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Space Science

Magnetic 'Braids' May Cook the Sun's Corona 32

astroengine writes "Scientists have long puzzled over why the surface of the sun is cooler than its corona, the outer hazy atmosphere visible during a solar eclipse. Now, thanks to a five-minute observation by a small, but very high-resolution ultraviolet telescope, they have some answers. Hi-C, which was launched aboard a suborbital rocket to study the sun without interference from Earth's atmosphere, revealed interwoven magnetic fields braided like hair. When the braids relaxed, they released energy, heating the corona (abstract). 'I had no idea we would see structures like that in the corona. Seeing these braids was very new to me,' astrophysicist Jonathan Cirtain with NASA's Marshall Space Flight Center in Huntsville, Ala., told Discovery News."
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Magnetic 'Braids' May Cook the Sun's Corona

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  • by vlm ( 69642 ) on Wednesday January 23, 2013 @04:33PM (#42673163)

    Other way around. Plasmas are unstable. Pretty much any time you dump energy into them, they get all whacked out on a small scale. This specific mode of instability on the sun wasn't expected, and it might even be a totally new instability mode, but speaking generally "plasmas behaving badly when you pump energy into them" has been a bug for fusion research for a very long time. You want the energy to be smoothly stable in the plasma not some whacked out thing because whacked out things tend to locally adsorb the energy from a big region, concentrate it in a little area getting hotter and hotter, which exceeds and breaks containment in its local area, end result is the plasma energy gets dumped into the diverter (or worst case, wall).

    Crappy cooking analogy is when you're melting chocolate and the chocolate instead of being smooth thru the entire bowl suddenly phase transitions (more or less) and siezes into ... whatever the hell siezed chocolate is. Crystallized chocolate I guess.. Whoops. Or you're trying to make a nice mayonnaise emulsion but something keeps breaking the F-ing emulsion so you just get icky oil and water instead of a bucket of mayo. Now I'm getting hungry...

    Crappy /. car analogy is something like car engines produce the most energy when they burn real smoothly. Crazy ass detonations aka pinging ruins the smooth burning and although you get the same CO2 out the tailpipe, you get much less power at the crankshaft. You can fix that with water injection, or modify the compression ratio, cool the intake air, or clean the cylinder/head walls if they're coated with soot... all stuff you can't do in a reactor. More or less.

Do you suffer painful hallucination? -- Don Juan, cited by Carlos Casteneda