Characteristics of Magnetically Focused Large-Signal Traveling-Wave Amplifiers.
MICHIGAN UNIV ANN ARBOR ELECTRON PHYSICS LAB
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This is an investigation of the performance of magnetically focused traveling-wave amplifiers directed toward obtaining a better understanding of the physical phenomena involved in the interaction, and to determine what optimization measures can be employed. A generalized two-dimensional nonlinear interaction theory is presented that describes the electron-wave interaction process. A Lagrangian formulation is used in which the electron beam is modeled in terms of axisymmetric charge rings which are allowed to move both axially and radially in response to the r-f circuit field, space-charge field and static magnetic field. Greens function techniques are employed to evaluate the space-charge field. Magnetic focusing fields which are periodic or tapered increased with distance along the device are considered in addition to the uniform magnetic field. The general interaction equations constitute a system of nonlinear integro-differential equations which are valid for traveling-wave amplifiers. The equations are systematically reduced by obtaining closed-form solutions where possible, and introducing appropriate simplifying approximations. These solutions are presented and discussed for a variety of operating conditions. A traveling-wave amplifier which employs a uniform magnetic focusing field was built in order to obtain some correlative experimental evidence. Excellent quantitative agreement was obtained with the predictions of the general theory. Author
- Electrical and Electronic Equipment