Grad Student Support for Hybrid Code Simulation of Whistler Chorus in Dipole Coordinates

该项目将开发一个二维、全电磁混合代码（使用粒子单元法处理离子，将电子作为流体处理），以研究斜哨声合唱波在磁层中的传播、演变和分布。 模拟将在现实的偶极磁场几何形状中进行。 该项目将测试这些波的现有理论，并将探索新的生成机制。 模拟将产生关于这种波在空间和频率上的分布的信息。 要研究的科学问题包括波在空间中的分布、频率和波的偏振。 此外，该项目将确定冷等离子体密度的变化是否可以解释波的快速启动，以及这种变化如何影响波能量沿沿着磁场线的传播。 最后，该项目将研究大斜哨声波如何在辐射带中将电子加速到高能量。最近的观测表明，大振幅哨声合唱波通常以相对于地磁场的大角度传播。 这使得平行于磁场传播的常见假设无效。 导致这种波的产生机制仍然没有确定。 该项目将进行的模拟将提高我们对这种波如何影响辐射带中电子的理解。 了解辐射带是空间天气学的一个重要课题。 该项目的大部分资金将用于支持一名女研究生进行的研究。

This project will develop a two-dimensional, fully electromagnetic hybrid code (ions treated using particle-in-cell method and electrons treated as a fluid) to investigate the propagation, evolution and distribution of oblique whistler chorus waves in the magnetosphere. The simulations will be carried out in a realistic dipole magnetic field geometry. The project will test existing theories of these waves and will explore new generation mechanisms. The simulations will yield information on the distribution of such waves with respect to both space and frequency. The scientific questions to be investigated include the distribution of the waves in space, in frequency, and the wave polarization. In additional the project will determine whether or not variations in the cold plasma density can explain the rapid initiation of the waves and how such variations affect the propagation of wave energy along magnetic field lines. Finally the project will examine how the large oblique whistler waves may accelerate electrons to high energies in the radiation belts.Recent observations have shown that large amplitude whistler chorus waves often propagate at a large angle relative to the terrestrial magnetic field. This makes the common assumption of propagation parallel to the magnetic field invalid. The generation mechanism that leads to such waves is still undetermined. The simulations that will be done by this project will improve our understanding of how such waves affect the electrons in the radiation belts. Understanding the radiation belts is an important topic in space weather. Most of the funding for this project will support research conducted by a female graduate student.