STABILITY OF INHOMOGENEOUS RELATIVISTIC ELECTRON BEAMS

Electrons are accelerated by a nonuniform electric field where the transverse dimension of the beam is significantly greater than the Debye radius and collective approach is necessary for describing small oscillations. For currents exceeding some critical value, there may develop an instability analogous to the 'slipping' instability of nonrelativistic electron beams with a nonuniform velocity profile. The energy spread of the electrons has a stabilizing effect on the beam instability. The slipping instability is characteristic of any nonuniform plasma flow. It may develop in an isotropic plasma if the flow velocities exceed the thermal velocity of the ions.