查看星期四, 25 6月 2015歷史檔案

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M7.9 solar flare

Yesterday's coronal mass ejection arrival (CME) has been largely disappointing and it took a while before the direction of the IMF turned southward. While we did reach the moderate G2 geomagnetic storming threshold earlier today, we can conclude that this event nonetheless was a disappointment as the expected G3 geomagnetic storming threshold was never within reach. To make matters worse, this night we came to the conclusion that sunspot region 2371 is in decay and that it is now only a shadow of it former self. It's delta structure is no longer there as it has ripped loose from the trailing sunspot cluster. The chance for even a low-level M-class solar flare seemed low. But boy, sunspot region 2371 showed us this morning that it doesn't even need a delta structure to produce a strong solar flare. It surprised us with an M7.9 (R2-moderate) solar flare that peaked at 08:16 UTC.

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