Estimation of the required current on the anode power supply for high power operation in the J-PARC Main Ring

The J-PARC Main Ring (MR) RF system has been undergoing upgrades in preparation for the Hyper-Kamiokande (Hyper-K) neutrino experiment, which is scheduled to begin receiving a 1.3 MW proton beam in 2028. The beam will be accelerated from 3 GeV to 30 GeV within the MR over a reduced cycle time of 0.58 seconds, down from the current 0.65 seconds. Additionally, the number of protons will be increased from $2.3 \times 10^{14}$ to $3.1 \times 10^{14}$to support high power operation. To accommodate these enhancements, additional RF cavities equipped with 600 kW vacuum tubes will be installed, and the anode current will be increased accordingly. Maintaining a constant RF voltage under these conditions requires more anode current to supply the necessary voltage and to compensate for beam loading effects. This paper presents an estimation of the anode current required for high-power beam operation.