The northern lights unveiled - Kristian Birkeland's Terrella experiment recreated

Norwegian scientist Kristian Birkeland used different vacuum chambers in his experiments on the aurora borealis around 1900. A working copy of the largest chamber is now on display on the National Museum of Science and Technology in Oslo, Norway.
Birkeland noticed that an electron beam directed toward a magnetised terrella was guided toward the magnetic poles and produced rings of light around the poles and concluded that the aurora could be produced in a similar way. He developed a theory in which energetic electrons were ejected from sunspots on the solar surface, directed to the Earth, and guided to the Earth's polar regions by the geomagnetic field where they produced the visible aurora. This is essentially the theory of the aurora today.