A turning point in auroral physics

Auroral studies have reached a turning point. It now seems clear that the ‘standard’ theory which claims that the electrons responsible for bright, curtain‐like auroral arcs gain their energy from static electric fields, is indefensible, while a theory which attributes the acceleration to plasma waves is poised as a possible successor. It was approximately 100 years ago that the Norwegian mathematician and physicist Kristian Birkeland inferred that the aurora was a scintillation of the atmosphere caused by an influx of charged particles. Just over half a century later, McIlwain [1960] discovered, from pioneering rocket flights made from near the town of Churchill in Manitoba, Canada, that Birkeland was right, and that the particles were primarily electrons. Moreover, Mcllwain was able to deduce that the electrons producing a curtain‐like auroral arc exhibited a local maximum, or peak, in their energy spectrum. This conclusion was confirmed with progressively increasing resolution and sensitivity by Albert [1967] and others in the 1960s.