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M Kotschenreuther

Publications and source records attributed to M Kotschenreuther.

2 recordsLinked to original sources

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 essentially electrostatic in character. The simulation results are qualitatively consistent with a model that balances linear and secondary mode growth rates. Significant streamer-dominated transport at long wavelengths occurs because the secondary modes that produce saturation become weak in the ETG limit.

Journal Article↗

Generation and stability of zonal flows in ion-temperature-gradient mode turbulence.

We address the mechanisms underlying zonal flow generation and stability in turbulent systems driven by the electrostatic ion-temperature-gradient (ITG) mode. In the case of zonal flow stability, we show the poloidal flows typical of numerical simulations become unstable when they exceed a critical level. Near marginal stability of the linear ITG mode, the system can generate zonal flows that are sufficiently weak to remain stable and sufficiently strong to suppress the linear ITG mode. This stable region corresponds to the parameter regime of the nonlinear Dimits up-shift.

Journal Article↗