A burst of high-energy radiation coincident with a solar flare has been detected during a balloon flight at 10 gm/cm2 atmosphere depth and 30° geomagnetic latitude over Cuba. The flare occurred at 1305 UT on March 20, 1958 and was associated with solar radio bursts on 1,500 and 10,000 Mc/s. Terrestrial effects included a SID, earth-current disturbances, and a magnetic crotchet. The 18-second burst was detected with an integrating ionization chamber and a single Geiger counter. From these two instruments and their ratio, it is inferred that the radiation is due to a gamma-ray flux of about 2×10−5 ergs/sec cm2 peaked in the 200 to 500-Kv region. This radiation can be interpreted as bremsstrahlung produced in the solar photosphere from electrons of 0.5 to 1 Mev energy. These same electrons, spiraling in a 1000-gauss field in the flare region, can produce the observed radio burst by betatron radiation. The high-energy electrons represent about 1 per cent of the flare energy. Only about 0.01 per cent of the emitted betatron radiation escaped from the flare region toward the earth.
[1]
E. Parker.
Origin and Dynamics of Cosmic Rays
,
1958
.
[2]
H. Dodson.
Studies at the McMath-Hulbert Observatory of Radio Frequency Radiation at the Time of Solar Flares
,
1958,
Proceedings of the IRE.
[3]
H. Zirin,et al.
Rocket Observation of X-Ray Emission in a Solar Flare
,
1957,
Nature.
[4]
H. Friedman,et al.
Rocket Observation of X-Ray Emission in a Solar Flare
,
1957,
Nature.
[5]
S. Singer,et al.
COSMIC-RAY INCREASES PRODUCED BY SMALL SOLAR FLARES
,
1958
.
[6]
J. Simpson.
SOLAR ORIGIN OF CHANGES IN THE PRIMARY COSMIC RADIATION
,
1957
.
[7]
A. Thompson,et al.
The Radio Spectrum of Solar Activity
,
1958,
Proceedings of the IRE.
[8]
R. Hoffman,et al.
X-Rays from Visible Aurorae at Minneapolis
,
1958
.
[9]
E. Parker.
ACCELERATION OF COSMIC RAYS IN SOLAR FLARES
,
1957
.
[10]
Julian Schwinger,et al.
On the Classical Radiation of Accelerated Electrons
,
1949
.