时间:2013年6月25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:Solar eruptions are observed as prominence/filament eruptions, coronal mass ejections (CMEs) and flares, or as a subset of these. They cause the major perturbations of plasma and field in interplanetary space known as Space Weather. A number of models for the eruptions have been competing in the past two decades, but consensus is growing that these can be grouped into two principal categories, flux rope models with an ideal-MHD instability, or catastrophe, being the dominant process and arcade models with magnetic reconnection being dominant; even these two categories possess common aspects. I will introduce the basic concepts in modeling the eruptions, focusing on two instabilities which, at least in the first category, appear to be key to their initiation and main drive -- the torus instability and the helical kink. Their thresholds represent quantitative onset criteria (in terms of the coronal magnetic field) which have received observational support. The good agreement between simulations of these instabilities and a number of solar events will be illustrated and current research projects in this area will be sketched.