Investigation of the disturbance of a Langmuir probe and its influence on measurement results

Measurements of plasma parameters by Langmuir probes are influenced by the probe system itself. This article considers the deviation of plasma parameters determined by probe measurements from those in the undisturbed plasma. For this reason the particle density of the excited atoms of a neon plasma in the very vicinity of the probe is compared with the particle density in the undisturbed case. The densities of the excited metastable 1s5 level were measured by laser absorption spectroscopy. By solving the plasma balance equations the deviation of the electron density and the deviation of the electric field could be deduced.