**Abstract**

In this chapter an investigation of a DC argon and neon abnormal glow discharges with metastable atom density is presented. The values of pressure are between 133.32 and 330 Pa, and the voltage range is from 250 to 400 V in the case of argon gas. In the case of neon gas, the pressure has the value of 399.92 Pa (3 Torr) and the voltage ranges from 300 to 500 V. In the frameworks, an analysis of abnormal glow discharge characteristics is carried out in the case of input data taken from the Boltzmann equation in multi term approximation (BMA), and in the case of input data obtained from BOLISG+ code. As conclusion of these differences of input data in the same gas the output results are different and it appears in the cathodic region. The spatiotemporal distributions of electron and ion densities, the potential and electric field, the mean electron energy and the metastable atom density are shown. A 1D fluid model is used to solve self-consistently the first three moments of the Boltzmann's equation coupled with the Poisson's equation. Our results are validated with those obtained by both recent paper and experimental results.

**Keywords:** metastable atom density, abnormal glow discharge, fluid model, input data
