Experimental test of coherent betatron resonance excitations

Sustained coherent betatron oscillations have been produced in the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS) using a high-frequency oscillating dipole field operating very near a subharmonic of the betatron tune. The betatron oscillations were adiabatically induced and manipulated in a controlled fashion so that the transverse emittance of the particle beam was preserved. This procedure will be used to induce spin flip in the AGS during the crossing of depolarizing resonances during polarized beam operation. It may also find applications toward measuring nonlinear parameters of transverse motion in synchrotrons and storage rings.