An evaluation of possible mechanisms for anomalous resistivity in the solar corona

TL;DR

This paper evaluates different mechanisms for anomalous resistivity in the solar corona, comparing theoretical models with observed reconnection rates to explain fast magnetic reconnection events.

Contribution

It assesses the viability of chaos-induced resistivity and KAW instability as explanations for fast reconnection in the solar corona using observational data.

Findings

Resistivities from chaos-induced and KAW mechanisms can explain observed Lundquist numbers.

Localized resistivity at ion skin depth scales supports fast reconnection.

The models reconcile theoretical resistivity with solar flare reconnection rates.

Abstract

A wide variety of transient events in the solar corona seem to require explanations that invoke fast reconnection. Theoretical models explaining fast reconnection often rely on enhanced resistivity. We start with data derived from observed reconnection rates in solar flares and seek to reconcile them with the chaos-induced resistivity model of Numata & Yoshida (2002) and with resistivity arising out of the kinetic Alfv\'en wave (KAW) instability. We find that the resistivities arising from either of these mechanisms, when localized over lengthscales of the order of an ion skin depth, are capable of explaining the observationally mandated Lundquist numbers.