Some Limits on the Effect of Coronal Self-Emission on the Excitation State of Coronal Ions.
Abstract
We continue our earlier work, which showed that isolation of the ground configuration from higher lying configurations is invalid in computing the excitation state of coronal ions, to inquire into the effect of self-emission in some of the resonance lines of these ions. We set limits on the optical thickness of the corona and upper chromosphere for ions of ionization state exceeding He ii, finding a value <= 10 for the range of ions and range of conditions from normal atmosphere to coronal condensations. With this limit on r, we show that mimicking the ionic configuration by that of a two-level atom sets an upper limit on the built-up radiation field. We approximate the atmospheric model and the solution to the transfer equation for a two-level atom with very small E, to compute the relation between this=upper limit on radiation field and r1, the optical thickness of the atmosphere. We conclude that n> 10 is to produce an observable effect on the line; and thus that the C-N-O-Si group in the undisturbed atmosphere is the most useful set of ions for more detailed investigation In coronal condensations, other ions may possibly be used
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1963
- DOI:
- 10.1086/147570
- Bibcode:
- 1963ApJ...137..967P