On January 6, the Polarlightcenter Geophysical Observatory detected a ground current event in northern Norway. The instrument detected a sudden and intense change in ground currents and local magnetic fields. Fifteen minutes before the event, NASA’s ACE probe detected a sudden 180-degree swing of the interplanetary magnetic field near Earth.
The density of the solar wind suddenly increased fivefold. The Earth may have passed through a layer of current, triggering a ground current event. As the current flows on the ground, the aurora fills the sky. Both aurora and ground currents are triggered by rapidly changing geomagnetic fields.