Observational signatures of the interaction between acoustic waves and the solar magnetic canopy
Istituto Tecnico Industriale Statale E. Fermi, via Trionfale 8737, Roma 00133, Italy e-mail: email@example.com
2 Institute for Astronomy, University of Hawai'i, 4761 Lower Kula Road, Kula, Hawaii 96790, USA e-mail: firstname.lastname@example.org
3 Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 400, 80302 Boulder, CO, USA e-mail: email@example.com
Accepted: 28 March 2007
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.
Key words: Sun: atmosphere / Sun: oscillations / Sun magnetic fields
© ESO, 2007