CERN Accelerating science

Article
Title	The Effect of Magnetic Field Errors on Dynamical Friction in Electron Coolers
Author(s)	Bruhwiler, David L ; Abell, Dan T ; Busby, Richard ; Fedotov, Alexei V ; Litvinenko, Vladimir N ; Veitzer, Seth A
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.4206
Subject category	Accelerators and Storage Rings
Abstract	A proposed luminosity upgrade to the Relativistic Heavy Ion Collider (RHIC) includes a novel electron cooling section,* which would use  55 MeV electrons to cool fully-ionized 100 GeV/nucleon gold ions. A strong (1-5 T) solenoidal field will be used to magnetize the electrons and thus enhance the dynamical friction force on the ions. The physics of magnetized friction is being simulated for RHIC parameters, using the VORPAL code.** Most theoretical treatments for magnetized dynamical friction do not consider the effect of magnetic field errors, except in a parametric fashion.*** However, field errors can in some cases dramatically reduce the velocity drag and corresponding cooling rate. We present a simple analytical model for the magnetic field errors, which must be Lorentz transformed into the beam frame for use in our simulations. The simulated dynamical friction for the case of a perfect solenoidal field will be compared with results from this new model, for parameters relevant to RHIC.