[en] The classical incompressible MHD or cold plasma phase mixing problem, which involves Alfven or plasma waves in inhomogeneous media, is re-examined using a spatial Fourier series rather than the usual temporal Fourier or Laplace transform approach. A number of exact and near-exact analytic and numerical results are derived which reveal an attractive picture of energy cascading to smaller length-scales in a manner reminiscent of turbulence. A simple and unambiguous description is presented of how a surface wave arises in the limit in which the inhomogeneity becomes a discontinuity. (author)