2023, Tishchenko, A. A., Sergeeva, D. Yu., Garaev, D. I., Гараев, Дамир Ильдарович, Сергеева, Дарья Юрьевна, Тищенко, Алексей Александрович

Terahertz radiation sources based on the radiation of electrons in external fi elds attracts the attention of researches due to the huge energy stored in relativistic electron beams. Even a little part of this energy, being radiated, makes it possible to produce powerful radiation in various parts of spectrum, including terahertz one, which is exploited in gyrotrons, magnetrons, orotrons etc. Besides its customary applications in powerful radiation sources and in non-destructive diagnostics of relativistic electron beams, the last decade SPR is intensively investigated for more exotic structures, like plasmonic crystals [1-3], graphene nanoscale gratings [4, 5], metasurfaces [6, 7]. These novel structures are widely investigated today due to their tunability, opportunity to tailor the properties of the surfaces, which results in developing novel modulators [8] and fi lters [9] — the key elements in applications of modern optics.

2020, Tishchenko, A. A., Feshchenko, A. M., Тищенко, Алексей Александрович

© 2020 OSA - The Optical Society. All rights reserved.We have constructed a theory for X-ray source based on Thomson inverse scattering from nano-modulated electron beams. In coherent mode form factor is proved to lead to a sharp increase in intensity, with factor 10 4

2019, Tishchenko, A., Тищенко, Алексей Александрович

2021, Savchenko, A. A., Tishchenko, A. A., Sergeeva, D. Yu., Савченко, Александр Алексеевич, Тищенко, Алексей Александрович, Сергеева, Дарья Юрьевна

© 27th Russian Particle Accelerator Conference, RuPAC 2021. All rights reserved.In this paper, creation and implementation of the Compton backscattering module into the Geant4 package are under consideration. Created module of Compton backscattering has been implemented as a discrete physical process and operates with a fixed light target (a virtual volume with the properties of a laser beam), with which a beam of charged particles interacts producing x-rays. Such a description allows user to flexibly change necessary parameters depending on the problem being solved, which opens up new possibilities for using Geant4 in the studied area.

2023, Gavrilenko, D. V., Potylitsyn, A. P., Tishchenko, A. A., Гавриленко, Дмитрий Владимирович, Потылицын, Александр Петрович, Тищенко, Алексей Александрович

Unipolar pulses of electromagnetic radiation — the waves with practically constant electric fi eld — were suggested by Bessonov in 1981 [1], and called “strange waves” even by the author.

2015, Tishchenko, A. A., Sergeeva, D. Yu., Strikhanov, M. N., Стриханов, Михаил Николаевич, Тищенко, Алексей Александрович, Сергеева, Дарья Юрьевна

Transition radiation (TR) and Diffraction radiation (DR) can be interpreted as a result of action of a charged particle upon a target. These types of radiation have similar nature and arise due to the dynamic polarization of the target material by the Coulomb field of the charged particles. TR is generated when the beam crosses the media surface; DR is generated when the beam moves above the inhomogeneous medium, e.g. above the side of a slab.

2019, Tishchenko, A. A., Sergeeva, D. Y., Тищенко, Алексей Александрович, Сергеева, Дарья Юрьевна

In this work we construct the first-principles theory for the near-field resonances arising in the system of two different coupled nanoparticles excited by the external field. The obtained expressions are valid for an arbitrary external field; the detailed analysis is performed for the case of a fast electron passing by. The energy of electron is arbitrary, so the results are valid both for relativistic and nonrelativistic electrons. We have obtained rigorous analytical solution for the radiation field and for distribution of radiation over angles and frequencies. The effect of interaction between the single particles manifests itself very distinctly in conditions of resonance, resulting in a spectral shift of the radiation maximum, significant increase of its altitude, and, interestingly, in clear oscillations in radiation intensity not only when the particles are very close to each other, but even when the distance between the particles exceeds considerably their sizes. It attests to the strong influence of interaction on the radiation processes in a system of coupling particles.

2023, Tishchenko, A. A., Sergeeva, D. Yu., Тищенко, Алексей Александрович, Сергеева, Дарья Юрьевна

Radiation from electron bunches is usually used for diagnostics of its transverse sizes in accelerators and colliders including FELs and synchrotron injectors [1,2]. However, the methods of diagnostics continue to improve. There are some ideas on single-short diagnostics, or non-destructive diagnostics, or using new types of targets, among which metamaterials and photonic crystals seem to be attractive. In this report we suggest using incoherent transition radiation from two-periodical targets in order to defi ne transversal sizes of the bunch. Usually the diagnostics is reduced to comparison the measured data to the theoretical one, which take in account the coherent eff ects [3,4]. The generally accepted approach to take into account coherence from electron bunches consists in multiplying the radiation intensity from one particle by the bunch form-factor, which takes into account its size, shape, and distribution of electrons. We show that in polarization radiation for a wide class of structures, such as photonic crystals and metasurfaces, this approach is incorrect [5,6].

2020, Tishchenko, A. A., Sergeeva, D. Yu., Garaev, D. I., Тищенко, Алексей Александрович, Сергеева, Дарья Юрьевна, Гараев, Дамир Ильдарович

© Санкт-Петербургский государственный университет, 2020In this paper we investigate analytically polarization radiation excited due to interaction of an electron with a cluster of coupled subwavelength particles. The results are valid both for nonrelativistic and for relativistic charged particles. The expression for the Fourier image of radiation field has been obtained, which allows direct calculating spectral and angular density of the radiated energy. In general case, to find the radiation field with taking into account the interaction between particles, it is necessary to solve a system of N! self-consistent tensor equations, where N is the number of particles in the cluster. We suggest the algorithm for reducing the system of N! equations to N equations. The reduction in the number of equations is achieved through the calculation of the fields at the each point in which the dipole moment is, rather than through calculation of the fields from the every source. This facilitates considerably the finding solutions in problems of radiation for the clusters of particles.

2019, Sergeeva, D. Yu., Tishchenko, A. A., Сергеева, Дарья Юрьевна, Тищенко, Алексей Александрович