A Statistical Study on the Frequency-dependent Damping of the Slow-mode Waves in Polar Plumes and Interplumes

Abstract

We perform a statistical study on the frequency-dependent damping of slow waves propagating along polar plumes and interplumes in the solar corona. Analysis of a large sample of extreme ultraviolet imaging data with high spatial and temporal resolutions obtained from Atmospheric Imaging Assembly ( AIA ) / Solar Dynamics Observatory suggests an inverse power-law dependence of the damping length on the periodicity of slow waves ( i.e., the shorter-period oscillations exhibit longer damping lengths ) , in agreement with the previous case studies. Similar behavior is observed in both plume and interplume regions studied in AIA 171 Å and AIA 193 Å passbands. It is found that the short-period ( 2 – 6 minutes ) waves are relatively more abundant than their long-period ( 7 – 30 minutes ) counterparts, in contrast to the general belief that the polar regions are dominated by the longer- period slow waves. We also derived the slope of the power spectra ( α , the power-law index ) statistically to better understand the characteristics of turbulence present in the region. It is found that the α values and their distributions are similar in both plume and interplume structures across the two AIA passbands. At the same time, the spread of these distributions also indicates the complexity of the underlying turbulence mechanism.