Analysis of a Broadband Cerenkov Amplifier.
Abstract
In the past several years, there has been widespread interest in a variety of wave generation devices based on un-neutralized beams of relativistic or mildly relativistic electrons. Such devices are potentially capable of producing high power, with high efficiency, in the centimeter, millimeter, and sub-millimeter spectral ranges. An example is the electron cyclotron maser, which has produced approximately 100 kW at centimeter wavelengths, with efficiencies ranging from 30% - 50%. The gyrotron mechanism involves azimuthal phase bunching of the electron beam, which occurs during resonant interaction of the Doppler-shifted beam cyclotron mode with a waveguide or cavity mode. The bandwidth of the gyrotron mechanism is typically of order 1-2%. For various military and communications applications, it could be of great interest to develop free-electron amplifiers with wide operating bandwidths. In this report, we present a linear analysis of a new principle for wideband amplification. The basic configuration is the use of an annular electron beam drifting in a dielectrically-loaded waveguide. In such a waveguide, the normal guide modes have phase velocities asymptotic of the speed of light the square root of the dielectric constant. The system is assumed to be immersed in an axial magnetic field sufficiently strong to render the motion of the beam electrons one-dimensional. In this case, the amplification mechanism depends on axial charge bunching in the Cerenkov interaction of a longitudinal space-charge wave of the beam with the Ez - component of a TM guide mode.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 06, 1980
- Accession Number
- ADA100628
Entities
People
- John Vomvoridis
- Robert W. Smith