Empirical models of solar flare X ray and EUV emission for use in studying their E and F region effects

Journal Article · Wed Sep 01 00:00:00 EDT 1976 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA081i025p04745· OSTI ID:7261795

Donnelly, R F

The time structure and spectra of X ray and extreme ultraviolet (EUV) bursts during solar flares are described from the viewpoint of evaluating their ionospheric effects. The impulsive flare component is strong in emission from solar source regions with temperatures in the range 10/sup 4/degreeK--10/sup 6/degreeK, which are strong in the 90- to 1027-A range. The strength of the impulsive EUV emissions incident on the ionosphere depends on the location of the flare on the sun. The impulsive EUV emission produces short-lived large absolute enhancements of photo-ionization rates above the bottom of the preflare E layer and in the F region. The slow components are very strong in emission from solar sources with temperatures in the range 1--30 x 10/sup 60/K and are particularly strong at soft X ray wavelengths (1--90 A). The slow 1- to 8-A burst causes the large percentage increase in ionization production below the bottom of the preflare E layer and in the D region. The large absolute flare emission in the 8- to 90-A emission and the K shell absorption edge of N/sub 2/ near 31 A causes the large slow enhancement of photo-ionization in the 100- to 130- km altitude range. (AIP)

• Research Organization: Space Environment Laboratory, NOAA Environmental Research Laboratories, Boulder, Colorado 80302
• OSTI ID: 7261795
• Journal Information: J. Geophys. Res.; (United States), Vol. 81:25
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
E REGION
IONIZATION
F REGION
SOLAR FLARES
EXTREME ULTRAVIOLET RADIATION
X RADIATION
SOLAR ACTIVITY
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
IONOSPHERE
RADIATIONS
ULTRAVIOLET RADIATION
640104* - Astrophysics & Cosmology- Solar Phenomena
640201 - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena