A STUDY OF THE EFFICIENCY OF INTELLIGENT SHELLS

An ''Intelligent Shell'' [C. M. Bishop, Plasma Phys. Controlled Fusion 31, 1179 (1985)] is a resistive wall equipped with feedback loops int ended to make it appear ideally conducting to the plasma. Two problems associated with intelligent shells an addressed, using a simple model solved numerically, namely, the influence on the stabilization effici ency of the number of feedback loops employed and of gaps between loop s of the feedback system. Without gaps between the sensor loops it is found that a modest number of loops per period (such as eight) is almo st as stabilizing as infinitely many loops. It is also found that the stabilizing effect is decreasing rapidly by increasing gaps between lo ops. (C) 1998 American Institute of Physics.