Abstract:
We recently presented evidence (Rajaguru et al. 2013) that seismic halos around expanding magnetic structures in the lower solar atmosphere are related to the acoustic to magnetoacoustic wave conversions, using multi-height data from Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA: 1700 and 1600 Å channels) onboard Solar Dynamics Observatory (SDO). Using the same data, we present and discuss here further evidence through analyses of maps of phase-shifts between observables from different heights and their correspondence with oscillation power. The phase shift maps provide more direct signatures of reflection and refraction of (magneto-)acoustic wave modes.
