Paper  Title  Page 

TUA1I1 
Inverse Stability Problem in Beam Dynamics  


Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DEAC0207CH11359 with the United States Department of Energy. Beam stability is conventionally described by means of the stability diagram, which is a threshold line in a complex plane of a particular intensity parameter, the coherent tune shift; the diagram separates stable and unstable states. The incoherent tune spread of the beam particles normally causes the transverse stability diagram to be an asymmetric bellshaped curve above the real axis; for a given optical nonlinearity, the diagram is determined by the beam distribution function only. Recently, such a diagram was measured by means of an antidamper, see S. Antipov et al., Phys. Rev. Lett. 126, 164801 (2021). Such measurements open the door to a new method of beam diagnostics, finding the beam phase space density as a solution of an inverse stability problem. The main idea, methods of its implementation, possible obstacles and optimizations are discussed. 

Slides TUA1I1 [0.761 MB]  
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THAFP04  Investigation of Taildominated Instability in the Fermilab Recycler Ring  403 


In our recent operational run, a single bunch, taildominated instability was observed in the Fermilab Recycler ring. This instability exclusively occurs in the vertical plane when the chromaticity is close to zero. In this study, we conduct a detailed analysis of this instability under different operational parameters. We investigate the impact of space charge on the headtail motion and propose potential interpretations of the underlying mechanism of the instability. Moreover, we explore methods to mitigate this instability in the future.  
Slides THAFP04 [1.429 MB]  
Poster THAFP04 [0.892 MB]  
DOI •  reference for this paper ※ doi:10.18429/JACoWHB2023THAFP04  
About •  Received ※ 25 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 29 October 2023  
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