Cooling of ions by electron beam of anisotropic velocity distribution with variable coulomb logarithm

The cooling rate of ion beam by cold electrons having a two-temperature Maxwellian velocity distribution with a small longitudinal temperature is obtained by analytical expressions. The dependences of Coulomb logarithm on the pitch angle of ion and the ion–electron relative velocity are taken into account. A potential modified by the logarithm is introduced besides the usual potential. The effect of a magnetic field is found to modify the average Coulomb logarithm Lo. For large Lo, cooling happens for all angles but as Lo is smaller the pitch angle dependence appears remarkably.