CNR ExploRA

Articolo in rivista, 2022, ENG, 10.1088/1742-6596/2397/1/012010

Kinematic viscosity estimates in reversed-field pinch fusion plasmas

Vivenzi N.; Spizzo G.; Veranda M.; Bonfiglio D.; Cappello S.; RFX-mod Team

Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova, Italy; CRF - University of Padova, Italy; CNR ISTP - Istituto per la Scienza e Tecnologia dei Plasmi, Sede di Padova, Italy.

This paper concerns the kinematic viscosity in reversed-field pinch fusion plasmas, including both the study of numerical magneto-hydrodynamics (MHD) simulations and the analysis of RFX-mod experimental data. In the first part, we study the role of non-uniform time-constant radial viscosity profiles in 3D non-linear visco-resistive MHD simulations. The new profiles induce a moderate damp (for the velocity field) and a correspondent enhancement (for the magnetic field) of the spectral components resonating in the regions where the viscosity is higher. In the second part, we evaluate the kinematic viscosity coefficient on a wide database of RFX-mod shots according to the transport theories of Braginskii (considering parallel, perpendicular and gyro viscosity coefficients), considering the action on viscosity of ITG modes (ion temperature gradient) and according to the transport theory of Finn. We then exploit the comparison with the visco-resistive MHD simulations (where the visco-resistive dissipation rules the MHD activity) to show that the classical Braginskii perpendicular viscosity produces the best agreement between simulations and data, followed by the Braginskii gyro-viscosity.

Journal of physics. Conference series (Online) 2397 , pp. 012010-1–012010-14