FEL2026 - 42nd International Free Electron Laser Conference

Session

Electron Beam Dynamics (Contributed)

WEC

26 Aug 2026, 14:50

177. Microbunching instability studies and lasing at FERMI with one-and two-stage compression scheme (WEC01)

Giovanni Campri (Elettra-Sincrotrone Trieste S.C.p.A.)

26/08/2026, 14:50

Session 8: Electron Beam Dynamics

Contributed Oral Presentation

We report on recent experimental sessions at FERMI FEL, characterizing the electron beam longitudinal phase space and the HGHG FEL, in single and double compression scheme. The impact of microbunching instability on the beam dynamics and lasing is recorded, and succesfully compared with predictions from a MBI instability integral model incorporating intrabeam scattering. With the addition of...

7. Beam Halo Formation via Longitudinal-Transverse Coupling in Continuous-Wave Photoinjectors (WEC02)

Zhen Zhang (SLAC National Accelerator Laboratory)

26/08/2026, 15:15

Session 8: Electron Beam Dynamics

Contributed Oral Presentation

Beam halo formation poses a critical challenge for high-repetition-rate continuous-wave (CW) free-electron lasers (FELs), directly affecting beam quality and machine protection, as observed during the LCLS-II commissioning. We identify and experimentally validate a previously unrecognized three-step mechanism for halo generation in the photoinjector, arising from coupled...