A 'minimal' kinetic model of plasmachemical processes in low-current discharges in highpressure air is formulated, which takes into account electrons, an effective species of positive ions, and three species of negative ions. The model is implemented as a part of numerical model of low-current quasi-stationary discharges in high-pressure air based on the use of stationary solvers, which offer important advantages in simulations of steady-state discharges compared to standard approaches that rely on time-dependent solvers. The model is validated by comparison of the computed inception voltage of corona discharges with several sets of experimental data on glow coronas. A good agreement with the experiment has been obtained for positive coronas between concentric cylinders in a wide range of pressures and diameters of the cylinders. The sensitivity of the computation results with respect to different factors is illustrated. Inception voltages of negative coronas, computed using the values of the secondary electron emission coefficient of 10 −4 -10 −3 , agree well with the experimental data. A simplified kinetic model for corona discharges in air, which does not include conservation equations for negative ion species, has been proposed and validated. Modelling of positive coronas in rod-to-plane electrode configuration has been performed and the computed inception voltage was compared with experimental data.

Self-organized patterns of cathodic spots have been observed in microdischarges operated in xenon, but not in other gases. However, modelling has indicated that it is, in principle, possible to observe the patterns of spots in discharges operated in other gases provided that experimental conditions, in particular pressure, are right. In this work, self-organized patterns of cathodic spots are for the first time observed in dc glow microdischarges operated in a gas other than xenon: krypton. The experiments have been guided by the modelling. According to both the experiment and the modelling, patterns in krypton are similar to those found earlier in xenon, however occur at higher pressures.

Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance (SPR) phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized.