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US 4,362,968 AGranted
Slow-wave wideband cyclotron amplifier
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsKwo R. Chu, Phillip A. Sprangle, Victor L. Granatstein
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Abstract
A slow-wave, cyclotron-type, travelling-wave-tube amplifier in which the m-wave interaction is the result of a Weibel-type instability. The travelling wave is slowed down in its propagation through the waveguide by a dielectric liner located on the inner wall of the waveguide. The bunching mechanism is the result of the V.sub..perp. .times.B.sub..perp. Lorentz force.
Claims8
A gyrotron travelling wave amplifier comprising:
- wave-launching means for launching a wave;
- beam producing means for forming an annular beam of electrons propagating along a path with velocity V.sub.z ;
- a dielectric lined slow-wave structure for slowing the group velocity, V.sub.g, of the wave so that V.sub.z .times.V.sub.g wherein V.sub.g is constant over a wide frequency range;
- said slow wave structure being coupled to said wave launching means and said beam producing means so that said wave and said beam co-propagate within said slow wave structure, and wherein said wave interacts with and is amplified by said electron beam;
- and
- means for generating a magnetic field B, within said slow wave structure, for causing cyclotronic motion of the electrons in said beam wherein the magnitude, B.sub.o, of said magnetic field is adjusted so that the interaction between said wave and said beam is due to electron bunching caused by the V.sub..perp. .times.B.sub..perp. Lorentz force, where V.sub..perp. is the traverse velocity of an electron in said electron beam and B.sub..perp. is the magnetic field of said wave.
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A method of amplifying a wave in a gyrotron traveling wave amplifier dielectric lined waveguide comprising:
- launching a wave, with magnetic field B.sub..perp. and group velocity V.sub.g, into the waveguide;
- injecting an annular electron beam into the waveguide wherein the beam velocity is V.sub.z ;
- slowing the wave in the waveguide so that V.sub.g =V.sub.z ;
- generating a magnetic field, B.sub.o, about said electron beam wherein the cyclotron frequency of the electrons in said electron beam is determined by B.sub.o ;
- and adjusting the amplitude of B.sub.o so that the wave is amplified by the beam due to bunching caused by the V.sub..perp. .times.B.sub..perp. Lorentz force where V.sub..perp. is the transverse velocity of the electrons in the beam.
2 more elements
Dependencies are inferred from the claim text.