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, η _e . 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 η _e 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 η _e 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.