Period dependence of physical quantities of slow magnetoacoustic waves in coronal loop structures of active regions with and without sunspots

Abstract

Recently, quasi-periodic propagating disturbances have been detected frequently in different structures of the solar corona. These propagating disturbances are interpreted as slow magnetoacoustic waves. They may be responsible for longitudinal intensity oscillations in coronal structures. The purpose of this study is to investigate the features of propagating disturbances in two different types of coronal loop structures of active regions with and without sunspots. In addition, the observational findings of this study are compared with theoretical predictions. Two categories of corona loop structures with and without sunspots are selected using Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO) space telescope. From each of these two types of coronal loop structures, several successive image data on 171 $\AA$ (Fe IX) passband with a time distance of 12 s are taken using AIA/SDO. The time series of intensities of successive macropixels on different paths along the active regions coronal loop structures are analyzed. Then, physical quantities such as apparent velocity, apparent damping length, damping time, and damping quality of propagating disturbances are investigated. The results of this analysis show that the magnitude values of the oscillation period, apparent velocity, apparent damping length, damping time, and damping quality of these extracted propagating disturbances are in the range of 7–35 min, 72–241 $\mathrm{km}\,\mathrm{s}^{-1}$, 17.5–82  $\mathrm{Mm}$, 1.14–11.27  $\mathrm{min}$, and 0.10–0.50, respectively. The calculated physical quantities for the active region loops with and without sunspots correspond to the predictions of the theoretical model. However, the periodicity dependence of some physical quantities of open coronal loop structures of active regions without a sunspot is not consistent with the predictions of theoretical models and the current linear magnetohydrodynamics wave theory.