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Chaotic dynamics driven by particle-core interactions

Batygin, Konstantin and Batygin, Yuri K. (2021) Chaotic dynamics driven by particle-core interactions. Physics of Plasmas, 28 (9). Art. No. 093104. ISSN 1070-664X. doi:10.1063/5.0056306.

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High-intensity beams in modern linacs are frequently encircled by diffuse halos, which drive sustained particle losses and result in the gradual degradation of accelerating structures. In large part, the growth of halos is facilitated by internal space-charge forces within the beams, and detailed characterization of this process constitutes an active area of ongoing research. A partial understanding of dynamics that ensue within space-charge dominated beams is presented by the particle-core interaction paradigm—a mathematical model wherein single particle dynamics, subject to the collective potential of the core, is treated as a proxy for the broader behavior of the beam. In this work, we investigate the conditions for the onset of large-scale chaos within the framework of this model and demonstrate that the propensity toward stochastic evolution is strongly dependent upon the charge distribution of the beam. In particular, we show that while particle motion within a uniformly charged beam is dominantly regular, rapid deterministic chaos readily arises within space-charge dominated Gaussian beams. Importantly, we find that for sufficiently high values of the beam's space charge and beam pulsation amplitude, enhanced chaotic mixing between the core and the halo can lead to an enhanced radial diffusion of charged particles. We explain our results from analytic grounds by demonstrating that chaotic motion is driven by the intersection of two principal resonances of the system and derives the relevant overlap conditions. Additionally, our analysis illuminates a close connection between the mathematical formulation of the particle-core interaction model and the Andoyer family of integrable Hamiltonians.

Item Type:Article
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URLURL TypeDescription Paper
Batygin, Konstantin0000-0002-7094-7908
Batygin, Yuri K.0000-0001-9422-6112
Additional Information:© 2021 Author(s). Published under an exclusive license by AIP Publishing. Submitted: 08 May 2021. Accepted: 16 August 2021. Published Online: 08 September 2021. K.B. is grateful to Caltech as well as the David and Lucile Packard Foundation for their generous support. Y.B. is grateful to the Los Alamos National Laboratory and the U.S. Department of Energy for their generous support, under U.S. DOE Contract No. 89233218CNA000001. DATA AVAILABILITY: The data that support the findings of this study are available from the corresponding author upon reasonable request.
Funding AgencyGrant Number
David and Lucile Packard FoundationUNSPECIFIED
Department of Energy (DOE)89233218CNA000001
Issue or Number:9
Record Number:CaltechAUTHORS:20210927-225705775
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111067
Deposited By: George Porter
Deposited On:28 Sep 2021 14:50
Last Modified:29 Nov 2021 21:38

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