CERN Accelerating science

Article
Title	Numerical Studies of the Friction Force for the RHIC Electron Cooler
Author(s)	Fedotov, Alexei V ; Abell, Dan T ; Ben-Zvi, Ilan ; Bruhwiler, David L ; Busby, Richard ; Litvinenko, Vladimir N ; Schoessow, Paul
Affiliation	(BNL, Upton, Long Island, New York) ; (Tech-X, Boulder, Colorado)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.4278
Subject category	Accelerators and Storage Rings
Abstract	Accurate calculation of electron cooling times requires an accurate description of the dynamical friction force. The proposed RHIC cooler will require  55 MeV electrons, which must be obtained from an RF linac, leading to very high transverse electron temperatures. A strong solenoid will be used to magnetize the electrons and suppress the transverse temperature, but the achievable magnetized cooling logarithm will not be large. Available formulas for magnetized dynamical friction are derived in the logarithmic approximation, which is questionable in this regime. In this paper, we explore the magnetized friction force for parameters of the RHIC cooler, using the VORPAL code.* VORPAL can simulate dynamical friction and diffusion coefficients directly from first principles.** Various aspects of the friction force, such as dependence on magnetic field, scaling with ion charge number and others, are addressed for the problem of high-energy electron cooling in the RHIC regime.