Using Coronal Cells to Infer the Magnetic Field Structure and Chirality of Filament Channels

TL;DR

Coronal cells observed in Fe XII images can be used to infer the magnetic field direction and chirality of filament channels in the solar corona, providing a new, easier method for magnetic field analysis at coronal heights.

Contribution

This paper introduces a novel technique using coronal cell morphology in Fe XII images to determine magnetic field direction and chirality in filament channels, complementing existing methods.

Findings

Coronal cell tails bend oppositely on each side of filament channels.

The method infers horizontal magnetic field direction up to ~50 Mm into the corona.

Coronal observations are easier to interpret than chromospheric fibril patterns.

Abstract

Coronal cells are visible at temperatures of ~ 1.2 MK in Fe XII coronal images obtained from the Solar Dynamics Observatory (SDO) and Solar Terrestrial Relations Observatory (STEREO) spacecraft. We show that near a filament channel, the plumelike tails of these cells bend horizontally in opposite directions on the two sides of the channel like fibrils in the chromosphere. Because the cells are rooted in magnetic flux concentrations of majority polarity, these observations can be used with photospheric magnetograms to infer the direction of the horizontal field in filament channels and the chirality of the associated magnetic field. This method is similar to the procedure for inferring the direction of the magnetic field and the chirality of the fibril pattern in filament channels from H-alpha observations. However, the coronal cell observations are easier to use and provide clear inferences of the horizontal field direction for heights up to ~ 50 Mm into the corona.