Thomson Scattering of Coherent Diffraction Radiation by an Electron Bunch

The paper considers the process of Thomson scattering of coherent diffraction radiation (CDR) produced by the preceding bunch of the accelerator on one of the following bunches. It is shown that the yield of scattered hard photons is proportional to N$_e^3$, where N$_e$ is the number of electrons per bunch. A geometry is chosen for the CDR generation and an expression is obtained for the scattered photon spectrum with regard to the geometry used, that depends in an explicit form on the bunch size. A technique is proposed for measuring the bunch length using scattered radiation characteristics.Comment: 14 pages, LATEX, 6 ps.gz figures, submitted to Phys.Rev.

Maser-beam instability of Bernstein waves

The present study constitutes a continuation and improvement of the preceding work by Yoon et al. [J. Geophys. Res. 104, 19801 (1999)]. In the present discussion, an instability of Bernstein waves excited by a beam of energetic electrons is investigated. Special attention is paid to the regime where the ratio of plasma frequency, vpe , to electron gyrofrequency, Ve , is sufficiently higher than unity. An approximate but fairly accurate scheme is introduced to deal with the situation dictated by the condition, vpe 2 /Ve 2e1. The present investigation is motivated by the research in solar radiophysics. However, in this article the emphasis is placed on basic properties of the instability rather than its application