North-south asymmetry in activity on the sun and cosmic-ray density gradients

Technical Report · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6060465

Swinson, D B; Shea, M A; Humble, J E

One method of detecting a perpendicular cosmic-ray density gradient (vNp) is to make use of the contribution of the drift term B x vNp to the solar cosmic-ray diurnal variation. The B x vNp term produces a flow in the ecliptic plane perpendicular to the IMF B, with the sense of the flow depending upon the sense of B; this field-dependent flow adds vectorially to the usual azimuthal streaming which produces a cosmic-ray intensity maximum at 18 hours solar time (after correction for geomagnetic bending). In the case of a southward perpendicular gradient, when the IMF is away from the sun, the resultant diurnal variation should have a larger amplitude, and the time of maximum should occur a little earlier, whereas if the IMF is toward the sun, the resultant diurnal variation should have a small amplitude with a later time of maximum. This method is used to analyze neutron-monitor and underground muon data, separated according to IMF sense, from 1965 to 1975, to show that there is a perpendicular cosmic-ray gradient that pointed southward prior to 1969, and a suggested northward pointing gradient after the reversal of the sun's polar magnetic field in 1969-71.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6060465
• Report Number(s): AD-A-162124/2/XAB; AFGL-TR-85-0286
• Country of Publication: United States
• Language: English

Related Subjects

640101 -- Astrophysics & Cosmology-- Cosmic Radiation
640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
AZIMUTH
BARYONS
BENDING
CORRELATIONS
COSMIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
HADRONS
IONIZING RADIATIONS
MEASURING INSTRUMENTS
MONITORS
NEUTRONS
NUCLEONS
RADIATIONS
SOLAR ACTIVITY