Spin stabilized magnetic levitation

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A brief demonstration and small explanation about the Levitron levitating top device which demonstrates spin stabilized magnetic levitation.
A brief demonstration and small explanation about the Levitron levitating top device which demonstrates spin stabilized magnetic levitation.

Spin stabilized magnetic levitation is a phenomenon of magnetic levitation originally discovered through invention by Vermont inventor Roy M. Harrigan in the late 1970s. He received a United States patent for his levitation device based upon this phenomenon on May 3, 1983.[1][2] A spin stabilized magnetic levitation device is marketed as an executive toy under the 'Levitron' trademark.

[edit] Physics

Earnshaw's theorem does not allow for a static configuration of permanent magnets to stably levitate another permanent magnet or materials that are paramagnetic or ferromagnetic against gravity.

This theorem does not apply to a non-static configurations however.

In spin stabilized magnetic levitation however, a magnetic base provides a cup shaped magnetic field. Withiin this a magnetic spinning top acts as a gyroscope which keeps the top from flipping over. Provided the spin rate is not too high this gyroscopic property combined with the top's precession allows the top to follow the field lines of its base magnet and remain levitating around a stable point in space above the base. At this point where the forces acting on the top (gravitational, magnetic, and gyroscopic) are in equilibrium thereby allowing the top to rest in an energy minima well.[3] (see: magnetic levitation)

In the laboratory, experimental setups are able to levitate tops for indefinite periods by measuring the spin rate and maintaining it using a drive coil. However, variations in temperature can affect the stability, and without ambient temperature control the top will eventually fall after hours or days due to the temperature coefficient of the magnets.[3]

The physics of the magnetic stability is similar to magnetic gradient traps.[3]

[edit] References

  1. ^ U.S. Patent 4,382,245 
  2. ^ a b c Martin D. Simon, UCLA Department of Physics, Lee O. Heflinger, S. L. Ridgway (1997). Spin stabilized magnetic levitation (HTML). American Journal of Physics. Retrieved on 2006-12-06.
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