Nasa’s THEMIS spacecraft recently re-discovered Birkeland currents, though without reference to Birkeland’s work published in 1908 (Norwegian Aurora Polaris Expedition, Vol I & II). NASA has likened the interaction to a 30kV battery in space, noting “THEMIS discovered a flux rope pumping a 650,000 Amp current into the Arctic.
“A Birkeland current is a set of currents that flow along geomagnetic field lines connecting the Earth’s magnetosphere to the Earth’s high latitude ionosphere. In the Earth’s magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field and by bulk motions of plasma through the magnetosphere (convection indirectly driven by the interplanetary environment). The strength of the Birkeland currents changes with activity in the magnetosphere (e.g. during substorms). Small scale variations in the upward current sheets (downward flowing electrons) accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis. In the high latitude ionosphere (or auroral zones), the Birkeland currents close through the region of the auroral electrojet, which flows perpendicular to the local magnetic field in the ionosphere.” Wiki