时间：2013年6月26日上午10：00
地点：教学行政楼1514
报告人：Dr. Bernhard Kliem
单位：University of Potsdam, Germany

摘要：Two current projects in CME modeling will be presented: the rapid formation and initial expansion of CME cavities and data-constrained simulations of the 2010-Apr-8 eruption.  A very rapid formation and expansion of "EUV cavities" in fast and impulsively commencing eruptions appears to be the trigger of large-scale EUV waves. The EUV cavity initially appears to be larger than the CME flux rope, but subsequently evolves into the white-light cavity. MHD simulations of flux rope eruptions conform to this picture. The initial expansion of ambient flux can be understood as the reverse of the well known pinch effect.

Three models from a series of nonlinear force-free coronal field models - a stable, a nearly marginally stable, and an unstable one - were used as initial condition in MHD simulations of the moderately fast CME and associated B3.7 flare on 2010-Apr-8. This investigation suggests that the slingshot effect of horizontally bent flux in the source region can contribute significantly to the inclination of the rise direction, and that the flux-imbalance condition for eruption onset corresponds very well to the threshold of the torus instability in the considered active region.