Horizontal Magnetic Fields in the Solar Photosphere

TL;DR

This study uses 2D MHD simulations to analyze horizontal magnetic fields in the solar photosphere, revealing their strength, distribution, and emergence, and comparing results with Hinode observations.

Contribution

It provides new insights into the properties and behavior of horizontal magnetic fields in the solar photosphere through detailed simulations.

Findings

Horizontal magnetic fields are on average stronger than vertical fields up to 400 km height.

Maximum horizontal field strength exceeds 500 G in flux tubes.

Simulated horizontal fields qualitatively agree with Hinode observations.

Abstract

The results of 2D MHD simulations of solar magnetogranulation are used to analyze the horizontal magnetic fields and the response of the synthesized Stokes profiles of the FeI 1564.85 nm line to the magnetic fields. Selected 1.5-h series of the 2D MHD models reproduces a region of the network fields with their immediate surrounding on the solar surface with the unsigned magnetic flux density of 192 G. According to the magnetic field distribution obtained, the most probable absolute strength of the horizontal magnetic field at an optical depth of tau_5 = 1 (tau_5 denotes tau at lambda = 500 nm) is 50 G, while the mean value is 244 G. On average, the horizontal magnetic fields are stronger than the vertical fields to heights of about 400 km in the photosphere due to their higher density and the larger area they occupy. The maximum factor by which the horizontal fields are greater is 1.5. Strong horizontal magnetic flux tubes emerge at the surface as spots with field strengths of more than 500 G. These are smaller than granules in size, and have lifetimes of 3.6 min. They form in the photosphere due to the expulsion of magnetic fields by convective flows coming from deep subphotospheric layers. The data obtained qualitatively agree with observations with the Hinode space observatory.