# Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide

## Abstract

This paper is devoted to the analysis of electromagnetic field excited by a charge moving in a circular waveguide, which consists of two semi-infinite parts. The charge moves with a constant velocity along the waveguide axis from the partially dielectric section into the homogeneous one. It is assumed that Cherenkov radiation is generated in the bilayer section. The total field is represented as a sum of a known forced field that is the field of the charge in the infinite regular waveguide and a free field resulting from the presence of the transverse boundary. The infinite system of algebraic equations for amplitudes of the free-field modes is derived. The further analysis is conducted using numerical calculations. Special attention is given to the study of the so-called Cherenkov-transition radiation (CTR) within the homogeneous part of the waveguide volume. Typical distributions of CTR over frequencies and modes are presented for the case when the channel and the homogeneous area are free of medium. Analytical results obtained for the point charge are generalized for the charged bunch with an arbitrary profile and verified using direct simulations for the case of Gaussian bunch.

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)

- Sponsoring Org.:
- Russian Foundation for Basic Research

- OSTI Identifier:
- 1489530

- DOE Contract Number:
- AC02-06CH11357

- Resource Type:
- Journal Article

- Journal Name:
- IEEE Transactions on Microwave Theory and Techniques

- Additional Journal Information:
- Journal Volume: 66; Journal Issue: 1; Journal ID: ISSN 0018-9480

- Publisher:
- IEEE

- Country of Publication:
- United States

- Language:
- English

- Subject:
- Cherenkov-transition radiation (CTR); mode transformation; radiation of charged particle bunch; waveguide with dielectric filling

### Citation Formats

```
Grigoreva, Aleksandra A., Tyukhtin, Andrey V., Vorobev, Viktor V., and Antipov, Sergey.
```*Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide*. United States: N. p., 2018.
Web. doi:10.1109/TMTT.2017.2738000.

```
Grigoreva, Aleksandra A., Tyukhtin, Andrey V., Vorobev, Viktor V., & Antipov, Sergey.
```*Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide*. United States. doi:10.1109/TMTT.2017.2738000.

```
Grigoreva, Aleksandra A., Tyukhtin, Andrey V., Vorobev, Viktor V., and Antipov, Sergey. Mon .
"Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide". United States. doi:10.1109/TMTT.2017.2738000.
```

```
@article{osti_1489530,
```

title = {Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide},

author = {Grigoreva, Aleksandra A. and Tyukhtin, Andrey V. and Vorobev, Viktor V. and Antipov, Sergey},

abstractNote = {This paper is devoted to the analysis of electromagnetic field excited by a charge moving in a circular waveguide, which consists of two semi-infinite parts. The charge moves with a constant velocity along the waveguide axis from the partially dielectric section into the homogeneous one. It is assumed that Cherenkov radiation is generated in the bilayer section. The total field is represented as a sum of a known forced field that is the field of the charge in the infinite regular waveguide and a free field resulting from the presence of the transverse boundary. The infinite system of algebraic equations for amplitudes of the free-field modes is derived. The further analysis is conducted using numerical calculations. Special attention is given to the study of the so-called Cherenkov-transition radiation (CTR) within the homogeneous part of the waveguide volume. Typical distributions of CTR over frequencies and modes are presented for the case when the channel and the homogeneous area are free of medium. Analytical results obtained for the point charge are generalized for the charged bunch with an arbitrary profile and verified using direct simulations for the case of Gaussian bunch.},

doi = {10.1109/TMTT.2017.2738000},

journal = {IEEE Transactions on Microwave Theory and Techniques},

issn = {0018-9480},

number = 1,

volume = 66,

place = {United States},

year = {2018},

month = {1}

}