| Paper | Title | Page |
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| MOPPH036 | Influence of Linear Fluctuations on Low- and High-Gain Cherenkov FELs | 118 |
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In a previous study* it was shown that irregularities in the liner result in phase fluctuations of the ponderomotive potential which affects the gain of a low energy Cerenkov FEL. Here we investigate numerically how sensitive a Cerenkov FEL is to such fluctuations when operating in different gain regimes. For this study we considered an increased transverse dimensions of the liner and electron beam as compared to the study presented in*, while the resonance frequency and beam voltage are held constant around 50 GHz and 80 kV respectively. The different gain regimes then correspond to different electron beam currents ranging from 0.8 A to 20 A. Without liner fluctuations, these beam currents result in a single pass saturated output power of approx. 200 W to 25 kW respectively, where the laser output saturates in a much shorter distance for the higher beam current. We have found that the low gain system (I=0.8 A) shows a much higher sensitivity to liner fluctuations than the high gain system (I=20 A).
* I de la Fuente, PJM van der Slot and K-J Boller. Proceedings of the 26th International Free-Electron Laser Conference and the 11th FEL User-Workshop. Trieste, Italy, p53-56 (2004) |