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World's Strongest Magnetic Field Is Demonstrated
lazarus_ writes "PORTLAND, Ore. -- Researchers at Florida State University's National High Magnetic Field Laboratory in Tallahassee achieved the holy grail of magnetism recently when their high-temperature superconductor attained the coveted 25-Tesla field strength record."
Magnetic flux is magnetic flux density multiplied (or integrated) by the surface. The unit of magnetic flux is Weber. That's where Earth wins over all man-made magnets.
No, this is the largest magnetic field ever created (that we know about), although it does cover a fairly small area. The Earth's magnetic field is weak but very, very large; magnetic fields drop off rapidly (Inverse cube of distance, if I recall correctly) as you move away from the source. Similarly, speaker magnets are fairly weak (on the order of a few hundred to a thousand gauss) but since they are large, they affect a greater area than a small rare-earth magnet that has a 1 Tesla (10,000 Gauss) field strength - a few meters away, the magnetic field is lost in the "background noise" of the Earth's magnetic field. While this is almost certainly smaller than a tiny rare-earth magnet, it still won't cause compass needles all over the Earth to point in funny directions; just those around the building it's installed in. In summary: powerful magnet != big field.
That's it. I'm no longer part of Team Sanity.
Creating a 25 tesla magnetic field is not a big deal in itself. People have been using ~ 40 tesla, pulsed magnetic fields to study superconductors for years. There are also techniques to generate 1000 tesla fields (first reference i googled: http://www.intas.be/catalog/94-3569.htm). They last about a millisecond. How? Well basically, by using explosives. While i only skimmed this article, the peice they are probably leaving out is that they are creating 25 tesla magnetic fields over a large area or for a significant amount of time (more than a second or two). This is really useful and takes tons of energy, so it's an achievement worth mentioning. What i don't understand is why the existence of those other magnets is overlooked, especially since the National High Magnetic Field Laboratory collaborates with lots of people who use them.
But higher transient fields have been produced for some time:
Large Z-Pinches routinely reach 100T, and may, at stagnation, quite conceivably reach fields as high as 10^4 T
In laser produced plasmas, magnetic fields have actually been measured to rise up to more than 3*10^4 T
Tatarakis et. al. Phys. of Plas. 9/5 pp. 2244 (2002)
Working for necessity's mother.
Magnetisme is electromagnetic radiation. So its force particle would be the photon.
One word: hemoglobin.