On the 3D Structure of the Magnetic Field in Regions of Emerging Flux

TL;DR

This study investigates the magnetic field structure in an emerging flux region, revealing that chromospheric magnetic fields resemble smoothed photospheric fields and may not always trace magnetic loops accurately.

Contribution

It provides new insights into the relationship between photospheric and chromospheric magnetic fields and highlights potential limitations in interpreting magnetic loop structures from single-component observations.

Findings

Chromospheric magnetic field strength resembles a smoothed version of the photospheric field.

Chromospheric field is uncorrelated with the He I 10830 A equivalent width map.

Possible misinterpretation of magnetic loops when using single-component line diagnostics.

Abstract

We explore the photospheric and chromospheric magnetic field in an emerging flux region. An image of the equivalent width of the He I 10830 A red blended component shows the presence of filamentary structures that might be interpreted as magnetic loops. We point out that the magnetic field strength in the chromosphere resembles a smoothed version of that found in the photosphere and that it is not correlated at all with the above-mentioned equivalent width map. Lacking other diagnostics, this suggests that one cannot discard the possibility that the chromospheric field we infer from the observations is tracing the lower chromosphere of the active region instead of tracing the magnetic field along loops. If the He I line is formed within magnetic loops, we point out a potential problem that appears when interpreting observations using only one component along the line-of-sight.