Paper 
Title 
Page 
TUBX02 
Collective Transverse Instabilities in the GSI Synchrotrons

131 

 V. Kornilov, O. BoineFrankenheim, I. Hofmann
GSI, Darmstadt



One of the primary challenges for the design of the FAIR synchrotrons at GSI Darmstadt is the high current operation close to the stability limits, with small tolerable beam losses. Collective instabilities are a potential limiting factor for the performance of the rings. We discuss results of experimental and numerical investigations of transverse collective beam behavior in the SIS 18 synchrotron. Also damping mechanisms in the presence of space charge, including the linear Landau damping and decoherence due to nonlinearities are discussed. These are the essential factors to define impedances budgets for the GSI synchrotrons. As a computational tool accounting the beam nonlinear dynamics with impedances and selfconsistent space charge, the particle tracking code PATRIC is used.


WEAX01 
Resonance trapping due to space charge and synchrotron motion, in theory, simulations, and experiments

167 

 G. Franchetti, I. Hofmann
GSI, Darmstadt



With the development of high intensity accelerator, the role of space charge effect in a nonlinear lattice gained special attention, as in the FAIR project at GSI, where long term storage of high intensity beams is required. The simultaneous presence of space charge and a nonlinear lattice creates an unprecedented challenge for ring designers as well as a new area of studies in beam physics. We present our understanding of the effect of space charge and chromaticity on the nonlinear beam dynamics of a bunched beam.


WEBX05 
Scaling laws for space charge resonances

268 

 I. Hofmann, G. Franchetti
GSI, Darmstadt
 S.Y. Lee
IUCF, Bloomington, Indiana



Space charge can be the driving term of nonlinear resonances, like the resonant emittance exchange 2Qx2Qy=0 ("Montague resonance", in linacs and highintensity rings), or the fourthorder structure resonance 4Qx=n (highintensity rings, FFAG's). In this study we present scaling laws to describe the dependence of the expected emittance growth effect on the initial emittances, the tune shift and/or the crossing rate through the resonance.


THBW01 
Code benchmarking on induce space charge particle trapping

344 

 G. Franchetti, I. Hofmann
GSI, Darmstadt
 S. Machida
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon



Trapping of particles in a high intensity bunch has been studied by using the MICROMAP. The numerical studies were used to interpret the CERNPS experiments and explore the underlying beam loss/emittance growth mechanisms. We present in this contributed talk the first attempt of code benchmarking in modeling the long term storage of a high intensity bunch. The code benchmarking is initiated between MICROMAP and SIMPSONS.


FRAP08 
Summary of General Working Group A+B+D with a Focus on Code Benchmarking

379 

 J. Wei
BNL, Upton, Long Island, New York
 I. Hofmann
GSI, Darmstadt
 E. N. Shaposhnikova, F. Zimmermann
CERN, Geneva

