A New Electric Field in Asymmetric Magnetic Reconnection

TL;DR

This paper introduces the Larmor electric field, a new in-plane electric field in asymmetric magnetic reconnection, supported by theory and numerical evidence, with implications for space mission observations.

Contribution

It presents the first theory and numerical validation of the Larmor electric field, a novel electric field component in collisionless asymmetric reconnection.

Findings

Identification of the Larmor electric field associated with finite Larmor radius effects.

Potential use of the Larmor electric field as an indicator for reconnection sites.

Predicted appearance of the electric field at the magnetopause reconnection site.

Abstract

We present a theory and numerical evidence for the existence of a previously unexplored in-plane electric field in collisionless asymmetric magnetic reconnection. This electric field, dubbed the "Larmor electric field," is associated with finite Larmor radius effects and is distinct from the known Hall electric field. Potentially, it could be an important indicator for the upcoming Magnetospheric Multiscale (MMS) mission to locate reconnection sites as we expect it to appear on the magnetospheric side, pointing Earthward, at the dayside magnetopause reconnection site.