The Acceleration of Ions in Solar Flares During Magnetic Reconnection

TL;DR

This study uses particle-in-cell simulations to investigate how ions are accelerated during solar flare magnetic reconnection, revealing a mass-to-charge threshold that favors heating of high M/Q ions, aligning with observations.

Contribution

It demonstrates that pickup behavior during magnetic reconnection with a guide field preferentially heats high M/Q ions, a novel insight into ion acceleration mechanisms.

Findings

Pickup behavior causes dominant transverse ion heating.

High M/Q ions are preferentially heated over protons.

Results align with impulsive flare observations.

Abstract

The acceleration of solar flare ions during magnetic reconnection is explored via particle-in-cell simulations that self-consistently follow the motions of both protons and $\alpha$ particles. We demonstrate that the dominant ion heating during reconnection with a guide field (a magnetic component perpendicular to the reconnection plane) results from pickup behavior during the entry into reconnection exhausts. In contrast with anti-parallel reconnection, the temperature increment is dominantly transverse, rather than parallel, to the local magnetic field. The comparison of protons and alphas reveals a mass-to-charge ($M/Q$) threshold in pickup behavior that favors heating of high $M/Q$ ions over protons, which is consistent with impulsive flare observations.