Evolution of Magnetic Helicity During Eruptive Flares and Coronal Mass Ejections

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• 作者：E. R. Priest ; D. W. Longcope ; M. Janvier
• 关键词：Sun ; flares ; Sun ; magnetic topology ; Magnetic reconnection ; Helicity
• 刊名：Solar Physics
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：291
• 期：7
• 页码：2017-2036
• 全文大小：1,416 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  Extraterrestrial Physics and Space Sciences
  Astrophysics
  
• 出版者：Springer Netherlands
• ISSN：1573-093X
• 卷排序：291

文摘

During eruptive solar flares and coronal mass ejections, a non-potential magnetic arcade with much excess magnetic energy goes unstable and reconnects. It produces a twisted erupting flux rope and leaves behind a sheared arcade of hot coronal loops. We suggest that the twist of the erupting flux rope can be determined from conservation of magnetic flux and magnetic helicity and equipartition of magnetic helicity. It depends on the geometry of the initial pre-eruptive structure. Two cases are considered, in the first of which a flux rope is not present initially but is created during the eruption by the reconnection. In the second case, a flux rope is present under the arcade in the pre-eruptive state, and the effect of the eruption and reconnection is to add an amount of magnetic helicity that depends on the fluxes of the rope and arcade and the geometry.