Kelvin-Helmholtz instability of sheared electron flow at the magnetopause

Magnetopause is the boundary layer formed by the interaction of solar wind with magnetosphere, and current flows upon it. The current was considered as the sheared electron flow, and the Kelvin-Helmholtz (K-H) instability induced by the sheared electron flow of nightside magnetopause was discussed. Because of the effect of the electric field, instabilities of the shear electron flow are a little more complicated than those of the shear plasma flow. From the results obtained from the paper, K-H instability rising from sheared electron flow is easy to occur at the inner boundary of the magnetopause, and, it is likely that K-H instability happens when the velocity of sheared electron flow is between two thresholds. And, comparing the nightside near earth magnetopause with the magnetotail, we found that when the ratio of electron number densities of magnetopause is constant, and high electron number density can raise K-H instability. It is obvious that the variations of n2/n1 influenced the effective growth rates: K-H wave centralizes the lower velocity region with bigger n2/n1, and its effective growth rate is smaller.