Rapid magnetic field dissipation via coupling between KH and LHD instabilities in the magnetotail current sheet (2)

Recently, using a 2D PIC code simulation, we find that the non-linear coupling between the Kelvin-Helmholtz and the lower-hybrid drift instabilities can produce rapid magnetic field dissipation in an ion-scale current sheet. Although no electric field along the neutral sheet is observed right at the neutral sheet during the non-linear coupling phase, it is quite unlikely that its effects on a subsequent process leading to reconnection may be ignored since the dissipation process drastically modifies the current sheet structure. In order to investigate the effect of the dissipation process on tearing mode, we have carried out a couple of 2D simulation runs with the oblique cases of the Kelvin-Helmholtz instability. With the oblique setting, we can treat the electron tearing mode instability in a short wavelength range. In the case of 88 deg. Propagation (the lower-hybrid drift instability can grow) small magnetic islands are formed in the current sheet associated with the rapid dissipation process, while no magnetic island is found in the case of 85 deg. Propagation (without lower-hybrid wave). These results suggest a possibility that the rapid dissipation process initiate magnetic reconnection.