Solar wind ion charge state distributions and compound cross sections for solar wind charge exchange X-ray emission

TL;DR

This paper compiles solar wind data and atomic cross-sections to accurately model solar wind charge exchange X-ray emissions, aiding interpretation of astrophysical observations and space mission planning.

Contribution

It provides new calculations of compound cross-sections for SWCX X-ray emission based on solar wind measurements and atomic data, improving modeling accuracy.

Findings

Calculated compound cross-sections for H and He interactions

Analyzed variations across solar wind types and cycles

Enhanced understanding of SWCX X-ray emission mechanisms

Abstract

Solar Wind Charge eXchange X-ray (SWCX) emission in the heliosphere and Earth's exosphere is a hard to avoid signal in soft X-ray observations of astrophysical targets. On the other hand, the X-ray imaging possibilities offered by the SWCX process has led to an increasing number of future dedicated space missions for investigating the solar wind-terrestrial interactions and magnetospheric interfaces. In both cases, accurate modelling of the SWCX emission is key to correctly interpret its signal, and remove it from observations, when needed. In this paper, we compile solar wind abundance measurements from ACE for different solar wind types, and atomic data from literature, including charge exchange cross-sections and emission probabilities, used for calculating the compound cross-section $\alpha$ for the SWCX X-ray emission. We calculate $\alpha$ values for charge-exchange with H and He, relevant to soft X-ray energy bands (0.1 - 2.0 keV) for various solar wind types and solar cycle conditions.