Drift wave solitons and zonal flows: implication on staircase formation

Fuente: arXiv
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Autori principali: Chen, Ningfei, Chen, Liu, Zonca, Fulvio, Qiu, Zhiyong
Natura: Preprint
Pubblicazione: 2024
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author Chen, Ningfei
Chen, Liu
Zonca, Fulvio
Qiu, Zhiyong
author_facet Chen, Ningfei
Chen, Liu
Zonca, Fulvio
Qiu, Zhiyong
contents The self-consistent nonlinear interaction of drift wave (DW) and zonal flow (ZF) is investigated using nonlinear gyrokinetic theory, with both spontaneous excitation and beat-driven of ZF by DW treated on the same footing. DW solitons are formed in the nonlinear DW-ZF interactions and are confined between radially spaced micro-barriers. The resulting radial structures in the nonlinear DW-ZF interactions exhibit similar pattern to the ExB "staircase" observed in numerical simulations. These micro-barriers are generated by the repulsive response due to spontaneously excited ZF, which, as a general property demonstrated in this work, also generate an attractive nonlinear potential in DW equation. Meanwhile, the nonlinear potential due to beat-driven ZF is always attractive and, as such, always serve as potential well to contribute to soliton formation. For spontaneously excited ZF from initial noise, the simultaneous excitation of solitons and micro-barriers is found to be universal, due to the zero frequency nature of ZF and spatial structure of the Reynolds stress. The present analysis, thus, provides a potential first-principle-based interpretation of the ExB staircase observed in simulations, which may contribute to micro transport barriers formation and enhance plasma confinement.
format Preprint
id arxiv_https___arxiv_org_abs_2408_05983
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Drift wave solitons and zonal flows: implication on staircase formation
Chen, Ningfei
Chen, Liu
Zonca, Fulvio
Qiu, Zhiyong
Plasma Physics
The self-consistent nonlinear interaction of drift wave (DW) and zonal flow (ZF) is investigated using nonlinear gyrokinetic theory, with both spontaneous excitation and beat-driven of ZF by DW treated on the same footing. DW solitons are formed in the nonlinear DW-ZF interactions and are confined between radially spaced micro-barriers. The resulting radial structures in the nonlinear DW-ZF interactions exhibit similar pattern to the ExB "staircase" observed in numerical simulations. These micro-barriers are generated by the repulsive response due to spontaneously excited ZF, which, as a general property demonstrated in this work, also generate an attractive nonlinear potential in DW equation. Meanwhile, the nonlinear potential due to beat-driven ZF is always attractive and, as such, always serve as potential well to contribute to soliton formation. For spontaneously excited ZF from initial noise, the simultaneous excitation of solitons and micro-barriers is found to be universal, due to the zero frequency nature of ZF and spatial structure of the Reynolds stress. The present analysis, thus, provides a potential first-principle-based interpretation of the ExB staircase observed in simulations, which may contribute to micro transport barriers formation and enhance plasma confinement.
title Drift wave solitons and zonal flows: implication on staircase formation
topic Plasma Physics
url https://arxiv.org/abs/2408.05983