A Magnetohydrodynamic Test of the Wang-Sheeley Model

Abstract

The Wang‐Sheeley relationship relates the solar wind speed at the Earth to the divergence rate of open magnetic flux tubes in the solar corona. This relationship is based on a statistically significant correlation between the flux tube divergence parameter “fs” derived from a photospheric field‐based potential field source surface model, and satellite observations of the solar wind speed. The fast solar wind emanates from regions of small magnetic divergence, while slow solar wind comes from regions of high magnetic divergence. Arge and Pizzo [2] improved the reliability of the method by relating the coronal flux tube expansion factor to the solar wind speed at the source surface instead of the satellite. We use a three‐dimensional MHD model of the solar corona to further investigate the implications of the Wang‐Sheeley relationship for solar wind acceleration. The results suggest what additional heating and momentum inputs may be necessary in an MHD model to obtain the observed relationship between flux ...