Energetic electrons, type III radio bursts, and impulsive solar flare X-rays

Journal Article · Sat Aug 01 04:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159121· OSTI ID:5973595

Kane, S R

Observations of impulsive hard X-ray and type III radio bursts made during the maximum of the last solar activity cycle have been analyzed for a statistical study of the relationship between these two solar flare phenomena. Spectral measurements of 10--68 keV X-rays, which covered 7068 hr of observation time and the range 10/sup -8/ to 10/sup -5/ ergs cm/sup -2/ s/sup -1/ of flux of X-rays > or approx. =20 keV, were made with the University of California (Berkeley) experiment aboard the OGO 5 satellite. The radio data consisted of copies of the original spectral records as well as tabulated data. The principle findings are: (1) about 20% of impulsive hard X-ray bursts are correlated with type III radio bursts; conversely, only approx.3% of the reported type III radio bursts are correlated with impulsive X-rays bursts; (2) the location of the associated H..cap alpha.. flare on the solar disk has little or no effect on the X-ray--type III burst correlation; (3) the magnitude of the X-ray--type III burst correlation increases systematically with the increase in the following quantities: intensity and starting frequency of the type III burst, peak energy flux and spectral hardness of the X-ray burst, and the peak nonthermal emission measure and spectral hardness of the ''instantaneous'' electron spectrum > or approx. =20 keV inside the x-ray source; (4) the observations are consistent with the electron populations responsible for both the X-ray and type III emissions being accelerated in a single acceleration process; (5) the observations suggest a flare model where the primary instability responsible for electron acceleration during the impulsive phase occurs in the corona. The exact location of this instability varies from one flare to another as well as during the impulsive phase of a single flare and determines the hardness of the accelerated electron spectrum and the characteristics of associated X-ray, EUV, optical, and radio emissions.

• Research Organization: Space Sciences Laboratory, University of California, Berkeley
• OSTI ID: 5973595
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 247:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTROMAGNETIC RADIATION
ELECTRON SPECTRA
ELECTRONS
ELEMENTARY PARTICLES
EMISSION
FERMIONS
LEPTONS
RADIATIONS
RADIOWAVE RADIATION
SOLAR ACTIVITY
SOLAR ELECTRONS
SOLAR FLARES
SOLAR PARTICLES
SOLAR RADIATION
SOLAR RADIO BURSTS
SOLAR RADIOWAVE RADIATION
SOLAR X-RAY BURSTS
SPECTRA
STELLAR RADIATION
X-RAY SPECTRA