Mode competition in fourth-harmonic magnicon amplifiers

Journal Article · Sat Jun 01 00:00:00 EDT 1996 · IEEE Transactions on Plasma Science

DOI:https://doi.org/10.1109/27.533101· OSTI ID:377858

Fliflet, A W; Gold, S H ^[1]

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1. Naval Research Lab., Washington, DC (United States)

The magnicon is under development as an efficient high-power microwave amplifier for powering the next generation of electron accelerators for high-energy physics research. In the magnicon RF amplifier, the drive and gain cavities are cylindrical deflection cavities which operate in a rotating TM{sub 110}-mode and spin up an electron beam to high transverse momentum. As a result of the rotating-mode interaction, the electron beam entry point into the output cavity rotates about the axis at the drive frequency. The gyrotron-like output cavity can be operated at m times the drive frequency by using a mode with an azimuthal index of m, as this mode rotates at m{sup {minus}1} times its RF frequency, thus maintaining synchronism with the electron beam. Previous frequency-multiplying magnicons have used m = 2; in this paper it is shown that magnicons with m = 4 may be practical, provided one also operates the output cavity at the m/2 harmonic of the cyclotron frequency. Operation at higher harmonics lowers the frequency of the deflection cavities allowing lower RF fields, reducing magnet cost and complexity; and a larger electron beam, relaxing beam quality constraints. On the other hand, higher order azimuthal-index magnicon modes interacting at higher order cyclotron interactions are subject to competition with nonsynchronous (gyrotron) modes and are more sensitive to electron beam scanning angle spread. A time-dependent multimode gyrotron code has been modified to examine competition in the output cavity between the phase-synchronous operating mode and other nonsynchronous modes which interact via the conventional gyrotron interaction.

• DOE Contract Number: AI02-94ER40861
• OSTI ID: 377858
• Journal Information: IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 3 Vol. 24; ISSN ITPSBD; ISSN 0093-3813
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
CAVITY RESONATORS
COMPUTERIZED SIMULATION
FREQUENCY MIXING
MICROWAVE AMPLIFIERS
OSCILLATION MODES
RF SYSTEMS