Estimate of Longitudinal Space-Charge in the ATF2 Final Focus

The ATF2 project at KEK in Japan is an essential part of the R&D effort for the future linear collider projects. One of the main goals of this R&D is to prove that it is possible to provide the nanometre beamsizes required for these colliders. The final goal of the ATF2 project is a beam size of 37 nm, while the current achievement is 65 nm. One explanation for this discrepancy could be longitudinal space-charge, which we estimate in this note.