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| Paper: |
Alfvénic Turbulence Simulation in a Realistic Solar Wind |
| Volume: |
429, Numerical Modeling of Space Plasma Flows, Astronum-2009 |
| Page: |
51 |
| Authors: |
Usmanov, A. V.; Goldstein, M. L. |
| Abstract: |
We present initial results from a new numerical model to
simulate magnetohydrodynamic (MHD) turbulence in the solar wind above the
Alfvénic critical point. Previously, we had defined a “virtual”
heliosphere that contained a tilted rotating current sheet, microstreams,
as well as Alfvén waves (Goldstein et al. 1999a). In this new
restructured approach, we use the global, time-stationary, WKB Alfvén
wave-driven solar wind model (Usmanov & Goldstein 2003a) to define
the initial state of the system. Consequently, current sheets, and fast and
slow streams are computed self-consistently from an inner photospheric
boundary. To this steady-state configuration, we add fluctuations close to,
but above, the surface where the flow becomes super-Alfvénic. The
time-dependent MHD equations are then solved using a semi-discrete
third-order Central Weighted Essentially Non-Oscillatory (CWENO) numerical
scheme in the frame of reference corotating with the Sun. The computational
domain now includes the entire sphere; the geometrical singularity at the
poles is removed using the multiple grid approach described in
Usmanov (1996). Wave packets are introduced at the inner boundary such
as to satisfy Faraday’s Law (Yeh & Dryer 1985) and their nonlinear
evolution is followed in time. |
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