• A.Y. Molodozhentsev
  J-PARC, KEK & JAEA, Ibaraki-ken

For operation of the JPARC Main Ring, low loss of the high-intensity bunches during the injection and acceleration processes is crucial to avoid radiation damage of the machine. This requires identification and correction the most dangerous resonances, which should be done in combination with the collective effects, in particular, the low energy space charge effects. In frame of this talk we review the status of the Main Ring commissioning process and compare it with the simulation results for the low intensity beam. For the future operation of the Main Ring with the moderate beam power we review the status of the simulation work and discuss the budget of the beam losses.

• A.Y. Molodozhentsev, E. Forest
  KEK, Ibaraki

Crossing different types of resonances is unavoidable for the high beam power operation of the JPARC Main Ring. The ‘lattice’ resonances are cause by the realistic machine imperfection including the field and alignment errors. In addition the ‘space charge’ resonances will lead to the emittance growth. The mechanism of the emittance dilution for the realistic machine imperfection in combination with the space charge effects should be studied in the self-consistent manner. In frame of this report we analyze different coherent modes of the space charge dominated beam at the injection energy for the JPARC Main Ring for some basic operation scenario of the machine. This analysis allows to identify the most dangerous resonances and to understand the effect of the emittance dilution remaining after the resonance correction. The study has been performed by using the PTC_{}ORBIT code.