On the absence of critical levels in the solar atmosphere

We consider the propagation of linear oscillations in a stratified atmosphere permeated by an oblique but nearly horizontal uniform magnetic field. Our results do not show any of the strong characteristics associated with critical level singularities in the exactly horizontal field case. This suggests that critical levels may be of more mathematical interest than physical relevance in the solar atmosphere where the planar horizontal field approximation is seldom adequate.Currently a Nuffield Foundation Science Research Fellow.