Frequency spectrum of fluctuations near a rational surface in a toroidal heliac

Tatsuya Zama, Sumio Kitajima, Masakazu Takayama, Nobunao Takeuchi, Hiroshige Watanabe

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Density and space potential fluctuations have been studied in electron cyclotron resonance heating (ECRH) plasma of a helical axis stellarator TU Heliac using Langmuir probe techniques. These fluctuations are coherent and global, which can be explained by a drift instability model in cylindrical geometry. A particular fluctuation mode vanishes inside a rational surface. The ratio of this mode, n/m, corresponds to the rotational transform Ƙ of this rational surface, (m, n: poloidal, toroidal fluctuation modes, respectively). This phenomenon near the rational surface can also be explained by a drift instability theory.

Original languageEnglish
Pages (from-to)L349-L352
JournalJapanese journal of applied physics
Volume32
Issue number3 A
DOIs
Publication statusPublished - 1993 Mar

Keywords

  • Drift instability
  • Fluctuation
  • Heliac
  • Plasma physics
  • Rational surface
  • Stellarator

ASJC Scopus subject areas

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

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