Abstract
A computer experiment is carried out to study the dynamic behavior of plasma particles in response to self-consistent electromagnetic and electrostatic fields produced by an artificial injection of a dense electron beam into the ambient plasma. A two-and-one-half dimensional electromagnetic particle code (KEMPO) is used for this purpose. The electron beam is assumed to be injected along the external magnetic field, B0, and to have a spatially finite extent in directions both parallel and perpendicular to the beam motion at t=0. Most of the beam electrons are decelerated, and this deceleration is accompanied by an elongation and splitting of the beam. However, a fraction of the electrons in the beam is not decelerated but instead is accelerated in both positive and negative directions along B0. A substantial heating of beam electrons is also observed. Associated with the acceleration and thermalization of the beam electrons, various kinds of electromagnetic and electrostatic waves are excited through wave-particle interactions. On a time scale of ion motion, ions are attracted toward the center of the moving beam, forming an ion density peak, which, in turn, causes a strong acceleration of electrons. A BGK type quasi-steady state is reached and maintained for a finite time.
