EFFECT OF THE RELATIVE FLOW VELOCITY ON THE STRUCTURE AND STABILITY OF THE MAGNETOPAUSE CURRENT LAYER

The Vlasov kinetic approach is used to study the stability of the magnetopause current layer (MCL) when a sheared flow velocity and a sheared magnetic field both exist simultaneously within it. A modified Harris-Sestero equilibrium where the magnetic field and bulk velocity are changing direction on the same spatial scale is suggested to illustrate the generation of a y component of the magnetic field in the center of the MCL. With this equilibrium it is shown that By(0) can be of the order of B(z) (infinity) when the value of the shear flow (U) tends to the ion drift velocity (U(d)). The modifications of the initial symmetrical Harris configuration, introduced by the presence of a shear flow, strongly influence the adiabatic interaction of the plasma with low-frequency tearing-type electromagnetic perturbations as well as the nonadiabatic response of the particles near the center of the MCL. This results in a reduction of the growth rate of the tearing mode.