File:Evolving Sigmoid Loops -Hinode XRT-.webm

From Wikimedia Commons, the free media repository
Jump to: navigation, search
Evolving_Sigmoid_Loops_-Hinode_XRT-.webm(WebM audio/video file, VP8/Vorbis, length 36 s, 360 × 360 pixels, 250 kbps overall)



This sequence of images (click for the movie) depicts active region 11093 on 11-Aug-2010. As you can see, the collection of loops, when viewed all together, resemble a large backwards 'S'. For this reason we call such an active region "sigmoidal". Most of the time, there's no one single loop that traces out a full S-shape, but in this case XRT happened to catch a pair of shorter loops joining together to complete the shape. At 01:50:20, there is a clear gap between the northern and southern loops; but just a few minutes later (01:56:37) a bright knot begins to appear. By 02:09:15, the bright knot is too intense for XRT's detector, resulting in the big bloom of saturated pixels. This indicates that a large amount of energy was released at the junction of those two loops, causing the plasma to be super-heated to millions of degrees. And at 02:16:35 we can see the result: the connection of "north loop" to "south loop" has created a single long, S-shaped loop. It's the act of connecting those loops -- a process referred to as "magnetic reconnection" -- that releases the energy and produces the heat.

Visit us at and view the original post at

Questions and comments welcome at xrtpow "at" gmail "dot" com

Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in co-operation with ESA and the NSC (Norway).



w:en:Creative Commons
This file is licensed under the Creative Commons Attribution 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).

This file, which was originally posted to, was reviewed on by the administrator or reviewer McZusatz, who confirmed that it was available there under the stated license on that date.

File history

Click on a date/time to view the file as it appeared at that time.

current14:21, 23 June 201336 s, 360 × 360 (1.07 MB)YtUPt (talk | contribs)Imported from
  • You cannot overwrite this file.

The following page links to this file:

Transcode status

Update transcode status
FormatBitrateDownloadStatusEncode time
WebM 360P497 kbps
Download file
Completed 14:23, 23 June 201319 s
WebM 240P126 kbps
Download file
Completed 07:43, 21 February 201714 s
WebM 160P65 kbps
Download file
Completed 21:12, 21 February 20178.0 s