Global two-fluid stability of bifurcated current sheets

摘要

Electromagnetic stability of modified Harris model, featuring a bifurcated current density profile, against lower-hybrid drift perturbation is investigated. The bifurcated current sheet is characterized by temperature and cross-field flow velocity profiles on different spatial scales across the current sheet. It is found that the eigenmodes of unstable solutions are mainly confined to the inner slopes of the bifurcated current sheet. That is, the fluctuations are trapped within the two current layers. This finding shows that the source of anomalous resistivity is focused near the neutral sheet, thus indicating that the excitation of electromagnetic lower-hybrid drift instability in a bifurcated current sheet may be a major cause of magnetic reconnection onset.