2015/06/01 by P. Manas, Y. Camenen, S. Benkadda +2 · 2 citations
Physics and Astronomy · #Dust and Plasma Wave Phenomena #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research
paper · doi:10.1063/1.4922754
crossref issued 2015/06/01 · crossref published 2015/06/01 · crossref published-print 2015/06/01 · openalex publication_date 2015/06/01 · crossref created 2015/06/17 · crossref deposited 2023/04/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22 · crossref indexed 2026/07/30
The collisional stabilisation via energy scattering and pitch-angle scattering of micro-instabilities in tokamak plasmas is investigated by means of gyrokinetic simulations with a special emphasis on the often neglected energy scattering operator. It is shown that in the linear regime energy scattering has a negligible effect on Ion Temperature Gradient (ITG) modes but enhances the stabilisation of Trapped Electron Modes (TEM) in presence of nonzero ion temperature and density gradients. This stabilisation is sensitive to the model used for the energy restoring term in the collision operator. The contributions of parallel and drift motion to the total growth rate in velocity space are used to characterize the complex stabilisation mechanisms behind pitch-angle and energy scattering for a range of relevant parameters such as the magnetic shear, the collisionality, the logarithmic density gradient, and the logarithmic ion temperature gradient. It is shown that depending on these parameters, energy scattering stabilisation of TEM can be either due to a decrease of the contribution from drifting trapped electrons or to an increase of the contribution from the parallel motion of passing electrons. Finally, for a standard ITG/TEM case, the effect of energy scattering on the nonlinear heat and particle fluxes is investigated.