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arXiv · 1909.02166

Phase-stable self-modulation of an electron-beam in a magnetic wiggler

James P. MacArthur·Joseph Duris·Zhen Zhang·Alberto Lutman·Alexander Zholents·Xinlu Xu·Zhirong Huang·Agostino Marinelli
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Abstract

Electron-beams with a sinusoidal energy modulation have the potential to emit sub-femtosecond x-ray pulses in a free-electron laser. The energy modulation can be generated by overlapping a powerful infrared laser with an electron-beam in a magnetic wiggler. Here we report on a new infrared source for this modulation, coherent radiation from the electron-beam itself. In this self-modulation process, the current spike on the tail of the electron-beam radiates coherently at the resonant wavelength of the wiggler, producing a six-period carrier-envelope-phase (CEP) stable infrared field with gigawatt power. This field creates a few MeV, phase-stable modulation in the electron-beam core. The modulated electron-beam is immediately useful for generating sub-femtosecond x-ray pulses at any machine repetition rate, and the CEP-stable infrared field may find application as an experimental pump or timing diagnostic.

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James P. MacArthur, Joseph Duris, Zhen Zhang, Alberto Lutman, Alexander Zholents, Xinlu Xu, Zhirong Huang, Agostino Marinelli. 2019-09-05. Phase-stable self-modulation of an electron-beam in a magnetic wiggler. https://doi.org/10.1103/physrevlett.123.214801

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