Three-dimensional MHD Simulation of Solar Wind Using a New Boundary Treatment: Comparison with In Situ Data at Earth

Zang Shen   Zicai Yang   Jie Zhang   Wenwen Wei   Xueshang Feng

Published 2018 October 5
The Astrophysical Journal, Volume 866, Number 1
Three-dimensional magnetohydrodynamics (MHD) numerical simulation is an important tool in the prediction of solar wind parameters. In this study, we improve our corona interplanetary total variation diminishing MHD model by using a new boundary applicable to all phases of solar cycles. This model uses synoptic magnetogram maps from the Global Oscillation Network Group as the input data. The empirical Wang–Sheeley–Arge relation is used to assign solar wind speed at the lower boundary, while temperature is specified accordingly based on its empirical relation with the solar wind speed. Magnetic field intensity and solar wind density at the boundary are obtained from observational data in the immediate past Carrington rotations, permitting the persistence of these two parameters in a short time period. The boundary conditions depend on only five tunable parameters when simulating the solar wind for different phases of the solar cycle. We apply this model to simulate the background solar wind from 2007 to 2017 and compare the modeled results with the observational data in the OMNI database. Visual inspection shows that our model can capture the time patterns of solar wind parameters well at most times. Statistical analysis shows that the simulated solar wind parameters are all in good agreement with the observations. This study demonstrates that the improved interplanetary total variation
diminishing model can be used for predicting all solar wind parameters near the Earth.