XUV spectra of the 1973 June 15 solar flare observed from Skylab. II. Intersystem and forbidden transitions in transition zone and coronal ions

Journal Article · Fri Jul 15 00:00:00 EDT 1977 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/155399· OSTI ID:7304700

Feldman, U; Doschek, G A; Rosenberg, F D

An analysis is given of the intersystem lines of transition zone ions and high-temperature forbidden lines for the 1973 June 15 flare. The electron density in the erupting part of the plasma is at least approx.10/sup 13/ cm/sup -3/ at temperatures of approx.1.3 x 10/sup 5/ K. The density of the stationary component of the flare plasma at similar temperatures varies between approx.1.5 x 10/sup 11/ cm/sup -3/ and approx.10/sup 12/ cm/sup -3/. A density decrease observed in the stationary component occurs nearly simultaneously with an intensity enhancement of forbidden coronal lines such as Fe XII. These lines are believed to originate in arch-type structures. The electron density in the temperature regions approx.1.5 x 10/sup 6/ K is between 2 x 10/sup 10/ cm/sup -3/ and 2 x 10/sup 11/ cm/sup -3/. These regions appear to be stationary. Their motion relative to the observer is less than 4 km s/sup -1/. A continuous energy input is necessary to account for the transition zone emission. The transition zone emission arises in small regions, perhaps filaments.

• Research Organization: E. O.,Hulburt Center for Space Research, Naval Research Laboratory, Washington, D.C.
• OSTI ID: 7304700
• Journal Information: Astrophys. J.; (United States), Vol. 215:2
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SOLAR FLARES
ULTRAVIOLET SPECTRA
CHEMICAL COMPOSITION
ELECTRON DENSITY
ENERGY LEVELS
FORBIDDEN TRANSITIONS
IONS
PLASMA
SOLAR CORONA
SPECTRAL FUNCTIONS
CHARGED PARTICLES
ENERGY-LEVEL TRANSITIONS
FUNCTIONS
SOLAR ACTIVITY
SPECTRA
640104* - Astrophysics & Cosmology- Solar Phenomena