2023/04/11 by S. T. Wang, V. Khachatryan, Wang, S. T. +3 · 1 citation
Engineering · Physics and Astronomy · #Accelerator Physics (physics.acc-ph) #FOS: Physical sciences #Gyrotron and Vacuum Electronics Research #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics
paper · pdf · doi:10.48550/arxiv.2304.05250
openalex publication_date 2023/04/11 · openalex created_date 2023/04/13 · openalex updated_date 2026/08/01
The predominant source of nonlinearity in most existing accelerators are sextupoles, which introduce nonlinear resonances. When the horizontal tune of an accelerator is near such a resonance line (nνx), stable fixed points (SFPs) may appear in the horizontal phase space to form a second closed orbit different from the "zero" closed orbit. The stable islands in phase space surrounding the SFPs are also referred as transverse resonance island "buckets" (TRIBs). However, the TRIBs are not always present near a resonance line in a storage ring. Necessary conditions for TRIBs formation will be discussed in this paper. A 6-GeV lattice with the horizontal tune near a 3rd-order resonance line at 3νx=50 is then designed for the Cornell Electron Storage Ring (CESR). After loading this lattice into CESR, the TRIBs are observed while adjusting the horizontal tune near the 3rd-order resonance, consistent with particle tracking simulations. TRIBs rotation in the horizontal phase space are also experimentally demonstrated with adjustment of a sextupole knob. These results are in good agreement with the theoretical calculation.