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Suppression of turbulence in the drift-resistive plasma where zonal flow changes direction

Published online by Cambridge University Press:  11 June 2020

Chang-Bae Kim*
Affiliation:
Physics Department and Research Institute for Origin of Matter and Evolution of Galaxies, Soongsil University, Seoul06978, Korea
*
Email address for correspondence: [email protected]

Abstract

The edge region of quasi-adiabatic plasma is pedagogically simulated by the dynamics between the electric potential $\unicode[STIX]{x1D711}$ and the electron density $n$ whose equilibrium density gradient is negative and held fixed. The zonal flow (ZF) $V$ is either enforced sinusoidally or generated self-consistently from the turbulence. Cross-phase $\unicode[STIX]{x1D6FF}$ between $\unicode[STIX]{x1D711}$ and $n$, which is important in the determination of the turbulence level and the transport, is strongly influenced by the ZF. In the region near $V=0$, $\unicode[STIX]{x1D6FF}$ becomes negative due to the large gradient of the ZF. It is found that the instabilities are quenched there, and the fluctuations decay. The ZF thus works as a transport barrier in the region where the ZF changes direction with large gradient.

Type
Research Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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