NONLINEAR DYNAMICS OF A THIN ELECTRON-ION BEAM IN A PLASMA

For the case of a small radius of an electron-ion beam interacting wit h a dense plasma, the nonlineardynamics of the instability is studied analytically and numerically. The field of quasi-transverse waves exci ted by a modulated beam, depending on the wave phase, has either a foc using or defocusing effect on the beam electrons and ions and causes b unching of the beam into a train of separated bunches. The parameters of these bunches depend on the ratio of the frequency of the initial m odulation and the electron Langmuir frequency. The considered mechanis m for the beam-plasma instability can be of interest in producing a tr ain with an alternating order of electron and ion bunches with paramet ers that provide a transportation of such a train in a plasma without significant energy losses.