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Author Johnston, G. L. ♦ Davidson, R. C.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ENGINEERING ♦ ELECTRON BEAMS ♦ BEAM OPTICS ♦ FREE ELECTRON LASERS ♦ KINETIC EQUATIONS ♦ BOLTZMANN-VLASOV EQUATION ♦ KINETICS ♦ MAGNETIC FIELDS ♦ RELATIVISTIC RANGE ♦ BEAMS ♦ DIFFERENTIAL EQUATIONS ♦ ENERGY RANGE ♦ EQUATIONS ♦ LASERS ♦ LEPTON BEAMS ♦ PARTIAL DIFFERENTIAL EQUATIONS ♦ PARTICLE BEAMS ♦ Engineering- Lasers- (-1989)
Abstract This paper extends the development of a self-consistent kinetic description of helically distorted relativistic electron beam equilibria for free electron laser applications to include particular conditions of beam propagation, not treated heretofore, which are of considerable practical interest. Radially confined equilibria are considered for a helically distorted electron beam propagating in the combined transverse wiggler and uniform axial guide fields described by B/sup 0/ = B/sub 0/e/sub z/ +deltaB = B/sub 0/e/sub z/-deltaB cos k/sub 0/z e/sub x/ -deltaB sin k/sub 0/ze/sub y/, where B/sub 0/ = const., deltaB = const., and lambda/sub 0/ = 2..pi../k/sub 0/ = const. is the axial wavelength of the wiggler field. It is assumed that the beam density and current are sufficiently small that the equilibrium self fields can be neglected in comparison with B/sup 0/. In this context, it is found that there are three useful (and exact) invariants (C/sub perpendicular/, C/sub h/, C/sub z/) associated with single-particle motion in the equilibrium field B/sub 0/e/sub z/ +deltaB. These invariants are used to construct radially confined Vlasov equilibria F/sup 0//sub b/ (C/sub perpendicular/, C/sub h/, C/sub z/) for an intense relativistic electron beam propagating in the z direction. Examples of both solid and hollow beam equilibria are considered, and it is shown that the transverse wiggler field can have a large modulational influence on the beam envelope, depending on the size of deltaB/B/sub 0/ and other parameters.
Educational Use Research
Learning Resource Type Article
Publisher Date 1984-03-01
Publisher Department Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Publisher Place United States
Journal J. Appl. Phys.
Volume Number 55
Issue Number 5
Organization Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139


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