Modulation of solar flare particles and track density profiles in gas-rich meteorite grains
Calculations of the time-averaged solar flare particle density distribution as a function of energy per nucleon and distance from the sun are presented via standard diffusion-convection-adiabatic decelaration theory with a diffusion coefficient independent of distance from the sun. Normalization at the orbit of earth is accomplished via observed track density versus depth profiles in lunar vug crystals. Applying the results of these calculations to irradiated grains from gas-rich meteorites leads to the prediction that if these grains were irradiated in the asteroid belt and if source and modulation parameters have changed little since irradiation, then the track density profile should be 'harder' than the lunar vug profile by about 0.2--0.3 in the index. Within this framework, knowledge of the time-averaged solar particle flux in the asteroid belt allows a quantitative determination of the solar flare particle exposure ages of the grains by comparison with lunar results; previously determined exposure ages (10/sup 3/--10/sup 4/ years) may be somewhat low. (AIP)
- Research Organization:
- McDonnell Center for the Space Sciences and Department of Physics, Washington Univeristy, St. Louis, Missouri 63130
- OSTI ID:
- 7342874
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 81:19; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CRYSTAL STRUCTURE
GRAIN DENSITY
METEORITES
METEOROIDS
MICROSTRUCTURE
MODULATION
PARTICLE TRACKS
RADIATIONS
SOLAR ACTIVITY
SOLAR FLARES
SOLAR PARTICLES
SOLAR RADIATION
SOLAR SYSTEM EVOLUTION
STELLAR RADIATION