Resistive wall instabilities for axisymmetric systems

Within the framework of MHD we study a confined plasma surrounded by a vacuum region and bounded by a resistive wall. We restrict ourselves to axisymmetric systems. To be more specific, we are interested here in the case where the configuration is stable in the presence of an infinitely conducting wall, but unstable without the wall. For physical reasons an infinitely conducting wall cannot be made. It is therefore of interest to study the effect of a resistive wall. The results depend upon knowledge of the solution for the stability problem in the two limiting cases which we refer to as Problem 1. The wall and the conductors in the vacuum region are not taken into account (wall and conductors at infinity). Problem 2. The wall and the conductors in the vacuum region are taken into account as infinitely conducting elements in the proximity of the plasma. (author) 3 refs