Analysis of optimal feedback control of vertical plasma position in a tokamak system

Shin Ichi Moriyama, Kazuo Nakamura, Yukio Nakamura, Satoshi Itoh

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)849-855
Number of pages7
JournalJapanese Journal of Applied Physics
Issue number7 R
Publication statusPublished - Jul 1985

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)


Dive into the research topics of 'Analysis of optimal feedback control of vertical plasma position in a tokamak system'. Together they form a unique fingerprint.

Cite this