Saturation of magnetised plasma turbulence by propagating zonal flows

Fuente: arXiv
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Autori principali: Nies, Richard, Parra, Felix, Barnes, Michael, Mandell, Noah, Dorland, William
Natura: Preprint
Pubblicazione: 2024
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author Nies, Richard
Parra, Felix
Barnes, Michael
Mandell, Noah
Dorland, William
author_facet Nies, Richard
Parra, Felix
Barnes, Michael
Mandell, Noah
Dorland, William
contents Strongly driven ion-scale turbulence in tokamak plasmas is shown to be regulated by a new propagating zonal flow mode, the toroidal secondary mode, which is nonlinearly supported by the turbulence. The mode grows and propagates due to the combined effects of zonal flow shearing and advection by the magnetic drift. Above a threshold in the turbulence level, small-scale toroidal secondary modes become unstable and shear apart turbulent eddies, forcing the turbulence level to remain near the threshold. This threshold condition is used to derive scaling laws for the turbulent heat flux, fluctuation spectra, and zonal flow amplitude, which are validated in nonlinear gyrokinetic simulations and explain previous experimental observations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02283
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Saturation of magnetised plasma turbulence by propagating zonal flows
Nies, Richard
Parra, Felix
Barnes, Michael
Mandell, Noah
Dorland, William
Plasma Physics
Strongly driven ion-scale turbulence in tokamak plasmas is shown to be regulated by a new propagating zonal flow mode, the toroidal secondary mode, which is nonlinearly supported by the turbulence. The mode grows and propagates due to the combined effects of zonal flow shearing and advection by the magnetic drift. Above a threshold in the turbulence level, small-scale toroidal secondary modes become unstable and shear apart turbulent eddies, forcing the turbulence level to remain near the threshold. This threshold condition is used to derive scaling laws for the turbulent heat flux, fluctuation spectra, and zonal flow amplitude, which are validated in nonlinear gyrokinetic simulations and explain previous experimental observations.
title Saturation of magnetised plasma turbulence by propagating zonal flows
topic Plasma Physics
url https://arxiv.org/abs/2409.02283