27-day recurrent effects in the diurnal anisotropy of galactic cosmic radiation and active solar regions

Journal Article · Thu Mar 01 04:00:00 EST 1973 · Indian J. Radio Space Phys., v. 2, no. 1, pp. 54-64

OSTI ID:4420725

Pathak, P N

During a period of 30 solar rotations from August 1962 to November 1964, the 27-day recurrent effects in the observed diurnal anisotropy of the galactic cosmic radiation have been examined. It is shown that, on the average, the amplitude of the diurnal anisotropy decreases in association with 27-day recurrent decreases of the cosmic-ray mean intensity and M-region geomagnetic storms. The observed recurrent effects are found to be well correlated with the longitudinal distributions of long-lasting Ca plages and of the coronal active regions having enhanced lambda 5303 emission. It is suggested that the observations can be understood in terms of corotating shocks in the interplanetary space that are produced as a result of the interaction between fast and slow solarwind streams. The reduction in the amplitude of the diurnal anisotropy is suggested to be due to an increase in the ratio of the coefficients of cosmic-ray diffuston perpendicular and parallel to interplanetary magnetic- field direction. It is suggested that various recurrence periods observed in cosmic-ray modulation or geomagretic activity can be directly related to the number of active regions on the Sun. (auth)

• Research Organization: Physical Research Lab., Ahmedabad, India
• NSA Number: NSA-29-008540
• OSTI ID: 4420725
• Journal Information: Indian J. Radio Space Phys., v. 2, no. 1, pp. 54-64, Journal Name: Indian J. Radio Space Phys., v. 2, no. 1, pp. 54-64; ISSN IJRSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*PRIMARY COSMIC RADIATION-- ANISOTROPY
DAILY VARIATIONS
GEOMAGNETIC FIELD
INTERACTIONS
INTERPLANETARY SPACE
MAGNETIC STORMS
N56400* --Physics (Astrophysics & Cosmology)--Solar Phenomena
PLAGES
ROTATION
SOLAR CYCLE
SOLAR WIND
SUN