MHD Simulation of the Inner-Heliospheric Magnetic Field

TL;DR

This paper presents a 3D MHD simulation of the inner heliospheric magnetic field using high-resolution solar surface flux transport data, providing realistic solar wind conditions at 1 AU for different solar activity phases.

Contribution

It introduces a novel approach combining high-resolution magnetic field maps with empirical initial conditions to simulate the solar wind from the Sun to Earth.

Findings

Simulation results match observational data at 1 AU.

The model captures differences between solar minimum and maximum conditions.

Provides a basis for outer-heliospheric modeling.

Abstract

Maps of the radial magnetic field at a heliocentric distance of ten solar radii are used as boundary conditions in the MHD code CRONOS to simulate a 3D inner-heliospheric solar wind emanating from the rotating Sun out to 1 AU. The input data for the magnetic field are the result of solar surface flux transport modelling using observational data of sunspot groups coupled with a current sheet source surface model. Amongst several advancements, this allows for higher angular resolution than that of comparable observational data from synoptic magnetograms. The required initial conditions for the other MHD quantities are obtained following an empirical approach using an inverse relation between flux tube expansion and radial solar wind speed. The computations are performed for representative solar minimum and maximum conditions, and the corresponding state of the solar wind up to the Earths orbit is obtained. After a successful comparison of the latter with observational data, they can be used to drive outer-heliospheric models.