Reflection and refraction of (magneto-)acoustic waves at the magnetic canopy: further evidences from multi-height seismic data

摘要

We recently presented evidences (Rajaguru et al. 2012) that seismic halosaround expanding magnetic structures in the lower solar atmosphere are relatedto the acoustic to magnetoacoustic wave conversions, using multi-height datafrom Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly(AIA) (1700 and 1600 \AA channels) onboard Solar Dynamics Observatory (SDO).Using the same data, we here present and discuss further evidences throughanalyses of maps of phase-shifts between observables from different heights andtheir correspondence with oscillation power. The phase shift maps provide moredirect signatures of reflection and refraction of (magneto-)acoustic wavemodes.