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2018-04-04. An Aurora of a Different Color.

posted Apr 6, 2018, 9:12 PM by Alan Gould
By Kimberly M. S. Cartier, AGU-Eos. For GSS Energy Flow chapter 5. Excerpt: Strong Thermal Emission Velocity Enhancement (STEVE) paints a green and purple streak across the sky from the bottom left to top right in the image above. In this image, this rare aurora-like event is crisscrossed by the dusty band of the Milky Way, which curves from the top left to bottom right. STEVE, captured, in this instance, last year at Childs Lake in Manitoba, Canada, is not an aurora in the traditional sense: Instead of the oval-shaped, blue/green glow of more common types of auroras, STEVE appears as a thin, purple streak dangling a wavy, green picket fence structure. STEVEs always appear at the same time as normal auroras, but they occur at lower latitudes, in an area of the atmosphere called the subauroral zone. ...New insight into the origin and behavior of this rare atmospheric event became possible when, in 2016, a team of amateur and professional scientists used ground- and space-based cameras to image STEVE and a simultaneous normal aurora. By combining all of the available images, the team discovered that STEVEs and auroras form from a similar process—charged particles interacting with Earth’s magnetic field—but the particles that create STEVEs travel along magnetic field lines much closer to Earth than those that make ordinary auroras. That’s why STEVEs occur at lower latitudes than auroras....  https://eos.org/articles/an-aurora-of-a-different-color