题 目：A Large Refracting Coronagraph to Measure Solar Coronal Magnetic Fields
报告人：Dr. Steven Tomczyk（High Altitude Observatory/NCAR）
摘 要：Advances in many fundamental problems in coronal physics such as the heating of the corona, and the storage and release of magnetic free energy, require the measurement of the strength and direction of coronal magnetic fields. Some progress has been made in recent years through observation of the Zeeman effect of forbidden IR coronal emission lines, but these efforts are hindered by the small apertures of available coronagraphs. Ideally, one requires a coronagraph with an objective of at least 1.5 meters, a very low level of scattered light, and a large field-of-view. These require-ments are best met by a coronagraph with a singlet lens objective. In this talk, I will outline the rationale for coronal magnetic field measurements,review recent progress in the field, and present the results of engineering studies which show that a refracting telescope of this size is feasible with current technology.
I will conclude with a description for the proposed Coronal Solar Magnetism Observatory (COSMO) which is a facility dedicated to the synoptic observation of coronal magnetism.
时 间：2011年5月27日（星期五）下午2:30
地 点：紫台大楼517房间（北京西路2号）
欢迎大家积极参加!
