Library Subscription: Guest
Begell Digital Portal Begell Digital Library eBooks Journals References & Proceedings Research Collections
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes

Impact factor: 0.058

ISSN Print: 1093-3611
ISSN Online: 1940-4360

High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes

DOI: 10.1615/HighTempMatProc.v14.i1-2.120
pages 141-156

KINETIC SIMULATION OF DISCHARGES AND AFTERGLOWS IN MOLECULAR GASES

V. Guerra
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa
K. Kutasi
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa, Portugal; Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, POB 49, H-1525 Budapest, Hungary
M. Lino da Silva
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa
P. A. Sa
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa; Dep. de Engenharia Fisica, Faculdade de Engenharia, Universidade do Porto
J. Loureiro
Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa

ABSTRACT

A detailed kinetic model is designed and developed in order to investigate gas discharges in molecular plasmas and their afterglows. The theoretical formulation comprises the description of the electron, vibrational, chemical, ionic and surface kinetics.
The model is applied to study and interpret two rather different phenomena. The first one is the nitrogen pink afterglow. It is established that the maxima present in the concentrations of several species - which appear downstream from the discharge in a flowing nitrogen afterglow, in a field-free region and after a dark zone - are formed as a result of the V-V up-pumping of N2(Χ1Σ+g) molecules, followed by V-E transfers producing locally the metastable states N2(Α3Σ+u) and N2(α,1Σ−u). The need for an accurate description of the high vibrational levels is pointed out. The vibrational energy levels are recalculated from the RKR method and used additionally in the study of dissociation in extreme re-entry conditions.
The second application is the study of a plasma sterilization system using an Ar-O2 mixture. It is shown that the Ar(4s) do not survive long enough to be responsible for the UV/VUV emissions in the reactor, and that O2 is strongly dissociated. Moreover, the choice of the wall material can contribute significantly to create a more homogeneous distribution of several active species.