Coherent radiation from a chain of charged particles on a circular orbit around a dielectric ball

Abstract

We investigate the electromagnetic radiation from a chain of relativistic charged particles uniformly rotating along equatorial orbit around a dielectric ball. For weak absorption of radiation in the ball material, at certain rotation frequency the radiation intensity becomes significantly higher than the corresponding value for a chain of charges rotating in free space or in a transparent medium with the same dielectric constant as that for the ball material. In the case of an equidistant distribution of charged particles along the orbit we determine the values of parameters of the problem for which the charges in the chain emit coherently. It is shown that the radiation intensity on a given harmonic increases in proportion to the square of the number of emitting charges. We also show that the relative shifts in the particles locations up to 10\% do not destroy the coherence properties of the radiation. It is demonstrated that the coherence effects may also dominate in the radiation intensity for chains with non-equidistant distributions of particles. The numerical results obtained for different dielectric balls have revealed the emitted radiation to be in the GHz/THz frequency ranges. The high-power radiation of the chain propagates in the angular range with respect to the rotation plane determined by the Cherenkov condition for the velocity of the chain projection onto the ball surface.

arXiv comment15 pages, 4 figures, discussion of peaks and references added

References in corpus (9)

• Synchrotron radiation from a charge moving along a helical orbit inside a dielectric cylinder
• Coherent Terahertz synchrotron radiation mastered by controlling the irregular dynamics of relativistic electron bunches
• Synchrotron radiation from a charge moving along a helix around a dielectric cylinder
• High power Cherenkov radiation from a relativistic particle rotating around a dielectric ball
• Cherenkov radiation and emission of surface polaritons from charges moving paraxially outside a dielectric cylindrical waveguide
• Synchrotron radiation inside a dielectric cylinder
• Angular distribution of high power radiation from a charge rotating around a dielectric ball
• Some features of electromagnetic field of charged particle revolving about dielectric ball
• Synchrotron and Smith-Purcell radiations from a charge rotating around a cylindrical grating