Lectures on the hydromagnetic stability of a cylindrical plasma. VI. POSSIBLE INFLUENCE OF PARTICLE MOTIONS ACROSS THE LINES OF FORCE

摘要

It has recently been shown by Rosenbluth and Suydam that the stabilized pinch may suffer from surface instabilities. These arise because, in a discharge with a current layer of finite thickness, perturbations can arise which affect the outer surface of the current layer but leave the inner surface unperturbed. For such perturbations the trapped axial field exerts little stabilizing influence. These surface instabilities are of a very localised character and rapidly enter a non¬linear phase.nIn deriving these results it has been assumed that the plasma is an ideal hydromagnetic fluid, which implies that particles are tied to the lines of magnetic force. In an actual plasma particles can move across lines of force in performing Larmor orbits and, in the case of surface instabilities, the distance moved may be comparable with the scale of the perturbation.