Variation of Plasma Properties in Cylindrical Inertial Electrostatic Confinement Device by Changing the Anode Transparency

Inertial electrostatic confinement (IEC) is investigated in terms of direct-current discharge in a cylindrical configuration using nitrogen gas in the pressure range between 0.028 and 0.09 Torr. Discharge characteristics are determined for different anode transparencies of 84%, 92%, and 96% corresponding to 24, 12, and 6 anode rods, respectively. I-V characteristic curves indicate that the electric discharge is in the abnormal glow discharge region. The discharge voltage has the highest values for the low anode transparency for the same value of the discharge current. A double electric probe has been used to measure electron temperature and ion density. The low anode transparency (24 anode rods) enhances field uniformity and aligns the motion of electrons into a chord so that better electrostatic confinement is achieved. This will raise the ion density and lead to thermalization of the plasma, which reduces the electron temperature. The behavior of the electron temperature and the ion density was studied as a function of the gas pressure at the center and near the edge. The variation of the density and temperature in both positions can confirm the plasma confinement. In the low-pressure regime, the confinement process is reinforced. Because of the longer mean free path, electrons cause ionization at the center, which raises the ion density to about 1.44 × 10¹⁵ m⁻³ and the electron temperature to about 2.9 eV.