NLN Aurora Briefs – February 24, 2015

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Sunspot activity has decreased. The main feature impacting Earth’s space weather has shifted from solar flares to coronal holes over the last month or so. Once again this week, we are seeing elevated solar winds as the result of a coronal hole high speed stream.

Solar winds picked up mid-yesterday and have been slowly increasing from 440km/s yesterday to over 500km/s as of this writing. There was a brief peak of winds over 550km/s. Two days ago, this small coronal hole was pointed directly at Earth:

AIA 211 image of coronal hole
Coronal Hole from 2/21/2015 influences Earth’s space weather on Feb 23, 2015

High solar winds make our geomagnetosphere more susceptible to the impacts of solar disturbances. Any high proton flux or high density have the potential to activate aurora as reflected by higher KP. Late on the 23rd, and so far early on the 24th, KP values have already increased to 4. If Bz stays south for an extended period of time, the wing-KP model will likely register higher values.

Even without sunspots, we’ll take the Aurora activity. Here’s a great Aurora shot in today’s featured tweet, shared by Sun Viewer @SunViewer (who does an awesome job curating really nice Aurora photos!):