On emittance growth of strongly coupled heavy ion beams

Seurer, M.; Reinhard, P.‐G.; Toepffer, C.

doi:10.1016/0168-9002(94)91355-2

Cited by 16 publications

(2 citation statements)

References 12 publications

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“…The high kinetic energy serves as a large reservoir, from which energy is permanently transferred into the thermal transverse motion. This beam heating results from intrabeam Coulomb scattering in the bending and alternatinggradient focusing structure of the storage ring [16,17]. The resulting growth of the horizontal temperature in an uncooled beam is much more pronounced than the vertical one, because the horizontal degree of freedom shows larger variations of the focusing strength, and also because of the dependence of the closed orbit on the longitudinal velocity, i.e., the storage-ring dispersion, which amounts to 1.2 m in an average over the TSR lattice.…”

Section: Efficient Indirect Transverse Laser Cooling Of a Fast Storementioning

confidence: 99%

Efficient, Indirect Transverse Laser Cooling of a Fast Stored Ion Beam

et al. 1996

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Three-dimensional laser cooling of a fast stored ion beam has been demonstrated at the Heidelberg Test Storage Ring. With a purely longitudinal cooling force applied to a 7.3 MeV 3 Be 1 beam, we have observed an efficient transverse cooling effect. We interpret this observation as being due to a thermal intrabeam relaxation between the different degrees of freedom that is caused by Coulomb collisions of the stored particles. [S0031-9007(96)

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Section: Efficient Indirect Transverse Laser Cooling Of a Fast Storementioning

confidence: 99%

Efficient, Indirect Transverse Laser Cooling of a Fast Stored Ion Beam

et al. 1996

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“…, where m is the mass ions beam and k b is the Boltzmann's constant [69,70]. This formula shows that envelope r j and acceptance a j variations cause temperature variations.…”

Section: Anisotropic Kinetic and Dynamic Processes In Equipartitmentioning

confidence: 98%

Transition from isotropic to anisotropic beam profiles in a uniform linear focusing channel

Simeoni

2007

2007 IEEE Particle Accelerator Conference (PAC)

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This paper examines the transition from isotropic to anisotropic beam profiles in a linear focusing channel. Considering a high-intensity ion beam in space-charge dominated regime and large mismatched RMS beam size initially, observe a fast anisotropy situation of the beam, characterized for a transition of the transversal section round to elliptical with a coupling of transversal emittance driven for instabilities of nonlinear space-charge forces. Space-charge interactions in high-intensity linear accelerator can lead to equipartitioning of energy between the degrees of freedom. The anisotropization phenomena suggest a kind of route to equipartition. In order to understand the initial dynamical behavior of an anisotropic beam, in particular, to study possible mechanisms of equipartition connected with phase space we have to know how we can compute the variables (volume, area of surface, and area projected) that characterize the anisotropic beam in phase space. The beam began in a nonequilibrium state evolved toward a metaequilibrium in which the particle orbits filled an invariant measure of phase space. We shall call this subspace of the phase space " ξ ", where ξ is the ratio of oscillations energies in the x and y directions. It is well-know [38] that an isolated difference ressonance of the form lωx − mωy = 0, where ωx is single particle frequency along of x-direction and ωy is single particle frequency along of y-direction, lead to the motion bounded in both directions and " ξ "remains unchanged. The purpose of this paper is to propose one definiton of the anisotropic equipartition [84]. Anisotropic equipartition corresponds to a phase space density uniform on the surface invariant of the ξ, a version of the ergodic hypothesis where the ξ invariant play the role of the conserved energy [62]. In the state of anisotropic equipartition, the beam temperature is stationary, the entropy grows in the cascade form, there is a coupling of transversal emittance, the beam develops an elliptical shape with a increase in its size along one direction and there is halo formation along one direction preferential.

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