DocumentCode :
1066248
Title :
Initial studies of a long-pulse relativistic backward-wave oscillator utilizing a disk cathode
Author :
Hahn, Kelly ; Fuks, Mikhail I. ; Schamiloglu, Edl
Author_Institution :
Dept. of Electr. & Comput. Eng., New Mexico Univ., Albuquerque, NM, USA
Volume :
30
Issue :
3
fYear :
2002
fDate :
6/1/2002 12:00:00 AM
Firstpage :
1112
Lastpage :
1119
Abstract :
One of the major issues in high-power microwave device operation is pulse shortening, which often limits microwave pulses to less than 100 ns. This has been the focus of many studies on the long-pulse backward-wave oscillator (BWO) at the University of New Mexico. Previous diagnostics have indicated that significant plasma is produced by a graphite knife-edge or "cookie cutter" geometry cathode. This plasma caused the beam to expand radially to match the dimensions of the cutoff neck upon entrance into the slow-wave structure. This effect led to an impedance collapse at which point the microwave production ceased. In recent studies by Loza and colleagues, they have produced intense annular relativistic electron beams that maintain a stable cross section for 1-μs duration utilizing a disk cathode. Whereas the beams produced by Loza and colleagues were not used in microwave sources, we have incorporated such a disk cathode in a long-pulse relativistic BWO to study its effort on pulse shortening. This simple solution has led to an increase in pulselength and radiated microwave power up to a factor of two as compared to the "cookie cutter" cathode.
Keywords :
backward wave oscillators; cathodes; microwave generation; relativistic electron beam tubes; slow wave structures; cookie cutter geometry cathode; diagnostics; disk cathode; electron diode; graphite knife-edge cathode; high-power microwave device operation; high-power microwaves; intense annular relativistic electron beams; long-pulse relativistic BWO; long-pulse relativistic backward-wave oscillator; microwave production; microwave pulses; microwave sources; plasma; pulse shortening; slow-wave structure; Cathodes; Geometry; Impedance; Microwave devices; Microwave oscillators; Neck; Particle beams; Plasma devices; Plasma diagnostics; Production;
fLanguage :
English
Journal_Title :
Plasma Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0093-3813
Type :
jour
DOI :
10.1109/TPS.2002.801628
Filename :
1158346
Link To Document :
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