This title appears in the Scientific Report : 2020 

The Balmer lines emission of fast hydrogen atoms at the plasma-solid interface in a low density plasma: challenges and applications
Dickheuer, Sven Oliver (Corresponding author)
Plasmaphysik; IEK-4
Jülich Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag 2020
Dissertation, Univ. Bochum, 2019
Dissertation / PhD Thesis
Schriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment 489
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The wide broadening of Lyman and Balmer lines in H or H mixed plasmas is a widelyobserved and studied phenomena in many kinds of different plasmas, ranging fromstellar to laboratory plasmas. The source of the fast H atoms in front of the surface aswell as the origin of the observed emission in laboratory plasmas is under controversialdiscussion. A. V. Phelps proposes a "sheath-collision" model in which H$^{+}$, H$^{+}_{2}$ and H$^{+}_{3}$ ions are accelerated in the sheath and create fast H atoms by charge transferor dissociation interaction with gas or the metallic surface. There are a number ofexperiments trying to explain the broadening of the lines, but the community couldonly agree on the fact that the broadening is caused by the Doppler effect. Usually experiments in this field are performed in high pressure plasmas (p $\geq$ 1 Pa), but this makes it very difficult to analyze the Doppler-shifted emission due to the following reasons. On the one hand, the high pressure leads to emission of accelerated ions and backscattered atoms which makes the detected signal a superposition of both effects. On the other hand, the emission of ions inside the Debye sheath leads to a Stark broadening of the emitted lines and makes the analysis of the emission spectra complicated. [...]