On stabilization of m = 1 MHD modes in a axisymmetric open system with the β ∼ 1 plasma

The paper studies the stability in relation to the global grooved (balloon) mode where every transverse section of plasma is shifted as a whole (such radial structure of perturbance occurs at strong effect of the finite Larmor radius). For one thing, one analyzes the possibility of stabilization by perfectly conducting enclosure for various radial profiles of pressure. Dependences of β value required for stability on pressure drop steepness and on enclosure position are determined for the case of corrugated field. Secondly, it is shown that at any value of β (in particular, at the stage of plasma accumulation till β does not reach values required for stabilization by enclosure) mode may be suppressed by magnetic system of feedbacks. 10 refs., 2 figs