The Formation of Electron Outflow Jets with Power-law Energy Distribution in Guide-field Magnetic Reconnection

Abstract

Observationally, electron beams with power-law energy spectra are commonly associated with solar flares. Previous studies have found that during magnetic reconnection with a guide field Bg larger than 0.1 times the asymptotic field B0, electron beams are unable to develop due to the strong deflection caused by the guide field. Using particle-in-cell simulations we show that in force-free reconnection, the development of an electron Kelvin–Helmholz instability can suppress the Hall effect and produce a flute-like outflow exhaust, in which both electrons and ions are nearly frozen-in with the magnetic field. The coupling of a continuously growing electron velocity shear and E × B drift drive the electrons out of magnetic vortices and results in collimated jets with a power-law energy spectrum in the elongated exhaust. The spatial density of electron jets is comparable to the background and is highly inhomogeneous, signifying on asymmetric density structure in guide field reconnection. © 2021 The American Astronomical Society