A note on the Mirnov signal analysis in tokamaks

The relation between Mirnov coil signals and the current perturbation on a rational surface is examined analytically by using the approximate Green's function for the case of large-aspect-ratio circular tokamaks. Satellite island formation, phase modulation effects due to the poloidal variation of the field line pitch, and the effect of the shift of the plasma column with respect to the centre of the vacuum chamber are examined. The detectability of these effects by Mirnov coils is discussed for the TFTR experiment. (author)