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

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    • Keywords


      Sun-corona; Sun-active region; Sun-longitudinal intensity oscillations.

    • 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 loopstructures, several successive image data on 171 Å (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, apparentdamping length, damping time, and damping quality of these extracted propagating disturbances are in the range of 7–35 min, 72–241 km s$^{-1}$, 17.5–82 Mm, 1.14–11.27 min, and 0.10–0.50, respectively. The calculatedphysical 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 theoreticalmodels and the current linear magnetohydrodynamics wave theory.

    • Author Affiliations


      A. ABEDINI1

      1. Department of Physics, University of Qom, Qom University Blvd Alghadir P.O. Box 3716146611, Qom, Islamic Republic of Iran.
    • Dates

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