Energetic Electron Interactions With Magnetic Islands in the Earth’s Magnetosphere

Abstract

This thesis investigates the interaction between magnetic islands and plasma electrons through analysis of data from NASA's Magnetospheric Multiscale (MMS) mission. To analyze MMS data, a semi-automated Python workflow was developed, which streamlines event selection based on bipolar signatures in the magnetic field and diagnostic plotting to detect magnetic islands. Data from the Fast Plasma Investigation (FPI) instrument and the Fly's Eye Energetic Particle Sensor (FEEPS) are used to analyze electron densities and energies for three distinct magnetic island structures – two in the magnetotail and one in the magnetosheath. In all cases, it was found that bulk plasma electron densities peak near island centers, or O-points, while bursts of energetic electrons were detected near island boundaries, or X-points. These findings mirror the behavior found in DIII-D magnetic islands, demonstrating that magnetic islands in magnetized plasma affect local electron densities and the observation of energetic electrons in both lab and space environments. Although the focus of this study is on observations of quasi-static islands, we also discuss how changes in magnetic island dynamics affect the resulting distribution of electron energies observed in both space and lab measurements. This study can further our understanding of cross-field transport processes relevant to both space weather prediction and fusion energy.