# Spectropolarimetric observations of the Ca II 8498 A and 8542 A lines in the quiet Sun

## TL;DR

This study presents spectropolarimetric observations of Ca II infrared triplet lines in the quiet Sun, revealing complex magnetic and dynamic behaviors that differ from simulations, especially in magnetic topology and wave activity.

## Contribution

It provides new observational insights into the magnetic and dynamic properties of the Ca II lines in the quiet Sun, highlighting differences from high plasma-beta simulations.

## Key findings

- Stokes V profiles often differ between the two lines despite close formation regions.
- Magnetic topology influences Stokes V shape more than wave phase in the network.
- Oscillatory behavior and shock waves are prominent in the network, with significant Stokes V asymmetries.

## Abstract

The Ca II infrared triplet is one of the few magnetically sensitive chromospheric lines available for ground-based observations. We present spectropolarimetric observations of the 8498 A and 8542 A lines in a quiet Sun region near a decaying active region and compare the results with a simulation of the lines in a high plasma-beta regime. Cluster analysis of Stokes V profile pairs shows that the two lines, despite arguably being formed fairly close, often do not have similar shapes. In the network, the local magnetic topology is more important in determining the shapes of the Stokes V profiles than the phase of the wave, contrary to what our simulations show. We also find that Stokes V asymmetries are very common in the network, and the histograms of the observed amplitude and area asymmetries differ significantly from the simulation. Both the network and internetwork show oscillatory behavior in the Ca II lines. It is stronger in the network, where shocking waves, similar to those in the high-beta simulation, are seen and large self-reversals in the intensity profiles are common.