Surprising forecasters, an interplanetary shock wave hit Earth's magnetic field on Jan. 11th. The impact just after 08:30 UT did not trigger a geomagnetic storm. However, strong magnetic fields downstream of the shockfront opened a crack in Earth's magnetosphere. Solar wind poured in to fuel a nice display of Arctic auroras:
"I was running around my apartment like a maniac, looking for pants and camera equipment," says photographer Markus Varik of Tromsø, Norway. " I didn't have enough time to go to completely dark location--but I didn't need to. The auroras were so bright."
The shock wave was not expected. In retrospect, perhaps, it should have been. On Jan. 8th, a huge filament of magnetism launched itself off the surface of the sun: movie. At first the blast did not seem to be Earth-directed. However, yesterday's event may have been a glancing blow from the debris. Aurora alerts: SMS Text.
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MEANWHILE IN ENGLAND: "The solar eruption and consequent shockwave reported on Spaceweather.com certainly was geoeffective, sparking not only auroras, but also twitching magnetometer needles," reports Stuart Green who recorded the shaking of his local magnetic field in Preston UK:
"It is always so exciting to experience the effects of space weather here at ground level," he says.
Green's magnetometer is buried in his backyard garden about 0.5 meters deep. This allows very sensitive (sub nanotesla) measurements of magnetic declination. The instrument has little trouble detecting geomagnetic storms, CMEs, and interplanetary transients like the one that hit Earth on Jan. 11th.
Space Weather News for Jan. 11, 2021