Macroscopic effect of the shadow of the electromagnetic field of relativistic electrons

The effect of the “formation zone” (“shadow” effect) on the characteristics of coherent diffraction radiation from a relativistic electron bunch passing near two conducting targets has been investigated experimentally as a function of the distance between the targets. The effect of the shadow behind absorbing and conducting screens on the diffraction radiation intensity has been studied in the experiments. In both cases, the same decrease in the diffraction radiation intensity almost to zero is observed with a decrease in the distance between the shadow source and target. The results indicate that two interpretations of the observed effect—the formation zone and shadow effect—are not equivalent.