CIR SPARKS G2-CLASS #GEOMAGNETIC #STORM: If you've never heard of a CIR, there's only one thing you really need to know: CIRs are good at making auroras. One hit Earth yesterday and lit up both ends of our planet--north and south. "The display in #NewZealand was one for the ages," reports Ian Griffin from #Hoopers Inlet on the #Otago Peninsula:
"The #aurora kept pulsing and, just as you thought it was going to end it exploded into life again," he says. "What a night!"
Short for "co-rotating interaction regions," CIRs are transition zones between fast- and slow-moving solar wind streams. Solar wind plasma piles up in these regions, producing shock-like structures that mimic CMEs. NOAA correctly predicted the arrival of a CIR on June 15th. Its impact opened a crack in our planet's magnetic field, fueling a G2-class geomagnetic storm that persisted through June 16th.
Because of the northern summer sun, Arctic observers couldn't see the show. Some #auroras, however, did spill into darkness at lower latitudes. Jeff Berkes sends this photo from #Cape-Cod, #Massachusetts:
