Electromagnetic Radiation from a Rotating Magnet

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SUMMARY

Accelerated charges, including spinning magnets, do emit electromagnetic radiation. A rotating bar magnet generates alternating magnetic fields that can be harnessed for energy through two primary methods: using a wire loop to generate electricity or employing a mechanical device that oscillates under the magnetic field. The energy extracted from these systems results in a loss of kinetic energy from the rotating magnet. Additionally, the efficiency of energy transfer diminishes over larger distances due to the poor conductivity of air and empty space for magnetic flux.

PREREQUISITES
  • Understanding of electromagnetic radiation principles
  • Familiarity with the operation of rotating magnets
  • Knowledge of energy conversion methods (electrical and mechanical)
  • Basic concepts of magnetic flux and its properties
NEXT STEPS
  • Research the principles of electromagnetic radiation from accelerated charges
  • Explore the design and function of electromagnetic generators
  • Study the mechanics of oscillating systems in magnetic fields
  • Investigate the behavior of pulsars and their energy radiation mechanisms
USEFUL FOR

Physicists, electrical engineers, and anyone interested in the principles of electromagnetic energy generation and the behavior of rotating magnetic fields.

acimarol
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I know that accelerated charges give off electromagnetic radiation, but does an accelerated (spinning) magnet give off electromagnetic radiation as well? If so, what is the energy loss from the magnet's kinetic energy?
 
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It seems to me that if you have a bar magnet, rotating in a horizontal plane about its centre so that an observer to (say) the west felt the effects of each pole in alternation as it spins, it would be possible to draw energy from the system in at least 2 ways:
1) a loop of wire leading to a load could be arranged to collect energy and dissipate it in the load (this is how electricity is generated commercially), or
2) a mechanical device composed of a spring and a piece of steel could be made to oscillate back and forward under the applied magnetic field and work would be done.

In either case, the work done by the mechanism, be it electric or mechanical, would be felt by the spinning magnet, and to the extent that energy (work) is supplied to the mechanism it would be lost by the rotating magnet.

Please notice that the air (and empty space) is a a very poor conductor of magnetic flux, so that these effects are usually useful only over very small distances.
 
I think maybe pulsars with rotating magnetic fields (dynamos) will radiate energy, because at large enough distances, the angular velocity of the moving magnetic field will approach the speed of light. See
http://en.wikipedia.org/wiki/Pulsar
Bob S
 

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