References on incoherent Electron Cloud
the electron pinch, and the effect of
compiled in chronologic order by F. Zimmermann
R&D and LHC Collective Effects
A team of the
M.A. Furman and A.A. Zholents,
Incoherent Effects driven by the Electron Cloud
presented at PAC 99, New York City. The two authors study the tune shift and synchro-betatron resonances driven by the electron-cloud pinch - which is
similar to the resonance trapping, and appears just to be a different way to look
at the same problem. They conclude that this is not a strong effect for
the PEP-II B factory.
In the fall of 1999 Katsunobu Oide hypothesized
an incoherent effect as explanation of the KEKB blow up. The KEKB case was
however soon shown to be dominated
by the fast blow up due to the TMC-like instability, an explanation which Kazuhito
Ohmi and Frank Zimmermann proposed at Christmas 1999, and which was afterwards
proven experimentally. Nevertheless it now looks as if there is a
small incoherent effect below the fast-instability threshold.
Katsunobu's proposal might be
found in one of the KEKB MACs. Certainly he discussed it with Frank
Zimmermann at the end of 1999. He
suspected that a spurious dispersion was generated by the cloud, but he
was also worried about the "pinch".
Electron Cloud Simulations: An Update,
Included in this paper was an estimate of the incoherent tune shift due to
electron cloud at the end of a bunch passage.
G. Rumolo, F. Zimmermann, "Electron-Cloud Instability with Space Charge or
Beam Beam", 3rd paper in
of the SL-AP Group to the Two-Stream Instabilities Workshop.
see the TWO-STREAM
Here a few-particle model is developed which includes the tune shift from
space charge, from electron-cloud, plus the synchrotron motion.
Kazuhito here continues the
analogy with space charge and interestingly enough he considers the effect
of a linear stopband resonance due to a quadrupole error.
E. Benedetto, et al.
Transverse 'Monopole' Instability driven by Electron Cloud?,
PAC 2003, CERN-AB-2003-036-ABP (2003). In this paper, the Lotov-Stupakov
cannot be reproduced, but the large tune
footprint created by the pinched electron cloud is calculated, by frequency
maps, which reveals several resonances potentially contributing to the incoherent emittance growth.
Also simulations with different synchrotron
tunes are compared.
E. Benedetto and F.
Analysis of the Electron Pinch during a Bunch Passage,
Proceedings ECLOUD'04 April 2004.
Here we compute analytically the
incoherent tune shift as a function of longitudinal and transverse position
along the bunch, assuming that this could be responsible for incoherent emittance growth.
between resonance-trapping phenomena which may explain beam losses observed at
the CERN PS (due to space charge) and at the SPS (due to electron cloud) were
hinted at in September 2004 during discussions at CERN in connection with the
workshop and later brought forward at the CARE
workshop by Giuliano Franchetti, Elias Métral, and Frank Zimmermann. At the
HHH-2004 workshop also the strong dependence of the simulated emittance growth
on the localization of e-cloud kicks along the ring was explained by Elena
Benedetto and Giuliano Franchetti.
There is also other and much earlier general
work on resonance trapping by Chao and Month, on modulational diffusion by
Vivaldi et al., etc.
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