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Super-Magnet Sheds Light on Semiconductors
Stony Stevenson writes "A group of researchers at Florida state have demonstrated a magnet design that could shed new light on nanoscience and semiconductor research. 'The Split Florida Helix magnet can direct and scatter laser light at a sample down the centre of the magnet and from four ports on the sides. Due to become fully operational in 2010, the device can generate fields above 25 tesla. The highest-field split magnet in the world currently attains 18 tesla ... The scientists will be able to expand the scope of their experimental approach, learning more about the intrinsic properties of materials by shining light on crystals from angles not previously available in such high magnetic fields.'"
More specifically, this happened at Florida State University's National High Magnetic Field Laboratory. Thanks!
Did I miss something in science class?
How is magnetism able to affect a beam of light?
Obama's legacy: (N)othing (S)ecure (A)nywhere and (T)error (S)imulation (A)dministration
From what I gather, this magnet isn't able to split/focus light, any more than lesser powered magnets. What makes this one different, is that usually, at such high fields, it is phisically imposible to get any sort of light inside, as the structure of the magnet has no gaps that can be used to shine a light in, ie, 100% enclosed. This magnet is constructed differently, in that even though it attains the highest magnetic fields, the insides are still viewable from outside, and so lasers/etc can be focused from the outside, onto the subject while its in operation.
NOW! Witness the power of this fully operational supermagnet!
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
According to the locals down here in Tally, the Mag Lab changes the weather, causes (or suppresses) hurricanes, and makes airplanes fall from the sky!
To put it into perspective:
1 Tesla is about 20000 times the strength of the magnetic field on earth.
Those rare-earth magnets that move the head inside of a hard drive are about 1.25 T.
MRIs in hospitals use about 3 T.
16 T will levitate a frog.
FOXTROT UNIFORM CHARLIE KILO
not only can it do these things to crystals, but it can also take a rather straightforward story summary, and twist it in such a way that it seems to imply that the magnet can bend light. that's a powerful magnet that can bend a story summary
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
To make really powerful magnets, of course, you need to use some tricks, such as shaping the system to concentrate the field at a particular point. In machines like MRIs and NMRs, the magnet is typically cooled (e.g. to liquid helium temperatures) which makes it superconducting. This allows a very large current to be passed through the coil, which generates extremely large fields at the center.
In this current case, they describe the magnet as: "created by packing together dense, high-performance copper alloys and running a current through them". (See picture here.) The article doesn't say whether they cool the coil to reduce resistance, or whether it is purely the shape of the coil that produces the extremely high field.
The split magnet mentioned in this story is a purely resistive magnet. This means that it will operate at room temperature and uses copper alloy coils (pretty sure its a copper-silver allow) along with a tremendous amount of current to generate a magnetic field. The resistive magnets at the NHMFL operate at up to 60,000A and at up to 500V which equates to about 30MW. This amount of power is difficult to dissipate and makes these some of the worlds most powerful hot water heaters. The coil technoloy used is known as Florida-Bitter. The tricky part about a split magnet is that you have to take the most efficient portion of the magnet, which are the coils close to the center and effectively move them to the farthest region of the magnet. For comparison, the most powerful resistive magnet at the NHMFL with comperable parameters generates 35T. The most powerful persistant magnets however are the hybrids which have superconducting coils in the low field regions and resistive coils in the high field regions. The most powerful is 45T A lot more information can be found at: http://www.magnet.fsu.edu/
Such risks are already well known:
Look at the picture halfway down this article.If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
In applications like MRI where you need not just high-intensity but also high-precision, you'll typically have a main superconducting coil and a couple of ancillary coils to iron out the kinks in the field pattern (eg. tesseral and shim coils).
Also depends on the frequency of operation; get high enough and the losses due to skin and proximity effects become unbearable (stuff like Litz wires and appropriate coil turns arrangement can help to mitigate this).
One more thing to worry apart with such high fields involved is whether the darned thing is going to fly apart when you hit the ON button. Lorentz forces are a bitch (I've looked at a group's work where they generate a 50T field using a single-turn micro-coil. They kinda cheat though - it's only a 40ns pulse and the single-turn coil literrally blows up after a couple of repetitions).