Properties of Magnetoacoustic Waves in Plasma with Heat Release Depending on the Magnetic Field

Abstract

We study the influence of the magnetic field dependence of the heating power on the dispersion properties of plane magnetoacoustic (MA) waves in the solar atmosphere. A dispersion relation is derived for MA waves in a homogeneous heat-releasing fully ionized plasma in the case when the specific heating power depends on the magnetic field strength, density, and temperature. Expressions are found for the phase velocities and decrements (increments) of slow and fast MA waves in the low-frequency and high-frequency approximations. For the conditions of the solar coronal plasma, stability regions of plane MA waves and entropy modes are constructed depending on the properties of the heating source, the propagation angle with respect to the magnetic field, and the plasma beta parameter. Anisotropy of propagation and damping (amplification) of both slow and fast MA waves is shown; this can lead to the observation of such waves in a limited angular sector with respect to the magnetic field, which is typical of the observed global waves in the solar atmosphere.