Analysis of electron injection in laser wakefield acceleration using betatron emission in capillary tubes

F. G. Desforges (1) , B. S. Paradkar (1) , M. Hansson (2) , T. L. Audet (1) , J. Ju (1) , I. Gallardo-González (2) , B. Aurand (2) , P. Lee (1) , L. Senje (2) , A. Persson (2) , S. Dobosz Dufrénoy (3, 4) , O. Lundh (2) , G. Maynard (1) , P. Monot (4, 3) , J. L. Vay (5) , C.-G. Wahlström (2, 6) , B. Cros (1)

1 LPGP - Laboratoire de physique des gaz et des plasmas
2 Lund University [Lund]
3 PHI - Physique à Haute Intensité
4 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
5 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
6 Department of Physics

The dynamics of ionization-induced electron injection in the high density (~ 1:2 × 1019cm-3) regime of Laser Wakefield Acceleration (LWFA) was investigated by analyzing betatron X-ray emission inside dielectric capillary tubes. A comparative study of the electron and betatron X-ray properties was performed for both self-injection and ionization-induced injection. Direct experimental evidence of early onset of ionization-induced injection into the plasma wave was obtained by mapping the X-ray emission zone inside the plasma. Particle-In-Cell (PIC) simulations showed that the early onset of ionization-induced injection, due to its lower trapping threshold, suppresses self-injection of electrons. An increase of X-ray fluence by at least a factor of two was observed in the case of ionization-induced injection due to an increased trapped charge compared to self-injection mechanism. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Keywords: Capillaries; Electrons; Lasers; Ionization; X-rays; Plasmas; Simulations; Particles

Domains: Physics [physics]

F. G. Desforges, B. S. Paradkar, M. Hansson, T. L. Audet, J. Ju, et al.. Analysis of electron injection in laser wakefield acceleration using betatron emission in capillary tubes. Laser Acceleration of Electrons, Protons, and Ions III; and Medical Applications of Laser-Generated Beams of Particles III, Kenneth W. D. Ledingham; Klaus Spohr; Paul McKenna; Paul R. Bolton; Eric Esarey; Carl B. Schroeder; Florian J. Grüner, Apr 2015, Prague, Czech Republic. ⟨10.1117/12.2178654⟩. ⟨cea-01245756⟩