飞秒激光与固体靶相互作用的前向快电子束发散研究  

A study for the divergence of forward fast-electron-beam produced by a femtosecond laser pulse on a solid target

作　　者：蔡达锋[1] 王剑[1] 谷渝秋[2] 郑志坚[2] CAI Da-feng;WANG Jian;GU Yu-qiu;ZHENG Zhi-jian(School of Physics and Electronic Information Engineering, Neijiang Normal University, Neijiang 641112;Research Center of Laser Fusion, CAEP, Mianyang 621900)

机构地区：[1]内江师范学院物理与电子信息工程学院,内江641112 [2]中国工程物理研究院激光聚变研究中心,绵阳621900

出　　处：《核聚变与等离子体物理》2018年第3期269-274,共6页Nuclear Fusion and Plasma Physics

基　　金：国家自然科学基金(10975121);四川省教育厅科研项目(10ZA012)

摘　　要：为了研究前向快电子束的发散问题,采用飞秒激光辐照平面铜靶,以电子角分布仪和氟化锂(LiF)热释光探测器探测快电子的前向发散角。实验显示前向快电子束发散角均在95°(半高宽FWHM)以上。理论计算指出预等离子体中电子的初速度以及加速后的电子在靶内碰撞效应均不是产生大发散角的重要原因。根据激光-等离子体相互作用理论,等离子体中的电磁场才是导致前向快电子束产生较大发散角的主要原因。这个研究为获取较小发散角的前向快电子束提供了实验设置的依据。In order to investigate the divergence of forward fast-electron-beam, the divergence angle of fast-electron-beam produced in the interaction of femtosecond laser with Cu target has been measured by using an angular distribution instrument adding the lithium fluoride(LiF) thermo-luminescent dosimeters. The results show that the divergence angle of forward fast-electron-beam is above 95°(Full width at half maximum, FWHM) level. The theoretic calculation show that the muzzle velocity of electrons from pre-plasma and the collision effect generated by the transmission of fast electrons through a target are not mostly factor. A larger divergence angle of the forward fast-electron-beam is attributed to the electromagnetic field. This investigation is helpful to select the laser and the target parameter for getting a fast electron beam with small divergence angle.

关 键 词：飞秒激光 铜膜靶 前向快电子 发散角 

分 类 号：O434.12[机械工程—光学工程]