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."
Re:sounds like... (Score:4, Interesting)
Or the neurons of a sun-spanning super-mind.
New energy source? (Score:2)
Yes. (Score:5, Informative)
As soon as fusion is mastered. These braids are just moderating the release of energy from the star.
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That's like saying fire is mastered because we know how to light a match and drop it on the forest floor.
You know that mastering fusion, in this context -- the context of producing energy -- means being able to safely control a fusion reaction with nontrivial net usable energy output. Right now, fusors do the safe control and H-bombs do the net energy output, but we don't have something that does both at once.
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I'm guessing the magnetic braids are somewhat similar to the fields used to contain the plasma in a fusion reactor.
http://en.wikipedia.org/wiki/Tokamak [wikipedia.org]
IANANP, but my armchair physicist understanding of fusion reactor containment is that you can't easily control the high energy neutrons in a hot plasma, just the protons. So the magnetic field is kind of a way to at least make the protons flow around in the plasma without touching the walls (and thus melting them). And perhaps they also help corral the neut
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You will never get out more energy than you originally used to create the fields.
Re:New energy source? (Score:5, Informative)
Conservation of Energy says no... if you make a magnetic field you get at most, in a perfect world, as much as energy back as you spent making the field. Positive energy production only comes from reduction of potential energy (lost mass, broken chemical bonds, etc.). If you aren't destroying something your not getting energy out.
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[...] broken chemical bonds, etc.). If you aren't destroying something your not getting energy out.
I hope I'm not being too pedantic here, but this isn't right. Adding chemical bonds is more likely to release energy than breaking them, so creating something is how you get the energy out of it, not destroying something.
A chemical bond that would release energy when it broke is an unstable bond so it's less likely to be found than a structure who could release energy by adding a chemical bond but hasn't had those circumstances occur. These unstable bonds were probably been formed in an environment with a
Re:New energy source? (Score:5, Insightful)
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.
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In fusion they need the plasma to be stable because the magnetic confinement can't adapt to deal with an unstable area. I wonder if "braided" magnetic fields (whatever the heck that actually means) would be more resilient, in the way that a basket can support an egg that would just fall through a layer of unwoven grass.
I really hope you're right, and it's not more like "Well, fusion is really messy and creates weird artifacts, and the only realistic way to contain it is a whole lot of vacuum, and enough mass to keep most of the reaction going with the occasional containment breach. Also known as a star, with solar flares."
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But what do I know, I'm not a nuclear physicist... perhaps this is all old hat.
Plasma dreads (Score:1)
HI-C (Score:3, Funny)
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And here I was thinking the next probe was going to be named "Hawaiian Punch".
Corona? (Score:3)
How many limes is it going to take to make it taste better?
Also proves (Score:5, Funny)
The Sun is Jamaican
If only! (Score:1)
My father was an astro-geophysicist of some note, who specialized in the solar corona. Unfortunately, he passed away in the early 1990's, but he would have been THRILLED with these observations! Some of my best remembrances of him are his solar corona photos taken during a sabatical at the observatory at Haleakala on Maui in the 1980's. Today they occupy a place of honor on our family wall of photos.
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Offtopic but cool video of the Sun (Score:5, Interesting)
Last week the Astronomy Picture of the Day web site had this impressive video of the eruption of a solar prominence. If you haven't seen it you should check it out.
http://apod.nasa.gov/apod/ap130115.html [nasa.gov]
Wait, not expected? (Score:3)
I thought the braided magnetic fields in the corona were already known? Isn't that what the Electric Universe people are on about? I could swear I've even seen the word "braided" in the context of solar magnetic fields in print somewhere before. Something about why sunspot eruptions tend to arc, rather than simply flow out in a straight line (for big ones that should be achieving escape velocity), or the shape of the arc for smaller ones. The arcs are too small to be purely gravitational, and the reason is the plasma is following magnetic field lines.
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Not braided (Score:1)
I just watched the video and they look twisted rather than braided.
Am I the only one ... (Score:3)
Sundiver (Score:1)
Oh man, where is David Brin when you need him ? :P