Effect on plasma performance of a single MHD mode feedback control in low-aspect-ratio RFP RELAX

Hiroyuki Tanaka, Sadao Masamune, Seiya Nakaki, Akio Sanpei, Kanae Nishimura, Ryosuke Kodera, Ryota Ueba, Go Ishii, Haruhiko Himura, Roberto Paccagnella

Research output: Contribution to journalArticle

Abstract

A feedback control system for the stabilization of resistive wall mode (RWM) was applied to a low-aspectratio reversed field pinch (RFP) with minimum power supply capabilities to control the single mode. The system consists of 64 saddle coils (4 and 16 in poloidal and toroidal direction, respectively) in the actuator covering the whole torus on the outer surface of the vacuum vessel. The sensor coils also have the same structure. The saddle coils are connected in series to control the single m/n = 1/2 mode, which has the largest growth rate in RELAX. The radial component of the magnetic field from the sensor coils was suppressed to the preset level and the m/n = 1/2 magnetic mode, which otherwise grows with field penetration time of the vessel, was reduced to 0.1% of the edge poloidal field throughout the discharge. The RFP discharge duration has been extended to ~3.5ms, the upper bound determined by the saturation of the iron core. Finally, the MHD control issues in a low-A machine are discussed.
Original languageEnglish
Article number1302057
Pages (from-to)-
JournalPlasma and Fusion Research
Volume9
DOIs
Publication statusPublished - 2014
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Tanaka, H., Masamune, S., Nakaki, S., Sanpei, A., Nishimura, K., Kodera, R., ... Paccagnella, R. (2014). Effect on plasma performance of a single MHD mode feedback control in low-aspect-ratio RFP RELAX. Plasma and Fusion Research, 9, -. [1302057]. https://doi.org/10.1585/pfr.9.1302057