Petawatt Laser Guiding and Electron Beam Acceleration to 8 GeV in a Laser-Heated Capillary Discharge Waveguide

Abstract

Guiding of relativistically intense laser pulses with peak power of 0.85 PW over 15 diffraction lengths was demonstrated by increasing the focusing strength of a capillary discharge waveguide using laser inverse Bremsstrahlung heating. This allowed for the production of electron beams with quasi-monoenergetic peaks up to 7.8 GeV, double the energy that was previously demonstrated. Charge was 5 pC at 7.8 GeV and up to 62 pC in 6 GeV peaks, and typical beam divergence was 0.2 mrad.

Spatio-temporal structure of a petawatt femtosecond laser beam

“…The development of such laser sources, now available or under construction in several laboratories worldwide, is motivated by two main prospects. The first is demonstrating compact particle accelerators for scientific or societal applications, with particle energies up to several GeV [4][5][6][7][8]. The second is exploring the physics of ultra-relativistic laser-matter interactions, and more particularly accessing regimes where highly nonlinear quantum electro-dynamical effects come into play, in order to perform new tests of this fundamental theory [9].…”

Generating high quality ultrarelativistic electron beams using an evolving electron beam driver

“…The effects of the driver intensity and vacuum CS parameters on the wake velocity and injected beam parameters are examined via theory and simulations. For plasma densities of ∼ 10 19 cm −3 , particle-in-cell (PIC) simulations demonstrate that peak normalized brightnesses 10 20 A/m 2 /rad 2 can be obtained with projected energy spreads of 1% within the middle section of the injected beam, and with normalized slice emittances as low as ∼ 10 nm.Over the past few decades, plasma-based acceleration (PBA), driven by either a laser pulse (LWFA) [1] or particle beam (PWFA) [2], has attracted significant interest in compact particle accelerator and x-ray free-electron-laser (XFEL) applications due to the high accelerating fields ∼ 10 − 100 GV/m they generate [3][4][5][6][7][8][9][10][11][12]. While the generation of ultra-relativistic electron beams through selfinjection in an evolving plasma wake has been observed in LWFA experiments [5][6][7][8] and demonstrated in simulations [13][14][15][16], the beams produced to date do not exhibit the sufficiently low energy spreads σ γ and high normalized brightnesses B n = 2I/ǫ 2 n required to drive XFEL devices [17] where I and ǫ n represent the current and normalized emittance, respectively.…”

“…For plasma densities of ∼ 10 19 cm −3 , particle-in-cell (PIC) simulations demonstrate that peak normalized brightnesses 10 20 A/m 2 /rad 2 can be obtained with projected energy spreads of 1% within the middle section of the injected beam, and with normalized slice emittances as low as ∼ 10 nm.Over the past few decades, plasma-based acceleration (PBA), driven by either a laser pulse (LWFA) [1] or particle beam (PWFA) [2], has attracted significant interest in compact particle accelerator and x-ray free-electron-laser (XFEL) applications due to the high accelerating fields ∼ 10 − 100 GV/m they generate [3][4][5][6][7][8][9][10][11][12]. While the generation of ultra-relativistic electron beams through selfinjection in an evolving plasma wake has been observed in LWFA experiments [5][6][7][8] and demonstrated in simulations [13][14][15][16], the beams produced to date do not exhibit the sufficiently low energy spreads σ γ and high normalized brightnesses B n = 2I/ǫ 2 n required to drive XFEL devices [17] where I and ǫ n represent the current and normalized emittance, respectively. In recent years, electron injection schemes involving field ionization [18][19][20][21][22][23] or the use of a plasma density down ramp (DDR) [24][25][26][27][28] have shown tremendous potential for high quality beam generation for XFEL applications.In this Letter, we propose and demonstrate a new method of controllable injection using an electron beam driver whose spot size is decreasing in the nonlinear blowout regime to control the wake phase velocity and hence induce electron trapping.…”

“…While the generation of ultra-relativistic electron beams through selfinjection in an evolving plasma wake has been observed in LWFA experiments [5][6][7][8] and demonstrated in simulations [13][14][15][16], the beams produced to date do not exhibit the sufficiently low energy spreads σ γ and high normalized brightnesses B n = 2I/ǫ 2 n required to drive XFEL devices [17] where I and ǫ n represent the current and normalized emittance, respectively. In recent years, electron injection schemes involving field ionization [18][19][20][21][22][23] or the use of a plasma density down ramp (DDR) [24][25][26][27][28] have shown tremendous potential for high quality beam generation for XFEL applications.In this Letter, we propose and demonstrate a new method of controllable injection using an electron beam driver whose spot size is decreasing in the nonlinear blowout regime to control the wake phase velocity and hence induce electron trapping. As when using a DDR, this proposed method relies on gradually elongating the ion column or cavity length as the drive beam propagates.…”

“…1 where results from OSIRIS simulations are shown. Simulations results presented in this Letter use the quasi-3D algorithm implemented in OSIRIS which expands the fields and currents into an arbitrary number of azimuthal modes m on an r-z grid [30,31]. For the results presented here, m=0 and m=4 were used for symmetric and asymmetric drivers, respectively.…”