Torsdagskollokvium (NB note the day!): Viktor Fedun: 3D Numerical Simulations of MHD Waves Driven by Photospheric motions
Dr. Viktor Fedun, The University of Sheffield, Space Systems Laboratory
Recent ground- and space-based observations reveal the presence of small-scale motions between convection cells in the solar photosphere. In my talk, I will focus on numerical simulation of these motions in regions of enhanced magnetic field, on magnetohydrodynamic wave excitation, propagation and energy flux from the solar photosphere up towards the solar corona. Particular attention will be given to the torsional oscillations and associated with such motions Alfven waves. It is of particular interest to study the excitation and propagation of torsional Alfven waves into the upper, magnetised atmosphere because they can channel photospheric energy into the corona. We examine numerically, the direct propagation of such torsional waves, driven at the foot-point of a solar magnetic flux tube, into a three-dimensional magnetised atmosphere representing the solar atmosphere between the photosphere and low corona. The simulations are based on fully compressible ideal magneto-hydrodynamical modelling. The model solar atmosphere is constructed based on realistic temperature and density stratification derived from VAL IIIF, and is most suitable perhaps for a bright network element or magnetic pore. We discuss the energetic implications as far as heating is concerned.
Also, I will pay special attention on possibility of analytically/numerically construction of various magnetic field configurations (single/multiple magnetic flux tubes) in the region from the photosphere to solar corona, i.e. in the region 0-10Mm. Finally, I will talk about implementation of Sheffield Advanced Code (SAC) on Graphical Processing Units platform (GPU), i.e. about the new code: Sheffield Magnetohydrodynamics Algorithm Using GPUs (SMAUG) https://code.google.com/p/smaug/.