| Paper |
Title |
Page |
| ROPB004 |
Effect of Lattice and Electron Distribution in Electron-Cloud Instability Simulations for the CERN SPS and LHC
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387 |
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- E. Benedetto, E. Benedetto
Politecnico di Torino, Torino
- G. Arduini, F. Roncarolo, F. Zimmermann
CERN, Geneva
- B. Feng, A.F. Ghalam, T.C. Katsouleas
USC, Los Angeles, California
- G. Franchetti
GSI, Darmstadt
- K. Ohmi
KEK, Ibaraki
- G. Rumolo
CELLS, Bellaterra (Cerdanyola del Vallès)
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Several simulation codes have been adapted so as to model the single-bunch electron-cloud instability including a realistic variation of the optical functions with longitudinal position. In addition, the electron cloud is typically not uniformly distributed around the ring, as frequently assumed, but it is mainly concentrated in certain regions with specific features, e.g., regions which give rise to strong multipacting or suffer from large synchrotron radiation flux. Particularly, electrons in a dipole magnet are forced to follow the vertical field lines and, depending on the bunch intensity, they may populate two vertical stripes, symmetrically located on either side of the beam. In this paper, we present simulation results for the CERN SPS and LHC, which can be compared with measurements or analytical predictions.
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| FPAP022 |
Long Time Simulation of LHC Beam Propagation in Electron Clouds
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1769 |
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- B. Feng, A.F. Ghalam, T.C. Katsouleas
USC, Los Angeles, California
- E. Benedetto, F. Zimmermann
CERN, Geneva
- V.K. Decyk, W.B. Mori
UCLA, Los Angeles, California
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In this report we show the simulation results of single-bunch instabilities caused by interaction of a proton beam with an electron cloud for the Large Hadron Collider (LHC) using the code QuickPIC [1]. We describe three new results: 1) We test the effect of the space charge of the beam on itself; 2) we add the effect of dispersion in the equation of motion in the x direction, and 3) we extend previous modeling by an order of magnitude (from 50ms to 500ms) of beam circulation time. The effect of including space charge is to change the emittance growth by less than a few percent. Including dispersion changes the plane of instability but keeps the total emittance approximately the same. The longer runs indicate that the long term growth of electron cloud instability of the LHC beam cannot be obtained by extrapolating the results of short runs.
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