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dc.contributor.authorManuel, R.
dc.contributor.authorFerreira, S.E.S.
dc.contributor.authorPotgieter, M.S.
dc.date.accessioned2016-08-30T07:19:29Z
dc.date.available2016-08-30T07:19:29Z
dc.date.issued2015
dc.identifier.citationManuel, R. et al. 2015. The effect of a dynamic inner heliosheath thickness on cosmic-ray modulation. Astrophysical journal, 799(2): Article no 223. [https://doi.org/10.1088/0004-637X/799/2/223]en_US
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357 (Online)
dc.identifier.urihttp://hdl.handle.net/10394/18439
dc.identifier.urihttps://doi.org/10.1088/0004-637X/799/2/223
dc.identifier.urihttp://iopscience.iop.org/article/10.1088/0004-637X/799/2/223
dc.description.abstractThe time-dependent modulation of galactic cosmic rays in the heliosphere is studied over different polarity cycles by computing 2.5 GV proton intensities using a two-dimensional, time-dependent modulationmodel. By incorporating recent theoretical advances in the relevant transport parameters in the model, we showed in previous work that this approach gave realistic computed intensities over a solar cycle. New in this work is that a time dependence of the solar wind termination shock (TS) position is implemented in our model to study the effect of a dynamic inner heliosheath thickness (the region between the TS and heliopause) on the solar modulation of galactic cosmic rays. The study reveals that changes in the inner heliosheath thickness, arising from a time-dependent shock position, does affect cosmic-ray intensities everywhere in the heliosphere over a solar cycle, with the smallest effect in the innermost heliosphere. A time-dependent TS position causes a phase difference between the solar activity periods and the corresponding intensity periods. The maximum intensities in response to a solarminimum activity period are found to be dependent on the time-dependent TS profile. It is found that changing the width of the inner heliosheath with time over a solar cycle can shift the time of when the maximum or minimum cosmic-ray intensities occur at various distances throughout the heliosphere, but more significantly in the outer heliosphere. The time-dependent extent of the inner heliosheath, as affected by solar activity conditions, is thus an additional time-dependent factor to be considered in the long-term modulation of cosmic raysen_US
dc.language.isoenen_US
dc.publisherIOP Publishingen_US
dc.subjectSun: activityen_US
dc.subjectCosmic raysen_US
dc.subjectDiffusionen_US
dc.subjectSun: heliosphereen_US
dc.titleThe effect of a dynamic inner heliosheath thickness on cosmic-ray modulationen_US
dc.typeArticleen_US
dc.contributor.researchID21245274 - Manuel, Rex
dc.contributor.researchID10713158 - Ferreira, Stephanus Esaias Salomon
dc.contributor.researchID10060014 - Potgieter, Marthinus Steenkamp


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