2 research outputs found
Wave modes excited by photospheric p-modes and mode conversion in a multi-loop system
Context. Waves are ubiquitous in the solar corona and there are indications
that they are excited by photospheric p-modes. However, it is unclear how
p-modes in coronal loops are converted to sausage modes and transverse (kink)
modes, which are observed in the corona. Aims. We aim to investigate how those
wave modes are excited in the lower corona by photospheric acoustic waves.
Methods. We built 3D magnetohydrostatic loop systems with multiple inclinations
spanning from the photosphere to the lower corona. We then simulated these
atmospheres with the MANCHA code, in which we perturb the equilibrium with a
p-mode driver at the bottom of the domain. By splitting the velocity
perturbation into components longitudinal, normal, and azimuthal to the
magnetic flux surfaces we can study wave behavior. Results. In vertical flux
tubes, we find that deformed fast sausage surface waves and slow sausage body
waves are excited. In inclined flux tubes fast kink surface waves, slow sausage
body waves, and either a fast sausage surface wave or a plane wave are excited.
In addition, we calculate a wave conversion factor (0 C 1) from
acoustic to magnetic wave behavior by taking the ratio of the mean magnetic
energy flux to the sum of the mean magnetic and acoustic energy flux and
compare it to a commonly used theoretical conversion factor. We find that
between magnetic field inclinations of 10 to 30 those two
methods lie within 40%. For smaller inclinations the absolute deviation is
smaller than 0.1.Comment: 14 pages, 14 figure