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Post Info TOPIC: Sun 09.12.06


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NOAA 10930
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Title: On the flare induced seismicity in the active region NOAA 10930 and related enhancement of global waves in the sun
Authors: Brajesh Kumar, P. Venkatakrishnan, Savita Mathur, Sanjiv Kumar Tiwari, R. A. Garcia

A major flare (of class X3.4) occurred on 13 December 2006 in the active region NOAA 10930. The energy released during flares is also known to induce acoustic oscillations in the Sun. Here, we analyse the line-of-sight velocity patterns in this active region during the X3.4 flare using the Dopplergrams obtained by GONG instrument. We have also analysed the disk-integrated velocity observations of the Sun obtained by GOLF instrument onboard SOHO spacecraft as well as full-disk collapsed velocity signals from GONG observations during this flare to study any possible connection between the flare related changes seen in the local and global velocity oscillations in the Sun. We apply wavelet transform to the time series of the localised velocity oscillations as well as the global velocity oscillations in the Sun spanning the flare event. The line-of-sight velocity shows significant enhancement in some localised regions of the penumbra of this active region during the flare. The affected region is seen to be away from the locations of the flare ribbons and the hard X-ray footpoints. The sudden enhancement in this velocity seems to be caused by the Lorentz force driven by the "magnetic jerk" in the localised penumbral region. Application of wavelet analysis to these flare induced localised seismic signals show significant enhancement in the high-frequency domain (5-8 mHz) and a feeble enhancement in the p-mode oscillations (2-5 mHz) during the flare. On the other hand, the wavelet analysis of GOLF velocity data and the full-disk collapsed GONG velocity data spanning the flare event indicate significant post-flare enhancements in the high-frequency global velocity oscillations in the Sun. We find indications of a connection between flare induced localised seismic signals and the excitation of global high-frequency oscillations in the Sun.

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RE: Sun 09.12.06
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The Hinode spacecraft captured sunspot No. 10930 on Dec. 13, 2006.
Credit: NASA/Hinode

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Video Weblink:
The Hinode spacecraft captures one of the most detailed videos ever of a sun storm.
Credit: NASA/Hinode

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RE: Sun 31.12.06
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Sunspot 10930 has re-emerged from the Sun's eastern limb.


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Posts: 131433
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RE: Sun 09.12.06
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An energetic storm on the Sun has forced ESA mission controllers to react to anomalies or take action to avoid damage to spacecraft. Several missions, including Integral, Cluster and Envisat, felt the storm's effects, highlighting the need for ESA's ongoing development of space weather forecasting tools.

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RE: Sun 12.12.06
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The Storm is over...

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RE: Sun 09.12.06
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Sunspot 10930 is a source for X-class solar flares.

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The solar radiation storm is still raging

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