飞秒激光-薄膜靶相互作用中快电子和快质子前向发射的研究  

Study for forward jet of fast electrons and fast protons generated by femtosecond laser interaction with foil targets

作　　者：蔡达锋[1] 谷渝秋[2] 郑志坚[2] 周维民[2] 焦春晔[2] 温天舒[2] 淳于书泰[2] 

机构地区：[1]内江师范学院物理系,四川内江641112 [2]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《核电子学与探测技术》2008年第1期23-29,共7页Nuclear Electronics & Detection Technology

基　　金：国家自然科学基金(10275057);省科技厅资助(04JY029-097)

摘　　要：采用飞秒激光与金属薄膜靶相互作用,测量了前向(靶背方向)发射的快电子和快质子。实验显示:快电子主要沿靶背法线附近发射且有较大的发散角,这与PIC模拟的结果一致;快质子发射方向与快电子大体一致,但其发散角远小于快电子。原因在于电子产生和加速在靶前(激光辐照面),在输运中受过密等离子体和靶的散射;而质子来源于靶背的含H污染物,并由靶法线鞘加速机制(TNSA)加速,未受散射地到达探测器。快电子和快质子能谱给出的快电子有效温度和质子最大能量较好地满足定标关系Emax=αTh,其中α≈2。Forward jet of fast electrons and fast protons from the interaction of femtoseeond laser with foil targets has been investigated. The results show that the fast electrons jet with a large angle width is along the direction of rear normal of target, which is better consistent with the PIC simulation. The direction of the fast protons jet is about consistent with that of the fast electrons. The angle width of fast protons jet is very smaller than that of the fast electrons, which is due to the forward fast protons generated from the rear of target contaminated with hydrocarbon and/or water vapor is not scattered, and the fast electrons from the front of target is scattered by dense plasma and target during transportation. The max- imal energy of fast protons and the effective temperature of fast electrons is well consistent with the scaling law Emax=aTh, and a≈2.

关 键 词：飞秒激光 薄膜靶 快电子 快质子 前向发射 

分 类 号：O434.12[机械工程—光学工程]