Langmuir Probe Measurements of an Expanding Argon Plasma

In this work, we studied the effects of the discharge current, gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement. The argon plasma was created by a one-cathode arc source. The experimental results show that with increasing discharge current and gas flow rate, the electron temperature and density increase. It is found that when the discharge current is 70 A, 90 A and 110 A at an argon flow rate of 2000 sccm, the electron densities at about 0.186 m distance from the nozzle are 13.00×10 ¹⁸ m ⁻³, 14.04×10¹⁸ m ⁻³ and 15.62×10¹⁸ m ⁻³, and the electron temperatures are 0.38 eV, 0.58 eV and 0.71 eV, respectively. The positive I-V characteristic is explained.