Abstract
Considering only the most dominant of many eddy current modes induced in a fusion reactor, the authors estimated the shell effect required for suppression of the axisymmetric vertical positional instability of an elongated plasma. Here more accurate analysis involving higher eddy current modes is used. Also using this analysis, dependence of the shell effect and the plasma control characteristics upon the reactor structure is investigated. The parameters under consideration are shell shapes, number of the shells around the torus, and thickness of the shell structures for the shell effect. The delay time on a vertical position detection for the plasma, and the dead time of a power supply for the control coils are chosen as parameters for the feedback control system of the plasma position, too. Moreover, field penetration on the vertical position control into the plasma center is studied in order to show the appropriateness for the results in this paper.
