acceleration techniques. Wakefields are excited using a drive beam produced by a 14 MeV high current photoinjector-based linac. A second photocathode gun generates a 4 MeV witness beam which is used as a probe of the wakefields in the device under test. The delay of the witness bunch with respect to the drive bunch can be continuously varied from -100 ps to >1 ns. The drive and witness bunches propagate along collinear or parallel trajectories through the test section. A dipole spectrometer is then used to measure the energy change of the witness beam. The complete wakefield measurement system has been commissioned and wakefield experiments using dielectric structures are underway. Initial experiments have focused on collinear wakefield device geometries where the drive and witness bunches traverse the same structure. For attaining very high gradients we will construct and study step-up transformer structures in which the rf pulse generated by the drive beam is compressed transversely and longitudinally.

  18. Front-to-end simulations of the design of a laser wakefield accelerator with external injection

    SciTech Connect

    Urbanus, W.H.; Dijk, W. van; Geer, S.B. van der; Brussaard, G.J.H.; Wiel, M.J. van der

    2006-06-01

    We report the design of a laser wakefield accelerator (LWA) with external injection by a rf photogun and acceleration by a linear wakefield in a capillary discharge channel. The design process is complex due to the large number of intricately coupled free parameters. To alleviate this problem, we performed front-to-end simulations of the complete system. The tool we used was the general particle-tracking code, extended with a module representing the linear wakefield by a two-dimensional traveling wave with appropriate wavelength and amplitude. Given the limitations of existing technology for the longest discharge plasma wavelength ({approx}50 {mu}m) and shortest electron bunch length ({approx}100 {mu}m), we studied the regime in which the wakefield acts as slicer and buncher, while rejecting a large fraction of the injected bunch. The optimized parameters for the injected bunch are 10 pC, 300 fs at 6.7 MeV, to be injected into a 70 mm long channel at a plasma density of 7x10{sup 23} m{sup -3}. A linear wakefield is generated by a 2 TW laser focused to 30 {mu}m. The simulations predict an accelerated output of 0.6 pC, 10 fs bunches at 90 MeV, with energy spread below 10%. The design is currently being implemented. The design process also led to an important conclusion: output specifications directly comparable to those reported recently from 'laser-into-gas jet' experiments are feasible, provided the performance of the rf photogun is considerably enhanced. The paper outlines a photogun design providing such a performance level.

  19. Electron Self-Injection in Multidimensional Relativistic-Plasma Wake Fields

    SciTech Connect

    Kostyukov, I.; Nerush, E.; Pukhov, A.; Seredov, V.

    2009-10-23

    We present an analytical model for electron self-injection in a nonlinear, multidimensional plasma wave excited by a short laser pulse in the bubble regime or by a short electron beam in the blowout regime. In these regimes, which are typical for electron acceleration, the laser radiation pressure or the electron beam charge pushes out background plasma electrons forming a plasma cavity--bubble--with a huge ion charge. The plasma electrons can be trapped in the bubble and accelerated by the plasma wakefields up to very high energies. The model predicts the condition for electron trapping and the trapping cross section in terms of the bubble radius and the bubble velocity. The obtained results are in a good agreement with results of 3D particle-in-cell simulations.

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

    SciTech Connect

    Cowan, B.; Bruhwiler, D.; Messmer, P.; Paul, K.; Cormier-Michel, E.; Geddes, C. G. R.; Esarey, E.

    2009-01-22

    Simulation of laser wakefield accelerator (LWFA) 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, making explicit PIC simulations enormously expensive and requiring massively parallel execution in 3D. We can substantially improve the performance of laser wakefield simulations by modeling the envelope modulation of the laser field rather than the field itself. This allows for much coarser grids, since we need only resolve the plasma wavelength and not the laser wavelength, and therefore larger timesteps. Thus an envelope model can result in savings of several orders of magnitude in computational resources. By propagating the laser envelope in a frame moving at the speed of light, dispersive errors can be avoided and simulations over long distances become possible. Here we describe the model and its implementation, and show simulations and benchmarking of laser wakefield phenomena such as channel propagation, self-focusing, wakefield generation, and downramp injection using the model.