IONIZATION AND EXCITATION EQUILIBRIUM OF Ca II IN THE SOLAR ATMOSPHERE
Ionization and excitation configurations for Ca II are computed for conditions appropriate to the solar chromosphere. The populations of energy levels are found to depart sharply from the local-thermodynamic-equilibrium values a corresponding values of T/sub e/. The dominant ionization process of Ca II is shown to be via collisions from the 3D level and to exhibit fundamental differences from H, He, and Mg I, as well as some similarities. For electron densities and temperatures such as are expected in most of the solar chromosphere and corona, the ratio Ca II/Ca III is shown to be essentially independent of electron density, rather than directly proportional as predicted by the Saha equation. Computations of opacities and occupation numbers indidate that the Ca II H and K lines in the Fraunhofer spectrum are formed near the top of the hydrogen temperature plateau, where Te approximately 15,000 deg , and that the Ca II emission from spicules arises from regions where Te approximately 15,000 deg rather than the much higher temperature derived from profiles of hydrogen and helium lines. (auth)
- Research Organization:
- High Altitude Observatory, Boulder, Colo
- NSA Number:
- NSA-16-029603
- OSTI ID:
- 4775307
- Journal Information:
- Astrophysical Journal (U.S.), Vol. Vol: 136; Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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