The method of plasma electron spectroscopy (PLES) is further developed for the analysis of impurities of organic molecules and ammonia in this work. In particular, for the first time the PLES method was used to detect the hydrocarbons impurities: alkanes (methane) and alkenes (ethylene), as well as their derivatives alcohols (ethanol), radicals, and ammonia. As the energies of the registered characteristic electrons are different for different chemical compounds, an important advantage of the PLES method is the fact that it allows simultaneous (in one measurement) registration of various impurities. This work presents a prototype of a PLES-gas analyzer based on nonlocal plasma of negative glow of a short glow discharge in helium.
A method for the calculation of the nonlocal electron distribution function (EDF) with programs commonly used for solving the one-dimensional Boltzmann kinetic equation (e.g., COMSOL Multiphysics) was proposed and implemented. The capabilities of the proposed method were illustrated using the example of the positive column plasma in argon. Significant differences between the local and nonlocal EDFs were observed, especially at the plasma periphery. This can result in significant differences in the electron transport coefficients and reaction rate constants for electron-induced processes. The proposed approach increases the precision of the numerical modeling of gas discharge devices and equipment.
We present a model of a direct-current glow discharge that self-consistently reproduces its full longitudinal structure and provides reliable estimates of main discharge parameters in all of its regions. The model is based on the fluid description of ions and bulk electrons and incorporates analytical formulation of non-local ionization and excitation sources induced by fast electrons. Spatial distributions of main discharge parameters obtained for the case of an extended glass tube filled with argon at 0.5 Torr show pronounced near-cathode regions-the cathode sheath, the negative glow and the Faraday dark space-as well as the autonomous positive column and the anode sheath. Formation of the second electric field reversal and the transitional region between the Faraday dark space and the positive column are revealed. This transitional region occupies a considerable fraction of the discharge tube length, over which the bulk electron temperature increases by more than an order of magnitude. Comparison of simulation results with those obtained with a 2D fluid model with the local energy approximation, as well as with experimental data taken from literature is presented. The model can be realised in most modern low-temperature plasma simulation software. The underlying physics and assumptions are discussed in detail.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.