Experimental and theoretical study of atmospheric-pressure argon microplasma jets. (22nd May 2015) - Amorim, J
Abstract: Surface-wave discharges in argon at atmospheric pressure were experimentally studied by optical emission spectroscopy (OES) and mass spectrometry (MS). OES was employed to determine the rotational temperature using the ultraviolet OH band, Q1 branch and found to be between 450 and 970 K. The electron density (5 × 10 13 cm −3 ≤ n e ≤ 7 × 10 14 cm −3 ) was estimated using the H β line profile, and produced by dissociation of the water present as an impurity in the Ar gas. The electron temperature (0.63 eV ≤ T e ≤ 1.3 eV) was estimated using a collisional–radiative (CR) model that takes the input measured intensities of four emission lines originating from 2p states including 2p2, 2p4, 2p6, and 2p10 . The density of the metastable state Ar(1s5 ) (2.0 × 10 11 cm −3 ≤ Ar(1s5 ) ≤ 4.2 × 10 12 cm −3 ) was estimated by means of OES using the self-absorbing method. Positive and negative ions were probed along the plasma column using MS. A theoretical model based on the solution of the homogeneous electron Boltzmann equation, considering inelastic and superelastic collisions with the Ar(1s) states and electron–electron collisions, coupled with a system of rate balance equations describing the creation and destruction of the most important heavy particles, is proposed. The experimental results are compared with theoretical ones obtained from a self-consistent model of these discharges, providing physical insight into the basic mechanisms and phenomena ruling the discharges.