#SOLAR #WIND SPARKS #ARCTIC #AURORAS: A co-rotating interaction region (CIR) hit Earth's #magnetic field on Dec. 30th, sparking a G1-class geomagnetic storm. Marianne Bergli photographed the light show from Kvaløya, Tromsø, #Norway:

"The solar wind is blowing out the old year and welcoming the new," says Bergli. "Happy New Year, everyone!"

CIRs are transition zones between slow- and fast-moving streams of solar wind. They contain shock waves and enhanced magnetic fields that do a good job sparking Arctic auroras. Fast solar wind following the CIR sustained the display for hours.
https://spaceweather.com/