Dyunin, E.

Paper	Title	Page
MOAAU01	FEL Prize Lecture: Coherent Electron-Beam Radiation Sources and FELs: A Theoretical Overview	1
	A. Gover, E. Dyunin University of Tel-Aviv, Faculty of Engineering, Tel-Aviv
	The theory of Coherent electron beam radiation devices in general, and FEL in particular, is reviewed in terms of a general simple formulation based on modal expansion of the radiation field. A variety of e-beam radiation mechanisms (FEL, TWT, Cerenkov Radiation) have common features. All these radiation mechanisms can emit coherent or partially coherent radiation by means of three basic kinds of radiation processes: Spontaneous emission (shot-noise radiation), Superradiance (bunched-beam coherent radiation) and Stimulated emission. The common radiation processes and their relations are explained, in both frequency and time domains, in terms of the radiation modes expansion formulation. It is shown that the coherence properties of the emitted radiation, in each radiation process, depend on the phase relations between the radiation wave-packets, emitted by the individual electrons and their entrance distribution statistics. In the high gain linear regime all these radiation mechanisms satisfy the Pierce dispersion equation, and all radiation characteristics are derived from the Pierce transfer functions. I employ the formulation to delineate limits of coherence of electron beam radiation sources, and particularly examine possible schemes for turning SASE FELs to operate as coherent radiation sources.
	Slides
	Talk
TUPPH019	Present Status of the Israeli FEL: Increasing FEL Power by Electron Beam Energy Boosting	352
	Y. Socol, E. Dyunin, A. Gover, M. Volshonok University of Tel-Aviv, Faculty of Engineering, Tel-Aviv M. Einat, Yu. Lurie, Y. Pinhasi, A. Yahalom CJS, Ariel
	The status of R&D work aimed on increasing FEL power by boosting the electron beam energy after the radiation build-up is reported. A fine control of the electron beam energy during the radiation pulse is designed to compensate the small energy degradation during the pulse. Also, a controlled ramp (up or down) in the electron energy during the pulse will be applicable as well. Theoretical estimations of the output power in the presence of electron energy change during the pulse compared to the obtained experimental results are presented. 2 models, showing good agreement between them and with the existing data, are compared: low-gain analytical model based on the pendulum equation, and rigorous 3D FEL interaction model solved numerically. Another expected result of the design is to further extend the pulse duration with stable conditions and to obtain improved coherency. The electrical and mechanical lay-outs of the high-voltage boosting (leading to electron beam energy boosting) are also presented.