GEM: Responses of Waves, Particles, and Precipitation to Solar Wind Dynamic Pressure Impulsive Changes

太阳风动态压力脉冲是可以在很大程度上影响地球磁层-电离层系统的最重要来源之一，包括正压脉冲（PPP;随时间呈阶梯状增加）和负压脉冲（NPP;随时间呈阶梯状减少）。这项研究解决了一个基本的问题，PPP和NPP对各种磁层波，高能电子，及其降水的影响，使用多点卫星观测和建模。科学结果将大大推进我们目前对太阳风-磁层-电离层耦合的理解，特别是波粒动力学，以及太阳风动态压力变化后驱动电子沉淀的相互作用。该项目将支持三名早期职业研究人员和一名研究生。 该项目使用OMNI数据集的太阳风动压和Sym-H指数来识别撞击磁层并具有地球效应的PPP和NPP事件。赤道附近的赤道（即，THEMIS、货车艾伦探针和MMS）提供等离子体波和电子测量以评估它们在压力脉冲之后的性质。低地球轨道卫星（NOAA POES/MetOp）提供电子沉淀测量，以量化压力脉冲引起的电子沉淀的全球分布。此外，基于准线性理论的全扩散代码将用于计算反弹平均扩散系数，其将进一步用于量化由观察到的等离子体波驱动的电子沉淀（即，嘶嘶声、合唱和电磁离子回旋波）。通过完成这些，将解决以下科学问题。(1)磁层等离子体波，包括嘶嘶声，合唱，和电磁离子回旋（EMIC）波，如何响应于不同的L壳和磁本地时（MLT）的正和负的太阳风压力脉冲？(2)在不同的L-MLT区域，被捕获的高能粒子如何对正压力脉冲和负压力脉冲作出反应？(3)高能粒子沉降对不同L-MLT区域的正、负压脉冲有何反应？(4)这些磁层波在正负压力脉冲事件中造成高能粒子沉淀的相对作用是什么？该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Solar wind dynamic pressure pulses are one of the most important sources that can largely affect the Earth’s magnetosphere-ionosphere system and include positive pressure pulse (PPP; step-like increase with time) and negative pressure pulse (NPP; step-like decrease with time). This research addresses a fundamental question regarding the effects of PPP and NPP on various magnetospheric waves, energetic electrons, and their precipitation, using multi-point satellite observations and modeling. The scientific results will significantly advance our current understanding of the Solar wind-Magnetosphere-Ionosphere coupling, specifically the wave-particle dynamics, and interactions in driving electron precipitation after solar wind dynamic pressure changes. This project will support three early career researchers and a graduate student. This project uses solar wind dynamic pressure and Sym-H index from the OMNI dataset to identify PPP and NPP events that hit the magnetosphere and are geoeffective. Satellites near the equator (i.e., THEMIS, Van Allen Probes, and MMS) provide plasma wave and electron measurements to evaluate their properties after pressure pulses. Low-Earth-Orbit (LEO) satellites (NOAA POES/MetOp) provide electron precipitation measurements to quantify the global distribution of pressure pulse-induced electron precipitation. Moreover, the Full Diffusion Code based on the quasi-linear theory will be used to calculate bounce-averaged diffusion coefficients, which will be further used to quantify electron precipitation driven by observed plasma waves (i.e., hiss, chorus, and electromagnetic ion cyclotron waves). By accomplishing these, the following science questions will be addressed. (1) How do magnetospheric plasma waves, including hiss, chorus, and electromagnetic ion cyclotron (EMIC) waves, respond to positive and negative solar wind pressure pulses at various L shells and magnetic local times (MLTs)? (2) How do the trapped energetic particles respond to positive and negative pressure pulses at various L-MLT regions? (3) How does the energetic particle precipitation respond to positive and negative pressure pulses at various L-MLT regions? (4) What are the relative roles of these magnetospheric waves in causing energetic particle precipitation during positive and negative pressure pulse events?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.