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arXiv · 1204.5470

Quasi-periodic Fast-mode Wave Trains Within a Global EUV Wave and Sequential Transverse Oscillations Detected by SDO/AIA

Wei Liu·Leon Ofman·Nariaki V. Nitta·Markus J. Aschwanden·Carolus J. Schrijver·Alan M. Title·Theodore D. Tarbell
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Abstract

We present the first unambiguous detection of quasi-periodic wave trains within the broad pulse of a global EUV wave (so-called "EIT wave") occurring on the limb. These wave trains, running ahead of the lateral CME front of 2-4 times slower, coherently travel to distances $>R_{sun}/2$ along the solar surface, with initial velocities up to 1400 km/s decelerating to ~650 km/s. The rapid expansion of the CME initiated at an elevated height of 110 Mm produces a strong downward and lateral compression, which may play an important role in driving the primary EUV wave and shaping its front forwardly inclined toward the solar surface. The waves have a dominant 2 min periodicity that matches the X-ray flare pulsations, suggesting a causal connection. The arrival of the leading EUV wave front at increasing distances produces an uninterrupted chain sequence of deflections and/or transverse (likely fast kink mode) oscillations of local structures, including a flux-rope coronal cavity and its embedded filament with delayed onsets consistent with the wave travel time at an elevated (by ~50%) velocity within it. This suggests that the EUV wave penetrates through a topological separatrix surface into the cavity, unexpected from CME caused magnetic reconfiguration. These observations, when taken together, provide compelling evidence of the fast-mode MHD wave nature of the {\it primary (outer) fast component} of a global EUV wave, running ahead of the {\it secondary (inner) slow} component of CME-caused restructuring.

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Wei Liu, Leon Ofman, Nariaki V. Nitta, Markus J. Aschwanden, Carolus J. Schrijver, Alan M. Title, Theodore D. Tarbell. 2012-04-24. Quasi-periodic Fast-mode Wave Trains Within a Global EUV Wave and Sequential Transverse Oscillations Detected by SDO/AIA. https://doi.org/10.1088/0004-637x/753/1/52

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