New insights into the variability of the cosmic ray diurnal anisotropy

Journal Article · Thu Nov 01 04:00:00 EST 1979 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA084iA11p06653· OSTI ID:5614833

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

A new study of the variation of the diurnal anisotropy has unambiguously confirmed the reality of a recurrence tendency that is related to the period of rotation of the sun. Data recorded at two equatorial viewing stations with essentially similar responses to the primary anisotropy (Swarthmore and Deep River) were analyzed by using three different techniques: power spectral analysis, harmonic analysis, and superposed epoch analysis. The following experimental results were obtained: (1) The variance of day-to-day changes in the diurnal anisotropy is greater for the component that is perpendicular to the anterplanetary magnetic field than that which is parallel to it. (2) The 27-day variation is maximum for the component of the diurnal anisotropy in the direction perpendicular to the interplanetary magnetic field. In contrast, there is no correlation between the sun's rotational period and the field-aligned component. Unlike the first result, the second, which was quite unexpected, cannot be accounted for by current theoretical models. This suggests that a new approach to this problem--probably including quasi-stationary corotating structure and particle drifts--is required.

• Research Organization: Bartol Research Foundation of the Franklin Institute, University of Delaware Newark, Delaware 19711
• OSTI ID: 5614833
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 84:A11; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
CORRELATIONS
COSMIC RADIATION
DAILY VARIATIONS
FOURIER ANALYSIS
INTERPLANETARY MAGNETIC FIELDS
IONIZING RADIATIONS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
MOTION
RADIATIONS
ROTATION
STARS
SUN
VARIATIONS