**5.1 Effect of the metastable lifetime on the characteristics of argon abnormal glow discharge**

We remind that the preceding computations are effected through the metastable lifetime equal to 1 μs [30], we remind that this value has been proposed by Becker et al. [30]. **Figure 7** represents the effect of the metastable lifetime on the curve of the metastable atom concentration in the study state. For this reason we have used a value of metastable lifetime equal to 56 s of the theories [49] and an experimental value equal to 38 s [50]. We remark that the most of the metastable atom concentration augments from 7.76 <sup>10</sup><sup>9</sup> to 2.249 <sup>10</sup><sup>11</sup> cm<sup>3</sup> . We note that this effect is noticed just for metastable atom concentration and all characteristic of argon abnormal glow discharge rest unmoved in the study stated. As a consequence, the utilization of the experimental or artificial value of the metastable lifetime has an inconsequential of the abnormal glow discharge characteristics.
