Velocity dependence of the widths of electron-loss cusps in the range 7-12.5 au

Abstract

The velocity dependence of the full width at half maximum of projectile electron-loss cusps is investigated. For Siq+, Oq+ and Cq+ projectiles traversing He, Ne and Ar targets in the velocity range 7-12.5 au, the FWHM is found to be independent of the ion velocity. These results disagree with theoretical predictions predating those of Day and restrict the velocity dependence of the anisotropy parameter beta in Day's theory (1980).