Energy exchange between fields and plasmas during asymmetric guide-field reconnection: MMS observations
Magnetic reconnection is often considered a multi-scale process. It is a fundamental process in plasmas that alters the magnetic field topology and exchanges energy from fields to plasmas in and around a highly localized electron diffusion region (EDR). These localized processes can have a large impact on the dynamics of the much larger system that contains the EDR.
NASA’s Magnetospheric MultiScale (MMS) mission is designed to detect EDRs in the Earth’s magnetosphere. At the Earth’s magnetopause the EDR fundamentally differs from traditional models of symmetric 2-D reconnection, as strong plasma density gradients and out-of-plane magnetic fields are common. In this study, we analyze a single MMS observation of an EDR with a guide field of ~1. We determine the work done on the plasma by the electromagnetic field (J.E) and analyze the currents (J) and electric fields (E) that participate in this energy exchange. We compare and contrast the dynamics of this event to two other asymmetric EDR events and suggest a mechanism by which the presence, or lack thereof, of a guide field may alter the reconnection process.