# Nonlinear theory of a generic Cerenkov free-electron laser

## Abstract

In this thesis a generic nonlinear model of the slow-wave FEL is presented. Both the single-particle (low beam current density) and collective (high beam current density) operation regimes of the device are studied. In the single-particle regime the maximum efficiency scales roughly as L/[lambda][gamma][sup 4], while the saturation electric field scales approximately as L/[lambda][gamma][sup 3], where [gamma] = 1/[radical](1[minus](v/c)[sup 2]), L is the length of interaction region, and [lambda] is the wavelength. In the collective regime the maximum efficiency scales as [gamma]J1/3 [lambda] 2/3, and the saturation electric field scales as [gamma]J2/3 [lambda]1/3, where J is the current density. These scaling relationships are confirmed by numerical simulation. The transverse motion of the electrons in the presence and absence of a longitudinal magnetic guiding field is also examined and the results suggest that it is possible to operate the device down to moderate beam energy without a guiding field. The basic Cerenkov devices may use either dielectric film or metal grating guide to couple the electron beam with the electromagnetic field. The guiding properties of the film are reviewed and a detailed discussion of the gain of a grating-based FEL operating near the zero-group-velocity point (the [open quote][pi] point[close quote]) ofmore »

- Authors:

- Publication Date:

- Research Org.:
- Dartmouth Coll., Hanover, NH (United States)

- OSTI Identifier:
- 7163434

- Alternate Identifier(s):
- OSTI ID: 7163434

- Resource Type:
- Miscellaneous

- Resource Relation:
- Other Information: Thesis (Ph.D.)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 42 ENGINEERING; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Ta; FREE ELECTRON LASERS; OPERATION; SCALING LAWS; CHERENKOV RADIATION; MATHEMATICAL MODELS; NONLINEAR OPTICS; ELECTROMAGNETIC RADIATION; LASERS; OPTICS; RADIATIONS 426002* -- Engineering-- Lasers & Masers-- (1990-); 661220 -- Particle Beam Production & Handling; Targets-- (1992-)

### Citation Formats

```
Jiang, W.
```*Nonlinear theory of a generic Cerenkov free-electron laser*. United States: N. p., 1992.
Web.

```
Jiang, W.
```*Nonlinear theory of a generic Cerenkov free-electron laser*. United States.

```
Jiang, W. Wed .
"Nonlinear theory of a generic Cerenkov free-electron laser". United States.
```

```
@article{osti_7163434,
```

title = {Nonlinear theory of a generic Cerenkov free-electron laser},

author = {Jiang, W.},

abstractNote = {In this thesis a generic nonlinear model of the slow-wave FEL is presented. Both the single-particle (low beam current density) and collective (high beam current density) operation regimes of the device are studied. In the single-particle regime the maximum efficiency scales roughly as L/[lambda][gamma][sup 4], while the saturation electric field scales approximately as L/[lambda][gamma][sup 3], where [gamma] = 1/[radical](1[minus](v/c)[sup 2]), L is the length of interaction region, and [lambda] is the wavelength. In the collective regime the maximum efficiency scales as [gamma]J1/3 [lambda] 2/3, and the saturation electric field scales as [gamma]J2/3 [lambda]1/3, where J is the current density. These scaling relationships are confirmed by numerical simulation. The transverse motion of the electrons in the presence and absence of a longitudinal magnetic guiding field is also examined and the results suggest that it is possible to operate the device down to moderate beam energy without a guiding field. The basic Cerenkov devices may use either dielectric film or metal grating guide to couple the electron beam with the electromagnetic field. The guiding properties of the film are reviewed and a detailed discussion of the gain of a grating-based FEL operating near the zero-group-velocity point (the [open quote][pi] point[close quote]) of the grating waveguide is included in the appendix.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {1992},

month = {1}

}