Influence of long-scale length radial electric field components on zonal flow-like structures in the TJ-II stellarator Articles uri icon

authors

  • LOSADA, U.
  • ALONSO, A.
  • VAN MILLIGEN, B.PH.
  • HIDALGO, C.
  • LIU, BING
  • PEDROSA, M.A.
  • SILVA, C.

publication date

  • August 2016

volume

  • 58

International Standard Serial Number (ISSN)

  • 0741-3335

Electronic International Standard Serial Number (EISSN)

  • 1361-6587

abstract

  • The influence of long-scale length radial electric fields on zonal flows-like structures has been studied in the TJ-II stellarator. This relation has been investigated in the edge plasma using two electrical rake probes. The results presented here show an empirical correlation between the properties of long-range correlations (LRCs) with zonal flow-like structures and the magnitude of radial (neoclassical, NC) electric fields in TJ-II neutral beam heated plasmas. These experimental findings show that the enhancement of the NC radial electric field E-r increases the magnitude of LRCs, considered as a proxy of zonal flows, while the radial correlation length of the plasma potential fluctuations was found to decrease by about 40%. A strong relation between the magnitude of electric field structures with long and short radial scales was found. The calculated E-r x B shearing rate corresponding to the short scale length structures of the radial electric field may be sufficient to regulate turbulence.

keywords

  • zonal flow; transport barrier; radial correlation length; hearing rate; plasmas