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diamagnetic levitation

diamagnetic levitation. dustin brumley. what it is. a look at diamagnetism a look at earnshaw’s theorem simple proof of earnshaw’s theorem physical picture of diamagnetic levitation experiment stuff experimental proof . what is diamagnetism.

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diamagnetic levitation

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  1. diamagnetic levitation dustin brumley

  2. what it is • a look at diamagnetism • a look at earnshaw’s theorem • simple proof of earnshaw’s theorem • physical picture of diamagnetic levitation • experiment stuff • experimental proof

  3. what is diamagnetism • diamagnets are objects with a mag. susceptibility χ < 0 • this means that diamagnetic objects repel mag. fields • many things are diamagnetic like water and wood and frogs

  4. earnshaw’s theorem • this theorem states that no stationary object made of charges, magnets and masses in a fixed configuration can be held in stable equilibrium by any combination of static electric, magnetic or gravitational forces

  5. simple proof • easiest way to look at earnshaw’s is thru laplace’s equation • ∆φ=0 for point charges and electrostatic potentials

  6. other ways to prove it • you can prove earnshaw’s theorem by using the virial of the forces • also you can prove it with gauss’ law but that’s not much fun either

  7. now for the physics

  8. is there a way around earnshaw’s theorem to stably levitate something? apparently so!

  9. levitation • earnshaw’s theorem does not apply to induced magnetism • possible for combination of gravitational and magnetic energy to have a minimum which is necessary to have stable levitation

  10. what’s happening • ferro and para-magnetic objects align with external fields and move toward the field maxima • diamagnetic material align anti-parallel to external fields and move toward the field minima

  11. what can we levitate? • theoretically we can levitate anything diamagnetic with a given magnetic field • this goes for walnuts, mice, leaves, diamonds…frogs

  12. atomic level

  13. analog to lenz’s law the orbital motion of electrons creates tiny atomic current loops, which produce magnetic fields. when an external magnetic field is applied to a material, these current loops will tend to align in such a way as to oppose the applied field

  14. the experiment placethe university of nijmegen HFML

  15. how to achieve a 16T fieldbitter magnet

  16. more about the bitter magnet • maximum field of 20 tesla (T) (this is 400000 times the earth magnetic field) consists of two concentric electrical coils. • the coils are powered by a 6000 kW (6MW) power supply. (20 kA, 300V)the magnet is cooled by de-ionized water of about 10°C • the cooling water goes in axial direction through the small holes in the bitter plates of the coils, which line up exactly in every plate

  17. can humans be levitated? was the frog ok? yes yes faqs

  18. levitating frog

  19. water floats too

  20. acknowledgements • mac herrera • Berry, Geim: Of Flying Frogs and Levitrons 1997 European Journal of Physics v. 18 pp. 307-313 • Jones, W: Earnshaw’s theorem and the stability of matter 1997 European Journal of Physics v. 1 pp. 85-88 • Simon, Geim: Diamagnetic Levitation: Flying Frogs and Floating Magnets 2000 Journal of Applied Physics v.87 #9

  21. fin

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