The 11- and 22- Year Cycles in Cosmic-Ray Modulation and Their Connection with the Solar Activity
Abstract
The observed 11- and 22-year cycles in galactic cosmic ray intensities are discussed in relation to the corresponding solar activity cycles. Yearly averaged ionization chamber data, seasonally averaged neutron monitor data and daily stratospheric gas-discharge counter data is presented which spans the period 1935 to 1980 and cut-off rigidities from 0.6 to 6.7 GV in the Northern Hemisphere and 0.02 in the Southern Hemisphere. The observed changes in cosmic ray intensity are found to be in satisfactory agreement with those calculated from the number of sunspot groups and their average heliolatitude for all years except the intervals of solar polar magnetic field reversal. Experimental intensities are noted to be less than calculated intensities during the transition from a solar magnetic moment parallel to the angular momentum to one antiparallel to the angular momentum, and to be greater than the calculated values during the opposite transition, demonstrating the dependence of galactic cosmic ray intensity on heliospheric magnetic field direction.
- Publication:
-
International Cosmic Ray Conference
- Pub Date:
- 1981
- Bibcode:
- 1981ICRC....3..223C
- Keywords:
-
- Cosmic Rays;
- Galactic Radiation;
- Neutron Flux Density;
- Solar Activity Effects;
- Solar Magnetic Field;
- Angular Momentum;
- Ionization Chambers;
- Magnetic Field Configurations;
- Northern Hemisphere;
- Periodic Variations;
- Solar Cycles;
- Southern Hemisphere;
- Temporal Distribution;
- Solar Physics;
- COSMIC RAYS;
- GALACTIC RADIATION;
- NEUTRON FLUX DENSITY;
- SOLAR ACTIVITY EFFECTS;
- SOLAR MAGNETIC FIELD;
- ANGULAR MOMENTUM;
- IONIZATION CHAMBERS;
- MAGNETIC FIELD CONFIGURATIONS;
- NORTHERN HEMISPHERE;
- PERIODIC VARIATIONS;
- SOLAR CYCLES;
- SOUTHERN HEMISPHERE;
- TEMPORAL DISTRIBUTION