Solar wind speed and density, respectively, in the solar equatorial plane at 1700UT on August 3, 2010, following a series of Earth-directed CMEs in the preceding three days.
Solar wind speed and density, respectively, in the solar equatorial plane at 1700UT on August 3, 2010, following a series of Earth-directed CMEs in the preceding three days.

Objective
Model the evolution of the solar wind from the Sun to the Earth and beyond, using both semi-empirical and advanced 3D MHD numerical modeling techniques. Predict key solar wind plasma and magnetic field parameters throughout the inner heliosphere during both quiet and disturbed solar wind conditions, including disturbances due to coronal mass ejections (CMEs) and co-rotating interaction regions (CIRs) at the boundary between slow and fast wind streams. CMEs and CIRs are the drivers of major geomagnetic storms and solar energetic particle (SEP) space weather events.

Approach
Wang-Sheeley (WS) Model:

  • The WS model uses magnetograph measurements of the solar photospheric field to predict the current daily-averaged solar wind speed and magnetic field polarity at Earth (or anywhere else in the heliosphere) ¬†

3DMHD Model:

  • The model is capable of simulating realistic background solar wind profiles as well as solar disturbances (e.g., CMEs/CIRs) from the surface of the Sun to the Earth and beyond¬†
  • The numerical simulation uses the observed line-of-sight (LOS) magnetic field at the solar photosphere extrapolated to 2.5 Rs by the WS model
  • This model combines two simulation codes: the Hakamada-Akasofu-Fry kinematic code (HAFv.2) + a fully 3-D, time-dependent magneto- hydrodynamic (MHD) simulation code

Deliverable/Value/Accomplishment

  • NRL delivered the WS model to NOAA and to the Air Force Weather Agency, where the model is used operationally to provide space weather forecast products and to provide key boundary conditions for detailed numerical simulations
  • 3DMHD model has been used to successfully model the major space weather events of the last solar cycle, including the intense Halloween storm events of 2003
  • NRL is currently using the 3DMHD model to support analysis of observations from the NRL-led SOHO/LASCO and STEREO/SECCHI experiments