Effect of fast electrons on the stability of resistive interchange modes in the TJ-II stellarator Articles uri icon

authors

  • GARCIA GONZALO, LUIS
  • OCHANDO, M. A.
  • CARRERAS VERDAGUER, BENJAMIN A.
  • CARRALERO, D.
  • HIDALGO, C.
  • VAN MILLIGEN, B.PH.

publication date

  • June 2016

issue

  • 6 (062319)

volume

  • 23

International Standard Serial Number (ISSN)

  • 1070-664X

Electronic International Standard Serial Number (EISSN)

  • 1089-7674

abstract

  • In this paper, we report on electromagnetic phenomena in low-beta plasmas at the TJ-II stellarator, controlled by external heating. To understand the observations qualitatively, we introduce a simple modification of the standard resistive MHD equations, to include the potential impact of fast electrons on instabilities. The dominant instabilities of the modeling regime are resistive interchange modes, and calculations are performed in a configuration with similar characteristics as the TJ-II stellarator. The main effect of the trapping of fast electrons by magnetic islands induced by MHD instabilities is to increase the magnetic component of the fluctuations, changing the character of the instability to tearing-like and modifying the frequency of the modes. These effects seem to be consistent with some of the experimental observations.

keywords

  • tearing modes; plasmas