Observation of magnetized cooling in the IUCF cooler

Measurements of the longitudinal drag rate (R/sub D/, the rate at which the electron beam can change the energy of the proton beam) for 45-MeV protons with longitudinal velocities relative to the electron beam, nu */sub p/// in the range from 1*10/sup -7/< nu */sub p////c<1*10/sup -2/, are summarized along with measurements of the effective longitudinal electron beam energy spread delta E/sub e,spread/ as function of electron beam current and angular misalignment between the electron and proton beams Theta /sub misalignment/. It was found that delta E/sub e,spread/ increases approximately linearly with Theta /sub misalignment/. For well-aligned beams, delta E/sub e,spread/ is consistent with electron beam intrabeam scattering, and in this regime, the normalized drag rate is enhanced considerably over the predictions of the nonmagnetized theory.<>