Presentation #107.18 in the session “ISM/Galaxies/Clusters (Poster)”.
Charge exchange between highly charged ions and neutrals offers a window on the plasma interactions between the solar wind and atmospheres of small bodies in the solar system, but it also introduces a problematic background in every astrophysical x-ray observation . For H-like ions produced by charge exchange between bare ions and neutrals, the angular momentum states l within each principle quantum n shell are degenerate. In the absence of nl-resolved charge exchange cross sections, n-resolved cross sections are typically used in spectral models. Two analytical angular momentum distributions are commonly applied to n-resolved cross sections: a ‘low energy’ distribution and a ‘statistical’ distribution. For typical solar wind velocities (300–1000 km/s or 0.5–5 keV/amu), the most appropriate choice is not known. We report nl-resolved charge exchange cross sections, calculated using the time-dependent close-coupling (TDCC) theory, for bare Ne incident on atomic H and He at solar wind velocities, 1–5 keV/amu. Using an x-ray cascade model, we compute important line ratios and compare our results against both n- and nl-resolved data in literature. We comment on trends between emergent l-distributions (TDCC, present work and ) and analytical models, e.g. the statistical l-distribution, and implications for the applicability of n-resolved charge exchange cross sections.
This work was supported in part by grants from the US National Science Foundation, the US National Aeronautics and Space Administration, and the US Department of Energy. Computational work was carried out at the National Energy Research Scientific Computing Center in Oakland, California, and the High Performance Computing Center in Stuttgart, Germany.
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