Toroidal Mhd Stability in Complex Magnetic Configuiutions

Abstaact-Mercier’s localized perturbation criterion near the magnetic axis is examhied for a particular type of toroidal configuration of non-planar magnetic axis of variable curvature and torsion with non-circular (elliptically and triangularly deformed) plasma cross section for the ‘resonance case’. As an application, a numerical calculation is carried out for a class of equilibria that belongs to the above configuration with constant torsion. The result of this numerical calculation indicates that in the absence of longitudinal current, it is possible to have a domain of stability in a system with a horizontally elliptical (and triangular) deformation with an ellipticity corresponding to (a = 2b) i.e. the minor axis is twice the major axis. In the presence of a longitudinal current, a domain of stability is also possible and it depends on the direction of the current. In addition it is shown that horizontally elliptical and triangular deformations are favourable for stability.