2025/08/13 by Grilo, Filipe, Botz, Marc, Shah, Chintan +3 · 1 citation
#Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Plasma Physics (physics.plasm-ph)
paper · doi:10.48550/arxiv.2508.09975
We report measurements of the Kα emission from the astrophysically very abundant Ca XIX (He-like ion) and its satellite lines resonantly excited by dielectronic recombination (DR). We achieve an electron-energy resolution of 8 eV in a cryogenic electron beam ion trap, and determine the energies of the exciting electrons and the emitted photons up to the KLn (n≤ 8) manifold with 0.05% and 0.1% respective uncertainties. For the KLL satellites, energies agree very well with our predictions using the Flexible Atomic Code (FAC) and previous state-of-the-art calculations. Our calculations also agree with our experimental direct excitation cross-sections for Kα within their 10% uncertainty. We extract DR coefficient rates and find good agreement with values tabulated in the OPEN-ADAS database. As an application, we experimentally benchmark Ca XIX atomic data used to model high-temperature astrophysical plasmas by comparing FAC synthetic spectra with recent XRISM observations revealing the contributions of DR satellites to the Ca XIX lines.