RF Amplitude Modulation to Suppress Longitudinal Coupled Bunch Instabilities in the SPS

Without specific counter measures, the LHC type beam in the SPS suffers from longitudinal coupled bunch instabilities. To get rid of them, the SPS impedance has been decreased in the last years and the operation of a high frequency Landau damping system has been established. In case of the absence of this Landau damping system one may alternatively introduce an RF amplitude modulation to stabilize the beam. We present results obtained by this method in the SPS and considerations for a potential increase of the longitudinal stability of the LHC.