报告题目：Modelling solar, stellar and magnetospheric MHD equilibria
报告人：Dr. Thomas Wieglemann Max Planck Institute for Solar System Research, Germany
报告人简介：Dr. Wiegelmann is a senior scientist in Max Planck Institute for Solar System Research. He is a solar and space plasma physicist with experience in theoretical physics, numerical modelling and data analysis. Research area is coronal physics, in particular modelling of the coronal magnetic field and plasma. The development of a state-of-the-art nonlinear force-free extrapolation code is widely used internationally. Dr. Wiegelmann is the Speaker of section Matter and Cosmos within the German Physical Society, and chair of division Extraterrestrial Physics within the German Physical Society. He has 129 refereed publications, 34 of them as a first author including 5 invited review papers. Up to now the total citations is 4273 with a H-index of 34.
报告摘要：The evolution of many complex physical systems like planetary magnetospheres and solar/stellar coronae can be distinguished between dynamic phases (magnetic storms, flares, Coronal mass ejections) and slowly evolving quasi-static phases (loading phase in magnetospheres, quiet solar and stellar coronae). During these slow phases the plasma and magnetic field are in equilibrium and the dynamic terms in full magneto-hydro-dynamics (MHD) can be neglected. During quiet times the photospheres and coronae of the Sun and can be modelled using magnetic field measurements on the surfaces of sun/stars as boundary conditions. Plasma convection below the surfaces cause changes in the boundary conditions and thereby coronal models based on these measurements can evolve and show for example the accumulation of magnetic energy and the formation of strong electric currents. An analysis of these coronal equilibria can tell about the possibility/likelihood of a transition to a dynamic phase with flares and coronal mass ejections.