Study of resistive drift and resistive interchange modes in a cylindrical plasma with magnetic shear.

Resistive drift mode and resistive interchange mode in the presence of a magnetic curvature and a shear are studied theoretically as well as computationally based on the model equations of isothermal electrons and two dimensional cold ions in a cylindrical geometry. There are two branches of unstable modes: one has characteristics similar to the resistive drift wave instability with a real frequency, omega sub r, of the order of a diamagnetic frequency, omega*, and the other is curvature driven mode ( the resistive interchange instability ) with |omega sub r|=|omega sub i| localized in the neighborhood of the resonant surface. Growth rates of both of these instabilities are proportional to nu sub (ei) sup (1/2) in the small nu sub (ei) limit, where nu sub (ei) is the electron ion collision frequency.