查看星期四, 8 1月 2015歷史檔案

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Surprise G3 geomagnetic storm, low solar activity

Yesterday we experienced a strong G3 geomagnetic storm (as reported by the NOAA SWPC, Wing-Kp reached Kp7-) with impressive auroral displays over Australia, New Zealand and the upper United States. Our header image comes from Tom Luttrell who managed to capture this shot of the Aurora Australis as seen from Tasmania during sunset! It was not even 100% dark yet! Amazing! Cause of this display which was perfectly timed for sky watchers in Australia and New Zealand was the direction of the IMF that went as low as -21nT during the morning UTC hours of 7 January and stayed that low for several hours. The geomagnetic field responded with several periods where we reached the geomagnetic storm threshold. The direction of the IMF (Bz) turned north around 12 UTC and the geomagnetic storm quickly subsided. Only high latitude sky watchers could still enjoy an occasional auroral display but geomagnetic storming is unlikely.

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