Semiempirical models of chromospheric flare regions

Journal Article · Sat Nov 15 04:00:00 EST 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158467· OSTI ID:6524983

Machado, M E; Avrett, E H; Vernazza, J E; Noyes, R W

We present homogeneous plane-parallel semiempirical flare model atmosphere that approximately reproduce observations in lines and continua of H I, Si I, C I, Ca II, and Mg II. The models have a thin transition zone at the top of an enhanced chromosphere, and they imply a substantial amount of heating from the transition zone down to the temperature minimum level. In these flare models the minimum temperature is located deeper and has a higher temperature than in quiet-Sun and active-region models. Our results are compared with theoretical models that invoke different modes of energy transfer from the corona into the chromosphere. Significant discrepancies are found in our comparison with the particle-heated models. We propose ways to resolve these discrepancies. Our radiative transfer solution shows that there is substantial L..cap alpha.. radiative heating in the upper chromosphere. The source of this heating may be the conductive energy flux in the transition zone where the L..cap alpha.. line cools the gas.

• Research Organization: Harvard-Smithsonian Center for Astrophysics
• OSTI ID: 6524983
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 241:4; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BALMER LINES
CHROMOSPHERE
COOLING
ENERGY SPECTRA
ENERGY TRANSFER
HEAT TRANSFER
LINE BROADENING
LINE WIDTHS
LYMAN LINES
MATHEMATICAL MODELS
RADIATION FLUX
RADIATION TRANSPORT
RADIATIVE COOLING
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR FLARES
SPECTRA
STAR MODELS
THERMAL CONDUCTION