Internal Gravity Waves in the Magnetized Solar Atmosphere. I. Magnetic Field Effects

Journal Article · Wed Feb 01 00:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/835/2/148· OSTI ID:22663957

Vigeesh, G.; Steiner, O. ^[1]

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1. Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg (Germany)

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magnetoacoustic waves. Here, we present a study of the acoustic-gravity wave spectrum emerging from a realistic, self-consistent simulation of solar (magneto)convection. A magnetic field free, hydrodynamic simulation and a magnetohydrodynamic (MHD) simulation with an initial, vertical, homogeneous field of 50 G flux density were carried out and compared with each other to highlight the effect of magnetic fields on the internal gravity wave propagation in the Sun’s atmosphere. We find that the internal gravity waves are absent or partially reflected back into the lower layers in the presence of magnetic fields and argue that the suppression is due to the coupling of internal gravity waves to slow magnetoacoustic waves still within the high- β region of the upper photosphere. The conversion to Alfvén waves is highly unlikely in our model because there is no strongly inclined magnetic field present. We argue that the suppression of internal waves observed within magnetic flux concentrations may also be due to nonlinear breaking of internal waves due to vortex flows that are ubiquitously present in the upper photosphere and the chromosphere.

• OSTI ID: 22663957
• Journal Information: Astrophysical Journal, Vol. 835, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALFVEN WAVES
CHROMOSPHERE
CONCENTRATION RATIO
FLUX DENSITY
GRANULATION
GRAVITATION
GRAVITY WAVES
HIGH-BETA PLASMA
INTERNAL WAVES
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETOACOUSTIC WAVES
MAGNETOACOUSTICS
MAGNETOHYDRODYNAMICS
PHOTOSPHERE
SIMULATION
SPECTRA
SUN
VORTEX FLOW
WAVE PROPAGATION