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Latitudinal and radial gradients of galactic cosmic ray protons in the inner heliosphere – PAMELA and Ulysses observations
- Source :
- Astrophysics and Space Sciences Transactions. 7:425-434
- Publication Year :
- 2011
- Publisher :
- Copernicus GmbH, 2011.
-
Abstract
- Ulysses, launched on 6 October 1990, was placed in an elliptical, high inclined (80.2) orbit around the Sun, and was switched off in June 2009. It has been the only spacecraft exploring high-latitude regions of the inner heliosphere. The Kiel Electron Telescope (KET) aboard Ulysses measures electrons from 3 MeV to a few GeV and protons and helium in the energy range from 6 MeV/nucleon to above 2 GeV/nucleon. The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) space borne experiment was launched on 15 June 2006 and is continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 MeV to several hundreds of GeV. Thus the combination of Ulysses and PAMELA measurements is ideally suited to determine the spatial gradients during the extended minimum of solar cycle 23. For protons in the rigidity interval 1.6−1.8 GV we find a radial gradient of 2.7%/AU and a latitudinal gradient of −0.024%/degree. Although the latitudinal gradient is as expected negative, its value is much smaller than predicted by current particle propagation models. This result is of relevance for the study of propagation parameters in the inner heliosphere.
- Subjects :
- 010504 meteorology & atmospheric sciences
Physics and Astronomy (miscellaneous)
Astrophysics::High Energy Astrophysical Phenomena
Solar cycle 23
Cosmic ray
Electron
Astrophysics
7. Clean energy
01 natural sciences
law.invention
Telescope
Positron
law
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Nuclear Experiment
010303 astronomy & astrophysics
0105 earth and related environmental sciences
Physics
Astronomy
Astronomy and Astrophysics
Antimatter
Physics::Space Physics
Astrophysics::Earth and Planetary Astrophysics
Nucleon
Heliosphere
Subjects
Details
- ISSN :
- 18106536
- Volume :
- 7
- Database :
- OpenAIRE
- Journal :
- Astrophysics and Space Sciences Transactions
- Accession number :
- edsair.doi.dedup.....38bbe958015dfcc0d0aee93893031c85