| Paper | Title | Page |
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| MOPCH001 | Modeling Coherence Decay in Broad Band Triplet Interaction | 0 |
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In the present analysis we study the transition from coherent to incoherent dynamics in a nonlinear triplet of broad band combs of waves*. We first reduce the original set of equations into a set where all submodes within a comb interact with all pairs of submodes in the remaining combs. We then develop a spectral formalism that in a self-contained way enables: (i) to determine the point of the transition; (ii) to obtain a convenient set of low dimensional equations modeling the full dynamics**. As shall be discussed in connection with accelerator physics, the results can be applied to a variety of parametric or nonlinear wave devices like beat wave accelerators, FELs, etc.
*G. I. Oliveira et al. Physica D 164, 59 (2002).**M. Frichembruder et al. submitted to Physica. D (2005). |
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| THPCH001 | Nonlinear Stability in the Transport of Mismatched Beams in a Uniform Focusing Field | 0 |
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| A nonlinear stability analysis of mismatched breathing beams considering nonaxysymmetric perturbations is performed. It is shown that breathing oscillations of an initially quasi-round beam may nonlinearly induce quadrupole-like oscillations, with a possible increase of the beam size along one direction. A simple model for the nonlinear coupling is developed to clarify the instability mechanism. Growth rates are determined and compared to that of other instabilities that affect mismatched beams, such as halo formation. Self-consistent simulations with different beam loading distributions are used to verify the findings. | ||
| THPCH002 | Combined Centroid-envelope Dynamics of Intense, Magnetically Focused Charged Beams Surrounded by Conducting Walls | 0 |
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This paper analyses the combined envelope-centroid dynamics of magnetically focused high-intensity charged beams surrounded by conducting walls. Similarly to the case were conducting walls are absent*, we show that the envelope and centroid dynamics decouples from each other. Mismatched envelopes still decay into equilibrium with simultaneous emittance growth, but the centroid keeps oscillating with no appreciable energy loss. Some estimates are performed to analytically obtain some characteristics of halo formation seen in the full simulations.
*Moraes et al. Phys. Rev. Lett. 93, 244801 (2004). |