Observing Propagation of Magnetoacoustic Waves from the Photosphere to the Corona in Sunspot Regions

Abstract:

Running penumbral waves in the chromosphere and slow magnetoacoustic waves in the lower coronal loops have been observed and studied for a long time. However, it is not clear whether these waves are connected, whether they have photospheric counterparts, and how they get excited. Recently, through cross-correlating oscillation signals in sunspots' umbrae with those in penumbrae and the sunspots' vicinity observed by SDO/HMI, we identified a fast-moving wave propagating from the sunspots to their outside. It is interesting to see whether this type of the photospheric wave is related to those waves observed above the photosphere in the chromopshere and corona. In this work, we analyze a well-observed sunspot region, using SDO/HMI data for the photosphere, AIA 1600Å and 1700Å data for the lower chromosphere, BBSO/NST Hα data for the chromosphere, AIA 304Å data for the transition region, and AIA 171Å data for the lower corona. Our results show that the wave phenomena observed at different atmospheric heights using different spectrum lines are actually a same slow magnetoacoustic wave propagating upward, likely with a wave source located a few megameters below the sunspots’ surface.