Publication Date:
2019-07-12
Description:
The paper presents a revised theory and atomic model for the line intensities emitted by O VII, taking into account all of the processes responsible for the emission. This is used to provide a revision of the density measurements made for solar active regions and during flares, as well as an attempt to understand the spectrum of the Puppis A supernova remnant. In order to explain the strange intensity ratios observed from Puppis A, previous authors have proposed an interpretation based upon a high-temperature thermal plasma in a nonequilibrium ionization state. An alternative model is presented here, based upon the assumed presence of a proportion of fast, nonthermal electrons imbedded in an otherwise thermal plasma at a temperature below 10 to the 6th K. This can adequately explain the observations without the necessity of invoking departures from the ionization balance.
Keywords:
ASTROPHYSICS
Type:
Astrophysical Journal, Part 1 (ISSN 0004-637X); 378; 438-444
Format:
text
