Proposal for a IR waveguide SASE FEL at the PEGASUS injector

UCLA - Department of Physics & Astronomy, 405 Hilgard Ave., Los Angeles, CA 90095-1444, USA
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (Impact Factor: 1.14). 01/2001; DOI: 10.1016/S0168-9002(01)01634-5
Source: IEEE Xplore

ABSTRACT Free Electron Lasers up to the visible regime are dominated by diffraction effects, resulting in a radiation size much larger than the electron beam. Thus the effective field amplitude at the location of the electron beam, driving the FEL process, is reduced. By using a waveguide, the radiation field is confined within a smaller aperture and an enhancement of the FEL performance can be expected. The PEGASUS injector at UCLA will be capable to provide the brilliance needed for an IR SASE FEL. The experiment Power Enhanced Radiation Source Experiment Using Structures (PERSEUS) is proposed to study the physics of a waveguide SASE FEL in a quasi 1D environment, where diffraction effects are strongly reduced as it is the case only for future FELs operating in the VUV and X-ray regime. The expected FEL performance is given by this presentation.

  • 01/1993; Wiley.
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    ABSTRACT: This is a revision of a book first published in 1960. As the revision is considerable and there has been a considerable increase in content, the book will be reviewed anew. Although numerical analysis of electromagnetic problems has developed considerably, the author feels that these depend on analytical techniques. Consequently there is little numerical content here, the stress being on the analytical approach. This is a long book and it is perhaps best to indicate what some of the most interesting contents are. There are eleven chapters. In the first, the author sets out the principles of electromagnetic theory as developed from Maxwell’s equations and comments on the niceties of dealing with corners. He also discusses the work of Babinet, Love, and Schelkunoff. The second chapter is concerned with Green’s functions. In this chapter there is a treatment of both scalar and dyadic functions, a discussion of the relation between eigenfunctions and modes, and a brief introduction to distribution theory. The third chapter is entitled Transverse Electromagnetic Waves. In this one the ideas of wave matrices are introduced, the differences between group, signal, phase, wavefront, and energy transport velocities are explained, and propagation in some more complicated types (anisotropic, ferrite, layered) of media is discussed. The next chapter introduces transmission line theory and indicates the possible use of methods such as conformal mapping, integral equations, and variational principles. The fifth chapter is concerned with waveguide theory. The usefulness of transmission line theory is pointed out leading to equivalent circuit representation of discontinuities. The coupling of modes and the modifications of classic waveguide theory caused by lossy walls are also treated. The subsequent chapter extends the previous one to the case of inhomogeneously filled waveguides and resonators. The ideas of longitudinal section electric and magnetic modes are introduced, and the application there of Rayleigh-Ritz techniques is discussed, together with a variational approach to ferrite filled guides. The seventh chapter deals with the ways in which fields may be excited in waveguides and cavities. In this chapter, topics such as probe impedance, radiation reaction fields, and coupling by small apertures are referred to. There is also a short treatment of transients in waveguides. The subsequent chapter gives an account of the use of variational methods for the discussion of waveguide discontinuities, much of which is due to Schwinger. Various iris problems are treated and there is a short reference to the general theory of scattering by obstacles in waveguides. The remainder of the book is concerned with a number of miscellaneous topics. The ninth chapter indicates how periodic waveguide structures can be represented by a set of lossless quadrupoles in a circuit and there is a discussion of matching. There is also a reference to an approximate theory for dealing with propagation along a sheath helix, a problem for which no exact solution is yet known. The next chapter brings in the ideas of Fourier/Laplace transforms and Wiener-Hopf problems such as those associated with bifurcation in a waveguide and an infinite array of parallel plates. The eleventh chapter is concerned with surface waveguides wherein the author discusses topics such as Zenneck waves, dielectric slabs and corrugated plates. The final chapter on artificial dielectrics involves Lorentz and Clausius-Mossotti theory. A variety of different shapes of obstacle elements are considered. The text closes with a mathematical appendix which provides the pure mathematical basis for many of the methods used in the main portion of the book. This is a book of fundamental importance and can be said to summarize the state of the art at the time of its publication. Each chapter is followed by a list of references (nearly 500 in all – practically all in English language) and examples (nearly 200 in all). The standard of printing is high and the style is easy, the arguments being generally uncondensed. The price is, for the size of the work, reasonable. Indeed, it could serve well as a textbook for an advanced course on waveguides. This book will be a necessity in all places where waveguides are a matter of importance.
    01/1991; IEEE Press.

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