IPAC2011 - List of Authors (Rivetta, C.H.)

Paper	Title	Page
MOPS089	Identification of Bunch Dynamics in the Presence of E-cloud and TMCI for the CERN SPS Ring	811
	O. Turgut, J.D. Fox, C.H. Rivetta, S. Uemura SLAC, Menlo Park, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work is supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). Measurements and multi-particle simulation codes (i.e. HEAD-TAIL, WARP, CMAD) indicate that bunched particle beams show unstable motions induced by electron-clouds and strong head-tail interactions. The bunch dynamics exhibits highly non-linear, complex and unstable behavior under certain operating conditions. Feedback control systems have been proposed to mitigate these instabilities in the CERN SPS ring. The design of feedback systems requires the knowledge of a reduced dynamic model of the bunch. It allows to include and quantify the effect of noise and signal perturbations, as well as system robustness to parameter variation. Identification techniques are used to estimate those models based on bunch motion measurements. In this work we present reduced mathematical models representing the transverse bunch dynamics and identification techniques to extract the model parameters based on measurements. These techniques are validated using time domain simulations of the bunch motion conducted using multi-particle simulation codes. For that, different sections of the bunch are driven by random signals, and the vertical motion of those areas is used to estimate the reduced model.

Paper

Title

Page

Identification of Bunch Dynamics in the Presence of E-cloud and TMCI for the CERN SPS Ring

811

O. Turgut, J.D. Fox, C.H. Rivetta, S. Uemura
SLAC, Menlo Park, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work is supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
Measurements and multi-particle simulation codes (i.e. HEAD-TAIL, WARP, CMAD) indicate that bunched particle beams show unstable motions induced by electron-clouds and strong head-tail interactions. The bunch dynamics exhibits highly non-linear, complex and unstable behavior under certain operating conditions. Feedback control systems have been proposed to mitigate these instabilities in the CERN SPS ring. The design of feedback systems requires the knowledge of a reduced dynamic model of the bunch. It allows to include and quantify the effect of noise and signal perturbations, as well as system robustness to parameter variation. Identification techniques are used to estimate those models based on bunch motion measurements. In this work we present reduced mathematical models representing the transverse bunch dynamics and identification techniques to extract the model parameters based on measurements. These techniques are validated using time domain simulations of the bunch motion conducted using multi-particle simulation codes. For that, different sections of the bunch are driven by random signals, and the vertical motion of those areas is used to estimate the reduced model.