INVESTIGATION OF THICKNESS AND ELECTRICAL RESISTIVITY OF THE CURRENT SHEETS IN SOLAR ERUPTIONS

Abstract

A discussion of the thickness of current sheets in solar eruptions, d, led Lin et al. in 2007 to estimate very large values for the effective resistivity, ηe. Here, we address some questions raised by that paper. We apply the limb synoptic map technique and find d between 5.0 × 104 and 4.6 × 105 km, increasing with both time and altitude. The possibility that large apparent d and ηe result from projection effects is examined and rejected. We derive theoretical scaling laws relating d to other observables that corroborate this conclusion and thus help confine both d and ηe to a reasonable range. The possible impact of our results on the existing models of particle acceleration in reconnecting current sheets is also briefly discussed.