P31 - Methodology for Estimating the Effective Dissipation Coefficients in Magnetohydrodynamic Simulations of Stellar Plasmas
Presenter
DescriptionA crucial step in the post processing of astrophysical magnetohydrodynamic (MHD) numerical simulations is the accurate determination of the effective viscosity and magnetic diffusivity effecting the MHD flow. Once these are known, one can determine the dimensionless numbers that characterise the flow such as Reynolds and Prandtl numbers. These are of particular significance for simulations of the solar and stellar small-scale dynamo. The proposed methodology relies on a post processing step carried out with numerical operators of higher order accuracy than the ones in the simulation code. The poster explains the methodology and presents application of it to a number of radiative MHD simulations of various effective viscosities and plasma resistivities. The proposed methodology provides a solid estimate of the dissipation coefficients affecting the momentum and induction equations of MHD simulations. It is found that small-scale dynamos are active and can amplify a small seed magnetic field up to significant values in simulations of the solar convection zone with a grid spacing better than 12 km, even at a magnetic Prandtl number as small as 0.65.
TimeTuesday, June 289:00 - 11:00 CEST
LocationFoyer 2nd Floor
Event Type
Poster
