EXPERIMENTAL-STUDY OF SYNCHRO-BETATRON COUPLING INDUCED BY DIPOLE MODULATION

Synchro-betatron coupling in a proton storage ring with electron cooli ng was studied experimentally by modulating a transverse dipole field close to the synchrotron frequency. The combination of the electron co oling and transverse field modulation on the synchrotron oscillation i s equivalent to a dissipative parametric resonant system. The proton b unch was observed to split longitudinally into two pieces, or beamlets , converging toward attractors of the dissipative system. These phenom ena might be important in understanding the effect of ground vibration on the Superconducting Super Collider beam, and the effect of power s upply ripple on the Relativistic Heavy-Ion Collider beam.