  The excitation and propagation of electrostatic solitary waves(ESWs) are
observed in two-dimensional particle-in-cell simulations of ion beam
neutralization by electron injection by a filament. Electrons from the filament
are attracted by positive ions and bounce inside ion beam pulse. Bouncing back
and forth electron streams then starts to mix, creating the two-stream
instability. The instability saturates with the formation of ESWs. These ESWs
reach several centimeters in longitudinal size and are stable for a long time.
The excitation of large-amplitude ESWs reduces the degree of neutralization of
the ion beam pulse. In addition, the dissipation of ESWs causes heating of
neutralizing electrons and their escape from the ion beam, leading to further
reduction of neutralization degree.

Plasma Physics