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in 1993. A charged sample of 2 mm in diameter can be levitated in a vacuum chamber between two electrodes positioned vertically with an electrostatic field in between. The field is controlled through a feedback system to keep the levitated sample at a predetermined position. Several copies of
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Earnshaw's theorem holds that a charged particle suspended in an electrostatic field is unstable, because the forces of attraction and repulsion vary at an equal rate that is proportional to the inverse square law and remain in balance wherever a particle moves. Since the forces remain in balance,
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W. K. Rhim, S. K. Chung, D. Barber, K. F. Man, G. Gutt, A. Rulison, and R. E. Spjut, Review of
Scientific Instruments 64, 2961 (1993).
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Sample of a titanium-zirconium-nickel alloy inside the
Electrostatic Levitator vacuum chamber at NASA's Marshall Space Flight Center.
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there is no inequality to provide a restoring force; and the particle remains unstable and can freely move without restriction.
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Samuel
Earnshaw "On the Nature of the Molecular Forces which regulate the Constitution of the Luminiferous Ether,"
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Electrostatic levitation of various materials including silicon, cobalt palladium, aluminium and other compounds
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on the surface forming an atmosphere of dust that floats in "fountains" over the surface of the Moon.
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techniques it is possible to adjust the charges to achieve a quasi static levitation.
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The London, Edinburgh, and Dublin
Philosophical Magazine and Journal of Science
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The idea of particle instability in an electrostatic field originated with
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Electrostatic levitation raises dust particles off the surface of the moon
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in 1874 who gave it the title "Earnshaw's theorem" and proved it with the
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Electrostatic levitation and transportation of glass or silicon plates
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with an upgraded setup of tetrahedra four beam laser heating system.
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The first electrostatic levitator was invented by Dr. Won-Kyu Rhim at
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Process of levitating a charged object using electric fields
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and NASA, and the original system has been transferred to
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Electrostatic levitator — Marshall Space Flight Center
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Cambridge
University Press, Vol. 7, pp. 97–122 (1842).
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Macmillan and Co., "Earnshaw's theorem" p. 139 (1873)
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Transactions of the
Cambridge Philosophical Society,
243:"I. On the constitution of atoms and molecules"
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103:in his atom model of 1913 when criticizing
54:and is used to suspend the gyroscopes in
229:A Treatise on Electricity and Magnetism,
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42:object and counteract the effects of
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331:Hybrid electric/acoustic levitation
134:California Institute of Technology
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289:Bell, Trudy E., "Moon fountains"
46:. It was used, for instance, in
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259:10.1080/14786441308634955
241:Bohr, Niels (July 1913).
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28:Electrostatic levitation
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196:Van de Graff generator
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147:charge fine layers of
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141:photoelectric effect
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67:unstable equilibrium
171:Acoustic levitation
161:Magnetic levitation
93:James Clerk Maxwell
52:oil drop experiment
336:2005-04-14 at the
166:Optical levitation
83:Earnshaw's theorem
77:Earnshaw's theorem
63:Earnshaw's theorem
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115:Levitation
101:Niels Bohr
267:1941-5982
186:Ionocraft
149:Moon dust
334:Archived
155:See also
71:feedback
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