Comparison of analytical methods to determine the electron density and temperature for a laser-based atmospheric plasma jet

Highly dependent on plasma properties and the energy range, different approaches are used for plasma diagnostics. Measurements of the plasma potential, electron density, electron temperature are imperative for a full characterisation. However, when comparing published studies it seems that different measuring systems produce different results for the same plasma. In order to show that by using different measurement methods varied results are achieved, the following analytical methods are applied for a high-energy laser-based thermal plasma: Langmuir probe measurement, bottleneck equation, emission spectroscopy by Finkelnburg and emission spectroscopy by the Saha equation. The electron density and temperature are determined between 10(17)-10(20) m(-3) and 1.1-1.8 eV by the use of Langmuir probes and 1.3.10(21) m(-3) and 1.0-3.5 eV using emission spectroscopy. Comparison to other studies shows that our results are in the same range, according to the method of analysis. It is conspicuous that the choice of a measurement method predetermines the results in a certain range. This indicates that the chosen method has a huge impact on the resulting outcomes. (C) 2016 Elsevier B.V. All rights reserved.