Dubois J-L, Lubrano-Lavaderci F, Raffestin D, Ribolzi J, Gazave J, Compant La Fontaine A, d'Humières E, Hulin S, Nicolaï Ph, Poyé A, Tikhonchuk V T
CEA/DAM/CESTA, BP 12, Le Barp 33405, France.
CEA/DAM/DIF, F-91297 Arpajon, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jan;89(1):013102. doi: 10.1103/PhysRevE.89.013102. Epub 2014 Jan 13.
Interaction of high-intensity laser pulses with solid targets results in generation of large quantities of energetic electrons that are the origin of various effects such as intense x-ray emission, ion acceleration, and so on. Some of these electrons are escaping the target, leaving behind a significant positive electric charge and creating a strong electromagnetic pulse long after the end of the laser pulse. We propose here a detailed model of the target electric polarization induced by a short and intense laser pulse and an escaping electron bunch. A specially designed experiment provides direct measurements of the target polarization and the discharge current in the function of the laser energy, pulse duration, and target size. Large-scale numerical simulations describe the energetic electron generation and their emission from the target. The model, experiment, and numerical simulations demonstrate that the hot-electron ejection may continue long after the laser pulse ends, enhancing significantly the polarization charge.
高强度激光脉冲与固体靶相互作用会产生大量高能电子，这些电子是诸如强X射线发射、离子加速等各种效应的起源。其中一些电子逃离靶，在激光脉冲结束很长时间后留下大量正电荷并产生强电磁脉冲。我们在此提出一个由短而强的激光脉冲和逃逸电子束诱导的靶电极化的详细模型。一个专门设计的实验直接测量了靶极化和作为激光能量、脉冲持续时间及靶尺寸函数的放电电流。大规模数值模拟描述了高能电子的产生及其从靶的发射。该模型、实验和数值模拟表明，热电子发射在激光脉冲结束后可能会持续很长时间，从而显著增强极化电荷。
