The Role of Magnetic Reconnection in the Structure & Dynamics of Fast Coronal Mass Ejections

TL;DR

This paper investigates how magnetic reconnection influences the acceleration and internal structure of fast coronal mass ejections through simulation analysis, highlighting the feedback loop between reconnection and Lorentz forces.

Contribution

It provides a detailed analysis of reconnection-driven Lorentz forces in CME dynamics using 2.5D MHD simulations, emphasizing flank currents and internal structural changes.

Findings

Reconnection significantly increases outward Lorentz forces during CME eruption.

Flank currents near the CME boundary are primary drivers of force enhancement.

Reconnection jets modify the internal structure of CMEs, observable in simulations.

Abstract

Both observations and models of flare-associated coronal mass ejections (CMEs) suggest that magnetic reconnection in an ejection's wake substantially increases the net, outward Lorentz force accelerating the CME. A stronger outward force can cause a feedback loop, driving further magnetic reconnection in a "reconnective instability." The flux accretion model captures this by relating reconnected flux (Delta Phi_rec) and magnetic field strength (B_CME) to increased outward Lorentz force (Delta F_r). To better understand reconnection's role in CME dynamics, we analyze two snapshots from a 2.5D, MHD simulation of a breakout eruption. Outward Lorentz forces increase substantially as reconnection proceeds, caused primarily by "flank currents," which flow just inside the boundary of the rising ejection's wake and parallel to its axis. This model's reconnection jet also alters the ejection's internal structure, an effect that could be sought in observations. Analyzing reconnection-induced Lorentz forces in 3D simulations could provide additional insights into CME dynamics.