Centre-to-limb spectro-polarimetric diagnostics of simulated solar photospheric magneto-convection: signatures of photospheric Alfven waves

TL;DR

This study uses advanced simulations and spectro-polarimetric diagnostics to identify signatures of torsional Alfven waves in the solar photosphere, highlighting their detectability and observational challenges.

Contribution

The paper presents the first detailed spectro-polarimetric analysis of Alfven waves in simulated solar photospheric intergranular lanes, linking wave signatures to observable spectral features.

Findings

Alfven waves produce Doppler shifts and Stokes-V asymmetry in simulations.

Wave signatures disappear when observational resolution is degraded.

Detection of Alfven waves in the photosphere remains observationally challenging.

Abstract

Using numerical simulations of the magnetised solar photosphere carried out with the radiative magneto-hydrodynamic code, MURaM, and detailed spectro-polarimetric diagnostics of the simulated photospheric 6302A FeI line, spectro-polarimetric signatures of Alfven waves in magnetised intergranular lanes of the simulated solar photosphere were analysed at different positions at the solar disk. The torsional Alfven waves in the intergranular lanes are horizontal plasma motions, which do not have a thermal perturbation counterpart. We find signatures of Alfven waves as small-scale line profile Doppler shifts and Stokes-V area asymmetry enhancements in the simulated off-disk centre observations. These photospheric features disappear when the simulated observations are degraded with a telescope PSF similar to the one of Hinode. We analyse the possibilities for direct observations and confirmation of Alfven wave presence in the solar photosphere.