For several years in some parts of Canada, an unusual glow has been observed in the sky - a ribbon of purple light, which sometimes turns purple. The unusual aurora was given its own name - Steve.
All this time, Elizabeth MacDonald, a NASA physicist, has been working on it. Usually auroras appear at the moment of ionization of the "solar wind" when interacting with the Earth's magnetic field, but in the case of Steve, in her opinion, the nature of the violet stripes cannot be explained.
Things cleared up a bit in July 2017 when ESA's Swarm satellite, created to study the Earth's magnetic field, found itself directly beneath a mysterious purple glow.
Using data from the satellite, E. MacDonald and her colleagues found that Steve appears when solar particles move rapidly from east to west due to the interaction of electric and magnetic fields. It only occurs at points about 60 degrees north of the equator.
Scientists have known about the existence of these particle streams since the 70s. Usually they were given names such as "polar ion transport", but nothing was known about any visual phenomena that accompany them.
According to scientists, the study of the unusual aurora will help to better understand the nature of the interaction of charged cosmic particles with the Earth's magnetic field.