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There have been some unusually large solar flares these past few days.
Charged particles emitted from the flares result in northern lights when the particles encounter earth's field.
A check of the NOAA x-ray flux does not show any recent large solar flares for the past week, but we have had a huge coronal hole that was geo-centered and from which solar winds were released. These solar winds will also spark auroras.
Below is a recent picture of the sun with that huge coronal hole still visible (in black).
Also shown is the GOES x-ray flux showing a flat-lined sun with no recent solar activity. Click the graph for an enlargement.