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arXiv 1101.4249astro-ph.SR
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日冕Kelvin-Helmholtz不稳定性的SDO/AIA观测

SDO/AIA Observation of Kelvin-Helmholtz Instability in the Solar Corona

Leon Ofman, Barbara J. Thompson

摘要:

本文介绍了2010年4月8日太阳动力学观测站(SDO)拍摄的日冕图像中涡旋状特征的形成、传播和衰减的观测结果,这些特征与2010年4月8日世界时2:30左右开始的一次喷发有关。沿着喷发(变暗)区域和周围日冕之间的界面形成的一系列漩涡。它们的大小从几角秒到十角秒不等,以6-14公里/秒的速度沿着界面行进。这些特征在大气成像组件(AIA)的七个不同EUV波段中的六个波段中清晰可见。基于这些特征的结构、形成、传播和衰减,我们将这些特征确定为EUV中日冕中Kelvin-Helmholtz(KH)不稳定性的第一个观测结果。线性分析和KH不稳定性的MHD模型都支持这种解释。我们认为,这种不稳定性是由日冕物质抛射(CME)的爆发磁场和闭合磁场之间的速度剪切驱动的。剪切流驱动的不稳定性在日冕等离子体的能量传递过程中起着重要的作用。

英文摘要:

We present observations of the formation, propagation and decay of vortex- shaped features in coronal images from the Solar Dynamics Observatory (SDO) associated with an eruption starting at about 2:30UT on Apr 8, 2010. The series of vortices formed along the interface between an erupting (dimming) region and the surrounding corona. They ranged in size from several to ten arcseconds, and traveled along the interface at 6-14 km/s. The features were clearly visible in six out of the seven different EUV wavebands of the Atmospheric Imaging Assembly (AIA). Based on the structure, formation, propagation and decay of these features, we identified these features as the first observations of the Kelvin-Helmholtz (KH) instability in the corona in EUV. The interpretation is supported by linear analysis and by MHD model of KH instability. We conclude that the instability is driven by the velocity shear between the erupting and closed magnetic field of the Coronal Mass Ejection (CME). The shear flow driven instability can play an important role in energy transfer processes in coronal plasma.

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