Bayesian approach for modeling global magnetic parameters of solar active regions

MANDRINI, C.H.; POISSON, M.; GRINGS, F.; LÓPEZ FUENTES, M.C.; DÉMOULIN, P.

Atenas

Congreso; 44th COSPAR General Assembly; 2022

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux tubes. The magnetic field of these flux tubes acquires twist as it crosses the convection zone, building magnetic flux ropes (FRs). Due to the presence of twist, during the emergence of these FRs the photospheric line-of-sight (LOS) magnetograms show elongations of the AR polarities, also known as magnetic tongues. Since magnetic tongues can affect the measurement of AR characteristics during their emergence phase (e.g. their tilt angle, magnetic flux, and size, among others), direct estimations of the FR global quantities which do not consider this effect have to be revised. In this work we aim to model the emergence of ARs using a FR model based on a half-torus magnetic structure. We generate synthetic magnetograms introducing non-linear perturbations in order to reproduce the small scale features, asymmetries, and noise observed in real magnetograms. We characterize the half-torus model by generating 1000 synthetic AR magnetograms using a Bayesian scheme to infer the posterior probability distribution of the model parameters. We propose models introducing different temporal correlations of the parameters; this allows us to estimate expectation values for the tilt angle, magnetic helicity, and magnetic flux, which are consistent with the input parameters of the generated ARs.