Interaction between kinetic ballooning perturbation and thin current sheet: Quasi-electrostatic field, local onset, and global characteristics

We present observation of plasma waves in the current sheet across multiple THEMIS satellites in a substorm event on March 5, 2008. It is shon that the arrival of a kinetic ballooning perturbation interacts with the local current sheet to generate a quasi-electrostatic wave a few minutes before local onset, consistent with the prediction that the current sheet thins after the passage of a rarefaction wave. The propagation speed of current disruption front is found to be similar to 100 km/s, about a tenth of the fast mode speed. The observed pattern of interaction was constant across radial distances between 10 and 20 R-E in the event reported. It is further proposed that the presence of the quasi-electrostatic field may change the local stability condition an induce local current disruption. Citation: Liu, W. W., j. Liang, and E. F. Donovan (2008), Interaction between kinetic ballooning perturbation and thin current sheet: Quasi-electrostatic field, local onset, and global characteristics, Geophys. Res. Lett., 35, L20107, doi: 10.1029/2008GL35757.