Fig. 6From: Non-invasive assessment of plasma parameters inside an ion thruster combining optical emission spectroscopy and principal component analysisPCA scores from the cw OES measurements of a xenon plasma (a) and the corresponding electron temperatures and densities from the simultaneously conducted Langmuir double probe measurements (b). The PCA scores of the spectra shown in Fig. 5a from the 0.10 sccm measurement series (shown in red here) are clearly distinguishable. The input power increases from left to right in both plots (a) and (b). The fits of the electron temperature (c) and density (d) over the PCA scores are the depict correlation between OES and plasma parametersBack to article page