Revision 1

Superseded · first revision · record

Title: Steady-state microbunching in a storage ring at EUV wavelengths
Plain: If electrons in a storage ring stayed bunched into slices a few nanometers long on every turn, they would emit strong coherent ultraviolet light continuously; only the first step of this scheme has been shown.
Precise: Steady-state microbunching (SSMB) uses laser modulators for longitudinal focusing in a low-momentum-compaction ring so that electrons stay in optical-scale microbunches turn after turn; retention of laser-induced microbunching at a $1.064e-4\,\mathrm{cm}$ wavelength over successive turns was reported at the Metrology Light Source, Berlin, in 2021 (Deng et al., https://doi.org/10.1038/s41586-021-03203-0). Determine whether a ring can hold microbunches of rms length below $\sim 2e-7\,\mathrm{cm}$ in steady state, with quantum excitation, intrabeam scattering and laser phase noise included, giving coherent radiation at $1.35e-6\,\mathrm{cm}$ ($13.5\,\mathrm{nm}$) with average power near $1e10\,\mathrm{erg}/\mathrm{s}$.
Settled by: Measured steady-state coherent emission at the target wavelength whose power scales as the square of the number of electrons per microbunch.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: INSPIRE records through 2026 show proof-of-principle work at the Metrology Light Source and ring design studies, with no steady-state operation reported.
Posed since: 2010