Solar Wind Acceleration Models in SWMF
Abstract
The choice of the solar wind model in numerical simulations of the processes in the Solar Corona (SC), Inner Heliosphere (IH) and Outer Heliosphere (OH) is a matter of a crucial importance. Since the available theoretical models for the turbulent processes and turbulent heating in the solar corona do not provide a reliable and quantitatively accurate agreement with the observed parameters of the solar wind at 1 AU, the preference should be given to semi-empirical models, as a first step. In the Space Weather Modeling Framework (SWMF), the solar wind heating and acceleration can be accounted in three different ways. I) Apply the solar wind parameters at 2.5-3.5 Rs as derived from Wang-Sheeley-Arge (WSA) model (using expansion factor) or the Fisk model (using the ratio of the radial to the absolute magnetic field on the solar surface) via the inner boundary condition of the Inner Heliosphere (IH) module with constant polytropic index of ~1.5. II) Relate the semi-empirical data for the solar wind velocity to the spatial distribution of the Bernoulli integral throughout the solar corona and inner heliosphere by employ a varied polytropic index model. This allows us to use gamma(r) varying from 1.1 on the solar surface to 1.5 at larger heliocentric distances (~10 Rs). III) Use the Alfven turbulence model. The coupled MHD-Turbulence model in this case allows us to relate the empirical data of the solar wind at 1 AU with the turbulence parameters in the solar corona, such as the Pointing flux at the solar surface. This more refined model can be also coupled with the model for turbulence solar energetic particles through the SWMF. All methods are semi-empirical, and are derived from potential field extrapolation of magnetogram data. We present the different methods and compare the results with solar wind data at 1 AU. The work is supported by the contract F014254 between the Jet Propulsion Laboratory and the University of Michigan.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2006
- Bibcode:
- 2006AGUSMSH53A..04C
- Keywords:
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- 7500 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7509 Corona;
- 7959 Models