Hybrid Vlasov-Maxwell simulations of two-dimensional turbulence in plasmas
Hybrid Vlasov-Maxwell simulations of two-dimensional turbulence in plasmas
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DOI：
10.1063/1.4893301
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发表时间：
2014-08
影响因子：
2.2
通讯作者：
F. Valentini;S. Servidio;D. Perrone;F. Califano;W. Matthaeus;P. Veltri
中科院分区：
文献类型：
--
作者：
F. Valentini;S. Servidio;D. Perrone;F. Califano;W. Matthaeus;P. Veltri
等离子体中的湍流是一个非常具有挑战性的问题，因为它涉及到波粒相互作用，这是负责的现象，如等离子体耗散，加速机制，加热，温度各向异性，等等。在本模型中，离子被视为一个动力学物种，而电子被认为是一种流体。正如最近在[S。Servidio，Phys. Rev. Lett. 108，045001（2012）]，在强磁活动的附近区域，动力学效应通过离子速度分布函数的变形而显现，其因此偏离平衡麦克斯韦构型。在这里，通过计算颗粒速度分布的高阶矩，即，温度、偏度和峰度。这种分析提供了定量信息的非麦克斯韦性质的系统动力学。这种对局部热力学平衡的偏离触发了许多天体物理和实验室等离子体中常见的几个过程。
Turbulence in plasmas is a very challenging problem since it involves wave-particle interactions, which are responsible for phenomena such as plasma dissipation, acceleration mechanisms, heating, temperature anisotropy, and so on. In this work, a hybrid Vlasov-Maxwell numerical code is employed to study local kinetic processes in a two-dimensional turbulent regime. In the present model, ions are treated as a kinetic species, while electrons are considered as a fluid. As recently reported in [S. Servidio, Phys. Rev. Lett. 108, 045001 (2012)], nearby regions of strong magnetic activity, kinetic effects manifest through a deformation of the ion velocity distribution function that consequently departs from the equilibrium Maxwellian configuration. Here, the structure of turbulence is investigated in detail in phase space, by evaluating the high-order moments of the particle velocity distribution, i.e., temperature, skewness, and kurtosis. This analysis provides quantitative information about the non-Maxwellian character of the system dynamics. This departure from local thermodynamic equilibrium triggers several processes commonly observed in many astrophysical and laboratory plasmas.