Are solar chromospheric fibrils tracing the magnetic field?

TL;DR

This study investigates whether solar chromospheric fibrils accurately trace magnetic field lines, finding they generally do but with notable exceptions, through high-resolution spectropolarimetric observations.

Contribution

It provides the first direct comparison between fibril orientation and magnetic field direction, challenging the traditional view that fibrils always trace magnetic fields.

Findings

Fibrils mostly align with magnetic field lines.

Exceptions where fibrils do not trace magnetic fields.

High-resolution spectropolarimetric data supports the analysis.

Abstract

Fibrils are thin elongated features visible in the solar chromosphere in and around magnetized regions. Because of their visual appearance, they have been traditionally considered a tracer of the magnetic field lines. For the first time, we challenge that notion, by comparing their orientation to that of the magnetic field, obtained via high-resolution spectropolarimetric observations of Ca ii lines. The short answer to the question posed in the title is that mostly yes, but not always.