An optimal control method was used to control the vertical position of a non-circular plasma with negative n-indices in a tokamak system. Taking the time delays in the control devices into consideration was found to improve the optimal feedback control law. Transient-response analysis of the control system in the TRIAM-1M tokamak showed that the optimal control technique can be used to control the plasma position in the stable region and that the ultimate lower limit of the n-index for the stabilization can be close to the limit nc for the fast-growing mode of positional instability. In addition, a pulsewidth-modulated inverter power supply with gate turn-off thyristors is proposed as a feedback power supply. This power supply has enabled the optimal position control of highly-elongated plasmas to be carried out an actual tokamak system.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)