Rajaguru, S. P; Couvidat, S; Sun, Xudong; Hayashi, K; Schunker, H
(Springer, 2013-10)
We study properties of waves of frequencies above the photospheric acoustic cut-off of ≈5.3 mHz, around four active regions, through spatial maps of their power estimated using data from the Helioseismic and Magnetic Imager ...