GEM Postdoc: Nonlinear Scattering of Radiation-Belt Electrons by Chorus Waves

合唱是一种高度非线性的哨声模式电磁辐射，它是在地磁活动条件下激发于等离子体层顶外的低密度区。这种重要的磁层波可以与外辐射带电子相互作用，引起俯仰角散射损耗和能量扩散。以前的波粒散射效应的计算一般是使用准线性方法进行的。本计画将量化非线性离散合唱元素的散射效应，并将结果与准线性理论进行比较。方法是对模拟波场中的大量电子进行试验粒子计算，模拟波场的构造包括在向更高纬度传播期间合唱的朗道阻尼效应。其结果随后将用于构建由于合唱散射和电离层电导率的相关变化而导致的降水通量的全球分布。这项研究与地球空间环境建模磁层-电离层耦合活动和美国国家航空航天局（美国航天局）未来的辐射带风暴探测器使命有关。它也是2002年国家研究理事会十年报告所列“理解太阳和空间等离子体中观察到的过程中所体现的基本物理原理”挑战的核心。

Chorus is a highly non-linear whistler mode electromagnetic emission, which is excited in the low-density region exterior to the plasmapause under geo-magnetically active conditions. This important magnetospheric wave can interact with outer radiation belt electrons, causing pitch-angle scattering loss and energy diffusion. Previous calculations of the effect of wave-particle scattering has generally been performed using a quasi-linear approach. This project will quantify the effects of scattering by non-linear discrete chorus elements and compare the results with quasi-linear theory. The approach will be to carry out test particle calculations for a large number of electrons in a simulated wave field, which will be constructed including the effect of Landau damping of chorus during propagation to higher latitude. The results will subsequently be used to construct the global distribution of precipitation flux due to chorus scattering and the associated changes in ionospheric conductivity. The research is relevant to the Geospace Environment Modeling (GEM) Magnetosphere-Ionosphere coupling campaign and to the future Radiation Belt Storm Probes (RBSP) mission of National Aeronautics and Space Administration (NASA). It is also central to the Challenge "Understanding the basic physical principles manifest in processes observed in solar and space plasmas" listed in the 2002 NRC (National Research Council) Decadal Report.