The onset of sunspot cycle 24 and galactic cosmic ray modulation
| Autor: | R.C. Ygbuhay, H. S. Ahluwalia |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Physics
Atmospheric Science Earth's orbit Astrophysics::High Energy Astrophysical Phenomena Aerospace Engineering Astronomy Astronomy and Astrophysics Cosmic ray Astrophysics Solar cycle 24 Solar wind Geophysics Rigidity (electromagnetism) Space and Planetary Science Physics::Space Physics General Earth and Planetary Sciences Neutron Heliospheric current sheet Interplanetary magnetic field |
| Zdroj: | Advances in Space Research. 48:61-64 |
| ISSN: | 0273-1177 |
| DOI: | 10.1016/j.asr.2011.01.003 |
| Popis: | The annual mean sunspot number (SSN) has a minimum value in 2008, while the monthly mean SSN has a value of zero in August 2009. The galactic cosmic ray modulation for cycle 24 began at earth orbit in January 2010. We study the onset characteristics of the new modulation cycle using data from the global network of neutron monitors. They respond to time variations in different segments of the galactic cosmic ray rigidity spectrum. The corresponding temporal variations in the interplanetary magnetic field intensity ( B ) and solar wind velocity ( V ) as well as the tilt angle of the heliospheric current sheet are also studied. There is a lag of 3 months between a large, sharp increase of the tilt angle of the heliospheric current sheet and the onset of modulation. Some neutron monitors are undergoing long-term drifts of unknown origin. |
| Databáze: | OpenAIRE |
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