Davies J R, Bell A R, Tatarakis M
Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 May;59(5 Pt B):6032-6. doi: 10.1103/physreve.59.6032.
The transport of fast electrons generated by a 1 ps, 20 J, 10(19) W cm(-2), 1 microm wavelength laser pulse through 70-250 microm thick deuterated polyethylene (CD2) targets is modeled with a Fokker-Planck hybrid code in r-z geometry. Initially, electric field generation inhibits propagation, which then proceeds by the formation of a low resistivity channel due to Ohmic heating. The magnetic field generated at the edge of the channel leads to strong collimation. This is observed for a wide range of parameters. Reflection of electrons at the rear surface forms a magnetic field which focuses the incident electrons on to the rear surface and forces the reflected electrons outwards. This would lead to the formation of a small diameter plasma on the rear surface, as observed in experiments. The reflected electrons are confined to a cone by a self-generated magnetic field, enhancing energy deposition at the rear of the target.
利用r-z几何结构的福克-普朗克混合代码，对1皮秒、20焦耳、10¹⁹瓦/平方厘米、1微米波长的激光脉冲产生的快电子在70 - 250微米厚的氘化聚乙烯（CD₂）靶中的输运进行了建模。最初，电场的产生会抑制传播，随后由于欧姆加热形成低电阻率通道，传播得以继续。通道边缘产生的磁场导致强烈的准直。在很宽的参数范围内都观察到了这一现象。电子在后表面的反射形成一个磁场，该磁场将入射电子聚焦到后表面，并迫使反射电子向外。这将导致在后表面形成一个小直径等离子体，正如实验中所观察到的那样。反射电子被自生磁场限制在一个圆锥内，增强了靶后部的能量沉积。
