Collaborative Research: GEM--Transition from Ion-Coupled to Electron-Only Reconnection

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Magnetic reconnection plays a fundamental role in energy transport from the solar wind magnetic fields to the Earth’s magnetic field. This process drives global energy releases in the magnetotail through sub-storms and in the magnetosheath. This project studies how reconnection in the magnetosheath occurs, focusing on the relative contributions from ion-coupled and electron-only reconnection. Understanding of magnetic reconnection is important to national security priorities related to satellites as these events produce space weather affects that can damage or destroy these systems. Additionally, the project will support the next generation of STEM scientists through training of a post-doc and a graduate student and providing internships for at-risk minority high school students. This project is a systematic study of key controlling factors and energy release properties of the transition from ion-coupled to electron-only magnetic reconnection. The primary sub-questions are: (1) What are the factors controlling the transition from ion-coupled to electron-only reconnection? (2) What are the factors controlling heating during reconnection with little or no ion coupling? And (3) Does 3D physics impact the transition from ion-coupled to electron-only reconnection? Kinetic particle-in-cell simulations will be conducted in 2-1/2 and 3 dimensions. The degree of ion coupling, ion exhaust velocities, electron exhaust velocities, and heating in the exhaust will be determined and compared with inflow conditions to determine the key controlling factors and ultimately all the creation of physical models. The simulations and models will be compared with MMS satellite observations of reconnection in the turbulent magnetosheath to both validate the models and find clues to the degree of ion coupling in the observations. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.