Effect of toroidal rotation on the linear stability of drift-resistive-inertial ballooning modes

Abstract

The two-fluid drift-resistive-inertial-ballooning mode model [Rafiq et al., Phys. Plasmas 17, 082511 (2010)] developed by Rafiq et al. has been improved with the inclusion of the effects of local toroidal rotation and its shear. Linear fluid simulations have shown that the drift-resistive-inertial ballooning modes (DRIBMs) are destabilized by the toroidal rotation. It has been discovered that the effect of velocity shear on the DRIBMs strongly depends on the type of driving force. For the case of the density gradient driven DRIBMs, the modes can be stabilized by large velocity shear, while for the electron temperature gradient driven DRIBMs (ηe-driven DRIBMs), the velocity shear is shown to have a more effective stabilizing effect. However, in the situation of the ion temperature gradient driven DRIBMs (ηi-driven DRIBMs), the modes are further destabilized by the velocity shear. The behaviors of DRIBMs driven by the coexistence of ion and electron temperature gradients are shown to be similar to the ηe-driven DRIBMs, suggesting that the electron temperature gradient is one kind of strong driving force for DRIBMs. Besides, the toroidal ion temperature gradient modes are shown to be destabilized by the rotation and the velocity shear.