Author:

Keywords:

Science & Technology, Physical Sciences, Astronomy & Astrophysics, magnetohydrodynamics (MHD), methods: numerical, Sun: corona, Sun: oscillations, MAGNETIC-FLUX TUBES, ALFVEN WAVES, MHD WAVES, BEHAVIOR, 0201 Astronomical and Space Sciences, 5101 Astronomical sciences, 5107 Particle and high energy physics, 5109 Space sciences

Abstract:

The resonant absorption of slow and fast magnetosonic waves in a nonuniform magnetic plasma is studied for a simple planar equilibrium model. Propagating slow and fast magnetosonic waves are launched upwards in a lower uniform layer. They are partially absorbed by coupling to local resonant waves in an overlying nonuniform plasma layer at the magnetic surface where the frequency of the incoming wave equals the local Alfvén continuum frequency or the local slow continuum frequency. The slow magnetosonic waves can only be coupled to resonant slow continuum waves. For the fast magnetosonic waves there are three possibilities as they can be coupled to resonant Alfvén continuum waves alone, resonant Alfvén continuum waves combined with resonant slow continuum waves, and resonant slow continuum waves alone. The present paper focuses on the absorption of magnetosonic waves by coupling to resonant slow continuum waves either alone or in combination with resonant Alfvén continuum waves. The results show that the resonant absorption of slow and fast magnetosonic waves at the slow resonance position strongly depends on the characteristics of the equilibrium model and of the driving wave. The absorption can produce efficient local heating of plasma under conditions as in the solar atmosphere.