Diagnostics of Argon Inductively Coupled Plasma and Dielectric Barrier Discharge Plasma by Optical Emission Spectroscopy

An experimental setup was built up to carry out radio frequency (RF) inductively coupled plasma (ICP) and dielectric barrier discharge (DBD), and to depict the optical emission spectra (OES) of the discharges. OES from argon ICP and DBD plasmas in visible and near ultraviolet region were measured. For argon ICP, the higher RF power input (higher than 500 W for our machine), the higher degree of argon plasma ionization. But that doesn't mean a higher mean electron energy. With the increase in the power input, the mean electron energy increases slightly, whereas the density of electron increases apparently On the contrary, argon DBD discharge behaves in the manner of a pulsed DC discharge on optical emission spectroscopy and V-I characteristics. DBD current is composed of a series of pulses equally spaced in temporal domain. The Kinetics of DBD emission strength is mainly governed by the frequency of the current pulse.

Conversion of an atomic to a molecular argon ion and low pressure argon relaxation

The dominant process in relaxation of DC glow discharge between two plane parallel electrodes in argon at pressure 200 Pa is analyzed by measuring the breakdown time delay and by analytical and numerical models. By using the approx- imate analytical model it is found that the relaxation in a range from 20 to 60 ms in afterglow is dominated by Ar＋ ions, produced by atomic-to-molecular conversion of Ar＋ ions in the first several milliseconds after the cessation of the discharge. This conversion is confirmed by the presence of double-Gaussian distribution for the formative time delay, as well as con- version maxima in a set of memory curves measured in different conditions. Finally, the numerical one-dimensional （1D） model for determining the number densities of dominant particles in stationary DC glow discharge and two-dimensional （2D） model for the relaxation are used to confirm the previous assumptions and to determine the corresponding collision and transport coefficients of dominant species and processes.

Numerical analysis of the non-equilibrium plasma flow in the gaseous electronics conference reference reactor

The capacitively coupled plasma in the gaseous electronics conference reference reactor is numerically investigated for argon flow using a non-equilibrium plasma fluid model. The finite rate chemistry is adopted for the chemical non-equilibrium among species including neutral metastable, whereas a two-temperature model is employed to resolve the thermal non-equilibrium between electrons and heavy species. The predicted plasma den- sity agrees very well with experimental data for the validation case. A strong thermal non-equilibrium is observed between heavy particles and electrons due to its low collision frequency, where the heavy species remains near ambient temperature for low pressure and low voltage conditions （0. t Torr, 100 V）. The effects of the operating parameters on the ion flux are also investigated, including the electrode voltage, chamber pressure, and gas flow rate. It is found that the ion flux can be increased by either elevating the electrode voltage or lowering the gas pressure