Magnetic Field Structure, Doppler Shift, and Intensity of Active Regions and Their Connections with the Solar Wind

Abstract

Abstract The properties of active regions and their connections with the solar wind are important issues. In this study, nine isolated active regions near the solar disk center were chosen. The relationships between blueshift, intensity, magnetic concentrated areas (MCAs), and the potential-field source-surface (PFSS) open magnetic field of active regions were analyzed. Whether an active region contributes to the solar wind was identified only based on the relationship between the properties of in situ solar wind and the large structure of the corona. Then the two phenomena (blueshift and PFSS open magnetic field) for inferring whether an active region contributes to the solar wind were tested. We find that the blueshift areas appear in all cases and the average Doppler speed ranges from −6 to −23 km s−1. The blueshift areas generally root inside MCAs and are far from the neutral lines. The intensity of blueshift areas negatively correlates with the blueshift speed. Statistically, 10 of 16 blueshift areas are associated with the PFSS open magnetic field lines, and all 10 PFSS open magnetic field areas are accompanied by blueshift. We demonstrate that a polarity of an active region generally contributes to the solar wind if it is associated with a PFSS open magnetic field. There are 9 of 10 (13 of 16) PFSS open magnetic field areas (blueshift regions) associated with the solar wind. The results of this study should help determine the observation target of SPICE on board the Solar Orbiter whose scientific goal is connecting the Sun and the heliosphere.