Li Y T, Zhang J, Sheng Z M, Zheng J, Chen Z L, Kodama R, Matsuoka T, Tampo M, Tanaka K A, Tsutsumi T, Yabuuchi T
Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 2):036405. doi: 10.1103/PhysRevE.69.036405. Epub 2004 Mar 23.
The characteristics of the forward hot electrons produced by subpicosecond laser-plasma interactions are studied for different laser polarizations at laser intensities from subrelativistic to relativistic. The peak of the hot electron beam produced by p-polarized laser beam shifts to the laser propagation direction from the target normal direction as the laser intensity reaches the relativistic. For s-polarized laser pulse, hot electrons are mainly directed to the laser axis direction. The temperature and the maximum energy of hot electrons are much higher than that expected by the empirical scaling law. The energy spectra of the hot electrons evolve to be a single-temperature structure at relativistic laser intensities from the two-temperature structure at subrelativistic intensities. For relativistic laser intensities, the forward hot electrons are less dependent on the laser polarization under the laser conditions. The existing of a preplasma formed by the laser amplified spontaneous emission pedestal plays an important role in the interaction. One-dimensional particle-in-cell simulations reproduce the most characteristics observed in the experiment.
研究了亚皮秒激光与等离子体相互作用产生的前向热电子在不同激光偏振态下，从亚相对论强度到相对论强度的特性。当激光强度达到相对论强度时，p偏振激光束产生的热电子束峰值从靶法线方向向激光传播方向移动。对于s偏振激光脉冲，热电子主要沿激光轴方向发射。热电子的温度和最大能量远高于经验标度律所预期的值。热电子的能谱在相对论激光强度下从亚相对论强度下的双温结构演变为单温结构。对于相对论激光强度，在前向热电子在激光条件下对激光偏振的依赖性较小。由激光放大自发辐射基座形成的预等离子体的存在在相互作用中起着重要作用。一维粒子模拟再现了实验中观察到的大部分特性。
