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Electromagnetic transport from microtearing mode turbulence
W Guttenfelder1, J Candy, S M Kaye
1Princeton Plasma Physics Laboratory, Princeton New Jersey 08543, USA.
Physical Review Letters
|May 17, 2011
Summary
Nonlinear gyrokinetic simulations show microtearing mode turbulence in fusion plasmas. Electron thermal transport is comparable to experiments, driven by magnetic field stochasticity, and reduced by flow shear.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Computational Astrophysics
Background:
- Microtearing mode turbulence is a key driver of anomalous transport in fusion devices.
- Understanding electron thermal transport is crucial for achieving controlled thermonuclear fusion.
- High-beta (high plasma pressure relative to magnetic pressure) regimes present unique challenges for plasma stability.
Purpose of the Study:
- To perform nonlinear gyrokinetic simulations of microtearing mode turbulence.
- To investigate the role of collisional and electromagnetic effects on electron thermal transport.
- To compare simulation predictions with experimental data from the National Spherical Torus Experiment (NSTX).
Main Methods:
- Nonlinear gyrokinetic simulations were employed.
- Simulations incorporated collisional and electromagnetic effects.
- Experimental parameters from a high-beta discharge in NSTX were used.
Main Results:
- Predicted electron thermal transport closely matched experimental analysis.
- Electromagnetic contributions, due to electrons streaming along stochastic magnetic field lines, dominated the transport.
- Observed experimental flow shear significantly reduced the simulated transport.
Conclusions:
- Gyrokinetic simulations accurately capture microtearing mode turbulence and associated electron thermal transport.
- Stochastic magnetic field lines play a critical role in electron thermal transport.
- Flow shear is an effective mechanism for mitigating turbulent transport in fusion plasmas.
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