Waves in the Inner Magnetosphere and their Effects on Radiation Belt Electrons

Introduction

The magnetosphere is a natural plasma laboratory. Radiation belts in the magnetosphere are full of high-energy particles. The energetic electrons in the Earth’s radiation belts can be hazardous to Earth-orbiting satellites and astronauts in space. Many of the space systems on which modern human society depends operate in this region.

Dynamics of Radiation Belt Electrons

The fluxes of radiation belt electrons are very dynamic, which is not fully understood due to the delicate balance between various acceleration and loss processes. Wave-particle interactions are believed to play a crucial role in the acceleration and loss of these particles.

Need for Comprehensive Wave Models

To quantify the effect of different waves on the dynamics of radiation belt electrons, comprehensive wave models are needed. Currently, there are some wave models based on satellite measurements. However, the space coverage of these wave models is not sufficient due to the orbit limit of satellites.

Project Objectives

In this project, combining state-of-the-art measurements from multiple satellites, comprehensive wave models will be developed. The objectives include:

1. Improving our sophisticated physics-based radiation belt dynamic model by using the wave models developed in this project.
2. Calculating diffusion coefficients using more realistic background magnetic field and plasma density models for the first time.
3. Quantifying fundamental acceleration and loss of energetic electrons caused by different waves in the Earth's radiation belts.

Validation of Results

We will systematically validate simulation results against satellite measurements to understand the competition between acceleration and loss caused by various mechanisms.

Scientific Importance

All these improvements will be critically important for answering the overarching scientific question: Why do the Earth’s radiation belts respond differently to geomagnetic storms which have approximately the same intensity? The knowledge gained in this project can be useful for basic plasma physics and astronomy physics because similar fundamental processes exist.