A theory of cavity excitation by modulated electron beam in connection with application to a klystron amplifier

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860924· OSTI ID:7057440

Uhm, H S ^[1]; Park, G S; Armstrong, C M ^[2]

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1. Naval Surface Warfare Center, 10901 New Hampshire Ave., White Oak, Silver Spring, Maryland 20903-5640 (United States)
2. Naval Research Laboratory, 4555 Overlook Ave. S. W., Washington, D.C. 20375 (United States)

Based on an equivalent circuit representation of a cavity impedance, a theoretical model of the cavity excitation by a modulated electron beam is developed. The beam current modulation is initiated by the first cavity and amplified in drift section between the first and second cavities. Properties of the second cavity excitation by the beam are described in terms of the phase shift [Psi] and amplitude [phi][sub 2] of induced voltage in the cavity. The phase shift [Psi] and amplitude [phi][sub 2] are determined in terms of the frequency difference ([eta]), the cavity [ital Q] value, the voltage multiplication factor ([chi]), and magnitude ([phi][sub 1]) of the first cavity voltage. The voltage multiplication factor is proportional to the beam intensity, [ital Q] value, and distance between the first and second cavities. On the other hand, it is inversely proportional to frequency and capacitance of the cavity, and beam electron velocity. Because the induced voltage in the second cavity is in phase with the first cavity voltage at upshifted cavity frequency, amplitude of the current modulation at the upshifted frequency is larger than that at the downshifted cavity frequency. Experimental study is carried out by making use of a klystron amplifier operable from 4.4 to 5 GHz. Experimental data from the klystron agree remarkably well with amplifier performance profiles predicted by the theory.

• OSTI ID: 7057440
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:4; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700350* -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
AMPLIFIERS
BEAMS
CAVITIES
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
EXCITATION
KLYSTRONS
LEPTON BEAMS
MICROWAVE EQUIPMENT
MICROWAVE RADIATION
MICROWAVE TUBES
MODULATION
PARTICLE BEAMS
PHASE SHIFT
PLASMA
RADIATIONS
RELATIVISTIC PLASMA
RELATIVISTIC RANGE