报告题目：Solar Magnetic Topology and Reconnection

报 告 人：Dana Longcope 教授

　　　　　 Department of Physics at Montana State University

摘　  要：Energy release by magnetic reconnection has been hypothesized to drive numerous energetic phenomena in the Sun's corona including flares, coronal mass ejections and bright points. Prior to its release, energy is stored in the magnetic field as it slowly evolves subject to constraints on the topology of magnetic field lines. While this energy is stored in the large-scale coronal field, its release can be initiated by an electric field localized to very small scales provided it eliminates one of the topological constraints. Energy release initiated through local topological change is the essence of magnetic reconnection.  It will be shown how observations of large-scale evolution of the Sun's photospheric field can be used to estimate the magnetic energy stored in the coronal field.  It is then demonstrated how magnetic energy is converted into heat following small scale topological change.  This is a transient, three-dimensional variant on the classic Petschek mechanism whereby rotational discontinuities convert magnetic energy into kinetic energy of bulk flows. The collision of these flows create slow magnetosonic shocks converting bulk kinetic energy into heat.

时　  间：2012年3月13日（周二）下午2：00

地　  点：苏富特 三楼 会议室

欢迎大家参加！

　　　　　　　　　　　　　　　　　　　　　　 南京大学天文与空间科学学院