The Correlation Between The Enhanced Sulfur Abundance in Slow Solar Winds and The Magnetic Field Geometry of Their Source Regions

We present an examination of the First Ionization Potential (FIP) fractionation scenario by the ponderomotive force in the chromosphere by using observations from The Solar Wind Ion Composition Spectrometer (SWICS) on board The Advanced Composition Explorer (ACE). Based on the prediction of the ponderomotive force model by Laming et al. (2019) that the abundance enhancements of intermediate FIP elements, S, P, and C, in slow solar wind can be explained by the release of plasma from strong open fields, much stronger than those usually associated with fast wind source regions, we examine the possible correspondence between the enhanced fractionation of intermediate FIP elements in slow solar winds and the magnetic field strength of their source regions. We do so by surveying the extensive record of solar wind speeds and composition from the ACE mission, and investigating the magnetic feature on the Sun associated with the repeated sulfur abundance anomaly corresponding to the decrease in the solar wind speed, found over about four solar rotation cycles in the beginning of 2008. We also obtain rough profiles of the magnetic field strength at the source regions of these slow winds, estimate the fractionation values of various elements using the ponderomotive force model with the field profiles as inputs, and compare the results with the observed fractionation values."