Presentation on theme: "1 PIC versus Frozen? 5/27/2013 FSOutcome of SC-13 PIC codes are definitely needed when coherent effects are relevant. In our case in presence of strong."— Presentation transcript:
1 PIC versus Frozen? 5/27/2013 FSOutcome of SC-13 PIC codes are definitely needed when coherent effects are relevant. In our case in presence of strong space charge, time varying fields, double RF at the beginning of injection using PTC-ORBIT makes a lot of sense! However, one of the main SC-13 outcomes is the fact that probably the most relevant issues are of incoherent nature ➔ Frozen space charge approach might be sufficient for many aspects of our studies. Frozen space charge codes are 10-100 faster ➔ Long time scales Clearly for the simulations of 1.2s of the PS only frozen space charge codes can do the job! It has been argued that the half integer resonance in the PSB is a good candidate for coherent phenomena. However, a half integer resonance compensation improves losses a lot ➔ needs studies. MAD-X in the newest version has the frozen space charge implemented and by the way with time varying fields. Example for the Fermilab Debuncher shows quite similar results.
Slow extraction in Debuncher using Orbit 3-order resonance with variable tune Qx and sext. str. K2 First “strange” results for extraction: “intensity drop” intensity vs turns “Intensity drop” was resolved simply at the beginning: Valery advised to make mesh refinements PIC: “Total Beam size increases at slow extraction => mesh number should be increased to keep the cell size”
V. Kapin (F. Schmidt)SC-133 Simulations with ORBIT by V. Nagaslaev Ramps are given in tables; Npart in bunch ~ 2.5e12
V. Kapin (F. Schmidt)SC-134 N_macro_surv vs Turn Number for the Debuncher Timing on CERN computer Macro version ~20-24h MADX-SC ~2-4h MAD-X V3 with Macros MADX-SC V5