The time behaviour of radial electric fields at the L-H transition from the observation of ripple-trapped ions

W. Herrmann, Jukka Heikkinen, Taina Kurki-Suonio, ASDEX Upgrade Team

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

The density of ripple-trapped ions is strongly influenced by negative radial electric fields that can compensate the grad B drift. This density can be monitored with a time resolution of about by the measurement of charge-exchange neutral particle fluxes. According to Monte Carlo and Fokker-Planck calculations these fluxes should respond with a time delay of less than , if the halfwidth of the electric field is reasonably large (a few centimetres). In the experiment, rise times of the fluxes after the L-H transition are longer or about 1 ms; jumps of the electric field in much shorter times can be excluded under such circumstances. The same is found for the H-L transition, where the flux measurement does not show any indication for a fast drop of the fields.
Original languageEnglish
Pages (from-to)683-687
JournalPlasma Physics and Controlled Fusion
Volume40
Issue number5
DOIs
Publication statusPublished - 1998
MoE publication typeA1 Journal article-refereed

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