Time-dependent simulation of helix traveling wave tubes
| Autor: | H. P. Freund, E. G. Zaidman |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Physics of Plasmas. 7:5182-5194 |
| ISSN: | 1089-7674 1070-664X |
| DOI: | 10.1063/1.1319338 |
| Popis: | A time-dependent nonlinear analysis of a helix traveling wave tube (TWT) is presented for a configuration where an electron beam propagates through a three-dimensional tape helix surrounded by a conducting wall. The effects of dielectric- and vane-loading are included as is efficiency enhancement by tapering the helix pitch and external focusing by means of either a uniform solenoidal magnetic field or a periodic field produced by a periodic permanent magnet stack. Dielectric-loading is described under the assumption that the gap between the helix and the wall is uniformly filled by a dielectric material. Vane-loading describes the insertion of an arbitrary number of vanes running the length of the helix. The electromagnetic field is represented as a superposition of waves in a vacuum tape helix. The propagation of each wave as well as the interaction of each wave with the electron beam is included by allowing the amplitudes of the waves to vary in z and t. The field equations are solved in conjunction with the three-dimensional Lorentz force equations for an ensemble of electrons. Collective effects are included by both a finite-difference grid formulation of Poisson’s equation and an analysis based upon a modal superposition of solutions of the Helmholtz equation. The time-dependent simulation is compared with a steady-state simulation for a model corresponding to a TWT built at Northrop–Grumman Corporation. |
| Databáze: | OpenAIRE |
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