Particle-in-cell Simulations of Quasi-Phase Matched Direct Laser Electron Acceleration with a Precursor Electron Bunch
C.-Y. Hsieh1*, M.-W. Lin2, S.-H. Chen1, I. Jovanovic2
1Physics, National Central University, Jhongli, Taiwan
2Mechanical and Nuclear Engineering, The Pennsylvania State University, Pennsylvania, United States of America
* presenting author:謝佳穎,
Three-dimensional particle-in-cell simulation was applied to study quasi-phase matched (QPM) direct laser acceleration (DLA) of electron beams. Energetic electron beams can be efficiently accelerated by well-guided radially polarized laser pulses in density-modulated plasma waveguides. However, the electrostatic field induced by the laser-driven plasma waves defocuses the accelerated electron beam, which limits the effective acceleration distance and deteriorates the beam quality. We introduce an additional precursor electron bunch, which is injected at a proper time prior to the main accelerated electron beam to induce a focusing electrostatic field in the background plasma to reduce the transverse expansion of the accelerated electron beam. Simulation results show that the brightness of the accelerated electron beam can be enhanced three-fold in a 2-mm accelerating distance, as compared to the acceleration without a precursor bunch. This study demonstrates that the introduction of the precursor bunch could help realize a practical DLA-based electron source.

Keywords: Particle-In-Cell Simulations, Quasi-Phase Matching method, Direct Laser Electron Acceleration