Speaker
David Alain Maurin
(Centre National de la Recherche Scientifique (FR))
Description
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.
Authors
Alexandre Ghelfi
(Centre National de la Recherche Scientifique (FR))
David Alain Maurin
(Centre National de la Recherche Scientifique (FR))
Co-authors
Fernando De Carvalho Barao
(LIP Laboratorio de Instrumentacao e Fisica Experimental de Part)
Laurent Yves Marie Derome
(Centre National de la Recherche Scientifique (FR))
