Abstract
Smith-Purcell radiation is a well-known phenomenon, which provides a noninvasive scheme for diagnostics of charged particle beams and is used as an effective source of electromagnetic waves, e.g., in the orotron, the free electron laser, etc. In this paper we develop the theory of Smith-Purcell radiation (SPR) for the little-investigated case of arbitrary angles between the charged particle trajectories and the rulings of a grating. The effect of conical diffraction arising here changes drastically the space distribution of the radiation. By contrast to the only existing approach, described by Haeberle et al. [Phys. Rev. E 55, 4675 (1997)], which requires difficult numerical calculations, we give a fully analytic theory of SPR. Also, in this paper we present for the first time the theory of x-ray Smith-Purcell radiation. Evanescent waves on the surface are shown to lead to strong enhancement of Smith-Purcell radiation, through a resonant mechanism. The results are important for the description of real divergent high-brightness beams and for the development of novel noninvasive diagnostic schemes based on the Smith-Purcell effect.
Highlights
There are two main ways for charged particles to radiate: first, when the particle changes its velocity in an external field
We talk about the widely known Cherenkov and transition radiations, and about diffraction radiation (DR), about Smith-Purcell radiation (SPR), a special case of DR for targets with periodical surface [1,2], and about parametric x-ray radiation (x-ray radiation of a charged particle moving in a crystal with constant velocity: see, e.g., [3])
Polarization-type interactions of particles with matter can be a good source of electromagnetic radiation [3,4,5], including free electron lasers based on SPR [6], but is especially useful for beam diagnostics [2,7]
Summary
There are two main ways for charged particles to radiate: first, when the particle changes its velocity in an external field. The principal approaches were developed by: (i) van den Berg ([10]: seminumerical, demands difficult numerical calculations); (ii) Shestopalov ([9]: very complicated mathematically, suitable for nonrelativistic beams mainly); (iii) Brownell, Doucas and others ([11]: physically clear and simple, valid mainly for ideally conductive gratings); (iv) Potylitsyn ([2,12], based on results of Kazantsev and Surdutovich for DR [13], only for ideally conductive gratings); (v) Karlovets ([14], the most general theory at present, valid for arbitrary dielectric properties of a target; it requires further development and comparison with experimental data). The second situation when oblique incidence can play a vital part arises in (e) the case of a few directions of periodicity, as happens in periodical structures like 2D and z k0
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Physical Review Special Topics - Accelerators and Beams
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
