A 2-D computer simulation of a coaxial plasma device depending on the conservation equations of electrons, ions and excited atoms together with the Poisson equation for a plasma gun is carried out. Some characteristics of the plasma focus device (PF) such as critical wave numbers a(c) and voltages U-c in the cases of various pressures P are estimated in order to satisfy the necessary conditions of traveling particle densities (i.e. plasma patterns) via a linear analysis. Oscillatory solutions are characterized by a nonzero imaginary part of the growth rate (sic)(sigma) for all cases. The model also predicts the minimal voltage ranges of the system for certain pressure intervals.