Ideal mhd instabilities with finite β-effect in reversed field pinch

The growth rates of m=1 ideal MHD instabilities in RFP configurations are calculated by the use of the Hain and Lust equation in RFP configuration with finite pressure. Two kinds of m=1 instabilities are studied in this paper; one is a current-driven internal mode whose plasma displacement is localized around the plasma center region, and the other is a pressure-driven external mode whose plasma displacement is localized on the plasma surface. The contours of the growth rate of both in-stabilities are present in [formula ommitted] diagram ([formula ommitted]), in which each point corresponds to a RFP configuration with a different current profile. This diagram shows that the growth rate of the internal mode is closely related to the degree of relaxation.