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dc.contributor.authorKopp, A.
dc.contributor.authorBüsching, I.
dc.contributor.authorPotgieter, M.S.
dc.contributor.authorStrauss, R.D.
dc.identifier.citationKopp, A. et al. 2014. A stochastic approach to galactic proton propagation: influence of the spiral arm structure. New astronomy, 30:32-37. []en_US
dc.description.abstractA newly developed numerical code solving Fokker–Planck type transport equations in currently four dimensions (space plus momentum or energy) and time by means of stochastic differential equations (SDEs) is applied to the Galactic propagation of Cosmic Ray protons, where the paths of pseudo particles originating in spiral arms and in the interarm region are traced back to a distribution of point sources. The transport equation in this first, simplified approach includes scalar spatial diffusion and catastrophic energy losses. In a first step we validate the code by obtaining results being consistent with previous ones obtained with finite-difference methods, revealing lower spectra with less variations in the interarm region compared to the inarm region. While Effenberger et al. (2012) used this approach to study the effects of a fully anisotropic diffusion tensor, we concentrate here on a diffusion coefficient taking into account the spiral arm structure. Such a variable diffusion coefficient is of importance e.g. for the longscale time-variation of the Cosmic Ray flux at Earth related to spiral arm crossings. For our choice of parameters, we find that a diffusion coefficient reflecting the spiral arm structure leads to a clearly enhanced flux ratio between the inarm and interarm regions. The strength of this effect depends, however, on the parameters chosenen_US
dc.description.sponsorshipSouth African National Research Foundation (NRF) and the South African Center for High Performance Computing (CHPC).en_US
dc.subjectGalaxy: disken_US
dc.subjectsolar neighbourhooden_US
dc.subjectcosmic raysen_US
dc.subjectmethods: numericalen_US
dc.titleA stochastic approach to galactic proton propagation: influence of the spiral arm structureen_US
dc.contributor.researchID10060014 - Potgieter, Marthinus Steenkamp
dc.contributor.researchID24483818 - Kopp, Andreas
dc.contributor.researchID13235176 - Büsching, Ingo
dc.contributor.researchID13065440 - Strauss, Roelf Du Toit

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