Structure and Evolution of Dayside Diffuse Aurora and Enhanced Magnetospheric Density Regions from Coordinated Observations of South Pole All-Sky Imager and THEMIS Spacecraft

等离子体密度是磁层-电离层(M-I)耦合的基本参数之一，它影响各种等离子体波模式的生长和传播、磁重联速率和电离层电导，所有这些都强烈地影响着M-I系统的能量和质量输运。通过利用近年来同步的卫星-地面连接，该奖项将有助于确定白天密度调制的来源区域，具体解决三个悬而未决的科学问题：增强的密度起源于哪里？高密度区域是如何随时间演变的？增强密度区的典型大小是什么？白天磁层中的等离子体密度是高度结构化的，这种结构可以对哨声模波的激发产生很大影响，哨声模波反过来会散射从黑夜漂移的等离子体片电子，并加速地球辐射带中的电子。最近发现，哨声模波驱动扩散极光的结构化斑块；这可以用来突出日侧磁层密度增强的区域。白天的“极光-波-密度”关系引出了关于增强的等离子体密度斑块的起源及其在白天磁层中的传播的问题。仅靠卫星观测很难分离空间和时间效应来追踪高密度区域的运动，但地面二维极光成像可以提供一种很好的技术来监测扩散极光的形状和运动，扩散极光是由与哨声模波相互作用的高能电子沉淀驱动的。拟议的调查将使用一种创造性的方法，通过南极的极光观测来了解日侧磁层密度的演变。特别是，南极是一个理想的白天极光观测站，因为它有世界上最长的极夜。产生哨声模波的波-粒子相互作用将被用作利用相关的南极全天极光成像仪和THEMIS航天器观测来成像日侧等离子体密度结构的工具。这项研究不仅可能影响其本身的扩散极光研究领域，而且还可能影响到日侧磁层动力学、波粒相互作用和等离子体波激发等相关领域。这项有趣而重要的科学研究为培养研究生提供了理想的机会，进一步促进了南极的科学协作与合作，并编制了THEMIS-南极极光成像仪“白天连接”事件清单和各自的地球磁场测绘结果，供更广泛的地球空间科学界使用。

Plasma density is one of the fundamental quantities of the magnetosphere-ionosphere (M-I) coupling that affects the growth and propagation of various plasma wave modes, magnetic reconnection rate, and ionospheric conductance; all of which strongly influence energy and mass transport in the M-I system. By taking advantage of simultaneous satellite-ground conjunctions in recent years, this award will help determining the source region of dayside density modulations, specifically addressing three outstanding scientific questions: Where does the enhanced density originate? How do enhanced density regions evolve in time? And what is the typical size of the enhanced density regions?The plasma density in the dayside magnetosphere is highly structured, and this structure can have a large impact on the excitation of whistler-mode waves that in turn scatter plasma sheet electrons drifting from the nightside and accelerate electrons in the Earth's radiation belts. It has been recently found that whistler-mode waves drive structured patches of the diffuse aurora; this can be used to highlight enhanced density regions in the dayside magnetosphere. The dayside 'aurora-wave-density' correlations lead to questions about the origin of enhanced plasma density patches and their propagation in the dayside magnetosphere. Satellite observations alone have difficulties separating spatial and temporal effects in tracing the motion of enhanced density regions, but ground-based 2D auroral imaging could offer an excellent technique for monitoring the shape and motion of diffuse aurora that is driven by precipitating energetic electrons interacting with whistler-mode waves. The proposed investigation will use a creative approach for understanding dayside magnetospheric density evolution by using Antarctic-based auroral observations. In particular, South Pole is an ideal dayside auroral observatory due to its longest polar night in the world. The wave-particle interaction producing whistler-mode waves will be used as a tool for imaging dayside plasma density structures using correlated South Pole all-sky auroral imager and THEMIS spacecraft observations. This research may influence not only its own field of diffuse auroral studies, but also related fields such as dayside magnetospheric dynamics, wave particle interactions, and excitation of plasma waves. This interesting and important scientific research provides an ideal opportunity to train a graduate student, further scientific collaboration and cooperation in Antarctica, and create a list of THEMIS-South Pole auroral imager 'dayside conjunction' events and respective geomagnetic field mapping results for the use by a broader geospace science community.