418 research outputs found
The experimental study of the surface current excitation under the influence of a relativistic electron electromagnetic field
The problem of the surface current excitation in a conductive targets by a
relativistic electron electric field as the origin of such radiation mechanisms
as diffraction and transition radiation of relativistic electron was considered
in frame of both surface current and pseudo-photon methods. The contradiction
between these viewpoints in respect to the surface current on the target
downstream surface necessitated the experimental test of this phenomenon. The
test performed on electron beam of the 6 MeV microtron showed, that not any
surface current is induced on the target downstream surface under the influence
of a relativistic electron electromagnetic field in contrast to the upstream
surface. This is important implication for the understanding of the forward
transition and diffraction radiation nature.Comment: Was Presented at the symposium Channeling 2008 (Charged and Neutral
Particles Channeling Phenomena), October 25 - November 1, 2008 Erice (Trapani
- Sicily), Italy, and was accepted for publication in proceedings of
symposiu
Experimental Research of the Diffraction and Vavilov-Cherenkov Radiation Generation in a Teflon Target
Geometry of Vavilov-Cherekov (VChR) radiation when an electron moves close to
a dielectric target is in analogy to diffraction radiation (DR) geometry. In
this case we may expect DR generation from the upstream face of the target
besides that VChR. The joint observation of these booth types of radiation is
very interesting from the pseudo-photon viewpoint, which is applicable for
relativistic electrons. Unexpected results obtained in our experiment insist on
reflection about nature both DR and VChR. The experiment was performed on the
relativistic electron beam of the microtron of Tomsk Polytechnic University.Comment: This article will be published in Journal of Physic
Electromagnetic field features at interaction of relativistic electron with matter
The features of electromagnetic field of relativistic electrons passing through a hole in an absorbing screen as a function of the distance from the screen in the range of radiation formation length were investigated for the transversal and longitudinal field components. The analysis of the obtained results allows approving the existence of a semi-bare electron with a particularly deprived Coulomb field, which turns into the stable state of the usual electron at the distance of radiation formation length
Shadowing of the electromagnetic field of a relativistic electron
In coherent radiation sources (diffraction radiation, Smith-Purcell effect,
etc.) based on relativistic electrons passing by a material radiator, the
electron self-field is partly shadowed after each part of the radiator over a
distance of the order of the formation length g2l. This effect has been
investigated on coherent diffraction radiation (DR) by electron bunches. An
absorbing half-plane screen was placed at various distances L before a standard
DR source (inclined half-plane mirror). The DR intensity was reduced when the
screen was at small L and on the same side as the mirror. No reduction was
observed when the screen was on the opposite side. The shadowing effect can
significantly reduce the total energy radiated in a long radiator.Comment: Was Presented at the symposium Channeling 2008 (Charged and Neutral
Particles Channeling Phenomena), October 25 - November 1, 2008 Erice (Trapani
- Sicily), Italy, and was accepted for publication in proceedings of
symposiu
Experimental test of the shadowing effect in Smith-Purcell radiation
The observation of a shadowing effect of a relativistic electron Coulomb field for the Smith-Purcell radiation generation is presented in this paper. For this purpose the surface current from the closest surface of grating element
to the electron beam was measured for a downstream one shadowed by upstream element. The experimental results showed that shadowing effect for Smith-Purcell radiation depends on grating geometry
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