Non-parametric determination of p and He interstellar fluxes from TOA cosmic ray data

Abstract : Top-of-atmosphere (TOA) cosmic-ray (CR) data from satellites and balloon-borne experiments are snapshots of the solar activity imprinted on the interstellar (IS) fluxes. Several snapshots are required to break the degeneracies between the ‘unknown’ IS flux shape and the modulation levels. Taking advantage of the recent high precision p and He data (AMS, BESS-Polar and PAMELA), we perform a fit of all available TOA snapshots to simultaneously constrain their modulation level and the underlying IS fluxes. The two novelties of this study are the use of a non-parametric shape for the IS fluxes, and of a Markov Chain Monte Carlo engine to extract the PDF and correlations (hence the confidence intervals) of the sought parameters. The outputs of the study are (i) the p and He IS fluxes (and uncertainties), and (ii) the solar modulation levels (and uncertainties) for each experiment. Although a systematic shift is observed between solar modulation levels extracted using either p or He TOA data, we find that within the uncertainties, the force-field approximation provides a good effective description of Solar modulation for TOA fluxes of CR nuclei.
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http://hal.in2p3.fr/in2p3-01218356
Contributor : Emmanuelle Vernay <>
Submitted on : Wednesday, October 21, 2015 - 9:00:29 AM
Last modification on : Tuesday, May 22, 2018 - 9:48:10 PM

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  • HAL Id : in2p3-01218356, version 1

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A. Ghelfi, D. Maurin, F. Barao, L. Derome. Non-parametric determination of p and He interstellar fluxes from TOA cosmic ray data. Solar Energetic Particles (SEP). Solar Modulation and Space Radiation: New Opportunities in the AMS-02 Era, Oct 2015, Honolulu, United States. ⟨in2p3-01218356⟩

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