THE NATURE OF THE GAMMA EMISSION OF SOLAR FLARES AND THE FORMATION OF COSMIC PARTICLES IN ACTIVE SOLAR REGIONS

Journal Article · Fri Jan 01 04:00:00 EST 1960 · Astron. Zhur.

OSTI ID:4017830

Gordon, I M

Balloon observations over Cuba were carried out during a chromospheric flare of class II. A short flare of gamma rays was detected with the energy 5 x 10/sup 5/ ev and the duration 18 sec. The gamma radiation was identified with bremsstrahlung radiation due to electrons with energies of the order of 1 Mev. The number of such electrons would have to be about 2.4 x 10/sup 34/ and should originate in the solar photosphere. This interpretation meets with serious difficulties. The present argument is that two-photon positron-electron annihilation is responsible for the gamma radiation. The necessary density of the part of the solar atmosphere in which this process takes place can be shown to be 5 x 10/sup -11/ g/cm/sup 3/ or n = 3 x 10/sup 13/ cm/sup -3/. This density corresponds to the lower layers of the chromosphere. It is also necessary at this density that the positrons should be decelerated before they take part in this annihilation process. If not, the gamma spectrum would extend far into the short-wave region. Calculations show that the time necessary for the positrons to be retarded to an energy of 0.1 mc/sup 2/ is much smaller than 0.1 sec. Thus, the positrons are in fact able to lose most of their energy prior to annihilation so that the energy of the photons produced in the annihilation is of the order of the rest mass of the electron. Assuming that the total energy emitted in the form of gamma rays during the flare was 3 8 x 10/sup 24/ ergs, it can be shown that the number of positrons necessary is 2.4 x 10/sup 30/. If the total area of the flare was 1.5 x 10/sup 20/ and the thickness of the region was 10/sup 8/ cm, then the necessary concentration of positrons is found to be 100 cm/sup -3/. If the annihilation hypothesis is correct, then the observed radiation should have an intensity discontinuity at 5 x 10/sup 5/ ev. (OTS)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-15-025375
• OSTI ID: 4017830
• Journal Information: Astron. Zhur., Journal Name: Astron. Zhur. Vol. Vol: 37
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACCELERATION
ANNIHILATION
BALLOONS
BREMSSTRAHLUNG
COSMIC RADIATION
DENSITY
ELECTRONS
ENERGY
ENERGY RANGE
LOSSES
MAGNETIC FIELDS
MEASURED VALUES
NUMERICALS
PHOTONS
PHYSICS
POSITRONS
PRODUCTION
SOLAR FLARES
SUN
THICKNESS