Recent Evidence for Convection in Sunspot Penumbrae

TL;DR

Recent observational and theoretical evidence suggests that overturning convection, rather than flux tube models, explains the filamentary structure and heat flux in sunspot penumbrae.

Contribution

The paper provides new observational and theoretical evidence supporting overturning convection as the origin of penumbral filamentary structures.

Findings

Challenging flux tube models with recent evidence

Supporting overturning convection as the cause of penumbral structure

Implications for understanding sunspot heat flux

Abstract

Whereas penumbral models during the last 15 years have been successful in explaining Evershed flows and magnetic field inclination variations in terms of flux tubes, the lack of contact between these models and a convective process needed to explain the penumbral radiative heat flux has been disturbing. We report on recent observational and theoretical evidence that challenge flux tube interpretations and conclude that the origin of penumbral filamentary structure is overturning convection.