21–28 Jun 2026
Yerevan & Jermuk
Asia/Yerevan timezone

Features of radiation from a charge in coaxial helical motion around a cylindrical waveguide

24 Jun 2026, 15:40
20m
Yerevan & Jermuk

Yerevan & Jermuk

IAPP NAS RA - Yerevan, Armenia

Speaker

Vardazar Kotanjyan (postgraduate student)

Description

We investigate the radiation emitted by a charged particle moving along a helical orbit around a
dielectric cylinder immersed in a homogeneous medium. Formulae are derived for the electromagnetic
potentials, electric and magnetic fields, and for the spectral-angular distribution of the radiation in the
exterior medium. It is shown that under the Cherenkov condition for the dielectric permittivity of the
cylinder and the velocity of the particle’s image on the cylinder surface, strong, narrow peaks appear in
the angular distribution for the number of quanta radiated on a given harmonic. At these peaks, the
radiated energy exceeds the corresponding quantity for a homogeneous medium by several dozen
times. Analytic estimates are given for the heights and widths of these peaks. The results of numerical
calculations of the angular distribution of the radiated quanta are presented. The conditions for surface-
type mode generation are also discussed. The dispersion relation and the results of numerical
evaluations of the energy losses on these modes are presented.

Author

Aram Saharian (Institute of Applied Problems of Physics of NAS RA)

Co-authors

Anna Kotanjyan (Yerevan State University) Vardazar Kotanjyan (postgraduate student)

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