Effects of parallel and poloidal flows on tearing mode stability in tokamak plasma

Effects of the plasma parallel and poloidal flows, as well as the flow shear, on the tearing mode stability are investigated in conjunction with the toroidal flow and the favorable average curvature stabilization, utilizing an updated version of the MARS-F code [Liu et al., Phys. Plasmas7, 3681–3690 (2000)]. With vanishing plasma equilibrium pressure, both parallel and poloidal flows destabilize the mode although the dominant effect still comes from the toroidal flow. At finite equilibrium pressure and in the presence of favorable average curvature effect, the parallel and toroidal flows synergistically stabilize the tearing mode. This synergy does not occur for the combination of the toroidal and poloidal flows, since the latter tends to weaken the favorable curvature stabilization. The parallel flow on the other hand enhances the curvature stabilization. Finally, although the tearing mode may not be completely stabilized, the growth rate of the mode is reduced with finite equilibrium pressure for all values of flow shear, with the suppression being more pronounced at low or moderate flow shear.