Ion-Temperature-Gradient-Driven Drift Mode Coupled to the Resistive Interchange Mode in a Heliotron/Torsatron

A new type of η i mode is studied in a sheared slab model including an averaged curvature by an electrostatic incompressible fluid model describing both ion-temperature-gradient-driven drift modes (η i modes) and resistive interchange modes ( g modes) for a heliotron/torsatron. This η i mode is destabilized by the coupling to the unstable g mode. In the low shear limit, the η i modes driven by the unfavorable average curvature remain, and their growth rates depend weakly on the compressibility effect. The η i modes are weakly destabilized by electron-ion collisions.