ABSTRACT
In this chapter, we first review the theory of wave propagation in vacuum, including focusing and diffraction; the interaction of relativistic electrons with such waves is then studied in some detail, and the phenomenon of ponderomotive scattering is described. We also turn our attention to vacuum laser acceleration processes, including the inverse free-electron laser (IFEL) interaction and free-wave acceleration in the presence of a dephasing static magnetic field. Such novel acceleration techniques offer the potential to reach extremely high accelerating gradients, well in excess of 1 GeV
/
m, which represents an upper bound for conventional rf acceleration technology, as described in the proceedings of the 1998 High Energy Density Microwaves workshop, which is cited in the references to this chapter. We also note that there are concurrent plasma-based schemes pursued around the world, including plasma beatwave and wakefield acceleration that have demonstrated promising gradients; some of this work is also cited in the bibliography. The current state of the art in laser-plasma acceleration and other exotic schemes is ably summarized in the proceedings of the 1996, 1998, and 2000 Advanced Accelerator Concept (AAC) workshops and the 1997 and 1999 Particle Accelerator Conference (PAC), which are listed in the reference section. The proceedings of the workshop on quantum aspects of beam physics, will also prove very useful to the interested reader, and we have listed these as well.
