Energetic electrons in impulsive solar flares

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5097061

Batchelor, D A

Impulsive bursts of hard X rays and microwaves are observed during most solar flares, and both emissions can be attributed to a common distribution of source electrons with energies from approximately 10 keV to several hundred keV. A detailed account of the evolution of the electron distribution is crucial to a complete description of the energy release process in flares. In this dissertation, a new analysis is made of a thermal flare model proposed by Brown, Melrose, and Spicer (1979) and Smith and Lilliequist (1979). Brown, Melrose, and Spicer (1979) and Smith and Brown (1980) argued that the source assumed in this model would not explain the simultaneous impulsive microwave emission. In contrast, the new results presented here show that this model leads to the development of a quasi-Maxwellian distribution of electrons that explains both the hard x-ray and microwave emissions. This implies that the source sizes can be determined from observations of the optically-thick portions of microwave spectra and the temperatures obtained from associated hard x-ray observations. The x-ray observations were obtained with the Hard X-ray Burst Spectrometer on board the Solar Maximum Mission spacecraft, and the microwave observations were obtained from the Bern Radio Observatory in Switzerland. The results of this investigation are in good agreement with the model and are not explained by any other flare models which have been considered. A re-evaluation of contradictory reports regarding the visibility of individual starspots led to the conclusion that large spots would indeed be observable with equipment of high precision. A comprehensive physical and evolutional model for the cumulative spectroscopic and photometric behavior of AR Lac was constructed by augmentation of other models and incorporation of the results of the present investigation.

• Research Organization: North Carolina Univ., Chapel Hill, NC (USA)
• OSTI ID: 5097061
• Country of Publication: United States
• Language: English

Related Subjects

640100* -- Astrophysics & Cosmology
640104 -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DATA
ELECTRON EMISSION
EMISSION
ENERGY RANGE
EXPERIMENTAL DATA
INFORMATION
KEV RANGE
KEV RANGE 10-100
KEV RANGE 100-1000
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEASURING METHODS
NUMERICAL DATA
SOLAR ACTIVITY
SOLAR FLARES