Surface filamentation of a relativistic electron beam in a plasma

The electromagnetic instability of a relativistic electron beam in a plasma that is current and charge neutralized in the beam channel. In addition to the usual filamentary instability one finds an instability that is localized to the surface of the beam. The large azimuthal mode number growth rate in cylindrical geometry is ω/sub i/ = ω/sub b// radical 2γ. The effects of collisions, a conducting wall, magnetic field, hollow beam geometry and different plasma densities, inside and outside the beam, are calculated