THE COSMIC RAY INTENSITY GRADIENT IN SPACE DURING SOLAR MODULATION

Journal Article · Mon Jan 01 04:00:00 EST 1962 · J. Phys. Soc. Japan

OSTI ID:4755074

Simpson, J A; Fan, C Y; Meyer, P

Measurements of cosmic radiation intensity have been made to approximates 0.1 a.u. from the earth in Pioneer V for investigating the heliocentric properties of the eleven year and Forbush decrease modulations of cosmic ray intensity by magnetic fields in interplanetary space. It is shown that during a Forbush decrease at 0.03 a.u. the cosmic ray spectrum undergoes a sudden change wherein approximately 10% of the total flux (mostly low energy particles) is removed from the spectrum. A second decrease at 0.1 a.u. (30 days later) shows that this low energy component does not return to the vicinity of Pioneer V. It is shown that this change in spectrum is important for determining the gradient of cosmic ray intensity in space at the time of solar maximum. The gradient for the eleven year intensity variation is (0.0 plus or minus 2.0)%/ 0.1 a.u. This result shows that if the cosmic ray flux at solar minimum approximates the galactic flux of cosmic rays, then the main heliocentric gradient in space lies beyond the orbit of the Earth. (auth)

• Research Organization: Univ. of Chicago
• NSA Number: NSA-17-012973
• OSTI ID: 4755074
• Journal Information: J. Phys. Soc. Japan, Journal Name: J. Phys. Soc. Japan Vol. Vol: 17: Suppl. A-II
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

COSMIC RADIATION
EARTH
ENERGY
MAGNETIC FIELDS
MEASURED VALUES
MODULATION
PHYSICS
PIONEER SPACE PROBES
SATELLITES
SPACE
SPECTRA
SUN
VARIATIONS