# Dynamics and connectivity of an extended arch filament system

## TL;DR

This paper investigates an extended arch filament system (AFS) connecting a decaying sunspot's magnetic features to the quiet Sun, revealing unique magnetic structures, dynamics, and asymmetries through multi-instrument solar observations.

## Contribution

It introduces the concept of an extended AFS, contrasting it with classical AFSs, and provides detailed analysis of its magnetic structure, dynamics, and connectivity using multi-instrument solar data.

## Key findings

- Strong downflows at the footpoints, increasing over 30 minutes.
- Asymmetric velocities with higher speeds at the southern footpoint.
- Flux decreases over time at the southern footpoint.

## Abstract

In this study, we analyzed a filament system, which expanded between moving magnetic features (MMFs) of a decaying sunspot and opposite flux outside of the active region from the nearby quiet-Sun network. This configuration deviated from a classical arch filament system (AFS), which typically connects two pores in an emerging flux region. Thus, we called this system an extended AFS. We contrasted classical and extended AFSs with an emphasis on the complex magnetic structure of the latter. Furthermore, we examined the physical properties of the extended AFS and described its dynamics and connectivity. At the southern footpoint, we measured that the flux decreases over time. We find strong downflow velocities at the footpoints of the extended AFS, which increase in a time period of 30 minutes. The velocities are asymmetric at both footpoints with higher velocities at the southern footpoint. The extended AFS was observed with two instruments at the Dunn Solar Telescope (DST). The Rapid Oscillations in the Solar Atmosphere (ROSA) imager provided images in three different wavelength regions. The Interferometric Bidimensional Spectropolarimeter (IBIS) provided spectroscopic H$\alpha$ data and spectropolarimetric data that was obtained in the near-infrared Ca II 8542 \AA\ line. We used He II 304 \AA\ extreme ultraviolet images of the Atmospheric Imaging Assembly (AIA) and LOS magnetograms of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) as context data.