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arXiv · 2011.08256

Excitation of Zonal Flow by Intermediate-Scale Toroidal Electron Temperature Gradient Turbulence

Haotian Chen·Stefan Tirkas·Scott E. Parker
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Abstract

We show that zonal flow can be preferentially excited by intermediate-scale toroidal electron temperature gradient (ETG) turbulence in tokamak plasmas. Previous theoretical studies that yielded an opposite conclusion assumed a fluid approximation for ETG modes. Here, we carry out a gyrokinetic analysis which ultimately yields a nonlinear Schr\"{o}dinger equation for the ETG dynamics with a Navier-Stokes type nonlinearity. For typical tokamak parameters, it is found that zonal flow generation plays an important role in the intermediate-scale ETG turbulence. This finding offers an explanation for recent multi-scale gyrokinetic simulations.

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Haotian Chen, Stefan Tirkas, Scott E. Parker. 2020-11-16. Excitation of Zonal Flow by Intermediate-Scale Toroidal Electron Temperature Gradient Turbulence. https://doi.org/10.1088/1741-4326/abf81a

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