Spectral evolution of multiply-impulsive solar bursts

Technical Report · Wed Nov 01 04:00:00 EST 1978

OSTI ID:5905921

Karpen, J T; Crannell, C J; Frost, K J

Hard X-ray and microwave observations of multiply-impulsive solar bursts, identified in the OSO-5 data, were analyzed. Spectra in both frequency ranges were used to determine whether or not the source properties change from peak to peak within individual bursts. Two categories of microwave spectral behavior were identified: those events during which the microwave turnover frequency and spectral shape remain the same from peak to peak, and those during which the turnover frequency and spectral shape change significantly. These categories correspond to two classes of multiply-impulsive bursts: those for which the emission can be characterized by a constant magnetic field and therefore a single source region, in which case the multiplicity may be due to modulation of the emission process; and those in which groups of component spikes appear to originate in regions of different magnetic-field strengths, corresponding to separate source regions which flare sequentially. Examples of the latter type of events are presented. The discrete flaring regions are analyzed, and their spatial separations, estimated.

• Research Organization: National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
• OSTI ID: 5905921
• Report Number(s): N-79-13985
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BREMSSTRAHLUNG
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
HARD X RADIATION
IONIZING RADIATIONS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
MICROWAVE RADIATION
MICROWAVE SPECTRA
ORBITING SOLAR OBSERVATORIES
RADIATIONS
SATELLITES
SOLAR ACTIVITY
SOLAR FLARES
SOLAR X-RAY BURSTS
SPATIAL DISTRIBUTION
SPECTRA
STARS
SUN
X RADIATION
X-RAY SPECTRA