Phase space vortex merging in electron plasma waves is researched by applying a periodically changing electric field in plasma space with Maxwellian velocity distribution. The pump electric field excites the electron plasma wave with large amplitude and electron phase space vortices are formed. The electron plasma wave can be transited to longer wave modes through vortex merging processes. Excepting the fundamental mode of electron plasma waves, two or more modes appear and grow exponentially before vortex merging. After merging, another mode replaces the initial pumping wave as the strongest wave mode. It is verified that the growth of this new strong mode is related to trapping particle instability. Vortex merging is one of the saturation mechanisms of trapped particle instability.

中文翻译：

---

电子等离子体波中涡旋合并引起的俘获粒子不稳定性的饱和

通过在等离子体空间中以麦克斯韦速度分布施加周期性变化的电场，研究了电子等离子体波中的相空间涡合并。泵浦电场以大幅度激发电子等离子体波，并形成电子相空间旋涡。电子等离子体波可以通过涡旋合并过程转变为更长的波模。除电子等离子体波的基本模式外，在涡旋合并之前，两个或多个模式出现并呈指数增长。合并后，另一种模式将初始泵浦波替换为最强波模式。证实了这种新的强模式的增长与俘获粒子的不稳定性有关。涡旋合并是俘获粒子不稳定性的饱和机制之一。