Dispersive Alfven Waves in Space and Laboratory Plasmas

研究人员将研究磁化、强不均匀、低β实验室和空间等离子体中的小尺度、色散Alfven波的结构和动力学特征。磁层赤道面产生的色散阿尔芬波可将电磁功率输送到电离层，并可在极光电离层上层和离散极光弧中产生小规模的强电场和电流。该研究将使用一个基于简化的双流体磁流体动力学（MHD）动力学方程的模型，该方程将有限电子和离子质量、温度以及有限离子Larmor半径的动力学效应纳入磁化等离子体中超低频电磁波的流体描述中。为了了解色散Alfven波的简化MHD描述的适用范围，研究人员将在大量控制良好的综合实验数据上验证物理模型及其数值实现。特别是，这项工作涉及到用加州大学洛杉矶分校的大型等离子体装置进行的实验室等离子体实验来测试理论模型的结果。这项研究的结果将用于进一步提高在火箭和卫星上解释在极光区测量到的强磁场、电流和粒子通量的能力，并促进对实验室等离子体实验的了解。

The investigators will study structural and dynamical features of small-scale, dispersive Alfven waves in magnetized, strongly inhomogeneous, low-beta laboratory and space plasmas. Dispersive Alfven waves generated at the equatorial plane of the magnetosphere may transport electromagnetic power into the ionosphere and can be responsible for small-scale, intense electric fields and currents in the topside auroral ionosphere and in discrete auroral arcs. The study will used a model based on the reduced two-fluid magnetohydrodynamic (MHD) kinetic equations which incorporate effects of finite electron and ion masses, temperatures, and kinetic effects of the finite ion Larmor radious in the fluid description of ultra-low-frequency electromagnetic waves in a magnetized plasma. To understand the range of applicability of the reduced MHD description of dispersive Alfven waves, the investigators will verify the physical model and its numerical implementation on a large set of well-controlled, comprehensive experimental data. In particular, the effort involves testing the results of theoretical models with laboratory plasma experiments performed on the Large Plasma Device at UCLA. Results of the study will be applied to further the capability to interpret intense fields, currents and particle fluxes measured in the auroral zone on rockets and satellites as well as to advance understanding of laboratory plasma experiments.