Accession Number:

ADA464569

Title:

Accelerated Particle Composition and Energetics and Ambient Abundances from Gamma-Ray Spectroscopy of the 1991 June 4 Solar Flare

Descriptive Note:

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC E O HULBURT CENTER FOR SPACE RESEARCH

Report Date:

1997-01-01

Pagination or Media Count:

59.0

Abstract:

The Oriented Scintillation Spectrometer Experiment OSSE on board the COMPTON Gamma Ray Observatory observed the 1991 June 4 X12 solar flare, one of the most intense nuclear gamma-ray line flares observed to date. Using these OSSE observations, we have derived time profiles of the various components of gamma-ray emission and obtained information about the accelerated particle spectra and composition and about the ambient plasma at the flare site. The main results are 1 the nuclear reactions associated with the impulsive phase of the are continued for at least 2 hours and resulted from ions that were probably continuously accelerated rather than impulsively accelerated and trapped 2 the total energy in these accelerated ions exceeded the energy in 0.1 MeV electrons 3 the accelerated alphaproton ratio was closer to 0.5 than to 0.1 4 there is evidence for a decrease of the accelerated heavy ion-to-proton ratio as the are progressed 5 there is evidence for a temporal change in the composition of the flare plasma 6 the ratio of electron bremsstrahlung to the flux in narrow gamma-ray lines decreased as the flare progressed 7 the high-energy 16 MeV component of the electron spectrum was much more impulsive than the lower-energy MeV component 8 a model-dependent upper limit of 2.3 x 10exp -5 was obtained for the photospheric 3HeH abundance ratio and 9 energetic ions may have been present for several hours prior to and following the impulsive phase of the flare.

Subject Categories:

  • Astrophysics
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE