飞秒强激光在临界密度气体靶中驱动带电粒子加速研究

Laser-driven charged particle accelerator provides ultra-high acceleration gradients, which are 3 orders of magnitude more intense than that in LINAC accelerator. Thus it opens up the new route to high-energy particle acceleration. The laser plasma accelerator has made progress at the rapid rate seen in the past decades. The femtosecond intense laser pulse propagating inside the near-critical-density plasma has significantly high efficiency to transfer its energy to charged particles, compared to in low-density gas targets and the solid targets. The proposed project aims at producing high-energy intense electron bunch and high-quality ion beam, based on femtosecond laser pulse interacting with the near-critical-density gas target. We will develop novel methods for improving the density of high-charge energetic electron bunch, which may benefit to secondary applications. Additionally, we will demonstrate the intense laser pulse interaction with high-Z clustering gas as well as hydrogen gas, producing high-energy ions beam with various ion species. Afterwards we will take the particle acceleration a step further——tentative experiments based on even higher intensity laser pulse, based on the 10 PW laser facility (SULF in Pudong). In this proposal, we will focus on the charged particle acceleration based on the interaction between intense laser pulse and high-density gas target, which deliver high-energy particles for further applications.

超短超强激光驱动的粒子加速器可以获得高于传统加速器三个量级的加速梯度，为粒子加速提供了一个全新的思路。近几十年来，激光等离子体加速器在理论和实验上均进展迅速。相对于低密度气体靶加速电子和基于固体靶加速离子，临界密度靶在激光驱动带电粒子加速中有独特优势，飞秒相对论强激光有更高的能量转换效率，可以将更多的能量传递给电子束和离子束。本项目拟采取飞秒相对论强激光与临界密度气体靶相互作用，从实验和理论上研究高能高密度电子束和高品质离子束加速：①研究提高大电量高能电子束密度的新方案。②研究激光在高Z气体团簇靶中加速高品质离子的新机制和在氢气靶中加速高能质子束，实现激光驱动加速不同种类高能离子束。③探索10PW飞秒激光脉冲对高能电子束和离子束的加速。总之，激光与临界密度气体靶相互作用有着丰富的物理现象，我们将着力关注带电粒子加速方面的应用，为高品质粒子的后续应用提供实验依据和技术基础。

利用飞秒相对论激光装置，实验研究了飞秒激光脉冲与气体靶相互作用中电子束的加速过程，找到一种可用于数GeV电子加速的控制注入方案。同时，我们也开展了基于超强飞秒激光产生高能反质子束和正电子束的可能方案，为后续实验开展超强激光反物质粒子研究提供了坚实的理论基础(10PW和100PW超强激光装置)。另外，利用激光与近临界密度靶相互作用，可以产生致密的电子片，进而产生TW量级单个半周期阿秒脉冲。当驱动激光改为涡旋光时，半周期的阿秒脉冲也可以携带角动量。