Electron beam control using shock-induced density downramp injection

Abstract

Abstract. In these experiments, we improve the quality of electrons injected along a shock-induced density downramp. We demonstrate that beam ellipticity and steering are influenced by the shock front tilt, and we present simple models to explain these effects. By adjusting the shock front angle, we minimize the beam's off-axis steering and ellipticity, producing high-quality electron beams over a tunable energy range.

Polarized Laser-WakeField-Accelerated Kiloampere Electron Beams

“…In our simulations, we trace all and only the electrons that remain in the accelerating phase of the wake. The initial region of trapped electrons constitutes the injection volume with a radius R inj ∝ w 0 [48].…”

“…( 2) for a 0 significantly larger than unity [32]. After the acceleration in the shock-front injector, which occurs within hundreds of micrometers [26,[47][48][49], the accelerator stage can be further extended to obtain GeV beams via multiacceleration-stage techniques powered by the same [50] or different [51] laser pulses. In fact, further acceleration of already ultrarelativistic polarized electron beams weakly alters the EBP [52].…”

“…Also, Stern-Gerlach and radiation reaction forces are negligible at the low intensities and copropagating geometry considered here [41,46]. In our PIC simulations we have chosen laser and plasma parameters similar to those already obtained in experiments with shock-front injection [26,[47][48][49]. The plasma density profile is shown in Fig.…”

“…In our simulations, we trace all and only the electrons that remain in the accelerating phase of the wake. The initial region of trapped electrons constitutes the injection volume with a radius R inj ∝ w 0 [48]. Stage II begins at t I , where the electrons of the injection volume undergo a transient acceleration phase due both to the laser and to the wake-wave fields, as shown in Figs.…”