Explosive plasma flows in a solar flare

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165919· OSTI ID:5438495

Zarro, D M; Canfield, R C; Metcalf, T R; Strong, K T

Solar Maximum Mission soft X-ray data and Sacramento Peak Observatory H-alpha observations are combined in a study of the impulsive phase of a solar flare. A blue asymmetry, indicative of upflows, was observed in the coronal Ca XIX line during the soft X-ray rise phase. A red asymmetry, indicative of downflows, was observed simultaneously in chromospheric H-alpha emitted from bright flare kernels during the period of hard X-ray emission. Combining the velocity data with a measurement of coronal electron density, it is shown that the impulsive phase momentum of upflowing soft X-ray-emitting plasma equalled that of the downflowing H-alpha-emitting plasma to within one order of magnitude. In particular, the momentum of the upflowing plasma was 2 x 10 to the 21st g cm/s while that of the downflowing plasma was 7 x 10 to the 21st g cm/s, with a factor of 2 uncertainty on each value. This equality supports the explosive chromospheric evaporation model of solar flares, in which a sudden pressure increase at the footprint of a coronal loop produces oppositely directed flows in the heated plasma. 21 references.

• Research Organization: Applied Research Corp., Greenbelt, MD (USA); Hawaii Univ., Honolulu (USA); California Univ., San Diego (USA); Lockheed Research Laboratories, Palo Alto, CA (USA)
• OSTI ID: 5438495
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 324; 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
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
EVAPORATION
FLUID MECHANICS
HARD X RADIATION
HYDRODYNAMICS
IONIZING RADIATIONS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PHASE TRANSFORMATIONS
PLASMA
RADIATIONS
SOFT X RADIATION
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR FLARES
X RADIATION