Effect of radiative cooling on wave dispersion in a homogeneous medium with a magnetic field

Field’s instability is revisited, and the results of a linear analysis of stability in a homogeneous medium with a magnetic field with allowance for radiative heating and cooling are reported. The allowance for cooling is shown to result in weak damping of acoustic and magnetoacoustic waves, and the instability of the entropy mode.Moreover, the entropy mode proves to be unstable at all wavelengths. This conclusion is shown to be true for the radiative cooling functions growing no faster than T 2.