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

该项目将开发一种二维、完全电磁的混合程序(使用粒子-细胞方法处理的离子和被视为流体的电子)，以研究倾斜哨声合唱波在磁层中的传播、演化和分布。模拟将在真实的偶极磁场几何结构中进行。该项目将检验现有的这些浪潮的理论，并将探索新的生成机制。模拟将提供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上的分布、在频率上的分布和波极化。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沿磁力线的传播。最后，该项目将研究大的倾斜哨声波如何将辐射带中的电子加速到高能量。最近的观测表明，大幅度的哨声合唱波通常以相对于地面磁场的大角度传播。这使得通常的传播平行于磁场的假设无效。导致这种浪潮的产生机制仍未确定。这个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的电子的理解。了解辐射带是空间气象中的一个重要课题。该项目的大部分资金将支持一名女性研究生进行的研究。

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.