Particle-in-cell simulation of ion-acoustic solitary waves in a bounded plasma*

We study some nonlinear waves in a viscous plasma which is confined in a finite cylinder. By averaging the physical quantities on the radial direction in some cases, we reduce this system to a simple one-dimensional model. It seems that the effects of the bounded geometry (the radius of the cylinder in this case) can be included in the damping coefficient. We notice that the amplitudes of both Korteweg-de Vries (KdV) solitary waves and dark envelope solitary waves decrease exponentially as time increases from the particle-in-cell (PIC) simulation. The dependence of damping coefficient on the cylinder radius and the viscosity coefficient is also obtained numerically and analytically. Both are in good agreement. By using a definition, we give a condition whether a solitary wave exists in a bounded plasma. Moreover, some of potential applications in laboratory experiments are suggested.