[Table of Contents]

Plasma and Fusion Research

Volume 3, S1020 (2008)

Regular Articles

Instability Driven by a Finitely Thick Annular Beam in a Dielectric-Loaded Cylindrical Waveguide
Shusuke TAMURA, Mitsuhisa YAMAKAWA, Yusuke TAKASHIMA and Kazuo OGURA
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
(Received 16 November 2007 / Accepted 11 March 2008 / Published 1 August 2008)

Abstract

The cherenkov and slow cyclotron instabilities driven by an axially injected electron beam in a cylindrical waveguide are studied using a new version of the self-consistent linear theory considering three-dimensional beam perturbations. There are three kinds of models for beam instability analysis, which are based on a cylindrical solid beam, an infinitesimally thin annular beam, and a finitely thick annular beam. Among these models, the beam shape properly representing the often used actual annular electron beams is the finitely thick annulus. We develop a numerical code for a cylindrical waveguide with a finitely thick annular beam. Our theory is valid for any beam velocity. We present eigen-modes of the cylindrical system with the plasma and beam. Instabilities driven by the annular beam in a dielectric-loaded waveguide are also examined.

Keywords

annular beam, finite thickness, low-frequency surface wave mode, high-frequency surface wave mode, Cherenkov instability, slow cyclotron instability

DOI: 10.1585/pfr.3.S1020

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References

  • [1] A.S. Gilmour, Jr., Principles of Traveling Wave Tubes (Artech House, Boston, 1994) P.233.
  • [2] R.J. Barker and E. Schamiloglu eds, High-Power Microwave Sources and Technologies (IEEE Press, New York, 2001) P.284.
  • [3] O. Watanabe et al., Phys. Rev. E. 63, 056503 (2001).
  • [4] K. Ogura et al., Jpn. J. Appl. Phys. 42, 7095 (2003).
  • [5] J.R. Pierce, Traveling-Wave Tube (Van Nostrand, Toronto, 1950) P.168.
  • [6] K. Ogura et al., J. Plasma Phys. 72, 905 (2006).
  • [7] H. Yamazaki et al., IEEJ Trans. FM 125, 739 (2005).
  • [8] Y. Kiuchi et al., Trans. Fusion Sci. Technol. 51, 331 (2007).

This paper may be cited as follows:

Shusuke TAMURA, Mitsuhisa YAMAKAWA, Yusuke TAKASHIMA and Kazuo OGURA, Plasma Fusion Res. 3, S1020 (2008).