Beam loading issues for SNS storage ring

In the Spallation Neutron Source (SNS) storage ring, the machine cycle is dominated by the multiturn injection. Therefore, the beam loading issues are quite different from the conventional beam loading. The evolution of the particle distribution due to beam loading needs attention. If not corrected, the beam loading effect will lead to a bunch to bucket mismatch in the injection, causing bunch leakage into the interbunch gap. The bunch leakage will increase the extraction beam loss, and lower the e-p instability threshold. On the other hand, the control of bunch leakage necessitates the beam loading factor to be small. Therefore, beam stabilities associated with the beam loading automatically satisfied. In this article, the simulation of the SNS beam loading effect (together with the space charge effect) will be presented. Same method has been applied to the PSR, where some beam loading effect is shown