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arXiv 1809.00985physics.plasm-phphysics.space-ph
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亚质子尺度的湍流电磁场:双流体和全动力学等离子体模拟

Turbulent electromagnetic fields at sub-proton scales: two-fluid and full-kinetic plasma simulations

C. A. González, T. Parashar, D. Gomez, W. H. Matthaeus, P. Dmitruk

摘要:

等离子体动力学是一个涉及多个时空尺度的多尺度问题。湍流通过由非线性相互作用建立的级联将该系统中的不同尺度连接起来。大多数天体物理等离子体系统是弱碰撞,使一个完整的动力学弗拉索夫描述系统的必要。使用简化的模型来研究这样的系统是计算上可取的,但在不同的模型物理仔细基准是必要的。我们在这里进行一个这样的比较完全动力学粒子在细胞(PIC)模型和双流体模型,包括霍尔物理和电子惯性,特别关注亚质子尺度电场。我们表明,在一般的两个流体模型捕捉大尺度动力学相当不错。在较小的尺度下,霍尔物理也被流体代码捕获得相当好,但电子特征显示偏离完全动力学模型。使用这种流体模型的影响进行了讨论。

英文摘要:

Plasma dynamics is a multi-scale problem that involves many spatial and temporal scales. Turbulence connects the disparate scales in this system through a cascade that is established by nonlinear interactions. Most astrophysical plasma systems are weakly collisional, making a fully kinetic Vlasov description of the system essential. Use of reduced models to study such systems is computationally desirable but careful benchmarking of physics in different models is needed. We perform one such comparison here between fully kinetic Particle-In-Cell (PIC) model and a two-fluid model that includes Hall physics and electron inertia, with a particular focus on the sub-proton scale electric field. We show that in general the two fluid model captures large scale dynamics reasonably well. At smaller scales the Hall physics is also captured reasonably well by the fluid code but electron features show departures from the fully kinetic model. Implications for use of such fluid models are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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