Heavy-ion<i>–</i>induced shock electrons from sputter-cleaned solid surfaces

Abstract

Heavy-ion (${\mathrm{C}}^{+}$,${\mathrm{N}}^{+}$,${\mathrm{Kr}}^{+}$)--induced low-energy electron emission (${\mathrm{E}}_{\mathrm{e}}$\ensuremath{\le}30 eV) has been measured from controlled surfaces of thin solid targets (C,Al,Cu) under ultrahigh-vacuum conditions (p\ensuremath{\simeq}${10}^{\mathrm{\ensuremath{-}}7}$ Pa). The angular distributions of low-energy electrons exhibit prominent structures. In each studied detail these structures agree with the predicted directed emission of ``shock electrons'' produced by the collective response of the electron plasma of the solid to the distortion of the penetrating heavy ion.