Diffusive Transport Analysis in Low Aspect Ratio Reversed Field Pinch

Yasuo Nagamine, Atsushi Fukuyama, Shoichi Shiina, Masamitsu Aizawa
2014 Journal of Physics, Conference Series  
Introduction To evaluate confinement properties of the low aspect ratio reversed field pinch (RFP) plasma, diffusive transport analysis including the neoclassical and turbulent transport models is studied. As for the conventional RFP plasma with laeger aspect ratio, resistive magnetohydrodynamic transport analyses by using the theoretical model or three-dimensional numerical simulations based on the cylindrical approximation have been performed and shown to be nearly consistent with
more » ... results such as the confinement scaling in the standard ohmically driven RFP [1, 2] . In the present RFP, it is considered that resistive diffusion in the relaxation process causes the anomalous transport of energy and particles. However, of transport phenomena in the steady state RFP without dynamo effect, the energy confinement time τ E might be determined by anomalous transport due to micro-instabilities like in tokamaks. Mechanism of the turbulent transport due to micro-instabilities such as ITG modes is not understood well in the RFP. In Ref. [3], linear gyro-kinetic calculations were applied to the RFP configuration to investigate the occurrence of ITG instabilities. This analysis reports ITG modes are in general stable in RFP plasmas in the area of experimental parameters. In this study, we focus on the low aspect ratio configuration with shaped magnetic surface and neoclassical effects. We assume two-dimensional RFP configuration to understand a basic characteristic about this type of transport. It is expected to use the gyro-fluid model as the turbulent transport model, which describes the dynamics of a limited set of fluid moments of the gyro-kinetic equations. In diffusive transport analysis, we apply TASK code [4] to the RFP configuration. As preliminary calculations of the modified TASK code, equilibrium and transport analyses of the low aspect ratio RFP were performed using the neoclassical and basic turbulent transport models. It is necessary to apply advanced transport models stated above for more detailed analysis.
doi:10.1088/1742-6596/511/1/012046 fatcat:ih7eiddnibe53gybmrjlr5ejly