Observational evidence for nonequilibrium ionization in the solar corona
Abstract
We investigate whether temperature sensitive EUV line ratios can be used as observational signatures for the presence of nonequilibrium ionization in transition region plasma. We compute the total intensity of some EUV lines of carbon and oxygen expected from coronal loop models with a steadystate flow and which are known to have significant departures from ionization equilibrium, selecting lines whose intensity ratios are useful for deducing the electron temperature in the coronal plasma. We calculate the intensity ratios with and without the approximation of ionization equilibrium, in order to determine the effects of any deviations from equilibrium on the numerical values of the line ratios examined.
 Publication:

Space Science Reviews
 Pub Date:
 October 1994
 DOI:
 10.1007/BF00777870
 Bibcode:
 1994SSRv...70..207S
 Keywords:

 Sun;
 Corona;
 EUV lines