The microphysics of magnetic reconnection in the presence of small magnetic shear

Michael Hesse

Abstract

Magnetic reconnection relies on the presence of a localized region in space, where the frozen flux constraint is violated and particles are not tied to the magnetic field any longer. The dimensions of this region depend on the particle species considered, i.e., particles with larger mass become unmagnetized on larger scales than particles with smaller mass. This property renders magnetic reconnection a multiscale problem. Further affecting the magnetic reconnection process is the magnetic shear across the reconnecting current sheet. Here less magnetic shear involves a potentially large (guide) magnetic field component in the reconnection region, which leads to stronger electron magnetization and accordingly to changes of the magnetic diffusion process. In order to study collisionless reconnection in this regime, we will compare models of high shear (anti-parallel) magnetic reconnection with models with smaller magnetic shear. We will discuss the geometry changes involved, and the modifications to the reconnection rate and physical scaling caused by strong guide magnetic fields. We will support our theoretical estimates with self-consistent particle-in-cell simulations.

 Organization: Electrodynamics Branch
NASA Goddard Space Flight Center