Toward low energy spread in plasma accelerators in quasilinear regime

Autor: Xiangkun Li, Phu Anh Phi Nghiem, Alban Mosnier
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Physical Review Accelerators and Beams, Vol 21, Iss 11, p 111301 (2018)
Druh dokumentu: article
ISSN: 2469-9888
DOI: 10.1103/PhysRevAccelBeams.21.111301
Popis: In this paper, we address the energy spread and slice energy spread of an externally injected electron beam in plasma wakefield accelerators operating in the linear or quasilinear regime. The energy spread is first derived taking into account the phase dependence of the wakefield along the finite-length bunch together with the dephasing during acceleration and found to be strongly dependent on the bunch length. This could be compensated by the beam loading effect, the energy spread from which is then derived and found to be nearly independent of the bunch length. However, the transverse dependence of the beam loading effect also makes the particles at the same longitudinal position experience different accelerating fields, introducing a significant slice energy spread. To estimate the slice energy spread, a theoretical analysis was conducted by taking the transverse betatron motion into account. As a study case, 3D simulations for the 5 GeV laser-plasma acceleration stage of the European Plasma Research Accelerator with eXcellence in Applications project have been performed. Careful optimization of the parameters allows one to obtain an energy spread of ≤1% and a slice energy spread of ≤0.1%, with good agreement between theories and simulations.
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