Time‐dependent MHD modeling of the global solar corona for year 2007: Driven by daily‐updated magnetic field synoptic data

In this paper, we develop a time-dependent MHD model driven by the daily-updated synoptic magnetograms (MHD-DUSM) to study the dynamic evolution of the global corona with the help of the 3D Solar-Interplanetary (SIP) adaptive mesh refinement (AMR) space-time conservation element and solution element (CESE) MHD model (SIP-AMR-CESE MHD Model). To accommodate the observations, the tangential component of the electric field at the lower boundary is specified to allow the flux evolution to match the observed changes of magnetic field. Meanwhile, the time-dependent solar surface boundary conditions derived from the method of characteristics and the mass flux limit are incorporated to couple the observation and the 3D MHD model. The simulated evolution of the global coronal structure during 2007 is compared with solar observations and solar wind measurements from both Ulysses and spacecrafts near the Earth. The MHD-DUSM model is also validated by comparisons with the standard potential field source surface (PFSS) model, the newly improved Wang-Sheeley-Arge (WSA) empirical formula, and the MHD simulation with a monthly synoptic magnetogram (MHD-MSM). Comparisons show that the MHD-DUSM results have good overall agreement with coronal and interplanetary structures, including the sizes and distributions of coronal holes, the positions and shapes of the streamer belts, and the transitions of the solar wind speeds and magnetic field polarities. The MHD-DUSM results also display many features different from those of the PFSS, the WSA, and the MHD-MSM models.