Study of GeV electron beam generation from Laser Wakefield Acceleration on the J-KAREN-P laser facility

We succeeded generating quasi-monoenergetic electron beams with peak energies up to GeV from (He:Ne) mixture gas using the J-KAREN-P laser. By incident of 300 TW laser pulses into a 10 mm gas jet, comparison studies were performed with pure (He), (He:Ne) mixture and (He:N2) mixture gases. We observed that the divergences, energies and charges of electron beams varied with different gas species and mixture ratios. The smallest divergence of electron beams from (He:Ne) was merely 0.18 mrad (rms), which was 5 times smaller than that from (He:N2) gas. For many shots, we got extremely high charge electron bunches with peak energy near GeV. This study shows the capability of the ionization injection regime in the manipulation of divergences and charges of the GeV class electron beams generated from laser wakefield acceleration.日本物理学会 第74回年次大会（2019年