Abstract/Summary

The aims of this thesis were to quantify the Sun’s open magnetic flux and understand its evolution with time. The Sun’s open solar flux (OSF) is the component of the Sun’s magnetic field that reaches a sufficient height to be dragged into the heliosphere by the solar wind. Photospheric estimates currently fail to accurately reconstruct the OSF as observed by in-situ spacecraft. As photospheric estimates are the basis for all long lead time space weather forecasts, the ability to reconstruct the OSF acts as a test of coronal models. The work in the thesis is comprised of three studies. The first study details how we determined the topology of the magnetic field from the combination of the electron and radial magnetic field data. Within this chapter, we used observational results from 4 studies to constrain the conditions used to determine the topology of the magnetic field. The second study used the topologies from the first chapter to calculate and correct the OSF. The biggest correction made to the OSF was the removal of locally inverted flux, which, being incorrectly assumed to be open flux, increases the calculated OSF. While this is part of the cause of the discrepancy between OSF estimates from in-situ and magnetograms, there is still a disagreement. Finally, the third study investigated the variation of different magnetic field topologies and solar wind properties at true polarity reversals. Within this chapter the combination of the topologies from the first chapter and solar wind properties allowed us to understand the formation of the detected inverted flux prior to polarity reversals.