Simulation studies on compensation for incoherent magnet error driven half-integer and 3rd-order resonances with space charge in HIAF-BRing

TL;DR

This paper develops a modified RDT approach to simulate and mitigate incoherent magnet error resonances caused by space charge effects in high-intensity synchrotrons, demonstrating effective suppression of beam instability.

Contribution

It introduces modified RDTs to better describe nonlinear resonance behavior under space-charge and magnetic imperfections, enabling improved resonance compensation strategies.

Findings

Compensation with modified RDTs reduces emittance growth.

Simulation shows suppression of unstable particle motion.

Effective against half-integer and 3rd-order resonances.

Abstract

Magnet error driven resonances under space-charge-induced resonance crossing represents a significant limitation on beam intensity in low-injection-energy high-intensity synchrotrons. Unstable particle motion arises from the combined effects of space-charge-induced tune spread and magnetic field imperfections, which limits the intensity. This paper introduces a space-charge-Twiss modification to the Resonance Driving Terms (RDTs). The new RDTs are named modified RDTs. Modified RDTs aim to describe the nonlinear behavior under incoherent error driven resonances induced by the combined effect of space charge and magnetic field imperfections. The feasibility of the compensation scheme with modified RDTs is demonstrated through coasting-beam simulations under space-charge-induced half-integer and 3rd-order resonances, using the lattice of the High Intensity Heavy-Ion Accelerator Facility Booster Ring (HIAF-BRing). The simulations demonstrate that the compensation through minimizing modified RDTs significantly suppresses the emittance growth and the unstable particle motion. Besides, the effect of compensation scheme with modified RDTs against periodical resonance crossing is evaluated in bunched-beam simulations.