Tech-X, Boulder, Colorado
BNL, Upton, Long Island, New York
Novel electron-hadron collider concepts are a high priority for the long-term plans of the international nuclear physics community. Orders of magnitude higher luminosity will be required for the relativistic ion beams in such particle accelerators. Electron cooling of highly relativistic ions is under consideration for the proposed RHIC II luminosity upgrade. The parallel VORPAL code is being used for molecular dynamics simulations of the friction force on individual ions, given expected parameters of the RHIC II cooling system, including the effects of an idealized helical undulator magnet and of estimated magnetic field errors. The well-known analytical formula for the field-free case is the basis for physical intuition regarding dynamical friction, but this is derived under the assumption of very long interaction times and symmetric ion/electron collisions. For RHIC II parameters, the interaction time is short compared to the electron plasma frequency, so there is essentially no shielding of the ion charge and one must consider finite time effects and asymmetric collisions. We present the current status of this work.
