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dc.contributor.advisorBurger, R.A.
dc.contributor.advisorHitge, M.
dc.contributor.authorKrüger, Tjaart Petrus Jakobus
dc.date.accessioned2009-02-26T09:02:59Z
dc.date.available2009-02-26T09:02:59Z
dc.date.issued2005
dc.identifier.urihttp://hdl.handle.net/10394/1205
dc.descriptionThesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2006.
dc.description.abstractThe existence of a Fisk-type heliospheric magnetic field (HMF) is one of the most debated questions in cosmic-ray modulation. Recently, Burger and Hitge [2004] developed a divergence-free Fisk-Parker hybrid magnetic field model to demonstrate the behaviour of cosmic rays in the heliosphere due to such a field. This approach has been refined and the properties of the consequent field are investigated. It is found that randomly directed magnetic field diffusion in and above the photosphere significantly influences the solar magnetic field both at the solar poles and near the polar coronal hole boundary. The solar cycle dependence of this field is investigated, a study which is of particular importance for studies of the long-term behaviour of cosmic rays, such as those undertaken at the SANAE base in Antarctica. The amplitudes of the 26-day recurrent cosmic-ray variations are modelled as function of both latitudinal gradient and heliolatitude and are found to agree qualitatively and in some cases quantitatively with the observational results reported by Zhang 119971 and Paizis et al. [1999]. Although magnetic field data do not clearly indicate the existence of the Fisk field [see, e.g., Fursyth et al., 2002], this study supports the existence of a Fisk-type HMF.
dc.publisherNorth-West University
dc.subjectFisk-type heliospheric magnetic fielden
dc.subjectCosmic raysen
dc.subjectModulationen
dc.subjectRecurrent cosmic-ray variationsen
dc.titleThe effect of a Fisk-Parker hybrid magnetic field on cosmic rays in the heliosphereen
dc.typeThesisen
dc.description.thesistypeMasters


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