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Zonal instability and wave trapping

Abstract : This paper presents a model for zonal flow generation based on a wave kinetic equation coupled to a poloidal momentum equation in a regime where wave trapping matters. Several models of the wave collision operator have been tested: Krook, diffusion and diffusion plus an instability growth rate. Conditions for zonal instability have been identified. It is found that a zonal instability is possible in all cases. However the force is a power law of the zonal velocity, so different from the quasi-linear case of random phases that produces a force that is linear in velocity. Also the zonal force may change sign, leading to flow radial profiles that are not sinusoidal.
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Preprints, Working Papers, ...
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https://hal.archives-ouvertes.fr/hal-03081047
Contributor : Xavier Garbet <>
Submitted on : Friday, December 18, 2020 - 8:14:30 AM
Last modification on : Tuesday, January 26, 2021 - 3:17:29 AM

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Garbet_VARENNA_20_paper.pdf
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  • HAL Id : hal-03081047, version 1

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Xavier Garbet, O Panico, R Varennes, C Gillot, G Dif-Pradalier, et al.. Zonal instability and wave trapping. 2020. ⟨hal-03081047⟩

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