A digital control system for external magnetohydrodynamic modes in tokamak plasmas.

Research paper by J M JM Hanson, A J AJ Klein, M E ME Mauel, D A DA Maurer, G A GA Navratil, T Sunn TS Pedersen

Indexed on: 02 May '09Published on: 02 May '09Published in: The Review of scientific instruments


A feedback system for controlling external, long-wavelength magnetohydrodynamic activity is described. The system is comprised of a network of localized magnetic pickup and control coils driven by four independent, low-latency field-programable gate array controllers. The control algorithm incorporates digital spatial filtering to resolve low mode number activity, temporal filtering to correct for frequency-dependent amplitude and phase transfer effects in the control hardware, and a Kalman filter to distinguish the unstable plasma mode from noise.