Magnetic Reconnection in Non-Equilibrium Ionization Plasma

TL;DR

This study investigates how non-equilibrium ionization affects magnetic reconnection in the solar corona, revealing significant differences in emission predictions and sensitivity to electron density, with implications for interpreting solar observations.

Contribution

It introduces a time-dependent ionization model for iron in magnetic reconnection regions, highlighting the importance of non-equilibrium effects on emission diagnostics.

Findings

Iron is mostly in non-equilibrium ionization during reconnection.

Line emission intensities differ significantly from equilibrium assumptions.

Time-dependent ionization effects are sensitive to electron density below 10^{10} cm^{-3}.

Abstract

We have studied the effect of time-dependent ionization and recombination processes on magnetic reconnection in the solar corona. Petschek-type steady reconnection, in which model the magnetic energy is mainly converted at the slow-mode shocks, was assumed. We carried out the time-dependent ionization calculation in the magnetic reconnection structure. We only calculated the transient ionization of iron; the other species were assumed to be in ionization equilibrium. The intensity of line emissions at specific wavelengths were also calculated for comparison with {\it Hinode} or other observations in future. What we found is as follows: (1) iron is mostly in non-equilibrium ionization in the reconnection region, (2) the intensity of line emission estimated by the time-dependent ionization calculation is significantly different from that with the ionization equilibrium assumption, (3) the effect of time-dependent ionization is sensitive to the electron density in the case that the electron density is less than $10^{10}$ cm$^{-3}$, (4) the effect of thermal conduction lessens the time-dependent ionization effect, (5) the effect of radiative cooling is negligibly small even if we take into account time-dependent ionization.