Features and Properties of Coronal Mass Ejection/Flare Current Sheets

Abstract

Solar eruptions occur when magnetic energy is suddenly converted into heat and kinetic energy by magnetic reconnection in a current sheet (CS). It is often assumed that CSs are too thin to be observable because the electric resistivity η_e in CSs is taken to be very small. In this work, we show the implications for the CS thickness d estimated from observations of three eruptions by the UVCS and the LASCO experiments on SOHO. We infer the effective η_e causing the rapid reconnection, which predicts much faster reconnection in a thick CS than that caused by the classical and anomalous resistivities. We find that in these events CSs are observable and have extremely large values of d and η_e, implying that large-scale turbulence is operating within CSs. We also discuss the properties of the so-called hyperresistivity caused by the tearing mode and the relation to our results.