Hemsing E, Marinelli A, Marcus G, Xiang D
SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
Department of Physics and Astronomy, Key Laboratory for Laser Plasmas (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200240, China.
Phys Rev Lett. 2014 Sep 26;113(13):134802. doi: 10.1103/PhysRevLett.113.134802. Epub 2014 Sep 22.
We study the effect of longitudinal space charge on the correlated energy spread of a relativistic high-brightness electron beam that has been density modulated for the emission of coherent, high-harmonic radiation. We show that, in the case of electron bunching induced by a laser modulator followed by a dispersive chicane, longitudinal space charge forces can act to strongly reduce the induced energy modulation of the beam without a significant reduction in the harmonic bunching content. This effect may be optimized to enhance the output power and overall performance of free-electron lasers that produce coherent light through high-gain harmonic generation. It also increases the harmonic number achievable in these devices, which are otherwise gain-limited by the induced energy modulation from the laser.
