Determination of electron density in a wall stabilized Ar–CO

The electron density is measured in an argon-CO2 thermal plasma by optical emission spectroscopy. Electron density is deduced from the Stark broadening of the argon line and hydrogen (H$_{\alpha}$) line. Different theories are used and compared. The effect of CO2 molecule upon this plasma is studied as a function of the Ar–CO2 mixture composition and discharge current. The electron density is ranging from $3 \times 10^{21}$ m-3 to $5.6 \times 10^{22}$ m-3. The influence of the arc confinement is studied and the electron density gradients are evaluated. Departure from local thermal equilibrium is also discussed