• D.L. Bruhwiler, G.I. Bell, A.V. Sobol
  Tech-X, Boulder, Colorado
• I. Ben-Zvi, V. Litvinenko
  BNL, Upton, Long Island, New York
• Y.S. Derbenev
  Jefferson Lab, Newport News, Virginia

Novel electron-hadron collider concepts are a long-term priority for the international nuclear physics community. Effective beam cooling for intense, relativistic hadron beams will be necessary to obtain the orders-of-magnitude higher luminosities being proposed. Coherent electron cooling (CEC) [1] combines the best features of electron cooling and stochastic cooling, via free-electron laser technology [2], to offer the possibility of cooling high-energy hadron beams much faster. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. The parallel VORPAL framework [3] is the ideal code for simulating the modulator and kicker regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. We present initial VORPAL simulations of the electron density wake driven by single ions in the modulator section. Also, we present a plan for simulating the full modulator-amplifier-kicker dynamics, by through use of a loosely-coupled code suite including VORPAL, an FEL code and a beam dynamics code.

[1] Y.S. Derbenev, Proc. COOL07, 149 (2007).
[2] V.N. Litvinenko & Y.S. Derbenev, Proc. FEL07, 268 (2007).
[3] G.I. Bell et. al., J. Comp. Phys. (2008), in press.

• D.T. Abell, G.I. Bell, A.V. Sobol
  Tech-X, Boulder, Colorado
• E. Forest
  KEK, Ibaraki

At low current, accelerators are dominated by their independent, separated-function magnets, and hence essentially all accelerator simulation codes have used not time but longitudinal distance, s, as the independent variable. The simulation of space-charge effects within this approach has been at best ad hoc, as it requires a (thoroughly approximate) transformation between a pancake of space charge at fixed s to a particle bunch at fixed t. We shall describe recent modifications to the accelerator simulation code PTC [1] that make it possible to, in effect, perform time-based particle tracking in a code that correctly handles the full geometry and wide dynamic range of current designs for FFAGs. In addition, we shall describe the associated space-charge computation and present initial results from simulations that cover a large energy gain in a model non-scaling FFAG.

[1] E. Forest, Y. Nogiwa, F. Schmidt, "The FPP and PTC Libraries", Proceedings of ICAP 2006.