Calculation of cross sections relevant for diagnostics of hot fusion plasmas

With the construction of the ITER device in Cadarache (France) thermonuclear fusion research is making another significant step toward the actual exploitation of fusion as a sustainable energy source. ITER is a so-called 'tokamak'-reactor, where the hot deuterium-tritium plasma is confined by strong magnetic fields while being heated by energetic neutral hydrogen beams or intense electromagnetic waves to the temperatures necessary to initiate fusion processes (typically more than 100 million oC). Despite this magnetic confinement particles can still exit the plasma, e.g. through open field lines or anomalous transport, and hit the wall of the plasma vessel. Although H-mode plasmas, the best operation scheme known today, are characterized by a steep temperature gradient at the plasma edge and the temperature of the particles in the scrape-off layer (the outermost layer of a fusion plasma in a tokamak) is much lower than in the plasma center, they are nevertheless at temperatures where it is still problematic for them to be brought into direct contact with a physical wall. It would degrade the wall and the debris from the wall would extinguish the plasma immediately. Magnetic confinement, however, is never perfect. Transport across the field lines eventually will lead to interaction between the plasma and the first wall. The intensity of this plasma-wall-interaction is largely governed by the impact energy (i.e. the local temperature) of the plasma (particles) at the material wall. Therefore, schemes are developed to cool down the plasma locally before it impacts on a physical surface. Among these schemes radiative edge cooling is very promising. A cold, highly radiative edge plasma distributes most of its power uniformly over the first wall. Structural damage due to high local heat deposition could thus be avoided, and the impurity concentration in the plasma caused by erosion of the wall material could be significantly reduced. Controlled injection of impurity gases is a promising technique for enhancement of radiation loss power in thermonuclear fusion experiments. For ITER the use of Argon as radiating impurity has been proposed. To understand the transport of Ar impurities in the plasma edge simulation calculations which model and experimental techniques that diagnose this transport are necessary. Both plasma-modeling and -diagnostics heavily rely on atomic collision cross sections involving Arq+ ions in various charge states and plasma particles like electrons, protons and neutral hydrogen atoms. It is the primary aim of this thesis to provide these cross sections, in particular those, which will be necessary to derive information on the density profiles of Arq+ ions via charge exchange recombination spectroscopy. These cross sections will be obtained by performing state of the art atomic orbital close coupling calculations. Due to the large number of atomic states involved these calculations are challenging and require novel approaches especially in the computational implementation of the problem. Although Argon stands out because of both its complexity and its future use in ITER, several other collision systems of relevance were calculated and studied, namely Be4+, C6+, N6+, N7+ and Neq+ impact on ground and excited state neutral hydrogen. The PhD thesis was performed in close collaboration with leading European fusion laboratories, e.g. the Max-Planck-Institute of Plasma Physics in Garching, Germany, and served as input for the data base on atomic collisions for fusion by the Atomic Data and Analysis (ADAS) group as well as the data base of the integrated tokamak modeling (ITM) task force of the European Fusion Development Agency (EFDA). (author)