2016/01/22 by Liyi Gu, Jelle Kaastra, J. S. Kaastra +1 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Atomic and Molecular Physics #Atomic physics #Charge (physics) #Charge exchange #Comet #Emission spectrum #High-pressure geophysics and materials #Ion #Nuclear physics #Optics #Physics #Plasma #Radiation #Radiative transfer #Solar wind #Spectral line #astro-ph.EP #astro-ph.GA #astro-ph.HE #astro-ph.IM #physics.atom-ph
paper · pdf · doi:10.1051/0004-6361/201527615
published as A&A 588, A52 (2016) · Accepted for publication in Astronomy & Astrophysics
arxiv created 2016/01/22 · openalex publication_date 2016/02/05 · arxiv updated 2016/03/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Charge exchange X-ray emission provides unique insight into the interactions between cold and hot astrophysical plasmas. Besides its own profound science, this emission is also technically crucial to all observations in the X-ray band, since charge exchange with the solar wind often contributes a significant foreground component that contaminates the signal of interest. By approximating the cross sections resolved to n and l atomic subshells and carrying out complete radiative cascade calculation, we have created a new spectral code to evaluate the charge exchange emission in the X-ray band. Compared to collisional thermal emission, charge exchange radiation exhibits enhanced lines from large-n shells to the ground, as well as large forbidden-to-resonance ratios of triplet transitions. Our new model successfully reproduces an observed high-quality spectrum of comet C/2000 WM1 (LINEAR), which emits purely by charge exchange between solar wind ions and cometary neutrals. It demonstrates that a proper charge exchange model will allow us to probe the ion properties remotely, including charge state, dynamics, and composition, at the interface between the cold and hot plasmas.