第三讲 激光在真空中加速电子  

Laser-induced electron acceleration in vacuum

作　　者：王平晓[1] 孔青[1] 霍裕昆[1] 

机构地区：[1]复旦大学现代物理研究所应用粒子束物理实验室,上海200433

出　　处：《物理》2007年第1期32-38,共7页Physics

基　　金：国家自然科学基金(批准号:10335030和10475018)资助项目

摘　　要：文章简要回顾了真空中激光加速电子的研究进展,着重介绍了真空俘获加速电子的动力学特点和物理机制.出现俘获加速(captureandaccelerationscenario,CAS)的经典物理机制是聚焦激光束的衍射效应导致光波沿俘获电子轨迹的有效相速度减慢,以致电子有可能被长时间俘获在加速相位中并从激光场获得足够多的能量.CAS出现需要的入射动量的相空间不小,而且在实验上可以达到.此外,最佳入射动能对激光强度并不敏感,在小角入射时大约在10—20MeV.研究发现,CAS出现需要的激光场强相当高,电子获得的能量在电子进入CAS通道时急剧上升.此外文章还介绍了有质动力加速模型的特点和机制、附加磁场的加速机制.We briefly review the progress in laser-driven electron acceleration in vacuum. The dynamical characteristics and physical mechanisms of the laser-induced capture and acceleration scenario （CAS） are introduced. The physical mechanism is that the diffraction effect of the focused laser beam leads to slowing down of the effective wave phase velocity along the captured electron trajectory, such that the electron can be trapped in the acceleration phase of the wave for a longer time and thus gain significant energy from the field. The phase space of the incident electron momenta required by CAS is not small and is readily achievable in experiments. Furthermore, the optimum incident momentum is not very sensitive to the laser intensity, which is around 10-20 MeV. Our study also shows that the required laser intensity for CAS to emerge is extremely high. The electron energy gain increases sharply after entering the CAS regime. In addition, the vacuum ponderomotive laser acceleration and vacuum acceleration by the laser plus stationary magnetic field are addressed.

关 键 词：激光加速 强激光 有质动力 

分 类 号：O46[理学—电子物理学]