A modal view of oscillations in inhomogeneous compressible MHD

The description of oscillations in inhomogeneous magnetohydrodynamic plasmas in terms of spatial Fourier modes is extended beyond the previous analyses of the incompressible case to a fully compressible plasma in a rigid box. Attention is focused upon the cusp and Alfven continua and the discrete fast-mode spectrum. As well as providing a convenient method of numerical solution, the modal approach yields novel insights; in particular, the energy ultimately 'absorbed' resonantly is just that initially (and always) residing in the continua, and is readily calculated.