Chang C-L, Hsieh C-T, Ho Y-C, Chen Y-S, Lin J-Y, Wang J, Chen S-Y
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Mar;75(3 Pt 2):036402. doi: 10.1103/PhysRevE.75.036402. Epub 2007 Mar 7.
Production of a monoenergetic electron bunch in a self-injected laser-wakefield accelerator is investigated with a tomographic method which resolves the electron injection and acceleration processes. It is found that all the electrons in the monoenergetic electron bunch are injected at the same location in the plasma column and then accelerated with an acceleration gradient exceeding 2 GeV/cm. The injection position shifts with the position of pump-pulse focus, and no significant deceleration is observed for the monoenergetic electron bunch after it reaches the maximum energy. The results are consistent with the model of transverse wave breaking and beam loading for the injection of monoenergetic electrons. The tomographic method adds a crucial dimension to the whole array of existing diagnostics for laser beams, plasma waves, and electron beams. With this method the details of the underlying physical processes in laser-plasma interactions can be resolved and compared directly to particle-in-cell simulations.
利用一种断层成像方法研究了自注入激光尾场加速器中单色电子束的产生，该方法能够解析电子注入和加速过程。研究发现，单色电子束中的所有电子都在等离子体柱中的同一位置注入，然后以超过2 GeV/cm的加速梯度加速。注入位置随泵浦脉冲焦点的位置而移动，单色电子束达到最大能量后未观察到明显的减速现象。这些结果与单色电子注入的横向波破裂和束流负载模型一致。断层成像方法为现有的激光束、等离子体波和电子束诊断方法增添了一个关键维度。通过这种方法，可以解析激光-等离子体相互作用中潜在物理过程的细节，并直接与粒子模拟进行比较。
