A free electron laser experiment on "angular steering"

Author

Cecere, M. ; Marshall, T.C.

Author_Institution

Dept. of Appl. Phys., Columbia Univ., New York, NY, USA

Volume

22

Issue

5

fYear

1994

fDate

10/1/1994 12:00:00 AM

Firstpage

654

Lastpage

658

Abstract

A paper by Jerby (1990) has discussed a number of mechanisms whereby FEL radiation may be directed electronically into different radiation patterns. We have devised an experiment (1992) to test this concept using the Columbia microwave FEL, which amplifies radiation at 24 GHz to a level <1 MW. A 4 mm dia, electron beam (580 kV) is propagated in a guiding field of 0.8 T inside an overmoded 24 mm dia. cylindrical waveguide. A TE11 mode is grown in a 33 cm long first undulator section (period 3.36 cm), and upon entering the following undulator section (period 2.26 cm, length 40 cm), the electron bunches convert to TM11 radiation which is further amplified. The far-field pattern of the TM11 emitted power is distinct from the TE11 pattern. Numerical and experimental studies are described in this paper showing the resulting radiation pattern.

Keywords

circular waveguides; digital simulation; free electron lasers; laser beams; laser modes; microwave generation; physics computing; undulator radiation; 1 MW; 2.26 cm; 24 GHz; 24 mm; 3.36 cm; 33 cm; 40 cm; 580 kV; Columbia microwave FEL; TE11 mode; TM11 radiation; angular steering; cylindrical waveguide; far-field pattern; free electron laser experiment; guiding field; radiation patterns; undulator section; Antenna radiation patterns; Electron beams; Free electron lasers; Frequency; Laser modes; Microwave propagation; Plasma waves; Power lasers; Testing; Undulators;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.338279

Filename

338279