Nonlinear analysis of the Cerenkov maser

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859515· OSTI ID:6379728

Freund, H P; Ganguly, A K ^[1]

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1. Naval Research Laboratory, Washington, DC (USA)

The nonlinear evolution of the Cerenkov maser amplifier is investigated numerically for a configuration that consists of an energetic electron beam propagating through a dielectric-lined cylindrical waveguide. An axial guide magnetic field is included in the formulation in order to improve beam confinement. A set of coupled nonlinear differential equations is derived in three dimensions that governs the evolution of both the electromagnetic field and the trajectories of an ensemble of electrons. The system is assumed to be azimuthally symmetric, and the electromagnetic field is represented as a superposition of the TM{sub 0{ital n}} modes of the vacuum waveguide. The initial conditions are chosen to model the simultaneous injection of either a solid or annular electron beam, and an electromagnetic wave of arbitrary input power. Thermal effects are treated under the assumption that the beam is {ital initially} monoenergetic but exhibits a pitch angle spread; however, the subsequent evolution of the beam is treated in a self-consistent manner. This class of distribution is appropriate to the treatment of diode-produced beams and describes a beam with an initial axial energy spread. This is the crucial determinant in the efficiency, since saturation occurs by means of an axial bunching mechanism that results in the phase trapping of the beam. The specific parameters used in the numerical analysis correspond to experiments conducted at Dartmouth College (J. Appl. Phys. {bold 58}, 627 (1985)), and good agreement is found between theory and experiment.

• OSTI ID: 6379728
• Journal Information: Physics of Fluids B; (USA), Vol. 2:10; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
MASERS
NONLINEAR PROBLEMS
AMPLIFICATION
AMPLIFIERS
AZIMUTH
CHERENKOV RADIATION
COUPLING
CYLINDERS
DIELECTRIC MATERIALS
DIFFERENTIAL EQUATIONS
EFFICIENCY
MAGNETIC FIELDS
NUMERICAL SOLUTION
SIMULATION
SYMMETRY
TEMPERATURE EFFECTS
THREE-DIMENSIONAL CALCULATIONS
WAVEGUIDES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUATIONS
EQUIPMENT
MATERIALS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
RADIATIONS
426002* - Engineering- Lasers & Masers- (1990-)