電漿學分學程系列演講 暨 通識認證講座

張貼者:2018年4月29日 下午9:27Ann-Chen Jang
 
日冕巨量噴發物理:理論與觀測 
A series of talks on interdisciplinary program in plasma : Physics of Coronal Mass Ejections (CMEs): Theory and Observation

演 講 者:Dr. James Chen

經     歷:Research Physicist (Ret)
                Naval Research Laboratory, USA

主辦單位:電漿學分學程/太空與電漿科學所

演講地點:綜合大樓2樓 48218教室

演講日期:2018/5/9 (三) 18:00~20:00 (現場敬備茶點)

演講大網:
Solar eruptions are manifested as coronal mass ejections (CMEs), solar flares, and eruptive prominences (EPs) depending on observing methods. The amount of energy released is estimated to be 10^{31}--10^{33} erg. CMEs and EPs represent acceleration of magnetized coronal structures (10^{14}--10^{16} g in mass) to a few thousand km/s in tens of minutes. The physical mechanisms responsible for these closely associated processes have been a major unanswered question in modern solar physics for nearly a century. CME physics also lies at the foundation of predicting the most severe form of space weather disturbances, i.e., geomagnetic storms, which are caused by the CME ejecta. Model concepts have evolved with improving observations. The recent STEREO mission has yielded data on CME dynamics from the Sun to 1 AU, providing much more stringent constraints on CME models than previously available. The prevailing paradigm envisions releasing magnetic energy stored in the coronal magnetic arcades via reconnection, and several large-scale numerical simulation models have been developed to model CMEs and EPs in which reconnection is accomplished by specified and/or numerical dissipations. They have not yet produced quantitative agreement with the observed CME acceleration and propagation to 1 AU. In this talk, I will present a new theoretical concept that yields model CME-EP dynamics in good quantitative agreement with data. The basic driving force is the toroidal Lorentz hoop force acting on a flux rope anchored in the Sun. This force is scalable to toroidal laboratory plasma structures such as tokamaks. New testable answers to the long-standing questions are emerging. 

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