Thin Current Sheets and the Evolution of Auroral Forms

薄电流片是一种普遍存在于各种等离子体环境中的现象。 该项目将研究在产生极光的区域驱动薄电流片动态演变的过程。 极光弧的动态演变是极光形式快速扭结、卷曲和折叠的原因，这使得观看极光如此引人注目。这些运动的结果是等离子体不稳定性的相互作用，在薄电流片上操作的规模大小，从小尺度动力学的大小，整个极光加速区域。该项目将利用Reimei航天器的观测结果，该航天器首次提供了极光形式的专用成像，并对驱动极光的粒子进行了磁共轭高时间分辨率测量。这些观测为定量分析极光运动和结构提供了前所未有的机会，同时提供了驱动光发射的粒子分布的细节。该项目将采用一种新的基于小波的技术来分析来自Reimei航天器的极光图像序列，以确定等离子体流的涡度随尺度的变化。涡度与电流或能量通量（光度）的分布将提供一种手段，以确定哪些过程在极光结构的演变中占主导地位。卫星观测将得到使用和进一步开发三维简化磁流体动力学数值模拟的帮助，其中包括电子惯性和电离层电阻率。FAST航天器的现有统计实地测量将用于增强Reimei成像仪和粒子观测，以提供极光形式的更完整的电动力学特征，并与模拟结果进行比较。该项目将有助于提高我们对一个众所周知和普遍观察到的公众利益现象的理解。它涉及与加州大学伯克利分校空间科学实验室科学教育中心的合作。 这项研究的结果将纳入一系列研讨会的教师谁是主要参与教学非洲裔美国人和拉丁美洲学生。该项目还通过为一名博士后学者和研究生研究员提供支助，促进教学、培训和学习。

Thin current sheets are a ubiquitous phenomena in a wide variety of plasma environments. This project will examine processes which drive the dynamic evolution of thin current sheets in the region where the auroras are generated. The dynamic evolution of auroral arcs is responsible for the rapid kinking, curling and folding of auroral forms that make watching the aurora so compelling. These motions are the consequence of the interaction of plasma instabilities in thin current sheets operating on scale sizes from small-scale kinetics up to the size of the full auroral acceleration region. This project will exploit observations from the Reimei spacecraft which provides the first dedicated imaging of auroral forms with magnetically conjugate high time resolution measurements of the particles which drive them. These observations provide the unprecedented opportunity for quantitative analysis of auroral motions and structuring to be performed while simultaneously providing details of the particle distributions driving the optical emissions. The project will implement a new wavelet-based technique for the analysis of sequences of auroral imagery from the Reimei spacecraft to ascertain the vorticity of plasma flows as a function of scale. The distribution of vorticity with current or energy flux (luminosity) will provide the means to identify which processes dominant in the evolution of the auroral structures. The satellite observations will be aided by the use and further development of a 3-D, reduced MHD numerical simulation that includes electron inertia and ionospheric resistivity. Existing statistical field measurements from the FAST spacecraft will be used to augment the Reimei imager and particle observations to provide a more complete characterization electrodynamics of the auroral forms and for comparison with simulation results. The project will help improve our understanding of a very well known and commonly observed phenomenon of public interest. It involves a collaboration with the Center for Science Education at the UC Berkeley Space Sciences Laboratory. The results from this research will be incorporated into a series of workshops for teachers who are primarily involved in teaching African-American and Latino students. The project also promotes teaching, training and learning by providing support for a postdoctoral scholar and graduate student researcher.