Magnetization effects in electron cooling

Abstract

The cooling of a heavy-particle beam in the accompanying electron beam, which is ''frozen'' by a longitudinal magnetic field, is studied. The longitudinal velocity spread of the electrons is assumed very small (..delta../sub e/parallelless than or equal toless than or equal to..delta../sub e/perpendicular). Under these conditions the effective electron temperature is governed by only the longitudinal-velocity spread in the region ..delta../sub i/<..delta../sub e/perpendicular (..delta../sub i/ is the ion velocity spread), because of the long-range nature of the Coulomb forces and the magnetization of the transverse electron motion. In this case the cooling rate is much higher than in the case ..delta../sub e/parallelapprox. =..delta../sub e/perpendicular, and the ion temperature can fall to the longitudinal electron temperature. Under certain conditions, this effect is limited by deviations of the magnetic lines of force from the direction of the closed orbit of the heavy particles in the cooling region.