In this work, the nitrogen molecular dissociation and ionization levels in Ar/N-2 flue plasma are evaluated as functions of plasma parameters such as Ar mixture quantity and N-2 flux in order to obtain the best condition for various applications such as thin film deposition and material surface modification. This plasma is operated at 10 kV and the nitrogen dissociation rate is determined by analyzing the optical emission of the nitrogen band. For different operating conditions, the dissociation rate [N] of N-2 molecules was enhanced, as the mixture quantity of Ar increased from 0.06 m(3) /h to 0.9 m(3) /h and the max of enhancement factor is 4.3. This factor becomes bigger when the N-2 flux becomes bigger. Moreover, the molecular nitrogen ionization density is calculated from the current intensity of the plasma. The ionization density was also enhanced, as the mixture quantity of Ar increased from 0.1 m(3) /h to 1.5 m(3)/h, under three different voltages. The max of enhancement factor of 1.96 is much smaller than the factor of the dissociation rate. These results are discussed in terms of the kinetics of the electrons, nitrogen ions, atoms and molecules. (C) 2004 Elsevier B.V. All rights reserved.