Onset and Evolution of Magnetic Reconnection in a Harris Plasma Current Sheet with Different Drift Velocities

Sammanfattning

Magnetic reconnection, a fundamental process converting magnetic field energy into kinetic particle energy and heat, occurs across various plasma environments and is widely observed. Despite its significance, the mechanisms of the magnetic reconnection process and how it is influenced by different variables remain relatively poorly understood. This project aims to gain a deeper understanding of these aspects by examining whether the velocity of ions and electrons in the magnetotail current sheet influences the onset and evolution of magnetic reconnection. Our hypothesis proposes that an initially higher ion velocity in the duskward direction within the current sheet will result in a more efficient reconnection process. In this project, we utilize particle-in-cell (PIC) simulations to conduct a comparative analysis between two simulations, where different ion-to-electron temperature ratios are employed to adjust the velocity of the ions and electrons in a Harris current sheet. We found that the simulation with lower initial ion velocity demonstrated an earlier reconnection onset, indicating a more efficient reconnection process, and thus contradicting our hypothesis. We discuss potential explanations for this result, focusing on how electron physics could be the catalyst for reconnection onset. No significant difference could be observed between the simulations regarding the evolution of the magnetic reconnection process. However, due to the limited size of the simulation box possibly altering these results, they were regarded as inconclusive. Increasing the simulation box size to investigate this aspect would therefore be recommended for future research. Additionally, it is also advised for future studies to research how the initial particle velocity in the current sheet affects the reconnection process independently of the temperature ratio.