Saturation Level of ETG Turbulence
Paper in proceeding, 2013

In this work the finite β-effects of an electron branch of the geodesic acoustic mode (el-GAM) driven by electron temperature gradient (ETG) modes is presented. The work is based on a fluid description of the ETG mode retaining nonadiabatic ions and the dispersion relation for el-GAMs driven non-linearly by ETG modes is derived. The ETG growth rate from the fluid model is compared to the results found from gyrokinetic simulations with good agreement. A new saturation mechanism for ETG turbulence through the interaction with el-GAMs is found, resulting in a significantly enhanced ETG turbulence saturation level compared to the mixing length estimate. It is shown that the el-GAM may be stabilized by an increase in finite β as well as by increasing non-adiabaticity. The decreased GAM growth rates is due to the inclusion of the Maxwell stress.


Johan Anderson

Chalmers, Applied Physics, Nuclear Engineering

Hans Nordman

Chalmers, Earth and Space Sciences

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Raghvendra Singh

Festival de Thorie

Vol. 7 4-

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Fusion, Plasma and Space Physics

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