Ion and electron heating during magnetic reconnection in weakly collisional plasmas

Abstract

Magnetic reconnection and associated heating of ions and electrons in strongly magnetised, weakly collisional plasmas are studied by means of gyrokinetic simulations. It is shown that an appreciable amount of the released magnetic energy is dissipated to yield (irreversible) electron and ion heating via phase mixing. Electron heating is mostly localized to the magnetic island, not the current sheet, and occurs after the dynamical reconnection stage. Ion heating is comparable to electron heating only in high-beta plasmas, and results from both parallel phase mixing and perpendicular phase mixing due to finite Larmor radius effects; in space, ion heating is localized to the interior of a secondary island (plasmoid) that arises from the instability of the current sheet.