Plasma and Fusion Research

Volume 5, S2063 (2010)

Regular Articles

Recent Progress in Low-A RFP Plasma Research in RELAX

Akio SANPEI, Ryuya IKEZOE, Takumi ONCHI, Kensuke OKI, Masaki SUGIHARA, Yuusuke KONISHI, Shin-ichi FUJITA, Mitsuru NAKAMURA, Akio HIGASHI, Hidehiko MOTOI, Haruhiko HIMURA and Sadao MASAMUNE

: Kyoto Institute of Technology, Kyoto 606-8585, Japan

(Received 24 January 2010 / Accepted 18 May 2010 / Published 10 December 2010)

Abstract

Recent results from a low-aspect-ratio (low-A) reversed field pinch (RFP) machine with an aspect ratio of 2 (R/a = 0.51/0.25) are reported. The discharge characteristics of low-A RFP plasmas are described. The discharge regime in F − Θ space indicates that lowering the aspect ratio expanded the operational F − Θ space to the extremely high-Θ (> 3), deep-reversal (F < −1) region and to the non reversal (F > 0) region. A rotating helical Ohmic equilibrium RFP state could be realized in shallow-reversal discharge on REversed field pinch of Low Aspect eXperiment (RELAX). A preliminary feedback system is developed that results in plasma current with a longer discharge duration of ∼2 ms.

Keywords

reversed field pinch (RFP), low-aspect ratio (low-A), nonlinear MHD

DOI: 10.1585/pfr.5.S2063

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This paper may be cited as follows:

Akio SANPEI, Ryuya IKEZOE, Takumi ONCHI, Kensuke OKI, Masaki SUGIHARA, Yuusuke KONISHI, Shin-ichi FUJITA, Mitsuru NAKAMURA, Akio HIGASHI, Hidehiko MOTOI, Haruhiko HIMURA and Sadao MASAMUNE, Plasma Fusion Res. 5, S2063 (2010).