物理学报Issue(14)：1-8,8.DOI:10.7498/aps.64.145201
低密等离子体通道中的非共振激光直接加速∗
Non-resonant direct laser acceleration in underdense plasma channels
摘要
Abstract
Mechanisms that electrons are directly accelerated by the laser-plasma interaction in non-resonant cases are studied. First, by use of a linearly polarized Gaussian laser beam, a three-dimensional model is presented to demonstrate that the frequency and the amplitude of electron oscillations can be significantly modulated by the transverse ponderomotive force, within the confinement of an underdense plasma channel. On the one hand, the transverse ponderomotive force can felicitously make electrons to experience the large amplitude oscillations and push them to the regions at a low dephasing rate. On the other hand, when the electrons oscillate across the channel with small amplitudes, the dephasing rate also can be effectively reduced by the nonlinear modulation arising from the transverse ponderomotive force. These kinds of modulations can lead electrons to stay in phase with the laser field for a longer time and thus enhance their energy gain, which also enables the mechanism of transverse ponderomotive modulation being in direct laser acceleration. This mechanism is determined by the plasma density and the laser intensity and radius. Detailed numerical results are also given which show that the electron acceleration induced by this ponderomotive modulation quite distinguishes from the parametric instability and the resonance from a driving force. Moreover, a theoretical model for the parametric amplification, which makes up the restriction of the quasi-two-dimensional model, is provided to verify that non-resonant direct laser acceleration can come from the parametric instability in the three-dimensional case.关键词
等离子体/激光直接加速/横向有质动力调制/参数放大Key words
plasma/direct laser acceleration/transverse ponderomotive modulation/parametric amplifi-cation引用本文复制引用
刘明伟,龚顺风,李劲,姜春蕾,张禹涛,周并举..低密等离子体通道中的非共振激光直接加速∗[J].物理学报,2015,(14):1-8,8.基金项目
国家自然科学基金(批准号:11104068)和强场激光物理国家重点实验室开放基金资助课题．@@@@* Project supported by the National Natural Science Foundation of China (Grant No.11104068), and the Open Fund of the State Key Laboratory of High Field Laser Physics, China (Shanghai Institute of Optics and Fine Mechanics) （批准号:11104068）
