The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - UNPB AU - Chin, Y.H. AU - Blaskiewicz, M. AU - Chao, A. AU - Shobuda, Y. ED - Eshraqi, Mohammad ED - Trahern, Garry ED - Schaa, Volker RW TI - A Two Particle Model for Study of Effects of Space-Charge Force on Strong Head-Tail Instabilities. J2 - Proc. of HB2016, Malmö, Sweden, July 3-8, 2016 C1 - Malmö, Sweden T2 - ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams T3 - 57 LA - english AB - In this talk, I present a new two particle model for study of strong head-tail instabilities in the presence of the space-charge force. It is a simple expansion of the well-known two particle model. No chromaticity effect is included. It leads to a formula for the growth rate as a function of the two dimensionless parameters: the space-charge tune shift parameter (normalized by the synchrotron tune) and the wake field strength, Υ. The 3-dimensional contour plot of the growth rate as a function of those two dimensionless parameters reveals stopband structures. Many simulation results generally indicate that a strong head-tail instability can be damped by a weak space-charge force, but the beam becomes unstable again when the space-charge force is further increased. The new two particle model indicates a similar behavior. In weak space-charge regions, additional tune shifts by the space-charge force dissolve the mode-coupling. As the space-charge force is increased, they conversely restore the mode-coupling, but then a further increase of the space-charge force decouples the modes again. This mode coupling/decoupling behavior creates the stopbands structures. PB - JACoW CP - Geneva, Switzerland ER -