An X-band high-impedance relativistic klystron amplifier with an annular explosive cathode
- College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
The feasibility of employing an annular beam instead of a solid one in the X-band high-impedance relativistic klystron amplifier (RKA) is investigated in theory and simulation. Small-signal theory analysis indicates that the optimum bunching distance, fundamental current modulation depth, beam-coupling coefficient, and beam-loaded quality factor of annular beams are all larger than the corresponding parameters of solid beams at the same beam voltage and current. An annular beam RKA and a solid beam RKA with almost the same geometric parameters are compared in particle-in-cell simulation. Output microwave power of 100 MW, gain of 50 dB, and power conversion efficiency of 42% are obtained in an annular beam RKA. The annular beam needs a 15% lower uniform guiding magnetic field than the solid beam. Our investigations demonstrate that we are able to use a simple annular explosive cathode immersed in a lower uniform magnetic field instead of a solid thermionic cathode in a complicated partially shielding magnetic field for designing high-impedance RKA, which avoids high temperature requirement, complicated electron-optical system, large area convergence, high current density, and emission uniformity for the solid beam. An equivalent method for the annular beam and the solid beam on bunching features is proposed and agrees with the simulation. The annular beam has the primary advantages over the solid beam that it can employ the immersing uniform magnetic field avoiding the complicated shielding magnetic field system and needs a lower optimum guiding field due to the smaller space charge effect.
- OSTI ID:
- 22489872
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 11 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMPLIFIERS
BEAMS
CATHODES
CURRENT DENSITY
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
GEOMETRY
IMPEDANCE
KLYSTRONS
MAGNETIC FIELDS
MICROWAVE RADIATION
MODULATION
OPTICAL SYSTEMS
PLASMA SIMULATION
QUALITY FACTOR
RELATIVISTIC RANGE
SHIELDING
SPACE CHARGE
TEMPERATURE RANGE 0400-1000 K