Scattering of Relativistic Electrons on Electric Field Concentrations in a Turbulent Plasma

The angle and energy distribution of a 800-keV, 6-kA, 100-ns electron beam have been measured in an experiment in which this beam interacts with an initially cold hydrogen plasma of density 7×${10}^{19}$ ${\mathrm{m}}^{-3\mathrm{}}$. Towards the end of the beam pulse both distributions become Gaussian. They are explained by the assumption of collisions of beam electrons with three-dimensional "blobs" containing fields with amplitudes of ${10}^8$ V/m. Spectroscopic measurements give average fields of ${10}^6$ V/cm. These observations are interpreted as evidence for the occurrence of Langmuir collapse.