Flow-shear destabilization of multiscale electron turbulence

IF 2.1 2区物理与天体物理 Q2 PHYSICS, FLUIDS & PLASMAS

Plasma Physics and Controlled Fusion Pub Date : 2024-03-07 DOI:10.1088/1361-6587/ad2c28

E A Belli, J Candy, I Sfiligoi

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引用次数: 0

Abstract

The impact of sheared

E×B

flow on multiscale turbulence is studied with nonlinear gyrokinetic simulations. Simulations are based on DIII-D-like, high-confinement mode (H-mode) pedestal parameters in the regime of low ion temperature gradient drive, where there is a broad spectrum of electron temperature gradient (ETG)-driven turbulence. It is found that

E×B

shear can have a significant effect on ETG-driven electron transport, with an unexpected transition from a turbulence stabilization regime at moderate to large shearing rates γ _E to a novel turbulence destabilization regime at low levels of γ _E. In the turbulence stabilization regime, the electron energy flux decreases monotonically with γ _E, even when γ _E is small compared to electron mode growth rates. The stabilizing effect comes dominantly from the electron, not ion, gyrokinetic equation. In the novel destabilization regime, reduction of zonal energy results from the interaction of γ _E-modulated nonlinear drive in the zonal ion gyrokinetic equation, increasing the electron transport over a broad range of shearing rates. Neither of these effects have been observed in previous electron-scale simulations.

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多尺度电子湍流的流动剪切失稳

通过非线性陀螺动力学模拟研究了剪切E×B流对多尺度湍流的影响。模拟基于低离子温度梯度驱动机制下的类似 DIII-D、高会聚模式（H-模式）基座参数，在该机制下存在广泛的电子温度梯度（ETG）驱动湍流谱。研究发现，E×B 剪切会对 ETG 驱动的电子传输产生重大影响，从中等到较大剪切率 γE 下的湍流稳定机制意外过渡到低水平 γE 下的新型湍流失稳机制。在湍流稳定系统中，电子能量通量随γE单调下降，即使γE与电子模式增长率相比很小。稳定效应主要来自电子，而不是离子的陀螺动力学方程。在新的失稳机制中，γE 调制的非线性驱动在带状离子陀螺动力学方程中的相互作用导致了带状能量的降低，从而在广泛的剪切速率范围内增加了电子传输。这两种效应在以前的电子尺度模拟中都没有观察到。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Plasma Physics and Controlled Fusion 物理-物理：核物理

CiteScore

4.50

自引率

13.60%

发文量

224

审稿时长

4.5 months

期刊介绍： Plasma Physics and Controlled Fusion covers all aspects of the physics of hot, highly ionised plasmas. This includes results of current experimental and theoretical research on all aspects of the physics of high-temperature plasmas and of controlled nuclear fusion, including the basic phenomena in highly-ionised gases in the laboratory, in the ionosphere and in space, in magnetic-confinement and inertial-confinement fusion as well as related diagnostic methods. Papers with a technological emphasis, for example in such topics as plasma control, fusion technology and diagnostics, are welcomed when the plasma physics is an integral part of the paper or when the technology is unique to plasma applications or new to the field of plasma physics. Papers on dusty plasma physics are welcome when there is a clear relevance to fusion.