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Advances in Astronomy
Volume 2013, Article ID 793072, 12 pages
Research Article

Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary Magnetic Field Polar Correction

1Institute of Experimental Physics, Watsonova 47, 040 01 Kosice, Slovakia
2INFN Sez. of Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
3CINECA, via R. Sanzio 4, Segrate (MI), Italy
4Department of Physics, University of Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
5Department of Science and High Tecnology, University of Insubria, Via Valleggio 11, 22100 Como, Italy

Received 11 October 2012; Accepted 6 December 2012

Academic Editor: José F. Valdés-Galicia

Copyright © 2013 P. Bobik et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The cosmic rays differential intensity inside the heliosphere, for energy below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field polarity. This variation, termed solar modulation, is described using a 2D (radius and colatitude) Monte Carlo approach for solving the Parker transport equation that includes diffusion, convection, magnetic drift, and adiabatic energy loss. Since the whole transport is strongly related to the interplanetary magnetic field (IMF) structure, a better understanding of his description is needed in order to reproduce the cosmic rays intensity at the Earth, as well as outside the ecliptic plane. In this work an interplanetary magnetic field model including the standard description on ecliptic region and a polar correction is presented. This treatment of the IMF, implemented in the HelMod Monte Carlo code (version 2.0), was used to determine the effects on the differential intensity of Proton at 1 AU and allowed one to investigate how latitudinal gradients of proton intensities, observed in the inner heliosphere with the Ulysses spacecraft during 1995, can be affected by the modification of the IMF in the polar regions.