| Paper |
Title |
Page |
| WEPLT029 |
Intensity Dependent Emittance Transfer Studies at the CERN Proton Synchrotron
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1891 |
| |
- E. Métral, C. Carli, M. Giovannozzi, M. Martini, R.R. Steerenberg
CERN, Geneva
- G. Franchetti, I. Hofmann
GSI, Darmstadt
- J. Qiang
LBNL, Berkeley, California
- R.D. Ryne
LBNL/CBP, Berkeley, California
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An intensive study has been undertaken since the year 2002 to understand better the various high-intensity bottlenecks of the CERN Proton Synchrotron machine. One of these limitations comes from the so-called Montague resonance. High-intensity proton synchrotrons, having larger horizontal than vertical emittance, may suffer from this fourth-order coupling resonance driven by space charge only. In particular, such resonance may lead to emittance sharing and, possibly, beam loss due to vertical acceptance limitation. Experimental observations made in the 2002 and 2003 runs on the Montague resonance are presented in this paper and compared with 3D particle-in-cell simulation results and theoretical predictions.
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| WEPLT047 |
A Test Suite of Space-charge Problems for Code Benchmarking
|
1939 |
| |
- A. Adelmann
PSI, Villigen
- J. Amundson, P. Spentzouris
Fermilab, Batavia, Illinois
- J. Qiang, R.D. Ryne
LBNL/CBP, Berkeley, California
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A set of problems is presented for benchmarking beam dynamics codes with space charge. As examples, we show comparisons using the IMPACT, MaryLie/IMPACT, and MAD9P codes. The accuracy and convergence of the solutions as a function of solver algorithms, simulations parameters such as number of macro particles, grid size, etc. are studied.
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| WEPLT053 |
Dynamical Effects of the Montague Resonance
|
1957 |
| |
- I. Hofmann, G. Franchetti
GSI, Darmstadt
- J. Qiang, R.D. Ryne
LBNL/CBP, Berkeley, California
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| |
In high-intensity accelerators emittance coupling, known as Montague resonance, may be an issue if the tune split is small. For static tunes within the stop-band of this fourth order space charge driven coupling the final emittances may become equal (equipartition). Using 2D computer simulation we show, however, that slow crossing of the resonance leads to merely an exchange of emittances. In 3D this is similar, if the crossing occurs over a time-scale shorter or comparable with a synchrotron period. For much slower crossing we find, instead, that the exchange may be suppressed by synchrotron motion. We explain this effect in terms of the mixing caused by the synchrotron motion.
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