基于自调制激光尾场加速原理的极小归一化发射度单能电子束产生的实验研究

项目名称： 基于自调制激光尾场加速原理的极小归一化发射度单能电子束产生的实验研究

项目编号： No.11305185

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 李大章

作者单位： 中国科学院高能物理研究所

项目金额： 30万元

中文摘要： 新一代同步辐射光源、对撞机和自由电子激光均需要强流、小发射度的电子源。因为加速梯度和空间电荷效应的制约，传统电子枪面临巨大挑战。激光等离子体加速具有超高加速梯度，在出射束团尺寸、发射度等方面有天然优势，有望在此领域取得突破。与之前大多数基于"空泡"机制的激光尾场加速实验研究不同，我们拟采用自调制激光尾场加速原理，利用高信噪比、高重复频率的小功率激光器与中等密度等离子体相互作用，产生极小发射度的单能电子束。人们一度认为此参数条件下无法形成单能电子束团，但近期在我们及其它一些实验中已经成功获得了高品质单能电子束团，初步证明了此方法的可行性。不仅如此，在模拟中我们发现，在一定参数条件下，自调制尾场加速可以平稳的过渡到空泡加速，结合两者优势形成极小归一化发射度的单能电子束团。我们希望借基金支持，进一步研究激光等离子体参数对束团品质的影响，利用太瓦激光器稳定地产生具有极小发射度的单能电子束。

中文关键词： 激光等离子体加速；极小归一化发射度；粒子模拟；；

英文摘要： One crucial requirement for realizing next-generation synchrotron light sources, colliders and linac-based free-electron lasers (FELs) is high brightness electron sources which possess extremely high-peak current and small normalized emittance. This is a tremendous challenge to traditional electron guns due to their relatively low accelerating gradient and strong bunch self-field interaction. Meanwhile, for its ultrahigh accelerating gradient and natural advantages in bunch length and emittance, laser plasma accelerators have the potential to make some breakthroughs in this subject. Unlike most previous LWFA experiments under "bubble" mechanisms, we plan to adopt Self-Modulate LWFA (SM-LWFA) method which use small power laser facilities with high contrast and high repetition rate interacting with moderate plasmas to generate monoenergetic electron bunches with ultra-low emittance. SM-LWFA was once thought to be unsuited for the generation of monoenergetic electron beams. But some recent successful experiments including ours have preliminarily proved its feasibility. Moreover, we found in simulations that the mechanism can smoothly shift from SM-LWFA to bubble acceleration with some special laser plasma parameters. By taking both advantages of these two mechanisms, we achieved monoenergetic electron bunches with

英文关键词： laser-plasma-acceleration；ultrasmall nomalized emittance；particle-in-cell simulation；；