Dynamics of ionization-induced electron injection in the high density regime of laser wakefield acceleration

作者：Desforges F G^*; Paradkar B S; Hansson M; Ju J; Senje L; Audet T L; Persson A; Dobosz Dufrenoy S; Lundh O; Maynard G; Monot P; Vay J L; Wahlstrom C G; Cros B

来源：Physics of Plasmas, 2014, 21(12): 120703.

DOI：10.1063/1.4903845

The dynamics of ionization-induced electron injection in high density (similar to 1.2 x 10(19) cm(-3)) regime of laser wakefield acceleration is investigated by analyzing the betatron X-ray emission. In such high density operation, the laser normalized vector potential exceeds the injection-thresholds of both ionization-injection and self-injection due to self-focusing. In this regime, direct experimental evidence of early on-set of ionization-induced injection into the plasma wave is given by mapping the X-ray emission zone inside the plasma. Particle-In-Cell simulations show that this early on-set of ionization-induced injection, due to its lower trapping threshold, suppresses the trapping of self-injected electrons. A comparative study of the electron and X-ray properties is performed for both self-injection and ionization-induced injection. An increase of X-ray fluence by at least a factor of two is observed in the case of ionization-induced injection due to increased trapped charge compared to self-injection mechanism.

• 出版日期2014-12
• 单位中国地震局