The Nonlinear Theory of Current-Driven Instability of Lower-Hybrid Drift Oscillations and Magnetic Field Reconnection in the Magnetopause

Abstract

The current-driven instability of short-wave drift oscillations propagated perpendicular to the magnetic field is investigated. The basic features of this instability are:

• a) This instability exists in plasma with hot ions T_i > T_e.

• b) The threshold value of the current velocity can be less than the ion thermal one.

• c) The instability can exist in plasma with β > 1.

There are such conditions in the region of the magnetopause. The main macroscopic effect due to current-driven instability - the appearance of anomalous collision frequency — is investigated. The saturation of the instability is due to modulational instability of excited oscillations.

The modurational instability leads to spectral transformation of energy into the region with k_z ≠ 0. In this region, the resonant interaction with electrons takes place. This resonant interaction leads to the instability saturation. The effective collision frequency is used to the estimation of the width of the transient sheet between plasma in the magnetosphere and plasma of the solar wind. Theoretical results are compared with results of satellite experiments.