Evaluation of wakefield effects caused by the orbit fluctuation on nanometer scale beams at the Accelerator Test Facility

Author(s): Y. Abe, K. Kubo, T. Okugi, and N. TerunumaNanometer-scale beams are essential for high luminosity in future electron-positron linear colliders, but even small kicks can strongly distort the beam at the interaction point. Transverse wakefields have mainly been interpreted as static effects caused by orbit distortion and misalignment; this work presents the first direct experimental and quantitative evaluation of dynamic wakefields arising from pulse-to- pulse orbit fluctuations. Measurements at the KEK Accelerator Test Facility, together with simulations including all beamline wakefield sources, show that these effects can significantly increase the beam size and must be considered to maintain stable nanometer-scale beams.[Phys. Rev. Accel. Beams 29, 083502] Published Fri Aug 07, 2026