Inelasticity in p-nucleus collisions and its application to high energy cosmic-ray cascades

We employ a simple multiple scattering model to investigate the inclusive reaction p + A --> p + X for projectile momenta in the 100-200 GeV/c range. We find that data are consistent with a class of interaction models in which the stopping power of nuclei is rather low. We discuss extrapolation to ultra-high energy and the application to interpretation of cosmic-ray air showers at energies up to 10^20 eV.