Interaction of magnetic fields with a vortex tube at solar subgranular scale

Abstract

Using high-resolution spectropolarimetric data recorded with the Swedish 1 m Solar Telescope, we have identified several instances of granular lanes traveling into granules. These are believed to be the observational signature of underlying tubes of vortical flow with their axis oriented parallel to the solar surface. Associated with these horizontal vortex tubes, we detect in some cases a significant signal in linear polarization, located at the trailing dark edge of the granular lane. The linear polarization appears at a later stage of the granular lane development, and is flanked by patches of circular polarization. Stokes inversions show that the elongated patch of linear polarization signal arises from the horizontal magnetic field aligned with the granular lane. We analyze snapshots of a magnetohydrodynamic numerical simulation and find cases in which the horizontal vortex tube of the granular lane redistributes and transports the magnetic field to the solar surface causing a polarimetric signature similar to what is observed. We thus witness a mechanism capable of transporting magnetic flux to the solar surface within granules. This mechanism is probably an important component of the small-scale dynamo supposedly acting at the solar surface and generating the quiet-Sun magnetic field.

arXiv comment3 Figures, 2 animations, accepted in ApJL

References in corpus (16)

• CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
• Simulations of stellar convection with CO5BOLD
• VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
• The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory
• CRISPRED: A data pipeline for the CRISP imaging spectropolarimeter
• Emergence of Small-Scale Magnetic Loops in the Quiet Sun Internetwork
• An Open Source, Massively Parallel Code for Non-LTE Synthesis and Inversion of Spectral Lines and Zeeman-induced Stokes Profiles
• Transverse component of the magnetic field in the solar photosphere observed by Sunrise
• Multi-frame blind deconvolution with linear equality constraints
• Detection of vortex tubes in solar granulation from observations with Sunrise
• Comparison of inversion codes for polarized line formation in MHD simulations. I. Milne-Eddington codes
• Small magnetic loops connecting the quiet surface and the hot outer atmosphere of the Sun
• Small-scale dynamo simulations: Magnetic field amplification in exploding granules and the role of deep and shallow recirculation
• Inferring the magnetic field vector in the quiet Sun. II. Interpreting results from the inversion of Stokes profiles
• Vortex Tubes of Turbulent Solar Convection
• On the origin of intergranular jets

Cited by in corpus (5)

• The European Solar Telescope
• Small-scale dynamos: From idealized models to solar and stellar applications
• Stirring the Base of the Solar Wind: On Heat Transfer and Vortex Formation
• The solar internetwork. III. Unipolar versus bipolar flux appearance
• Emergence of magnetic flux sheets in the quiet Sun. I. Statistical properties