Coherent transition radiation is used to evaluate fast electron transport of a laser-driven relativistic electron beam in ultrathin targets in selected materials. By preheating the targets with a low-intensity laser pulse, the bulk resistivity effects on electron transport in heated and unheated aluminum foils were compared with those in polyethylene (CH) foils. Unheated aluminum foils showed a pinched electron beam that was 50% smaller than the laser full-width at half-maximum focal spot. On the contrary, it was found that in preheated material Al and unheated CH, both materials with high bulk resistivity, the hot electrons experienced greater divergence and reduced energy.

中文翻译：

---

激光产生的热电子通过相干过渡辐射在冷热致密铝中的传播特性

相干过渡辐射用于评估选定材料中超薄靶中激光驱动的相对论电子束的快速电子传输。通过用低强度激光脉冲对靶进行预热，将加热和未加热的铝箔中的体电阻率对电子传输的影响与聚乙烯（CH）箔中的相比。未加热的铝箔显示出收缩的电子束，在一半最大焦点处，其收缩率比激光器的全宽度小50％。相反，发现在预热的材料Al和未加热的CH中，这两种材料都具有高体电阻率，热电子发散性更大，能量降低。