GeV量级等时性固定场交变梯度（FFAG）加速器共振问题研究

高能强流质子束在核物理与粒子物理前沿、大众健康、先进能源、国防安全等领域有重要应用。等时性固定场交变梯度（FFAG）加速器作为一种具有竞争力的技术路线，有望同时实现高能（GeV量级）、强流（mA量级）的目标。.制约GeV量级FFAG加速器实现等时性的瓶颈问题是：在等时性条件下，加速过程中工作点将会跨越整数共振线，限制了束流能量的提升。本项目首次系统性地分析GeV量级FFAG加速器的共振问题，包括：1.在等时性条件限制下，GeV量级等时性FFAG加速器规避或抑制整数共振的问题。2.GeV量级等时性FFAG加速器圈间距小，利用整数共振线进动引出问题。3.GeV量级等时性FFAG加速器的工作路径跨度大，大量穿越危险共振线的问题。4. GeV量级等时性FFAG加速器的磁场非线性强，高阶非线性共振需要精确、保辛地分析。.通过对共振问题的研究，突破GeV量级等时性FFAG加速器的瓶颈，彻底解决能量受限难题。

High energy and high intensity proton beam have important applications in the cutting edge research of nuclear physics and particle physics, public health, advanced energy solutions, national defense and other fields. As a competitive solution, isochronous fixed field alternating gradient (FFAG) accelerators have the potential to achieve the objectives of high energy(GeV) and high intensity(mA).. However, the resonance crossing problems hinder the development of multi-GeV isochronous FFAG accelerators. This application will make systematic analysis on resonance problems of multi-GeV isochronous FFAG accelerators. Firstly, the integer resonance avoiding or suppressing problem. Secondly, the problem of exploitation of integer resonance for beam extraction. Thirdly, lots of resonance lines are crossed due to large tune excursion. The risk of those resonances need careful investigation and analysis. Fourthly, high order nonlinear resonances should be analysed accurately and symplecticly due to strong nonlinear magnetic field. . Via the research of the resonance problems, this application will break through the bottleneck and expand the energy range of multi-GeV isochronous FFAG accelerators.