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Reduced models of turbulent transport in helical plasmas including effects of zonal flows and trapped electrons

Part of: Focus on Fusion

Published online by Cambridge University Press:  26 May 2020

S. Toda Open the ORCID record for S. Toda [Opens in a new window] ,
M. Nunami Open the ORCID record for M. Nunami [Opens in a new window]  and
H. Sugama Open the ORCID record for H. Sugama [Opens in a new window]
S. Toda*
Affiliation:
National Institute for Fusion Science/The Graduate University for Advanced Studies, Toki 509-5292, Gifu, Japan
M. Nunami
Affiliation:
National Institute for Fusion Science/The Graduate University for Advanced Studies, Toki 509-5292, Gifu, Japan
H. Sugama
Affiliation:
National Institute for Fusion Science/The Graduate University for Advanced Studies, Toki 509-5292, Gifu, Japan
*
†Email address for correspondence: toda@nifs.ac.jp
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Abstract

Using transport models, the impacts of trapped electrons on zonal flows and turbulence in helical field configurations are studied. The effect of the trapped electrons on the characteristic quantities of the linear response for zonal flows is investigated for two different field configurations in the Large Helical Device. The turbulent potential fluctuation, zonal flow potential fluctuation and ion energy transport are quickly predicted by the reduced models for which the linear and nonlinear simulation results are used to determine dimensionless parameters related to turbulent saturation levels and typical zonal flow wavenumbers. The effects of zonal flows on the turbulent transport for the case of the kinetic electron response are much smaller than or comparable to those in an adiabatic electron condition for the two different field configurations. It is clarified that the effect of zonal flows on the turbulent transport due to the trapped electrons changes, depending on the field configurations.

Keywords

plasma instabilitiesplasma confinementplasma simulation
Type
Research Article
Information
Journal of Plasma Physics , Volume 86 , Issue 3 , June 2020 , 815860304
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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