Transport of parallel momentum by toroidal ion temperature gradient instability near marginality

The turbulent angular momentum flux carried by ions resonant with toroidal ion temperature gradient (ITG) instability is calculated via quasilinear calculation using the phase-space conserving gyrokinetic equation in the laboratory frame. The results near ITG marginality indicate that the inward turbulent equipartition momentum pinch (Hahm et al 2007 Phys. Plasmas 14 072302) remains as the most robust part of pinch. In addition, ITG driven momentum flux is inward for typical parameters, while density gradient driven momentum flux is outward as in the previous kinetic result in slab geometry

Physics of non-diffusive turbulent transport of momentum and the origins of spontaneous rotation in tokamaks

International audienceRecent results in the theory of turbulent momentum transport and the origins of intrinsic rotation are summarized. Special attention is focused on aspects of momentum transport critical to intrinsic rotation, namely the residual stress and the edge toroidal flow velocity pinch. Novel results include a systematic decomposition of the physical processes which drive intrinsic rotation, a calculation of the critical external torque necessary to hold the plasma stationary against the intrinsic residual stress, a simple model of net velocity scaling which recovers the salient features of the experimental trends and the elucidation of the impact of the particle flux on the net toroidal velocity pinch. Specific suggestions for future experiments are offered

Towards an emerging understanding of non-locality phenomena and non-local transport

International audienceIn this paper, recent progress on experimental analysis and theoretical models for non-local transport (non-Fickian fluxes in real space) is reviewed. The non-locality in the heat and momentum transport observed in the plasma, the departures from linear flux-gradient proportionality, and externally triggered non-local transport phenomena are described in both L-mode and improved-mode plasmas. Ongoing evaluation of 'fast front' and 'intrinsically non-local' models, and their success in comparisons with experimental data, are discusse