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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."
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.