Oberseminar Numerical Mathematics / Scientific Computing
Piotr Smolarkiewicz
ECMWF
EULAG-MHD: Simulation of the Global Solar Dynamo
Abstract:
The lecture introduces a magneto-hydrodynamic (MHD) adaptation of the general-purpose hydrodynamical simulation code EULAG [Prusa et al., Comput. Fluids 37, 1193 (2008)]. This MHD code has been recently shown to produce unprecedented solar-like magnetic cycles and dynamo action in global large-eddy simulations of solar magneto-convection [Ghizaru et al., ApJL 715, L133 (2010); Racine et al., ApJ 735, 46 (2011)]. Because of its meteorological heritage, EULAG incorporates some features non-standard in anelastic solar codes, which prove beneficial for our simulation of the global dynamo. In this lecture I present EULAG's anelastic MHD equations and identify the modifications adopted from the atmospheric experience. For this purpose, I use a physically intuitive, Cartesian vector form of the governing equations in disregard of the model geometry and curvilinear coordinate framework adopted. Then, I recast the governing equations in the form consistent with the problem geometry and the solution procedures, and document the numerical algorithm for integrating these governing equations. Some sample results highlighting practical advantages of the our Implicit Large Eddy Simulation approach are presented, together with evidence that numerical treatment of small scales may be critical for the production of cyclic behaviour and regular polarity reversals in this type of global simulations.
| Date: | 08.07.13 | Time: | 18:00 Uhr | Location: | FU Berlin, Institut für Mathematik, Arnimallee 6, 14195 Berlin. | Room: | 031 Basement |