发表机构
Physikalisches Institut, Universität Bayreuth（拜罗伊特大学物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文以匹配渐近展开法解决Vlasov-Poisson动力学中粒子俘获的理论缺口，揭示无碰撞等离子体中与漂移无关的空结构的瞬态后出现机制，还发现空间周期性朗缪尔空穴及自加速的驱动源。
AI 中文摘要
无碰撞等离子体中结构形成的一个关键方面是粒子俘获，更准确地说，是该过程在理论描述中留下的缺口。在俘获开始前，动力学由朗道物理和相位混合主导；而非线性的全部效应仅在俘获阶段显现，目前对此缺乏明确描述。因此，该缺口将时间演化分为转变前的线性Vlasov-Poisson阶段，以及以多种粒子俘获场景和相关Schamel平衡为特征的瞬态后Vlasov-Poisson阶段。从隐喻角度看，该俘获过程可与流体动力学中的瀑布相类比，两者的级联上下区域间均无法建立明确的动力学联系。为解决这一缺口问题，本文提出采用匹配渐近展开法进行分析。将该方法应用于 separatrix 区的奇异边界时，采用了由两粒子关联函数介导的局部平滑技术，为转变后阶段的空平衡选择提供了合适机制。此外，本文还报道了空间周期性朗缪尔空穴的存在，若正则性要求过严，该空穴会消失；并证明了伴随从慢电子声空穴向快朗缪尔空穴转变的自加速，由深俘获电子的释放驱动。
英文摘要
A key aspect of structure formation in collisionless plasmas is particle trapping or, more precisely, the gap this process leaves in the theoretical description. While the dynamics prior to the onset of trapping are governed by Landau physics and phase mixing, the full effects of nonlinearity only emerge during the trapping phase, for which an explicit description is lacking. Consequently, this gap divides the temporal evolution into a linear Vlasov-Poisson phase preceding the transition and a post-transient Vlasov-Poisson phase characterized by a wide spectrum of particle trapping scenarios and associated Schamel equilibria. Metaphorically, this trapping process can thus be compared to a waterfall in fluid dynamics, where, similarly, no explicit dynamic link can be established between the regions above and below the cascade. To resolve this problem of the gap, an analysis using the method of matched asymptotic expansions is proposed. Applied to the singular boundary of the separatrix zone, this approach employs local smoothing techniques, such as those mediated by the two-particle correlation function. It offers a suitable mechanism for selecting hole equilibria in the post-transition phase. Furthermore, we report the existence of a spatially periodic Langmuir hole that vanishes if regularity requirements are too stringent, and we demonstrate that self-acceleration, accompanying the transition from a slow electron acoustic hole to a fast Langmuir hole, is driven by the release of particularly deeply trapped electrons.
Comments13 pages, 1 figure
