Dynamic evolution of the source volumes of gradual and impulsive solar flare emissions

Technical Report · Tue Dec 01 04:00:00 EST 1987

OSTI ID:5438542

Bruner, M E; Crannell, C J; Goetz, F; Magun, A; Mckenzie, D L

This study compares flare source volumes inferred from impulsive hard x rays and microwaves with those derived from density sensitive soft x ray line ratios in the O VII spectrum. The data for this study were obtained with the SMM Hard X-Ray Burst Spectrometer, Earth-based radio observatories, and the SOLEX-B spectrometer on the P78-1 satellite. Data were available for the flares of 1980 April 8, 1980 May 9, and 1981 February 26. The hard x ray/microwave source volume is determined under the assumption that the same electron temperature or power law index characterizes both the source of hard x rays and the source of microwaves. The O VII line ratios yield the density and volume of the 2 X 10 to the 6th K plasma. For all three flares, the O VII source volume is found to be smallest at the beginning of the flare, near the time when the impulsive hard x ray/microwave volume reaches its first maximum. At this time, the O VII volume is three to four orders of magnitude smaller than that inferred from the hard x ray/microwave analysis. Subsequently, the O VII source volume increases by one or two orders of magnitude then remains almost constant until the end of the flare when it apparently increases again.

• Research Organization: National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
• OSTI ID: 5438542
• Report Number(s): N-88-16621; NASA-TM-87815; REPT-88-B-0077; NAS-1.15:87815
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ATMOSPHERES
CHROMOSPHERE
DATA
ELECTROMAGNETIC RADIATION
EVAPORATION
EXPERIMENTAL DATA
INFORMATION
IONIZING RADIATIONS
MICROWAVE RADIATION
NUMERICAL DATA
PHASE TRANSFORMATIONS
RADIATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR FLARES
SOLAR RADIATION
SPECTRA
STELLAR RADIATION
X RADIATION