MAGNETO-ATMOSPHERIC WAVES

The nature and properties of magneto-atmospheric (MA) waves are discussed here. A simple model atmosphere, isothermal and permeated by a uniform vertical magnetic field, was used to find that there are two type of modes with avoided crossing of the eigencurves in a K - Ω diagram. The properties of these waves are found to be identical to the uncoupled fast and slow MA waves away from the crossings (specially for small horizontal wave number K ≪ 1). The energy density for the fast modes is found to vanish with height and is responsible for the 3-min umbral oscillations, while the slow mode energy density is harmonic. © 1990 Kluwer Academic Publishers.