Analysis of Mirnov Signals from Coils Mounted in a Rectangular Array

摘要

Data analysis techniques for determining the structure of MHD instabilities in the ISX-B tokamak from Mirnov signals have been under development. Standard techniques cannot be applied directly in this case since the rectangular shape of the vacuum chamber requires a similar shape for the poloidal array of magnetic pickup coils. Components of the poloidal field perturbation are considered both parallel and perpendicular to the chamber walls and a twofold problem is addressed: (a) determining the relative signal phases as a function of poloidal angle along the array for any particular poloidal structure of plasma perturbation, without boundary effects; and (b) determining distortions of these phase lines due to eddy currents in the chamber. Results from simulation of plasma perturbations and from ISX-B experimental data are discussed. (ERA citation 05:019819)