Stability of anisotropic beams with space charge

Hofmann, I.

doi:10.1103/physreve.57.4713

Cited by 133 publications

(150 citation statements)

References 8 publications

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“…This contribution is most significant for low-order resonances [24,25]. For a round beam near a half-integer resonance (m 2), when the horizontal and vertical tunes are close to each other, C 2 1͞2 for the symmetric mode, and C 2 3͞4 for the antisymmetric mode.…”

Section: Effective Space-charge Tune Shiftmentioning

confidence: 99%

Low-loss design for the high-intensity accumulator ring of the Spallation Neutron Source

Wei

Abell

Beebe‐Wang

et al. 2000

Phys. Rev. ST Accel. Beams

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This paper summarizes the low-loss design for the Spallation Neutron Source accumulator ring ["Spallation Neutron Source Design Manual" (unpublished)]. A hybrid lattice consisting of FODO arcs and doublet straights provides optimum matching and flexibility for injection and collimation. For this lattice, optimization focuses on six design goals: a space-charge tune shift low enough ( below 0.15) to avoid strong resonances, adequate transverse and momentum acceptance for efficient beam collimation, injection optimized for desired target beam shape and minimal halo development, compensation of magnet field errors, control of impedance and instability, and prevention against accidental system malfunction. With an expected collimation efficiency of more than 90%, the uncontrolled fractional beam loss is expected to be at the 10 24 level.

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Section: Effective Space-charge Tune Shiftmentioning

confidence: 99%

Low-loss design for the high-intensity accumulator ring of the Spallation Neutron Source

Wei

Abell

Beebe‐Wang

et al. 2000

Phys. Rev. ST Accel. Beams

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“…On the other hand, an approach based on solving the Vlasov-Poisson equations is more general and, in some cases (in the smooth approximation and for beam distributions entailing purely linear space charge forces), the calculation can be carried out analytically. A 1D model of a beam in a uniform focusing was studied using this method by Sacherer [6]; the extension to 2D for an isotropic Kapchinskij-Vladimirskij (KV) [8] beam was carried out by Gluckstern [7], and a further generalization to an unisotropic KV beam (i.e., with unequal emittances and depressed tunes in the horizontal and vertical planes) has recently been presented by Hofmann [9]. This is the method that we will employ in this paper.…”

Section: Introductionmentioning

confidence: 99%

Resonance analysis for a space charge dominated beam in a circular lattice

Venturini

Gluckstern

2000

Phys. Rev. ST Accel. Beams

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We use the linearized Vlasov-Poisson equations to study the response of a Kapchinskij-Vladimirskij beam to magnetic multipole errors in a circular lattice. This work extends the calculation of Gluckstern [Proceedings of the Linac Conference, 1970 (Fermilab, Batavia, IL, 1970, p. 811] to the case of nonideal periodic lattices. The smooth approximation is assumed. We determine the resonance conditions as well as the amplitude of the excited collective modes as a function of the error size outside the stopbands. We find that the frequencies associated with lattice resonances are a subset of the beam natural eigenfrequencies. The result is used to study the motion of test particles crossing the boundary of the beam core. Close to resonance the model predicts the emergence of a halo if sufficiently large gradient errors are present. Application is made to the University of Maryland Electron Ring.

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“…Hence, we predict the number of survival real particles per a spill as 6×10 6 particles/(macro particle)/(turn)×1000 (macro particles) ×20(turns)×injection Figures 7 and 8 reveal structures of the phase space. This is believed to be higher-order resonances caused by tune shifts in the presence of space charge effect [9] but it requires more study.…”

Section: Optimization Of the Bump Magnet Parametersmentioning

confidence: 99%