On the 3-D structure and dissipation of reconnection-driven flow bursts

Abstract

The structure of magnetic reconnection-driven outflows and their dissipation are explored with 3-D particle-in-cell simulations. Outflow jets resulting from 3-D reconnection with a finite length x-line form fronts as they propagate into the downstream medium. A large pressure increase ahead of this "reconnection jet front" (RJF) due to reflected ions slows the front so that its velocity is well below that of the ambient ions in the core of the jet. As a result, the RJF slows and diverts the high-speed flow into the direction perpendicular to the reconnection plane. The RJF therefore acts as a thermalization site for the ion bulk flow and contributes significantly to the dissipation of magnetic energy during reconnection even though the outflow jet is subsonic. This behavior has no counterpart in 2-D reconnection. A simple analytic model predicts the front velocity and the fraction of the ion bulk flow energy that is dissipated. © 2014. American Geophysical Union. All Rights Reserved.