On the origin of reverse polarity patches found by Hinode in sunspot penumbrae

TL;DR

This paper explains the reverse polarity patches observed in sunspot penumbrae by Hinode as manifestations of micro-structured magnetic atmospheres, linking observations with existing magnetic models and spectral asymmetries.

Contribution

It demonstrates how the Micro-Structured Magnetic Atmospheres (MISMAs) model accounts for Hinode's reverse polarity features and asymmetric Stokes profiles in sunspot penumbrae.

Findings

MISMAs produce strongly redshifted reverse polarity structures.

MISMAs explain asymmetric Stokes profiles observed by Hinode.

Dark cores in penumbral filaments may be associated with reverse polarity.

Abstract

The satellite Hinode has recently revealed penumbral structures with a magnetic polarity opposite to the main sunspot polarity. They may be a direct confirmation of magnetic field lines and mass flows returning to the solar interior throughout the penumbra, a configuration previously inferred from interpretation of observed Stokes profile asymmetries. The paper points out the relationship between the reverse polarity features found by Hinode, and the model Micro-Structured Magnetic Atmospheres (MISMAs) proposed for sunspots. We show how the existing model MISMAs produce strongly redshifted reverse polarity structures as found by Hinode. Ad hoc model MISMAs also explain the asymmetric Stokes profiles observed by Hinode. The same modeling may be consistent with magnetograms of dark cored penumbral filaments if the dark cores are associated with the reverse polarity. Such hypothetical relationship will show up only in the far red wings of the spectral lines.