Work

The Temperature and First Ionization Potential Bias of Active Regions and Their Relations to In Situ Solar Wind

Year: 2025

Type: article

Abstract: Active regions (ARs) are important sources of the slow solar wind. Connecting the properties of ARs and their associated solar wind can improve our understanding of the origin and generation mechanisms of the slow solar wind. In this study, we compare the physics properties of the AR upflow regions and nonupflow regions. The relationships between the properties of these regions and the associated solar wind parameters are analyzed. We find that the electron densities of the upflow regions are significantly lower than those of the nonupflow regions. The temperatures of the upflow regions are generally close to those of the nonupflow regions. The first ionization potential (FIP) bias varies significantly among different ARs. The FIP bias of upflow regions and that of nonupflow regions are generally similar for the same AR. The FIP bias of both upflow and nonupflow regions positively correlates with their associated solar wind. There is no relationship between the solar wind O7+/O6+ and the temperature of the source regions. The results suggest that in the upflow regions, the magnetic reconnection between closed loops and open field lines may be important for generating the nascent slow solar wind. We conclude that it is unreliable to infer the temperatures of ARs directly from the O7+/O6+ ratios of the in situ solar wind.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/adc1b8

Authors: Chi Ma, Hui Fu, Maria S. Madjarska, Zhenghua Huang, Haixia Xie, Lidong Xia