Field theory of a traveling wave tube amplifier with tape helix

Journal Article · Wed Dec 01 04:00:00 EST 1993 · IEEE Transactions on Plasma Science

DOI:https://doi.org/10.1109/27.256785· OSTI ID:142408

Freund, H P ^[1]; Vanderplaats, N R; Kodis, M A ^[2]

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1. Science Applications International Corp., McLean, VA (United States)
2. Naval Research Lab., Washington, DC (United States). Vacuum Electronics Branch

A self-consistent relativistic field theory of a helix traveling wave tube (TWT) is presented for a configuration in which a magnetized pencil beam propagates through a tape helix enclosed with a loss-free wall. A linear analysis of the interaction is solved subject to the boundary conditions imposed by the beam, helix, and wall. The wave equation for the fields within the electron beam corresponds to the Appleton-Hartree magneto ionic wave modes that are of mixed electrostatic/electromagnetic polarization. Hence, the determinantal dispersion equation that is obtained implicitly includes beam space-charge effects without recourse to a heuristic model of the space-charge field. This dispersion equation includes azimuthal variations and all spatial harmonics of the tape helix. Solutions are found numerically, which correspond to both the extraordinary (X) and ordinary (O) solutions for the Appleton-Hartree modes. Note that the O- and X-mode designations are more properly applied for waves propagating perpendicular to the ambient magnetic field in a uniform plasma. In the present case, the authors are interested in the modes propagating parallel to the ambient magnetic field in a bounded system in which an electron beam is enclosed by a tape helix and a conducting wall.

• OSTI ID: 142408
• Journal Information: IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 6 Vol. 21; ISSN ITPSBD; ISSN 0093-3813
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DISPERSION RELATIONS
FIELD THEORIES
MATHEMATICAL MODELS
MAXWELL EQUATIONS
NUMERICAL SOLUTION
TRAVELLING WAVE TUBES