labview1958 Posted July 25, 2005 Posted July 25, 2005 If a magnet is brought near a rotating copper disc, the disc will slow down. This is because of the electromagnetic drag force. Does the same thing happens to a rotating superconductor disc?
Meir Achuz Posted July 25, 2005 Posted July 25, 2005 Probably not. The copper slows down because of resistive energy loss, which doesn't occur for a SC. Also the Meissner effect means that the magnetic field would not enter the SC. Now, do the expt and prove me wrong.
DQW Posted July 25, 2005 Posted July 25, 2005 Also the Meissner effect means that the magnetic field would not enter the SC.As long as the temperature and field are low enough that the SC is not in the Abrikosov phase; else flux pinning would slow the SC down pretty quickly.
labview1958 Posted July 26, 2005 Author Posted July 26, 2005 "flux pinning would slow the SC down pretty quickly." Where can I find experimental results regarding such behaviour? Is it reported anywhere? Is there a plain english explaination regarding this? My hunch is that the superconductor will not slow down because of the absence of electromagnetic drag force?
DQW Posted July 26, 2005 Posted July 26, 2005 It is flux-pinning that greatly stabilizes the SC in a typical levitation demo. http://superconductors.org/terms.htm#ferr http://www.spacedaily.com/news/future-99f.html http://www.iop.org/EJ/abstract/0953-2048/12/9/306
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