الملخص

Abstract:The DC glow discharge in the capillary tubes acquired considerable attention in many applications due to its important electrical characteristics. In the present work, an electrical discharge system was designed consisting of a capillary tube and two electrodes. The cathode was made with a hollow shape from nickel material to obtain a high current density. The anode electrode is tungsten material. The distance between the electrodes was chosen as 13 cm. The Langmuir double probe was used as a diagnostic technique to measure the plasma parameters at different ranges of gas pressure. The I-V characteristics of the double probe were measured at pressures 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 torr. All measurements are conducted at a constant power of 0.6 watt. Electron temperature and ion saturation current were extracted from the I-V characteristics curves. While the electron density, Debye length, and plasma frequency were calculated. It was observed that the electron temperature decreases with increasing working gas pressure. The effects of pressure on electron density and ion saturation current gave a clear similarity to the change in them with pressure. The results were in reasonable agreement with previous research