Investigation of ionization-induced electron injection in a wakefield driven by laser inside a gas cell

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

Ionization-induced electron injection was investigated experimentally by focusing a driving laser pulse with a maximum normalized potential of 1.2 at different positions along the plasma density profile inside a gas cell, filled with a gas mixture composed of 99%H2 þ 1%N2. Changing the laser focus position relative to the gas cell entrance controls the accelerated electron bunch properties, such as the spectrum width, maximum energy, and accelerated charge. Simulations performed using the 3D particle-in-cell code WARP with a realistic density profile give results that are in good agreement with the experimental ones. The interest of this regime for optimizing the bunch charge in a selected energy window is discussed.

Keywords: Plasma waves; Charge injection; Particle-in-cell method; Electric fields; Focal points

Domains: Physics [physics]

T.-L. Audet, M. Hansson, P. Lee, F.-G. Desforges, G. Maynard, et al.. Investigation of ionization-induced electron injection in a wakefield driven by laser inside a gas cell. Physics of Plasmas, 2016, 23, 023110 (6 p.). ⟨10.1063/1.4942033⟩. ⟨cea-01290453⟩