SOLITARY WAVES IN AN ION-BEAM-PLASMA SYSTEM

Solitary waves in an ion-beam-plasma system are investigated theoretic ally using the pseudo-potential method, including finite temperatures of plasma ions and beam ions. The beam velocity is high enough to avoi d ion-ion instability. Three kinds of solitary waves are possible, cor responding to ion-acoustic waves and to fast and slow space-charge wav es in the beam. To observe the formation of solitary waves from an ini tial positive pulse, numerical simulations are performed. For the slow beam mode, a smaller solitary wave appears at the leading part of the pulse, which is a result of negative nonlinearity and anomalous dispe rsion of the slow mode, and is the opposite behaviour to the cases of the ion-acoustic wave and to the fast beam mode. Overtaking collisions of a solitary wave with a fast-mode solitary wave or with a slow-mode solitary wave are simulated.