Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-27T13:46:53.412Z Has data issue: false hasContentIssue false

Upper bound for the space-charge limiting current of annular electron beams

Published online by Cambridge University Press:  13 March 2009

T. C. Genoni
Affiliation:
Air Force Weapons Laboratory, Kirtland Air Force Base, New Mexico 87117
W. A. Proctor
Affiliation:
Air Force Weapons Laboratory, Kirtland Air Force Base, New Mexico 87117

Abstract

We report here on a two-dimensional analytical calculation of an upper bound on the space-charge limiting current for a relativistic electron beam in cylindrical geometry. Voronin and co-workers have previously obtained an analytical estimate for the maximum steady-state current that can be propagated in a solid, unneutralized electron beam which completely fills a drift tube immersed in an infinite magnetic guide field. We generalize their method to include annular beams of arbitrary thickness and length, specifying a rigorous upper bound on the limiting current in terms of an eigenvalue of Bessel' s differential equation and separated, homogeneous boundary conditions of the most general form. For the special cases of a thin solid beam in a drift tube of infinite length and a thin annular beam in a drift tube of finite length, we find closed-form analytical expressions for the upper bound which are in good agreement with numerical solutions for the actual space-charge limiting current.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1980

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Birkoff, G. & Rota, G. 1962 Ordinary Differential Equations. Ginn.Google Scholar
Bogdankevich, L. S. & Rukhadze, A. A. 1971 Soviet Phys. Uspekhi, 14, 163.Google Scholar
Brejzman, B. N., & Ryutov, D. D. 1974 Nucl. Fusion, 14, 873.Google Scholar
Genoni, T. C. & Proctor, W. A. 1977 Bull. Am. Phys. Soc. 22, 1085.Google Scholar
Haeff, A. V. 1939 Proc. I.R.E. 27, 586.Google Scholar
Reiser, M. 1977 Phys. Fluids, 20, 477.Google Scholar
Smith, L. P. & Hartman, P. L. 1940 J. Appl. Phys. 11, 220.CrossRefGoogle Scholar
Thode, L. E., Godfrey, B. B. & Shanahan, W. R. 1979 Phys. Fluids, 22, 747.Google Scholar
Thompson, J. R. & Sloan, M. L. 1978 Phys. Fluids, 21, 2032.Google Scholar
Voronin, V. S., Zozulaya, Yu. T. & Lebedev, A. N. 1972 Soviet Phys. Tech. Phys. 17, 432.Google Scholar