THE COSMIC RAY ALPHA-PARTICLE FLUX DURING SHARP FORBUSH INTENSITY DECREASES

Journal Article · Thu Dec 01 04:00:00 EST 1960 · J. Geophys. Research

DOI:https://doi.org/10.1029/JZ065i012p03881· OSTI ID:4083947

Meyer, P

During three large Forbush-type intensity decreases that occurred on May 12, July l5, and July 18, 1959 the primary cosmic-ray alpha -particle flux was measured at balloon altitudes. A comparison with the alpha -partlcle flux in an undisturbed period on Sept. 28, 1959, and with the total cosmic-ray intensity as observed by neutron monitor stations showed a close correlation between the alpha -particle flux and the total cosmic-ray flux during Forbush decreases. This evidence clearly established the fact that the proten and alpha -particle components are modulated by a common mechanism during the sharp intensity decreases. The measurement of May 16, 19b9, exhibited an increase in the alpha - particle flux by 30% within approximately 9 hr which was not accompanied by a comparable variation in the proten flux. Similar, independent changes in the alpha particle flux earlier were noted to follow Forbush- decreases. During quiet days the primary alpha -particle flux with energies exceeding 560 Mev/ nucleon was about 20% higher in 1959 than in 1958. This change in intensity is probably related to the beginning decline in average solar activity. (auth)

• Research Organization: Univ. of Chicago
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-005565
• OSTI ID: 4083947
• Journal Information: J. Geophys. Research, Journal Name: J. Geophys. Research Vol. Vol: 65
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA PARTICLES
BALLOONS
COSMIC RADIATION
ENERGY
FORBUSH DEPRESSION
MAGNETIC FIELDS
MEASURED VALUES
MONITORING
NEUTRONS
PHYSICS
PROTONS
SUN