Solar Magnetic Carpet I: Simulation of Synthetic Magnetograms

TL;DR

This paper introduces a 2D model simulating the evolution of the solar magnetic carpet, reproducing observed magnetic properties and serving as a foundation for future 3D non-potential solar magnetic field models.

Contribution

A novel 2D model for the solar magnetic carpet that accurately reproduces observed magnetic field quantities and dynamics, facilitating future 3D modeling efforts.

Findings

Model reaches steady state with balanced emergence and cancellation rates.

Reproduces observed flux distribution, mean field, and cancellation rates.

Best fit to observations with minimum bipole flux of 4e16 Mx.

Abstract

This paper describes a new 2D model for the photospheric evolution of the magnetic carpet. It is the first in a series of papers working towards constructing a realistic 3D non-potential model for the interaction of small-scale solar magnetic fields. In the model, the basic evolution of the magnetic elements is governed by a supergranular flow profile. In addition, magnetic elements may evolve through the processes of emergence, cancellation, coalescence and fragmentation. Model parameters for the emergence of bipoles are based upon the results of observational studies. Using this model, several simulations are considered, where the range of flux with which bipoles may emerge is varied. In all cases the model quickly reaches a steady state where the rates of emergence and cancellation balance. Analysis of the resulting magnetic field shows that we reproduce observed quantities such as the flux distribution, mean field, cancellation rates, photospheric recycle time and a magnetic network. As expected, the simulation matches observations more closely when a larger, and consequently more realistic, range of emerging flux values is allowed (4e16 - 1e19 Mx). The model best reproduces the current observed properties of the magnetic carpet when we take the minimum absolute flux for emerging bipoles to be 4e16 Mx. In future, this 2D model will be used as an evolving photospheric boundary condition for 3D non-potential modeling.