Longitudinal Beam Dynamics Design for Super Tau-Charm Facility

The project of Super Tau-Charm Facility (STCF) pro-posed in China, as a new-generation high-luminosity e⁺/e⁻ collider in the low-energy region with the center-of-mass energy of 2¿7 GeV, is well underway. The luminosity is targeted at 1.0×10³⁵ cm⁻²s⁻¹ at the optimized beam energy of 2 GeV. Longitudinal beam dynamics becomes of great importance for the STCF due to the constraints from the novel beam-beam effect called coherent X-Z instability and severe beam collective effects. In this paper, we will develop an iterative optimization model for the STCF longitudinal beam dynamics design, which takes into account the influence of transverse dynamics, coherent X-Z instability, and collective effects.