超强激光驱动近临界密度等离子体中的QED效应研究

随着超短超强激光技术的飞速发展以及大型拍瓦激光装置的陆续兴建，极端相对论激光与等离子体相互作用中的QED效应研究逐渐成为多学科领域交叉研究的热点和难点。一方面，由于大量次级粒子的产生，相互作用过程对模拟技术本身提出了巨大挑战；另一方面，超强激光辐照等离子体将带来前所未有的新现象和新效应。本项目针对极端相对论激光与近临界密度等离子体相互作用过程进行理论分析和数值模拟研究，重点突破QED-PIC模拟带来的技术瓶颈，有效降低电子辐射捕获对应的激光强度阈值，阐明复杂电磁环境下的电子、离子动力学，深入研究近临界密度离子体中激发的QED效应，如多光子辐射和非线性Breit-Wheeler过程，细致分析强流正电子束的产生、加速、输运和约束的基本原理，探索高能量密度正负电子对和超高亮度伽马射线在高能物理和天体物理中的应用，为未来在数拍瓦激光装置上开展QED效应的实验研究提供可表征参数和关键技术方案。

With the rapid development of the laser technologies and the advent of the PW laser facilities around the word, ultra-relativistic laser-plasma interaction has been becoming research hotspot and difficulty of multi-crossed disciplines. On the one hand, numerous secondary particles generation poses a great challenge to the numerical technologies; on the other hand, the extreme laser fields bring unprecedented new phenomena, new physics and new effects. In this project, we plan to investigate, analytically and numerically, the interaction of ultra-relativistic laser pulses and near-critical-density plasmas. It is intended to make a breakthrough in the technologies of QED-PIC simulations. On this basis, the threshold of electron radiation trapping is to be reduced; the dynamics of electrons and ions in complex electromagnetic environment is to be clarified and some new QED effects such as the multi-photon emission process and nonlinear Breit-Wheeler process are to be investigated. Afterwards, the electron-positron pair production, acceleration, transport in the plasmas, and confinement in the ultra-relativistic laser fields are to be analyzed carefully. Meanwhile, the applications of the high-energy-density electron-positron pairs and ultra-brilliant gamma-rays in high-energy physics and astrophysics are to be explored. These studies will pave the way to the experimental demonstration of the QED effects in the future PW laser facilitates.