THE EFFECT OF HOT CORONAL ELECTRONS ON EXTREME-ULTRAVIOLET SPECTRAL LINES OF He II EMITTED BY SOLAR TRANSITION REGION PLASMAS
- Artep Inc. 2922 Excelsior Spring Circle, Ellicott City, Columbia, MD 21042 (United States)
- Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)
- Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)
The cause of the lower intensities of extreme-ultraviolet (EUV) He II lines emitted by coronal hole (CH) plasmas compared with quiet Sun (QS) plasmas has been the subject of many studies dating back over half a century. In this paper, we study the effect of small amounts of 'hot' electrons at coronal temperatures (T{sub e} = 1.4 x 10{sup 6} K) on the intensities of EUV He II lines, as well as on the intensities of EUV lines of C III, C IV, O III, and O IV emitted by 1.5 x 10{sup 4} K-1.5 x 10{sup 5} K (4.2 <= log T{sub e} <= 5.2) plasmas in the QS. We show that although the influence of a fraction as small as 10{sup -4}-10{sup -3} of hot electrons on the intensities of the C and O lines is noticeable, the effect on the intensities of the He lines is much larger, to the extent that it could explain the excess brightness of He II lines emitted by QS regions relative to CH plasmas.
- OSTI ID:
- 21392482
- Journal Information:
- Astrophysical Journal, Vol. 708, Issue 1; Other Information: DOI: 10.1088/0004-637X/708/1/244; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
AGE ESTIMATION
BRIGHTNESS
EXTREME ULTRAVIOLET RADIATION
PLASMA
SOLAR ELECTRONS
STELLAR ATMOSPHERES
SUN
ATMOSPHERES
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
MAIN SEQUENCE STARS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SOLAR PARTICLES
SOLAR RADIATION
STARS
STELLAR RADIATION
ULTRAVIOLET RADIATION