Plasmoid instability in the semi-collisional regime

Abstract

We investigate analytically and numerically the semi-collisional regime of the plasmoid instability, defined by the inequality δSP≫ρs≫δin, where δSP is the width of a Sweet-Parker current sheet, ρs is the ion sound Larmor radius and δin is the width of the boundary layer that arises in the plasmoid instability analysis. Theoretically, this regime is predicted to exist if the Lundquist number S and the length of the current sheet L are such that (L/ρs)14/9 < S