MHD properties of low-aspect ratio RFP in RELAX

S. Masamune, A. Sanpei, Ryuya Ikezoe, Takumi Onchi, K. Oki, T. Yamashita, H. Shimazu, H. Himura, R. Paccagnella

Research output: Contribution to journalArticle

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Abstract

The low-aspect-ratio (A) reversed field pinch (RFP) offers attractive properties such as enhanced bootstrap current and simpler MHD mode dynamics. The RELAX (REversed field pinch of Low-Aspect ratio eXperiment) machine with the world's lowest A of 2 (R/a = 0.5 m/0.25 m) has been constructed to explore the RFP properties in low-A regime. In flat-topped low-A RFP discharges in RELAX, plasma current of ~50 kA has been attained with discharge duration of ~2 ms. In round-topped discharges with plasma current of ~70 kA, quasi-periodic growth of a single helical mode has been observed. When the dominant m = 1/n = 4 mode grows, the toroidal mode spectrum looks like that of the quasi-single helicity (QSH) RFP state with higher amplitude. MHD equilibrium analyses using a reconstruction code have shown that the bootstrap current fraction is lower than ~5% in the present RELAX plasmas, and it will be ~25% if we could achieve the plasma density of 4 × 10 19 m -3 and electron temperature of 300 eV at plasma current of ~100 kA.

Original languageEnglish
Pages (from-to)187-190
Number of pages4
JournalJournal of Fusion Energy
Volume28
Issue number2 SPEC. ISS.
DOIs
Publication statusPublished - Jun 1 2009
Externally publishedYes

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low aspect ratio
Magnetohydrodynamics
Aspect ratio
plasma currents
Plasmas
Plasma density
Electron temperature
plasma density
electron energy
Experiments

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering

Cite this

Masamune, S., Sanpei, A., Ikezoe, R., Onchi, T., Oki, K., Yamashita, T., ... Paccagnella, R. (2009). MHD properties of low-aspect ratio RFP in RELAX. Journal of Fusion Energy, 28(2 SPEC. ISS.), 187-190. https://doi.org/10.1007/s10894-008-9172-z

MHD properties of low-aspect ratio RFP in RELAX. / Masamune, S.; Sanpei, A.; Ikezoe, Ryuya; Onchi, Takumi; Oki, K.; Yamashita, T.; Shimazu, H.; Himura, H.; Paccagnella, R.

In: Journal of Fusion Energy, Vol. 28, No. 2 SPEC. ISS., 01.06.2009, p. 187-190.

Research output: Contribution to journalArticle

Masamune, S, Sanpei, A, Ikezoe, R, Onchi, T, Oki, K, Yamashita, T, Shimazu, H, Himura, H & Paccagnella, R 2009, 'MHD properties of low-aspect ratio RFP in RELAX', Journal of Fusion Energy, vol. 28, no. 2 SPEC. ISS., pp. 187-190. https://doi.org/10.1007/s10894-008-9172-z
Masamune S, Sanpei A, Ikezoe R, Onchi T, Oki K, Yamashita T et al. MHD properties of low-aspect ratio RFP in RELAX. Journal of Fusion Energy. 2009 Jun 1;28(2 SPEC. ISS.):187-190. https://doi.org/10.1007/s10894-008-9172-z
Masamune, S. ; Sanpei, A. ; Ikezoe, Ryuya ; Onchi, Takumi ; Oki, K. ; Yamashita, T. ; Shimazu, H. ; Himura, H. ; Paccagnella, R. / MHD properties of low-aspect ratio RFP in RELAX. In: Journal of Fusion Energy. 2009 ; Vol. 28, No. 2 SPEC. ISS. pp. 187-190.
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