Collaborative Research: GEM--Multi-harmonic Whistler Waves, Their Origin and Contribution to Electron Scattering

多次谐波哨声波能够在地球内部磁层和其他等离子体环境中散射电子并将其加速到高速。了解这些波的起源以及它们如何与电子相互作用，对于预测和预报空间天气及其对卫星和航天器等敏感系统的影响非常重要。该项目支持三名早期职业科学家和本科生的研究机会。该项目有三个主要目标：1)什么等离子体参数决定哨波能量级联到静电分量的多个谐波频率的可能性和速率？2)什么等离子体参数决定哨波能量级联到电磁分量的多个谐波频率的可能性和速率？3)哨波能量级联到更高的频率如何影响哨声波加速电子的效率？这将通过分析Van Allen探测器的多次谐波哨声测量结果、地球内磁层亚暴飞行任务期间事件和大尺度相互作用的时间历史以及磁层多尺度飞行任务日侧磁层顶重联来实现。航天器观测将与哨声波陡化的数值模拟(多流体磁流体力学代码)和电子与哨声波相互作用的测试粒子模拟相结合。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Multi-harmonic whistler waves are capable of scattering and accelerating electrons to high speeds in the Earth’s inner magnetosphere and other plasma environments. Understanding the origins of these waves and how they interact with electrons is important for forecasting and predicting space weather and its effects on sensitive systems such as satellites and space craft. The project supports three early career scientists and undergraduate research opportunities.There are three main objectives to this project: 1) What plasma parameters determine the possibility and rate of the whistler wave energy cascade to multi-harmonic frequencies of the electrostatic component? 2) What plasma parameters determine the possibility and rate of the whistler wave energy cascade to multi-harmonic frequencies of the electromagnetic components? 3) How does the whistler wave energy cascade to higher frequencies influence the efficiency of whistler waves in accelerating electrons? This will be accomplished by analysis of multi-harmonic whistler wave measurements from the Van Allen Probes and the Time History of Events and Macroscale Interactions during Substorms mission in the Earth’s inner magnetosphere and by the Magnetospheric Multiscale Mission in the day-side magnetopause reconnection. Spacecraft observations will be combined with numerical simulations (multi-fluid magnetohydrodynamic code) of whistler wave steepening and test-particle simulations of electron interaction with these whistler waves.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.