Abstract: The principle of plasma diagnosis by Langmuir double-probe is described, and the parameters of glow discharge plasma are measured. Electron temperature and electron density are calculated according to the double-probe I-V characteristic curve, and the variations of electron density are analyzed as a function of discharge current. The diagnosed results are compared with results obtained from quasi-optical cavity, and they show good agreement with each other. They have negligible difference and are in agreement of same variation. The reliability and correctness of using Langmuir double-probe to diagnose glow discharge plasma are verified.

Key words: Langmuir double-probe, Glow discharge, Plasma, Electron density, Volt-ampere characteristic, Curve, Diagnosis