Cause of Aurora Borealis Confirmed

An anonymous reader writes "There are reports that satellites have aided scientists in confirming why the Aurora Borealis (Northern Lights) exists. 'New data from NASA's Themis mission, a quintet of satellites launched this winter, found the energy comes from a stream of charged particles from the sun flowing like a current through twisted bundles of magnetic fields connecting Earth's upper atmosphere to the sun. The energy is then abruptly released in the form of a shimmering display of lights.'"

Not offtopic. Pop-culture humor.

[StefanJ]

By "dust," he means the mysterious substance that drives the powers-that-be of Phillip Pullman's "His Dark Materials" trilogy to distraction. And it's the cause of the Northern Lights in that alternate universe.

The first book of the trilogy -- known as "The Golden Compass" in the U.S. and "The Northern Lights" in Britain -- opened in theaters last week.

Re:The More Important Discovery

[jnik]

If astrophysicists realize this is essentially an electrical engineering problem, why has it not been diagrammed as such

Because it isn't essentially an electrical engineering problem. Fluid dynamics plays a major role. "Winds," "rains," and "shocks" are all fundamentally fluid dynamics concepts. BTW, this isn't an astrophysics field...we're space physicists. The lines are blurry--one space physicist in our department is doing heliospheric research, and one astrophysicist does a lot of work on magnetic processes (esp. magnetohydrodynamic shocks) beyond the solar system.

We do talk about double layers [harvard.edu] (and the plasma mantle, and the low latitude boundary layer....), and Birkeland currents, and current [harvard.edu] closure [harvard.edu]. We use the terminology that seems best to describe the processes. Sometimes we really are talking about different things and that needs different terminology.

There's a lot of crossover between lab plasma and space plasma research. One of the professors I work with started in fusion research; in the other direction, I know several space physicists who are doing lab work to try and pinpoint processes observed in space. As far as EE, these people build their own instruments. My advisor has dual appointments to astronomy and EE. We use Chen [amazon.com] as one textbook.

If you're really interested in the field, Kivelson and Russell [amazon.com] is a pretty good introduction, written at roughly an advanced undergrad level (i.e. real E&M). It is getting a bit dated, though; AGU monographs are a decent source of semi-digested information. I do like the Cravens text for something a little meatier (IMO) than K&R, although less applied. Gurnett and Bhattacharjee [amazon.com] is up to date and rigorous, but somewhat dense.