Observation of solar coronal heating powered by magneto-acoustic oscillations in a moss region

Abstract

In this paper, we report the observed temporal correlation between extremeviolet (EUV) emission and magneto-acoustic oscillations in a EUV moss region, which is the footpoint region only connected by magnetic loops with million-degree plasma. The result is obtained from a detailed multi-wavelength data analysis to the region with the purpose of resolving fine-scale mass and energy flows that come from the photosphere, pass through the chromosphere and finally heat solar transition region or the corona. The data set covers three atmospheric levels on the Sun, consisting of high-resolution broadband imaging at TiO 7057 Å and the line of sight magnetograms for the photosphere, high-resolution narrow-band images at Helium I 10830 Å for the chromosphere and EUV images at 171 Å for the corona. The 10830 Å narrow band images and the TiO 7057 Å broad-band images are from a much earlier observation on July 22, 2012 with the 1.6 meter aperture Goode Solar Telescope (GST) at Big Bear Solar Observatory (BBSO) and the EUV 171 Å images and the magnetograms are from observations made by Atmospheric Imaging Assembly (AIA) or Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We report following new phenomena: 1) Repeated injections of chromospheric material shown as 10830 Å absorption are squirted out from inter-granular lanes with the period of ∼ 5 minutes. 2) EUV emissions are found to be periodically modulated with the similar periods of ∼ 5 minutes. 3) Around the injection area where 10830 Å absorption is enhanced, both EUV emissions and the strength of magnetic field are remarkably stronger. 4) The peaks on the time profile of the EUV emissions are found to be in sync with oscillatory peaks of the stronger magnetic field in the region. These findings may give a series of strong evidences supporting the scenario that coronal heating is powered by magneto-acoustic waves.

Magneto-acoustic oscillations observed in a solar plage region

“…For completeness of the paper, we give here the necessary context of observations for the following analysis of magnetic field oscillations. A more extended analysis for the plage region has been given by Hashim et al (2020). Fig.…”

“…The dark inclusions are found to jointly appear and disappear, a signature of oscillatory fine-scale mass and energy flows going upward (Fletcher et al 1999;De Pontieu et al 2003;De Pontieu & Erdélyi 2006). With high-resolution narrow-band imaging at He I 10830 Å for an EUV moss inside a plage region (Ji Cao and Goode 2012), Hashim et al (2020) reported correlations between EUV emissions and magnetic perturbations with the period of ∼ 5 minutes. Understanding the nature of these magnetic perturbations and their coupling with underlying global p-mode is an important topic since they are related to heating of the upper atmosphere.…”

“…In his paper, we give a detailed observational analysis to magnetic oscillations in a plage region, the same plage analyzed by Hashim et al (2020). We take a qualitative approach to understand the observed phenomena in an MHD framework, assuming that plasma β is much larger than 1.…”

Magneto-acoustic oscillations observed in a solar plage region

“…The dark inclusions are found to jointly appear and disappear, a signature of oscillatory fine-scale mass and energy flows going upward De Pontieu et al 2003;De Pontieu & Erdélyi 2006). With high-resolution narrow-band imaging at He I 10830 Å for an EUV moss inside a plage region (Ji et al 2012), Hashim et al (2020) reported correlations between EUV emissions and magnetic perturbations with the period of ∼ 5 minutes. Understanding the nature of these magnetic perturbations and their coupling with underlying global pmode is an important topic since they are related to the heating of the upper atmosphere.…”

“…In this paper, we give a detailed observational analysis to magnetic oscillations in a plage region, the same plage analyzed by Hashim et al (2020). We take a qualitative approach to understand the observed phenomena in an MHD framework, assuming that plasma β is much larger than 1.…”