The dissipation of magneto-acoustic waves

AbstractIn this paper, we will study the propagation of magneto-acoustic waves in a thermally conducting isothermal atmosphere. We will consider the case of a dominant magnetic field. It is shown that the atmosphere may be divided into two distinct regions. For the small Newtonian cooling coefficient compared to the adiabatic cutoff frequency, the motion in the lower region, is approximately adiabatic. When the Newtonian cooling coefficient goes to infinity it will act directly to eliminate the temperature perturbation associated with the wave in a time small compared to the adiabatic cutoff frequency. In the upper region, the solution will decay with the altitude to a constant value. These two regions are connected by a transition region, in which the reflection and the wave modification take place. Reflection coefficients and two equations for resonances are derived