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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Trapped ions
ripples
Electric fields
Fluxes
electric fields
ions
neutral particles
flux (rate)
charge exchange
indication
time lag
Time delay
Experiments

Cite this

Herrmann, W. ; Heikkinen, Jukka ; Kurki-Suonio, Taina ; Team, ASDEX Upgrade. / The time behaviour of radial electric fields at the L-H transition from the observation of ripple-trapped ions. In: Plasma Physics and Controlled Fusion. 1998 ; Vol. 40, No. 5. pp. 683-687.
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The time behaviour of radial electric fields at the L-H transition from the observation of ripple-trapped ions. / Herrmann, W.; Heikkinen, Jukka; Kurki-Suonio, Taina; Team, ASDEX Upgrade.

In: Plasma Physics and Controlled Fusion, Vol. 40, No. 5, 1998, p. 683-687.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The time behaviour of radial electric fields at the L-H transition from the observation of ripple-trapped ions

AU - Herrmann, W.

AU - Heikkinen, Jukka

AU - Kurki-Suonio, Taina

AU - Team, ASDEX Upgrade

PY - 1998

Y1 - 1998

N2 - 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.

AB - 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.

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DO - 10.1088/0741-3335/40/5/023

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