Abstract
EXPERIMENTS have been reported which verified that at low frequencies a time-varying polarisation P in a dielectric, if taking place in a magnetic field H, results in a mechanical force of density Ṗ×μ0H. This force is not predicted by the Minkowski energy momentum tensor, but the Abraham form of that tensor gives a force density in an homogeneous isotropic body of magnitude [(ɛrμr−1)/c2]∂//∂t(E×H) usually called the ‘Abraham Force’. In a dielectric this can be written Ṗ×μ0H+P×μ0Ḣ. It is not surprising that Ṗ×μ0H should give a mechanical force, since Ṗ corresponds to a movement of electric charge associated with polarisation, but it is difficult to understand why P×μ0Ḣ should give a force.
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Walker, G. B., and Lahoz, D. G., Nature, 253, 339–340 (1975).
Walker, G. B., Lahoz, D. G., and Walker, G., Can. J. Phys., 53, 2577–2586 (1975).
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WALKER, G., WALKER, G. Mechanical forces of electromagnetic origin. Nature 263, 401 (1976). https://doi.org/10.1038/263401a0
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DOI: https://doi.org/10.1038/263401a0
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