XRT Picture of the Week (XPOW)

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2013 September 04

Click image for flare movie and here for post-flare movie.

M Flares and Sigmoid Sea Creatures

This interesting structure, looking like a jellyfish or squid, was observed between the peak times of the two M-class flares on 17-Aug, 2013, from the sigmoid region named AR11818. The first eruption (GOES class M3.3, peaks at 18:24), occurred at the upper (or northwestern) part of the sigmoid, and from which the second eruption (M1.4 peaks at 19:33) was induced at the lower (or SW) part of the sigmoid (see movie 1). You can see two major cusp-shaped loops corresponding to these eruptions in the images taken around 20:20 UT. These cusp loops maintained their shape for more than 6 hours, later waning and shrinking with the downflows called supra arcade downflows (see movie 2).

Keywords: Sigmoid, Flare, Cusp, Downflows
Filters: Be_thin

(Prepared by Aki Takeda)

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