Dynamically stable electron bunches in beam interaction with an electromagnetic wave packet

Nonlinear interaction of electron beam with a whistler wave packet that eff ectively dissipates through collisions or wave leakage is studied. Independ ently of the dissipation type and nature of waves, self-organization of the beam structure leads to the formation of bunches continuously decelerated by waves. Strong dissipation prevents phase mixing required for the quasili near theory and keeps wave phases in the packet correlated. Thus, dynamical ly stable bunches are present together with a plateau in the velocity distr ibution; asymptotically, wave emission by bunches is the main process. (C) 2000 MAIK "Nauka/Interperiodica".