Probing the quiet solar atmosphere from the photosphere to the corona

TL;DR

This study explores the structure and variability of the quiet Sun's atmosphere across multiple layers, revealing the significant role of small magnetic structures and their connection to chromospheric and coronal dynamics.

Contribution

It provides the first detailed analysis of how small-scale magnetic structures influence EUV emission and the transition region's dual components, linking chromospheric motions to EUV variability.

Findings

Small magnetic structures contribute significantly to EUV emission.

Two components of transition region emission are identified.

EUV intensity enhancements are linked to chromospheric upflows.

Abstract

We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along with H$\alpha$ observations and high resolution spectropolarimetric observations of the photospheric magnetic field. The photospheric magnetic field is extrapolated up to the corona showing a multitude of large and small scale structures. We show for the first time that the smallest magnetic structures both at the network and the internetwork contribute significantly to the emission in EUV lines, with temperatures ranging from 8 10$^{4}$ K to 6 10$^{5}$ K. Two components of transition region emission are present, one associated with small-scale loops that do not reach coronal temperatures and another one acting as an interface between coronal and chromospheric plasma. Both components are associated with persistent chromospheric structures. The temporal variability of the EUV intensity at the network region is also associated with chromospheric motions, pointing to a connection between transition region and chromospheric features. Intensity enhancements in the EUV transition region lines are preferentially produced by H$\alpha$ upflows. Examination of two individual chromospheric jets shows that their evolution is associated with intensity variations in transition region and coronal temperatures.