On MHD Oscillations of a Plasma Column of Finite Conductivity with a Jump of Parameters in the Near-Wall Region

Abstract

In a straight-cylinder model in a strong longitudinal magnetic field, the MHD oscillations of a plasma of a finite conductivity are considered in a situation when there is no resonant surface in the plasma on which the component of the perturbation wave vector vanishes along the field. At high conductivity, there are large-scale oscillations with a radial wavelength on the order of the column radius, which in the entire volume differ little from those described by an ideal MHD. It is shown that with a jump in the density and electron temperature on a certain magnetic surface near the wall, another MHD mode may exist along with such oscillations due to the finite conductivity. In this mode, the perturbations are large-scale and almost ideal in most of the plasma volume, but small-scale in the radial coordinate and not ideal in the wall region.