Density and temperature profile of argon plasma in a plasma device

A single Langmuir probe measurements were performed in argon plasma of a plasma device. The plasma device is a cylindrical tube with a filament electrode at one end and plane electrode at the other end. Probe was designed to move longitudinally along the cylinder and to rotate around its axis for sweeping points at any radial position. A straight forward method based on the theory of Langmuir probe is generated for obtaining the plasma temperature and density from I-V characteristics of the probe in non-equilibrium cold plasma. Results show that for the argon plasma at 1.2×10-2 mbar working pressure and 2000 V voltage of discharge, the number density of electrons is much larger than that for ions, while the ion saturation current is negligible and the distance for plasma generation in this range of plasma pressure and discharge voltage is about 6 cm from the cathode toward the anode.