Toroidal Effects on Nonlocal Collisionless Drift Instability

Abstract

Toroidal curvature effects on the electrostatic collisionless drift instability in a sheared magnetic field is investigated. The magnetic curvature drift of ions reduces or even annihilates the shear convective damping and causes the mode ballooning. It is found that the universal mode is stable (or marginally stable at most) so long as the convective damping remains finite, and the critical current density for the current-driven drift instability becomes lower.