Dual Harmonic Operation with Broadband MA Cavities in J-PARC RCS

In the J-PARC RCS RF system, the fundamental rf acceleration voltage and the 2nd higher harmonic one are applied to each cavity. This is possible, because the magnetic alloy loaded cavities have a broadband characteristic and require no resonant frequency tuning. The tube amplifier provides both rf components. We calculate the operation of the tube under the condition of the dual harmonic, the non-pure resistive load and the class AB push-pull mode. We also describe about the single harmonic operation from the view point of the higher harmonic push-push mode.