Wave generation at the spin-up process in the rotating plasma

Abstract

This paper deals with some transient in the semi-infinite plasma column rotating as a rigid body with the constant angular velocity Ω. The plasma is penetrated by the homogeneous magnetic field, parallel to the column axis, it is collisionless, cold, incompressible. The response of this system to the small abrupt change in the angular velocity at the column base is studied by performing the Laplace transform of the perturbations in time. It is found that there are effectively two distinct modes of wave-propagation generated by the complicated interaction and balance among the viscous-magnetic diffusion, ion-cyclotron gyration, plasma centrifugal action and Alfvén propagation. The region between their respective wave fronts supports an important class of spatial harmonic oscillations produced by the coupling effect of ion-gyration and inertial oscillations. The characteristics of these waves are discussed for many cases of greatest interest. The solution so obtained is found to be valid for all times.