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Title: High-power microwave production by gyroharmonic conversion and co-generation

Abstract

An rf accelerator that adds significant gyration energy to a relativistic electron beam, and mechanisms for extracting coherent radiation from the beam, are described. The accelerator is a cyclotron autoresonance accelerator (CARA), underlying theory and experimental tests of which are reviewed. The measurements illustrate the utility of CARA in preparing beams for high harmonic gyro interactions. Examples of preparation of gyrating axis-encircling beams of {approximately}400kV, 25 A with 1{lt}a{lt}2 using a 2.856 GHz CARA are discussed. Generation of MW-level harmonic power emanating from a beam prepared in CARA into an output cavity structure is predicted by theory. First measurements of intense superradiant 2nd through 6th harmonic emission from a CARA beam are described. Gyroharmonic conversion (GHC) at MW power levels into an appropriate resonator can be anticipated, in view of the results described here. Another radiation mechanism, closely related to GHC, is also described. This mechanism, dubbed {open_quotes}co-generation,{close_quotes} is based on the fact that the lowest TE{sub sm} mode in a cylindrical waveguide at frequency sw with group velocity nearly identical to group velocity for the TE{sub 11} mode at frequency w is that with s=7, m=2. This allows coherent radiation to be generated at the 7th harmonic co-existent withmore » CARA and in the self-same rf structure. Conditions are found where co-generation of 7th harmonic power at 20 GHz is possible with overall efficiency greater than 80{percent}. It is shown that operation of a cw co-generator can take place without need of a power supply for the gun. Efficiency for a multi-MW 20 GHz co-generator is predicted to be high enough to compete with other sources, even after taking into account the finite efficiency of the rf driver required for CARA. {copyright} {ital 1997 American Institute of Physics.}« less

Authors:
 [1]; ;  [2];  [1];  [2];  [1];  [3]
  1. Omega-P, Inc., 202008 Yale Station, New Haven, Connecticut 06520 (United States)
  2. Physics Department, Yale University, New Haven, Connecticut 06511 (United States)
  3. Omega-P, Inc., 202008 Yale Station, New Haven, Connecticut 06520 (United States) [Physics Department, Yale University, New Haven, Connecticut 06511 (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
587027
Report Number(s):
CONF-9610281-
Journal ID: APCPCS; ISSN 0094-243X; TRN: 98:004469
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 398; Journal Issue: 1; Conference: 7. advanced accelerator concepts workshop, Lake Tahoe, NV (United States), Oct 1996; Other Information: PBD: Mar 1997
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; LINEAR COLLIDERS; RF SYSTEMS; DESIGN; PERFORMANCE; GHZ RANGE 01-100; POWER RANGE 100-1000 MW; ELECTRON BEAMS; HARMONIC GENERATION; EFFICIENCY; MICROWAVE AMPLIFIERS; KLYSTRONS

Citation Formats

LaPointe, M.A., Yoder, R.B., Wang, M., Ganguly, A.K., Wang, C., Hafizi, B., and Hirshfield, J.L. High-power microwave production by gyroharmonic conversion and co-generation. United States: N. p., 1997. Web. doi:10.1063/1.53033.
LaPointe, M.A., Yoder, R.B., Wang, M., Ganguly, A.K., Wang, C., Hafizi, B., & Hirshfield, J.L. High-power microwave production by gyroharmonic conversion and co-generation. United States. doi:10.1063/1.53033.
LaPointe, M.A., Yoder, R.B., Wang, M., Ganguly, A.K., Wang, C., Hafizi, B., and Hirshfield, J.L. Sat . "High-power microwave production by gyroharmonic conversion and co-generation". United States. doi:10.1063/1.53033.
@article{osti_587027,
title = {High-power microwave production by gyroharmonic conversion and co-generation},
author = {LaPointe, M.A. and Yoder, R.B. and Wang, M. and Ganguly, A.K. and Wang, C. and Hafizi, B. and Hirshfield, J.L.},
abstractNote = {An rf accelerator that adds significant gyration energy to a relativistic electron beam, and mechanisms for extracting coherent radiation from the beam, are described. The accelerator is a cyclotron autoresonance accelerator (CARA), underlying theory and experimental tests of which are reviewed. The measurements illustrate the utility of CARA in preparing beams for high harmonic gyro interactions. Examples of preparation of gyrating axis-encircling beams of {approximately}400kV, 25 A with 1{lt}a{lt}2 using a 2.856 GHz CARA are discussed. Generation of MW-level harmonic power emanating from a beam prepared in CARA into an output cavity structure is predicted by theory. First measurements of intense superradiant 2nd through 6th harmonic emission from a CARA beam are described. Gyroharmonic conversion (GHC) at MW power levels into an appropriate resonator can be anticipated, in view of the results described here. Another radiation mechanism, closely related to GHC, is also described. This mechanism, dubbed {open_quotes}co-generation,{close_quotes} is based on the fact that the lowest TE{sub sm} mode in a cylindrical waveguide at frequency sw with group velocity nearly identical to group velocity for the TE{sub 11} mode at frequency w is that with s=7, m=2. This allows coherent radiation to be generated at the 7th harmonic co-existent with CARA and in the self-same rf structure. Conditions are found where co-generation of 7th harmonic power at 20 GHz is possible with overall efficiency greater than 80{percent}. It is shown that operation of a cw co-generator can take place without need of a power supply for the gun. Efficiency for a multi-MW 20 GHz co-generator is predicted to be high enough to compete with other sources, even after taking into account the finite efficiency of the rf driver required for CARA. {copyright} {ital 1997 American Institute of Physics.}},
doi = {10.1063/1.53033},
journal = {AIP Conference Proceedings},
number = 1,
volume = 398,
place = {United States},
year = {Sat Mar 01 00:00:00 EST 1997},
month = {Sat Mar 01 00:00:00 EST 1997}
}