Methling, Ralf

Double-pulse laser induced breakdown spectroscopy (LIBS) measurements in water with up to 600 bar hydrostatic pressure and 150 mJ energy of each pulse were done to select a setup which promote separated spectral lines in the observed plasma emission even at elevated pressures, where line broadening until loss of the most spectral information can occur. For this a compact spectrometer und a Czerny-Turner spectrometer, both fiber-based, has been applied to investigate the dependence of the emitted radiation on different parameters and hydrostatic pressure.

This work presents the datasets of the results of a self-consistent modelling analysis on microwave plasma generated in Ar-O₂ mixtures at a frequency of 2.45 GHz at atmospheric pressure. The study focuses on how the plasma properties are in uenced by the increase of the oxygen fraction in the gas mixture. The oxygen admixture is increased from 1 up to 95 % in mass for values of the input microwave power of 1 and 1.5 kW.

In this work we present for the first time a unified model of a low-current short-length arc between copper electrodes. The model employs one-dimensional fluid description of the plasma in argon and copper vapour at atmospheric pressure and the heat transfer in the electrodes made of copper. The solution of the particle and energy conservation of electrons and heavy particles is coupled with the solution of the Poisson equation, from which the self-consistent electric field is obtained. The operation of the non-refractory cathode is based on thermo-field emission.