Synchronized observations of bright points from the solar photosphere to the corona

Ehsan Tavabi

doi:10.1093/mnras/sty020

Abstract

One of the most important features in the solar atmosphere is magnetic network and its rela- tionship with the transition region (TR), and coronal brightness. It is important to understand how energy is transported into the corona and how it travels along the magnetic-field lines be- tween deep photosphere and chromosphere through the TR and corona. An excellent proxy for transportation is the Interface Region Imaging Spectrograph (IRIS) raster scans and imaging observations in near-ultraviolet (NUV) and far-ultraviolet (FUV) emission channels with high time-spatial resolutions. In this study, we focus on the quiet Sun as observed with IRIS. The data with high signal to noise ratio in Si IV, C II and Mg II k lines and with strong emission intensities show a high correlation in TR bright network points. The results of the IRIS intensity maps and dopplergrams are compared with those of Atmo- spheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard the Solar Dynamical Observatory (SDO). The average network intensity profiles show a strong correlation with AIA coronal channels. Furthermore, we applied simultaneous observations of magnetic network from HMI and found a strong relationship between the network bright points in all levels of the solar atmosphere. These features in network elements exhibited high doppler velocity regions and large mag- netic signatures. A dominative fraction of corona bright points emission, accompanied by the magnetic origins in photosphere, suggest that magnetic-field concentrations in the network rosettes could help couple between inner and outer solar atmosphere.

Highlights

The quiet Sun observed in chromosphere layers is dominated by magnetic bright points (MBPs) or magnetic network at rosettes of supergranule cells (Dunn and Zirker 1973; Tavabi 2014)
3 RESULTS With reference to Figs. 2 up to 6, one could clearly notice that the supergranular cell velocity map is mainly concentrated at the network and much larger line-of-sight velocities and population density placed at the rosettes, as the signal approximately disappears near the center of cells, which is defined as internetwork regions and the flows are dominated by horizontal motions
4 CONCLUSIONS In this study, we used co-observations from Helioseismic and Magnetic Imager (HMI), Atmospheric Imaging Assembly (AIA) and Interface Region Imaging Spectrograph (IRIS) instruments that contain photosphere magnetic field, transition region (TR), and coronal data, including NUV and FUV spectra of the chromosphere, TR, and coronal filtergrams from the AIA to establish an indirect correlation between bright features observed in the quiet Sun

Summary

Introduction

The quiet Sun observed in chromosphere layers is dominated by magnetic bright points (MBPs) or magnetic network at rosettes of supergranule cells (Dunn and Zirker 1973; Tavabi 2014). These characteristics, associated in TR dopplergrams with areas of high line-of-sight velocities, suggest that some of these bright points may result from magnetic reconnections of loops (Tavabi et al 2015) at source regions in the lower layers of TR and chromosphere.

Results

Conclusion