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

多谐哨声波能够在地球内部磁层和其他等离子体环境中散射和加速电子到高速。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测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研究机会。这个项目有三个主要目标：1)什么样的等离子体参数决定了哨声波能量级联到静电分量的多谐波频率的可能性和速率？2)哪些等离子体参数决定了哨声波能量级联到电磁元件多谐波频率的可能性和速率？3)哨声波能量级联到更高频率如何影响哨声波加速电子的效率？这将通过范艾伦探测器的多谐哨声波测量和地球内磁层亚暴任务期间事件和宏观尺度相互作用的时间历史的分析，以及在日侧磁层顶重联的磁层多尺度任务来完成。航天器观测将结合惠斯勒波陡增的数值模拟（多流体磁流体力学代码）和电子与这些惠斯勒波相互作用的测试粒子模拟。该奖项反映了美国国家科学基金会的法定使命，并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，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.