Flow-shear stabilization of ion temperature gradient-driven instability in a tokamak: Slab theory

A simple physical model for the flow-shear stabilization of ion temperature gradient (ITG)-driven instability in the presence of dissipative trapped electrons is presented. Reduced fluid equations and magnetic sheared slab geometry are adopted. From analytical analyses and numerical calculations, it was found that the coupling between the sheared flows and non-adiabatic electrons will result in the stabilization of both toroidal sheared flow and poloidal sheared flow on hybrid dissipative trapped electron ITG mode. This implies that the confinement improvement in tokamaks can be obtained not only through the poloidal sheared rotation in the edge region of tokamaks for the H-mode (high-confinement mode), but also through the toroidal sheared rotation in the core region for further confinement improvement associated with internal transport barrier (ITB) and negative shear (or reversed magnetic shear). When the poloidal and toroidal sheared flows are simultaneously considered, it was found that in the presen...