Multi-Spacecraft Investigations of Coupling at Auroral Latitudes (MuSICAL): Field-Aligned Current Energetics and Scales

极光场向电流对磁层-电离层系统的电磁耦合和能量输运具有重要意义。利用Swarm多航天器磁场、电场测量和地球空间平面结构的多点重建方法，对极光场向电流片的精细结构进行了详细的分析和研究。优选的空间尺度有望帮助确定极光加速机制。我们的结果将与地球空间环境中其他无力等离子体结构的当前概况进行比较，例如太阳风中的定向不连续。与我们的合作伙伴一起，我们计划利用极光区的群磁场和电场测量来量化高度积分焦耳加热速率并估计能量沉积到高层大气中。

Auroral field-aligned currents are of key importance for the electromagnetic coupling and the energy transport in the magnetosphere-ionosphere system. Using Swarm multi-spacecraft magnetic and electric field measurements and multi-point reconstruction methods for planar structures in geospace, we are going to analyze and study in detail the fine structure of sheets of auroral field-aligned currents. Preferred spatial scales are expected to help identifying auroral acceleration mechanisms. Our results will be compared with current profiles of other force-free plasma structures in the Earth's space environment such as directional discontinuities in the solar wind. With our collaboration partners we plan to make use of Swarm magnetic and electric field measurements in the auroral zone for quantifying height-integrated Joule heating rates and estimating the energy deposition into the upper atmosphere.