Accession Number : ADA136266

Title :   Characteristics of Gamma-Ray Line Flares,

Corporate Author : STANFORD UNIV CA INST FOR PLASMA RESEARCH

Personal Author(s) : Bai,T ; Dennis,B

PDF Url : ADA136266

Report Date : Oct 1983

Pagination or Media Count : 54

Abstract : Observations of solar gamma rays by the Solar Maximum Mission (SMM) have demonstrated that energetic protons and ions are rapidly accelerated during the impulsive phase. In order to understand the acceleration mechanisms for these particles, we have studied the characteristics of the gamma-ray line flares observed by SMM. Because we discovered that the gamma-ray line flares emit very intense hard X-rays, we have also studied very intense hard X-ray flares without detectable gamma-ray lines. The following characteristics distinguish gamma-ray line flares from other flares: Intense hard X-ray and microwave emissions; Delay of high-energy hard X-ray; Emission of type II and/or type IV radio bursts; and Flat hard X-ray spectra (average power-law index: 3.1). The majority of the gamma-ray line flares shared all these characteristics, and the remainder shared at least three of them. Among gamma-ray line flares we have found positive correlations between the following pairs of quantities: duration of spike bursts and spatial sizes to flare loops; and delay times and durations of spike bursts.

Descriptors :   *Solar flares, *Gamma rays, *Gamma ray spectra, Protons, Heavy ions, Energetic properties, Acceleration, Spectral lines, Hard x rays, Intensity, Emission, Microwaves, Burst transmission, Radio signals, X ray spectra

Subject Categories : Astrophysics
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE