Results 1 - 10 of 13622
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[en] Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail
[en] The equality of the averaged densities of the electrical and magnetic energies in the electromagnetic wave is associated, using a very simple argument, with the requirement that the velocity of the wave is c = (εoμo)−1/2. This may be a heuristically useful point for a discussion in the classroom. (paper)
[en] The evidence for cellular effects of exposure to electromagnetic (EM) fields has been reviewed. The cellular responses which may be relevant to carcinogenesis have been briefly identified, and evidence for modulation of these responses by EM field exposure has been discussed. Experimental evidence indicates that EM field exposure does not produce adverse genetic effects and is unlikely to have a direct effect on tumour initiation. There are, however, some reports suggesting that exposure may lead to subtle changes in cell behaviour, including effects on cell division. Such responses could be consistent with an effect at the level of tumour promotion. Furthermore, some reports indicate that EM field exposure may induce alterations in cellular characteristics of a similar nature to those resulting from tumour progression. It is emphasised, however, that available evidence is frequently of poor quality, and falls far short of indicating a definite effect of EM fields on carcinogenesis. (Author)
[en] Recent publications devoted to the electrodynamics of media in which waves with a negative group velocity can exist are discussed. The properties of such waves have been studied from the beginning of the past century, and the most important results in this field were obtained by Soviet physicists in the 1940s-1950s. However, in most recent publications, this circumstance has not been taken into account.
[en] Criticisms are answered on the new theory of the constancy of the speed of light. All criticisms are answered, and it is shown that the new theory is not logically inconsistent for the reasons expressed. 17 references
[en] The concept of an active drain has been used recently to provide an optical element which manages to perfectly sink incoming electromagnetic radiation. Here I show that, without prior knowledge of the incoming signal, an element attempting to respond as an active localized drain cannot succeed.
[en] A rigorous theory of electromagnetic wave scattering by small perfectly conducting particles is developed. The limiting case when the number of particles tends to infinity is discussed. (fast track communication)
[en] The time-average power radiated by a pair of infinitesimal dipoles is examined as their spacing is varied. The results elucidate the effect of the interaction of the dipoles on their radiation.