Observational signatures of the interaction between acoustic waves and the solar magnetic canopy

Abstract

Aims:We show that the spatial distribution (and its variation with frequency) of the power spectra of the velocity and intensity signals, in and around solar active regions, is a manifestation of the interaction of acoustic waves at the magnetic canopy.
Methods: We analysed 6 h of simultaneous, full-disk, velocity and intensity images obtained using the MOTH instrument tuned in the Na D2 line at 589 nm and K D1 line at 770 nm, and full-disk velocity images from the SOHO/MDI experiment using the Ni line at 677 nm.
Results: We propose that more than one type of magneto-acoustic-gravity wave is required to explain the well-known phenomena of p-mode absorption and power halos.