Nonlinear Beam Dynamics Experiments at the Srrc

Nonlinear field is of importance for the design and operation of circular machines and nonlinear beam dynamics has been intensively investigated both theoretically and experimentally [1]. Theoretically, nonlinear elements are designed on purpose to assist the operation of the machines e.g., the correction of the chromatic aberration and/or slow extraction with the help of sextupole magnets, the enhancement of the Landau damping with the octupole field, etc. On the other hand, the existence of the nonlinear components in the beam line will introduce the nonlinear behavior of the moving particle, and if the driving source of such nonlinear field is strong enough, the particle motion could be so large and lost. In the design stage of the machine components, the error tolerance of the field ought to be specified to assure the expected performance of the machine. In this paper, we employ a turn-by-turn electron position monitoring system to measure the behavior of the perturbed particle at the TLS. The simulation results with the existence of the measured nonlinear field errors are compared with the extracted parameters from the experiments.