A finite element approach to the computation of the MHD spectrum of straight noncircular plasma equilibria

A numerical scheme to compute the MHD spectrum of a straight plasma column of arbitrary cross section is described. It is based on a finite element expansion in terms of a carefully chosen set of basis functions. Numerical tests show that kink modes are well reproduced for plasmas of arbitrary low β but that the weakly growing internal modes are difficult to obtain in the low-β regime. (Auth.)