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In this paper, the plasma parameters of hydrogen glow discharge were measured using Langmuir probe system. To measure these parameters in Damavand tokamak, different parts of the Langmuir probe were designed and fabricated. The electrode used in this system is a tungsten wire with diameter and length of 0.1 and 6 mm, respectively. The electrical circuit constructed for this system is capable of supplying voltage and current in the order of 400 V and 1 A, and can produce triangular pulses in the frequency range of 10 Hz to 10 kHz, respectively. Glow discharge hydrogen plasma, which is used for vacuum vessel cleaning and conditioning, is produced by two electrodes located in the lower part of the Damavand tokamak with the voltage of 450 V, current of 1.5 A and pressure of 10-3 Torr. By applying voltage to the electrode of probe, in the range of 200 to 350 V, the current drawn from the probe was measured. By interpreting the current-voltage characteristic, the plasma parameters were determined. The electron temperature, plasma density, plasma potential, and Debye length of the hydrogen glow discharge measured using this system are 5.8e V, 1.17×1015 m-3, 236 V and 523 μm, respectively.

In this paper, a one-dimensional simulation for discus plate dielectric barrier discharge (DBD) is done by COMSOL Multiphysics software. The effects of different parameters such as voltage, frequency, dielectric thickness, dielectric constant and electrode’s material on the temperature and density of electrons are investigated, it is found that secondary electron emission coefficient of the electrode, dielectric constant and the thickness of dielectric have a direct impact on the density of electron. The voltage increment from 5 to 50 kV, causes electron density growing from 4×1017m-3 to 3.2×1018m-3. Based on this study, electron density could reach up to the orders of 1018m-3 by optimizing material and dimensions of dielectric and electrodes without applying high voltage and frequency which results a significant lower production cost.

In this paper we have used plasma electron cyclotron emissions at the second harmonic frequency of extraordinary mode to determine the temperature profile of the plasma produced in IR-T1 Tokamak. The emissions obtained at different frequencies by a 5-channel heterodyne receiver, have been analyzed to determine the spatial variation of the electron temperature on the plasma cross section. The results have been also used to show the three-dimensional time evolution of the temperature profile during the period of confinement.