Plasma position control

The accurate control of the plasma position is essential in a tokamak reactor, where a large plasma current has to be created and maintained for several minutes. In the INTOR study it has been shown that an elongated plasma cross-section is advantageous in many respects for a reactor. The aim of this paper is to show how the position control impacts on the overall design of the reactor, where all aspects with their correlations and reciprocal constraints have to be consistently examined. Attention is focused on the analysis model and its consequences in terms of design guidelines. The first section of the paper is dedicated to the analysis of the passive and active control of purely vertical displacements. The second section deals with the possible coupling between radical and vertical displacements, especially in case of up-down non-symmetric plasma equilibria