On March 29th at 17:52 UT, the magnetic canopy of sunspot AR1890 erupted, producing a brief but intense X1-class solar flare. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash.
Radiation from the flare caused a surge in the ionization of Earth’s upper atmosphere–and this led to a rare magnetic crochet, measuring 17 nT at the magnetometer in Boulder, Colorado.
A magnetic crochet is a ripple in Earth’s magnetic field caused by electrical currents flowing in air 60 km to 100 km above our heads. Unlike geomagnetic disturbances that arrive with CMEs days after a flare, a magnetic crochet occurs while the flare is in progress. They tend to occur during fast impulsive flares like this one.
The explosion also hurled a CME into space: movie. The bulk of the CME is sailing north of the sun-Earth line, but there appears to be a faint Earth-directed component that could deliver a glancing blow to our planet’s magnetic field on April 1-2.