Magnetic Levitation
Earnshaw's theorem says that paramagnetic objects (or
ferromagnetic objects, or permanent magnets) cannot be levitated
stablely by static magnetic fields. Diamagnetic objects can be so
supported, a notable case being superconducting objects.
However, magnetic levitation of paramagnetic objects
is possible through the use of feedback. The late Professor Jesse
Beams of this department developed this technique for a variety of
applications. Examples are described in papers by Towler
and Beams
and by Ritter
and Molloy.
Previous work in this lab course can be found in
reports by
Jim Clarke and by Cahlan
Mazur 2
3
4
5
6
7
8.
[A few more files are not linked]