Scaling method of hot electron temperature using bremsstrahlung spectra

超短超强激光打靶产生的超热电子与固体靶相互作用时会产生轫致辐射X射线.利用蒙特卡罗方法,对电子在固体靶中传输产生的轫致辐射X射线进行了模拟.1 MeV电子束与固体靶作用产生的轫致辐射谱模拟结果表明,轫致辐射谱高能段斜率受靶厚度及靶材料的影响不明显.麦克斯韦分布的电子束及单能电子束与30 μm铜靶作用的模拟结果显示,两种电子源产生的轫致辐射谱在电子束能量或温度较高时基本一致.给出了一种利用轫致辐射谱斜率反推超热电子温度的定标方法.模拟了不同温度下超热电子产生的轫致辐射光子的能量角分布及光子数角分布,结果显示辐射光子能量通量和光子数随着电子温度的提高越来越向前倾,并给出了另外一种由轫致辐射能量角分布反推超热电子温度的定标关系.Bremsstrahlung X-rays are generated when the ultra-short ultra-intense laser interacts with solid targets. The transport of hot electrons in solid targets and the generation of bremsstrahlung X-rays were simulated using Monte Carlo method. Simulation results of the bremsstrahlung produced by 1 MeV electrons interacting with targets show that the slopes of high energy part of bremsstrahlung spectra can not be influenced obviously by target thickness and target material. Simulation of Maxwellian distribution and mono-energetic electron beams interacting with a 30 ??m thick Cu target shows that the bremsstrahlung photon spectra from these two electron sources are in agreement with each other. A scaling method of hot electron temperature according to the slope of high energy part of the bremsstrahlung spectrum is presented. The bremsstrahlung energy and number angular distributions were studied for different hot electron temperatures. The results indicate that the forward peaking trait of angular distributions can be enhanced by increasing the electron temperature, thus another scaling method based on this relation is proposed.国家自然科学基金项目; 中国工程物理研究院发展基金项目; 中国工程物理研究院等离子体物理重点实验室基金项目EI中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)01241-2442