TIME VARIATIONS OF DIRECTIONAL COSMIC RAY INTENSITY AT LOW LATITUDES. III. INTERPRETATION OF SOLAR DAILY VARIATION AND CHANGES OF EAST-WEST ASYMMETRY

Journal Article · Tue Aug 22 04:00:00 EDT 1961 · Proc. Roy. Soc. (London)

DOI:https://doi.org/10.1098/rspa.1961.0151· OSTI ID:4842145

Rao, U R; Sarabhai, V

The daily variation of cosmic ray intensity at low latitudes can under certain conditions be associated with an anisotropy of primary radiation. During 1957--8, this anisotropy had an energy spectrum of variation of the form ae/sup - 0.//sup 8 s/sup 0/ >s/sup .3/ and corresponded to a source situated at an angle of 112 plus or minus 10 deg to the left of the earth-sun line. The daily variation which can be associated with a local source situated along the earth- sun line has an energy spectrum of variation of the form ae/sup 0/. Increases in east-west asymmetry and the associated daily variation for east and west directions can be explained by the acceleration of cosmic ray particles crossing beams of solar plasma in the neighborhocd of the earth. For beams of width 5 x 10/sup 12/ cm with a frozen magnetic field of the order of 10/sup -4/ gauss, a radial velocity of about 1.5 x 10/sup 8/ cm/s is required. The process is possible only if the ejection of beams takes place in rarefled regions of interplanetary space which extend radially over active solar regions. An explanation of Forbush type decreases observed at great distances from the earth requires similar limitation on the plasma density and conductivity of regions of interplanetary space. The decrease of east-west asymmetry associated with world- wide decreases of intensity and with SC magnetic storms is consistent with a screening of the low-energy cosmic ray particles due to magnetic fields in plasma clouds. (auth)

• Research Organization: Physical Research Lab., Ahmedabad, India
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-029876
• OSTI ID: 4842145
• Journal Information: Proc. Roy. Soc. (London), Journal Name: Proc. Roy. Soc. (London) Vol. Vol: A263
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACCELERATION
ANGULAR DISTRIBUTION
ANISOTROPY
COSMIC RADIATION
DENSITY
DISTRIBUTION
DIURNAL VARIATION
EARTH
EAST-WEST ASYMMETRY
ELECTRIC CONDUCTIVITY
ENERGY
ENERGY RANGE
FORBUSH DEPRESSION
GEOMAGNETIC COORDINATES
MAGNETIC FIELDS
MAGNETIC STORMS
MEASURED VALUES
PHYSICS
PLANETS
PLASMA
PRIMARY COSMIC RADIATION
PRODUCTION
SPACE
SUN
TURBULENCE
VARIATIONS
VELOCITY