Comparison of Solar Wind Parameters with Characteristics of Coronal Holes

Abstract

Determining the speed of the solar wind emanating from coronal holes near the Sun is a key problem for modeling plasma parameters throughout the heliosphere. Plasma temperature and density, in addition to speed, are the input parameters to global magnetohydrodynamics models, but the estimated temperature and density boundary conditions are calculated from the simulated solar wind speed. In this study, we analyzed how long-term variations in the properties of open magnetic field sources modeled from different series of magnetograph observations are related to the plasma parameters measured by satellite. The analysis also considers coronal holes based on SDO/AIA 193 Å and solar wind speed observations in the Wang-Sheeley-Arge approximation (WSA). We found that during the period 2015–2023, the areas of equatorial coronal holes correlate better with the observed solar wind speed than the results of WSA simulations. Among the three considered series of magnetographic observations (STOP, SDO/HMI, GONG), during the period of minimum solar activity, calculations based on STOP data perform better.