Wake-riding electrons emitted by antiprotons traversing solid targets

The dielectric response of the medium to a swift ion induces collective charge-density fluctuations which result in an oscillatory polarization potential trailing the ion (''wake''). The concept of such a ''wake'' dates back to Bohr. Meanwhile, a large number of investigations implementing approximations at various levels of sophistication have been performed. The plasmon-pole approximation is one of the simplest approximation which still accounts qualitatively for most of the features of the wake. Clearly, more subtle effects like bow waves and other dispersion effects are neglected. We will restrict ourselves in this paper to the plasmon-pole approximation including a phenomenological damping. We will neglect the effects of the self-wake which can affect the shape of the wake potential. 21 refs., 8 figs