State-selective electron capture by Ar 16 + from H*( n = 2 ) and H( 1 s ): implications for charge exchange recombination spectroscopy diagnostics

Abstract

In this work, we report total and state-selective cross sections for the electron capture of atomic hydrogen in its ground and first excited states by Ar16+ ions at an impact energy range characteristic of relevant fusion devices. These are calculated by means of an extension of the classical trajectory Monte Carlo method, which consideres a target varying nuclear charge scheme, and benchmarked with other state-of-the-art classical and quantum theoretical models of H(1s). Besides, cross sections regarding H*(n=2) targets are observed to be more than an order of magnitude greater at low energies, with respect to the ones considering the target ground state. Spontaneous emission cross sections in the visible spectral range are also calculated, showing an increase of this magnitude difference between the two targets considered. Present results suggest that excited atomic hydrogen provides a significant contribution during the analysis of visible emission spectrum in Ar16+ charge exchange recombination spectroscopy.