Cosmic ray north-south anisotropy: The role of the interplanetary magnetic field

Journal Article · Wed Dec 01 04:00:00 EST 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA087iA12p10325· OSTI ID:6249767

Pomerantz, M A; Duggal, S P; Owens, A J; Tolba, M F; Tsao, C H

Nucleonic intensity data from the north and south polar stations Thule and McMurdo are analyzed to determine the nature of periodicities in the north-south asymmetry of relativistic galactic cosmic rays. The 24-hour average intensity differences of individual days range from 0 to +- 1.5%, and the most prominent time variation is recurrence tendency with a period consistent with the 27-day solar rotation period. A recently developed procedure for evaluating the statistical significance of quasipersistent data has been utilized to establish the reality of the 27-day signal disclosed by superposed epoch analysis of the north-south asymmetry data. Analyses of various components of the interplanetary magnetic field reveal that the IMF component B-bar/sub ..mu../ (parallel to the nominal garden hose direction) also displays a 27-day variation with maximum amplitude. Furthermore, a significant relationship between B-bar/sub ..mu../ and the north-south asymmetry is established by Chree analysis. On the basis of this relationship, it is suggested that the 27-day variation in the north-south asymmetry arises from the B-bar/sub ..mu../ x del-bar(n) drift, where del-bar(n) represents the radial gradient of cosmic rays.

• Research Organization: Bartol Research Foundation of the Franklin Institute University of Delaware, Newark, Delaware 19711
• OSTI ID: 6249767
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:A12; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
COSMIC RADIATION
FREQUENCY DEPENDENCE
INTERPLANETARY MAGNETIC FIELDS
IONIZING RADIATIONS
MAGNETIC FIELDS
MATHEMATICS
NORTH-SOUTH ASYMMETRY
PRIMARY COSMIC RADIATION
RADIATIONS
STATISTICS
VARIATIONS