**7. Conclusion**

In order to study the effect of metastable atom density, a second order fluid electric model has been used in the case of a DC low-pressure Ar and Ne abnormal glow discharges. The Poisson equation for the potential and electric field is joined to the first three moments of the Boltzmann's conservation equations ignoring inertia of the charged particles. In the framework of the local energy approximation, the basic data employed in this chapter are calculated by Becker et al. in the case of multiterm estimation of Boltzmann equation (BMA) [30] and from BOLSIG+ software. The task of metastable atom concentration in the discharge is obvious for study into side of plasma glow discharge for several pure gases and mixed gas. We note that the abnormal glow discharge is sustained by secondary electron emission coefficient and the existence of the metastable atom concentration in this particular discharge.
