Charge Exchange Reaction Rate Evaluation for Different Impurities at Moderate Temperatures

Abstract

This bachelor thesis is dedicated to the Gas Puff-Charge Exchange Recombination Spectroscopy (GP-CXRS), a spectroscopy diagnostic that provides information on different parameters in a plasma such as the impurity ion temperature, rotation and density along the viewing lines of sight (LOS). The method consists in the injection of a thermal neutral gas in the plasma. The neutrals experience a charge-exchange reaction leading to a transfer of one electron to an impurity ion. As the impurity ion is now in an excited state, it will decay to a lower energy state emitting a characteristic photon. This is, a characteristic radiation that can be measured in the form of spectroscopy. As for impurity ion density, charge exchange effective emission rates are needed, a code written in Python is developed in order to calculate those rates from raw CXRS cross-sections. The cross-sections for every studied CXRS reaction are taken from the database OpenAdas. Different effects in the charge exchange (CX) reaction must be considered: nl-cascade and l-mixing effects. The objective is to have a code that can then be used to study any CXRS reaction. Thus, the final results will be first compared with the ones obtained by [1] to make sure that the code performs as expected. Moreover, a suitable reaction for CXRS at the SMART tokamak of the University of Sevilla will be identified.