预等离子体通道中超短超强激光脉冲驱动的尾场粒子加速的理论与数值模拟研究

Laser plasma accelerators have the accelerating gradients thousands of times greater than those of conventional accelerators, therefore are advantageous to the miniaturization of particle accelerators, and have important value in the areas of high-energy particle acceleration, free-electron laser, fusion physics, and some industrial and medical applications. A laser wakefield can accelerate electrons and ions over long distances, to generate high-quality particle beams with high energy, low energy spread and low emittance. A preformed plasma channel can guide the driving laser and change the wakefield structure, help to increase energy gain in a single acceleration stage and improve the beam quality..This project is planed to carry out theoretical and simulation studies of the wakefield particle acceleration driven by ultrashort ultraintense laser pulses in preformed plasma channels, to increase energy gain in a single acceleration stage and improve the beam quality. It includes the studies of the effects of dense-plasma tubes and parabolic plasma density channels on the laser guiding, wakefield structure and particle acceleration, the injection methods of electrons and ions, and the ion beam transverse bunching methods in the wakefield. This project may provide some useful theoretical guidance to the relevant experimental research, such as in laser wakefield acceleration, fast ignition of inertial confinement fusion and particle beams for cancer therapy.

激光等离子体加速器由于其加速梯度高于传统加速器千倍以上，有利于粒子加速器的小型化，在高能粒子加速、自由电子激光、聚变物理和一些工业医学应用等领域有重要的价值。激光尾场可以长距离地加速电子和离子，获得高能量、低能散度和低发射度的高品质粒子束。预等离子体通道可以导引驱动激光和改变尾场结构，有利于提高单次加速能量和粒子束品质。.本项目拟从理论分析和数值模拟上研究预等离子体通道中超短超强激光脉冲驱动的尾场粒子加速问题，以提高单次加速能量和粒子束品质。包括研究高密度等离子体管和抛物形等离子体通道对激光导引、尾场结构和粒子加速的影响，电子和离子的注入方法，以及尾场中离子的横向聚束方法。本项目将为激光尾场加速、惯性约束聚变中的快点火和癌症的粒子束治疗等相关的实验研究提供有用的理论指导。

激光等离子体尾场加速研究的最终目标是实现粒子加速器的小型化，并对高能粒子加速、自由电子激光、聚变物理、医疗和工业等领域产生重要的应用价值。本项目从理论分析和数值模拟上研究了激光尾场中的电子和离子加速问题。研究发现，空泡尾场横向边缘附近的高密度等离子体环或棒，可以引发电子注入和控制注入位置；收缩的高密度等离子体管可以导致空泡尾场的收缩，减缓电子加速失相，提高电子加速能量到通常情况的两倍以上；激光尾场离子加速中，沿激光传播轴放置的纳米丝，可以导致正的纵向电流，对离子束起聚束作用，实现长距离的离子加速；从激光脉冲前方注入离子束，可以降低外部注入离子束的能量要求，纳米丝可以作为超强激光脉冲驱动的尾场中的质子注入源。本项目的研究成果将对激光尾场粒子加速实验研究提供一些有意义的理论指导。