The determination of dynamic aperture in storage rings and colliders is a numerically intensive procedure. When realistic space-charge forces come into consideration, the numerical load becomes even heavier. Furthermore, dynamic aperture estimation using chaos indicators like frequency map analysis (FMA) raises reliability issues when the dynamical system has a time-dependent perturbation like the space-charge force. In this article, we apply a rapidly converging chaos indicator called reversibility error method (REM) to study the space-charge contribution to the dynamic aperture of the integrable optics test accelerator (IOTA) storage ring at a small value of the space charge tune shift. The strength of REM is addressed through examples, including a particle-core model of halo formation. We also develop a toy model of the IOTA lattice to further reduce the computing time required to estimate the dynamic aperture, and we compare this model with a realistic space-charge simulation for verification.

中文翻译：

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快速收敛的混沌指示器，用于研究带电荷的存储环中的动态孔径

确定存储环和对撞机中的动态孔径是一项数字密集的过程。当考虑到实际的空间电荷力时，数字负载将变得更重。此外，当动态系统具有与时间相关的扰动（如空间电荷力）时，使用频率图分析（FMA）等混沌指标进行的动态孔径估计会引发可靠性问题。在本文中，我们应用称为可逆性误差方法（REM）的快速收敛的混沌指标来研究在空间电荷调谐偏移较小的情况下，空间电荷对可积分光学测试加速器（IOTA）存储环的动态孔径的贡献。REM的强度通过示例解决，包括晕圈形成的粒子核心模型。