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Dear All: A question for the theory-erudite: X-rays are electromagnetic radiation. Most of the time in crystallography we concern ourselves only with the electric field vector, which rings the electrons etc etc. ok. Interactions between dielectric matter and magnetic field are generally six orders of magniture smaller than for electrostatic interactions (so much for the magnetic wonder water treatments and crystallization secrets). However, for the self-propagation of the photon package, the magnetic field vector, perpendicular to the electric field, is equally important. I have seen a drawing - I recall in Eisenberg's Physical Chemistry, that shows Electric and magnetic field vector at the maximum at the same point. If I look at the Maxwell equations, it appears however, that at the maximal change of H, induced E is largest, and at maximal change of E, the induced H. So should not H peak, when E goes though zero? This would create some 'selfinduction' or 'propagation'. Obviously something is wrong with my picture. Can anyone shed light on the phase relation between H and E in a wave packet? I did not find any other drawing or explicit explanation in any of my older (German) physics books, and I was never really hot on electrodynamics. Any references would be welcome. Cheers, br
