A New Approach to Kinetic Energy Flux at the Different Frequencies above the IRIS Bright Points* * Released on 2021 March 1

Abstract

Various bright structures abound in the chromosphere playing an essential role in the dynamics and evolution therein. Tentatively identifying the wave characteristics in the outer solar atmosphere helps to understand this layer better. One of the most significant aspects of these characteristics is the wave phase speed (PS), which is a dominant contribution to solar coronal heating and energy distribution in the Sun’s atmosphere layers. To obtain energy flux (EF), it is necessary to calculate the filling factor (FF) and the PS. In this study, the FF was determined by tracking the size and intensity of the IRIS bright points (BPs). To estimate an accurate PS and EF, it is necessary to know the chromosphere and transition region (TR) thickness and the phase difference between the two desired levels. Chromosphere and TR thickness cannot be measured directly on the disk; this study is performed using spectral data and calibrated based on Doppler velocities. As a result, the PSs in active regions (ARs) and coronal holes (CHs), as well as the IRIS BPs, have been calculated using the cross-power wavelet transform of Doppler velocities. Consequently, about the CH, the PS mean values are from 40 to 180 km s−1 at the network and from 30 to 140 km s−1 at the internetwork; and about the AR, they are from 80 to 540 km s−1 at the network and 70 to 220 km s−1 at the internetwork. Finally, the EF for the IRIS BPs has been calculated in three different frequencies. The results indicate that the network BPs have an influential role in heating the higher layers, while in the internetwork BPs most of the energy returns to the lower layers.