A model for the reversal of the toroidal rotation in tokamak

摘要: The transition from toroidal counter- to co- rotation in the core plasma has been observed at L H several tokamaks. Spontaneous reversal also TCV beyond a threshold density. We develop model based on following phenomenology: (1) increase of gradient pressure triggers formation fast time scale cells convection (similar Rayleigh-Benard (RB), but with single sign vorticity); (2) poloidal is induced by envelope peripheric velocity cells; via baroclinic term gradients temperature and density sustain against decay due parallel viscosity; (3) flow induces high derivative radial electric field; (4) neoclassical polarization creates series accelerations (kiks each bounce) trapped ions, leading an precession or its reversal; source energy work done field. (5) diffusion transfers resistive momentum ions untrapped ones. correlated interactions are examined estimated scales found be compatible observations.