Kinetics of charged species in non-equilibrium plasma in water vapor- and hydrocarbon-containing gaseous mixtures

In this review we describe the kinetics of non-equilibrium discharge plasma when the ion composition is dominated by water or hydrocarbon ions. Plasmas with water ions are formed in atmospheric discharges and discharges in the presence of liquid water or water vapor, including plasma applications for air purification, medicine and combustion. Reactions with hydrocarbon ions play an important role in interstellar chemistry, plasma enhanced chemical vapor deposition, synthetic diamond film deposition and plasma assisted combustion. The modeling of water ion chemistry and chemistry of hydrocarbon-containing plasmas requires large amount of data on the rates of ion formation and loss. This review provides the core database for the rate coefficients describing the kinetics of charged particles in plasmas with water and hydrocarbon ions as a function of temperature, pressure, and local electric field. Particular attention is given to cluster ions, which are important at not-too-low gas pressures, whereas the majority of studies of ion-molecule reactions have been performed at low pressures in the absence of cluster ions. To illustrate importance of the described processes, the development of streamer discharges in long humid air gaps is discussed and the influence of water ions on the streamer properties is demonstrated. In addition, the decay of non-equilibrium plasma with water and hydrocarbon ions is analyzed in combustible gaseous mixtures excited by a repetitively pulsed nanosecond discharge.

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In this review, the kinetics of non-equilibrium discharge plasma with water and hydrocarbon ions is described. This includes a core database of rate coefficients as a function of temperature, pressure, and local electric field. Cluster ions are highlighted as important in plasmas at not-too-low gas pressures, while most studies of ion-molecule reactions have been performed at low pressures without considering cluster ions. The influence of water ions on the properties of streamer discharges in humid air gaps and the decay of non-equilibrium plasma with water and hydrocarbon ions in combustible gaseous mixtures are also analyzed.