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arXiv · 1105.0412

On Free-Electron Laser Growing Modes and their Bandwidth

Stephen Webb·Gang Wang·Vladimir Litvinenko
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Abstract

Free-electron lasers play an increasing role in science, from generating unique femtosecond X- ray pulses for single short recording of the protein structures to amplifying feeble interactions in advanced cooling systems for high-energy hadron colliders. While modern Free-electron laser codes can describe their amplification mechanism, a deep analytical understanding of the mechanism is of extreme importance for a number of applications. Mode competition, their growth rates and amplification bandwidth are among the most important parameters of a free-electron laser. A dispersion relation, which defines these important characteristics, can be solved analytically only for a very few simple cases. In this letter we show that for a typical bell-shape energy distribution in electron beam there is no more that one growing mode. We also derive an analytical expression which determines the bandwidth of the free-electron laser.

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Stephen Webb, Gang Wang, Vladimir Litvinenko. 2011-05-02. On Free-Electron Laser Growing Modes and their Bandwidth. https://doi.org/10.1103/physrevstab.15.080701

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