Excitation of zonal flow by intermediate-scale toroidal electron temperature gradient turbulence

Fine-Scale Zonal Flow Suppression of Electron Temperature Gradient Turbulence

Abstract. It is found in collisionless Electron Temperature Gradient (ETG) turbulence simulations that, while zonal flows are weak at early times, the zonal flows continue to grow algebraically (proportional to time). These fine-scale zonal flows have a radial wave number such that krρi > 1 and krρe < 1. Eventually, the zonal flows grow to a level that suppresses the turbulence due to ExB shear...

Role of nonlinear toroidal coupling in electron temperature gradient turbulence

Global gyrokinetic particle simulation and nonlinear gyrokinetic theory find that electron temperature gradient sETGd instability saturates via nonlinear toroidal coupling, which is a nonlocal interaction in the wave vector space that transfers energy successively from unstable modes to damped modes preferentially with lower toroidal mode numbers. The electrostatic ETG turbulence is dominated b...

Zonal flow generation in ion temperature gradient mode turbulence

In the present work the zonal flow ~ZF! growth rate in toroidal ion-temperature-gradient ~ITG! mode turbulence including the effects of elongation is studied analytically. The scaling of the ZF growth with plasma parameters is examined for typical tokamak parameter values. The physical model used for the toroidal ITG driven mode is based on the ion continuity and ion temperature equations where...

Coherent structures in ion temperature gradient turbulence-zonal flow

Electron temperature gradient turbulence.

The first toroidal, gyrokinetic, electromagnetic simulations of small scale plasma turbulence are presented. The turbulence considered is driven by gradients in the electron temperature. It is found that electron temperature gradient (ETG) turbulence can induce experimentally relevant thermal losses in magnetic confinement fusion devices. For typical tokamak parameters, the transport is essenti...