Influence of Non-Potential Coronal Magnetic Topology on Solar-Wind Models

• Published in: arXiv.org 2015-11
• Main Authors: Edwards, S J, Yeates, A R, Bocquet, F -X, Mackay, D H
• Format: Article
• Language: English
• Subjects: Magnetic flux; Magnetic structure; Magnetism; Potential fields; Sheet modelling; Solar corona; Solar magnetic field; Solar surface; Topology; Tubes; Wind speed
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1511.00427

By comparing a magneto-frictional model of the low coronal magnetic field to a potential-field source-surface model, we investigate the possible impact of non-potential magnetic structure on empirical solar-wind models. These empirical models (such as Wang-Sheeley-Arge) estimate the distribution of solar-wind speed solely from the magnetic-field structure in the low corona. Our models are computed in a domain between the solar surface and 2.5 solar radii, and are extended to 0.1 AU using a Schatten current-sheet model. The non-potential field has a more complex magnetic skeleton and quasi-separatrix structures than the potential field, leading to different sub-structure in the solar-wind speed proxies. It contains twisted magnetic structures that can perturb the separatrix surfaces traced down from the base of the heliospheric current sheet. A significant difference between the models is the greater amount of open magnetic flux in the non-potential model. Using existing empirical formulae this leads to higher predicted wind speeds for two reasons: partly because magnetic flux tubes expand less rapidly with height, but more importantly because more open field lines are further from coronal-hole boundaries.