Acoustic oscillations in a field-free cavity under solar small-scale bipolar magnetic canopy

Abstract

Observations show the increase of high-frequency wave power near magnetic network cores and active regions in the solar lower atmosphere. This phenomenon can be explained by the interaction of acoustic waves with a magnetic field. We consider small-scale, bipolar, magnetic field canopy structure near the network cores and active regions overlying field-free cylindrical cavities of the photosphere. Solving the plasma equations we get the analytical dispersion relation of acoustic oscillations in the field-free cavity area. We found that the m = 1 mode, where m is azimuthal wave number, cannot be trapped under the canopy due to energy leakage upwards. However, higher ($m\ge 2$) harmonics can be easily trapped leading to the observed acoustic power halos under the canopy.

7 pages, 4 figures, accepted in Annales Geophysicae

References in corpus (5)

• Emergence of Small-Scale Magnetic Loops in the Quiet Sun Internetwork
• Solar Atmospheric Oscillations and the Chromospheric Magnetic Topology
• Two-wave interaction in ideal magnetohydrodynamics
• On the effect of the inhomogeneous subsurface flows on the high degree solar p-modes
• Resonant energy conversion of 3-minute intensity oscillations into Alfven waves in the solar atmosphere

Cited by in corpus (18)

• Modeling the Subsurface Structure of Sunspots
• Characteristics of transverse waves in chromospheric mottles
• Sunspot seismic halos generated by fast MHD wave refraction
• Properties of high-frequency wave power halos around active regions: an analysis of multi-height data from HMI and AIA onboard SDO
• Magnetohydrodynamic waves driven by p-modes
• Dynamics of Coronal Bright Points as seen by Sun Watcher using Active Pixel System detector and Image Processing (SWAP), Atmospheric Imaging Assembly AIA), and Helioseismic and Magnetic Imager (HMI)
• Newly identified properties of surface acoustic power
• Acoustic oscillations in the field-free, gravitationally stratified Acoustic oscillations in the field-free, gravitationally stratified cavities under solar bipolar magnetic canopies
• 3D simulations of realistic power halos in magneto-hydrostatic sunspot atmospheres: linking theory and observation
• A Wave Scattering Theory of Solar Seismic Power Haloes
• MHD wave refraction and the acoustic halo effect around solar active regions - a 3D study
• Numerical Simulations of Magnetoacoustic-Gravity Waves in the Solar Atmosphere
• Modeling solar coronal bright point oscillations with multiple nanoflare heated loops
• Enhanced Acoustic Emission in Relation to the Acoustic Halo Surrounding Active Region 11429
• A study of the propagation of magnetoacoustic waves in small-scale magnetic fields using solar photospheric and chromospheric Dopplergrams: HMI/SDO and MAST observations
• Local helioseismology and the active Sun
• Enhanced sources of acoustic power surrounding AR11429
• Network Loop Oscillations with EIS/Hinode