Ionization equilibrium in solar flares as determined from x-ray emission lines of Ca XVIII and Ca XIX

Journal Article · Tue Dec 15 00:00:00 EST 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159522· OSTI ID:5652611

Doschek, G A; Feldman, U

X-ray emission lines of Ca XIX and Ca XVIII are used for diagnostics of high-temperature flare plasmas (T/sub e/ >10/sup 7/ K). One of the Ca XVIII lines ( q), originating from the transition 1s(2s2p/sup 3/P)/sup 2/P/sub 3/2/..-->..1s/sup 2/2s/sup 2/S/sub 1/2/ is more intense than expected from theoretical calculations. We show that a blend with a line of Ar XVII and possibly another blend with two lines that belong to Ni XXVII may remove part of the discrepancy. After consideration of the accuracy of various ionization equilibrium calculations, it appears that flare plasmas are in or near ionization equilibrium, at least up to helium-like ionization stages.

• Research Organization: E. O. Hulburt Center for Space Research, Naval Research Laboratory
• OSTI ID: 5652611
• Journal Information: Astrophys. J.; (United States), Vol. 251:2
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALCIUM IONS
X-RAY SPECTRA
SOLAR FLARES
IONIZATION
ARGON IONS
EMISSION SPECTRA
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EQUILIBRIUM
NICKEL IONS
PLASMA
CHARGED PARTICLES
IONS
SOLAR ACTIVITY
SPECTRA
640104* - Astrophysics & Cosmology- Solar Phenomena