Analysis of Mirnov oscillations on PDX

Abstract

Mirnov coils have been used to study MHD oscillations in PDX. We first review the information that can be obtained from Mirnov coils concerning the amplitude of these oscillations and their toroidal and poloidal mode numbers. The usual techniques for analyzing Mirnov coil data do not work well on PDX because of the rectangular arrangement of the coils, substantial noise levels, and poloidal amplitude asymmetries. A technique using digital Fourier analysis to focus attention on the fundamental frequency component of the signals has been successful in determining the m and n model numbers of Mirnov oscillations in the PDX tokamak.