Open AccessAn MHD simulation model of time‐dependent co‐rotating solar wind
Author(s) -
Hayashi K.
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja017490
Subject(s) - solar wind , physics , magnetohydrodynamics , interplanetary magnetic field , magnetopause , boundary value problem , solar observatory , geophysics , computational physics , mechanics , magnetic field , quantum mechanics
We present a treatment of observation‐based time‐dependent boundary conditions for the inner boundary sphere in the time‐dependent three‐dimensional MHD simulations of the global solar wind. With this boundary treatment, we obtain super‐Alfvenic MHD solutions of time‐dependent co‐rotating solar wind structures. The boundary variables on the inner boundary sphere, at 50 solar radii in this study, are assumed to change linearly from one instant to the next. A new feature is that, in order to maintain the divergence‐free condition of the magnetic field, the changes of the time‐dependent boundary magnetic field are expressed as the potential field in a thin shell volume. The solar magnetic field data from the Wilcox Solar Observatory (WSO) and the solar wind speed data from the interplanetary scintillation (IPS) observations at Nagoya University, Japan, are used as the input boundary data. The solar wind simulated with the time‐dependent boundary condition is compared with the near‐Earth and Ulysses in situ measurement data and the solar wind simulated with the fixed boundary condition over a 7‐month period in 1991. Reasonable agreements with the in situ measurements are obtained. The differences between the two simulations in the interplanetary field line paths are significant. The three‐dimensional time‐dependent MHD solution of the global solar wind will help enhance space weather models and other fields in heliophysics.