Now showing items 1-10 of 129

    • An ab initio approach to the heliospheric modulation of galactic cosmic rays 

      Minnie, Jaco (North-West University, 2006)
      In the present study we aim to further our understanding of charged particle transport in a magnetized medium. To this end, we perform direct numerical simulations of particle transport in a turbulent magnetic field. From ...
    • An AB initio model for cosmic-ray modulation 

      Engelbrecht, N.E.; Burger, R.A. (IOP Publishing, 2013)
      A proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays (CRs) is of vital importance for a better understanding of CR modulation in the heliosphere. This study presents an ab initio ...
    • An AB initio model for the modulation of galactic cosmic-ray electrons 

      Engelbrecht, N.E.; Burger, R.A. (IOP Publishing, 2013)
      The modulation of galactic cosmic-ray electrons is studied using an ab initio three-dimensional steady state cosmicraymodulation code in which the effects of turbulence on both the diffusion and drift of these cosmic-rays ...
    • Acceleration of cosmic rays in the outer heliosphere 

      Prinsloo, Phillip Lourens (North-West University (South Africa), Potchefstroom Campus, 2016)
      Shortly before the Voyager spacecraft crossed the heliospheric termination shock, they encountered narrow, peak-like enhancements in the intensities of low-energy electrons. These enhancements were associated at the time ...
    • Are anomalous cosmic rays the main contribution to the low-energy galactic cosmic ray spectrum? 

      Scherer, K.; Ferreira, S.E.S.; Büsching, I.; Potgieter, M.S.; Fichtner, H. (IOP Publishing, 2008)
      While the high-energy part of the Galactic cosmic ray spectrum is well observed, its nature at energies below about 1 GeV nucleon-1 is still not known well. Recent in situ measurements made with the Voyager 1 spacecraft in ...
    • Aspects of the modulation of cosmic rays in the outer heliosphere 

      Ngobeni, Mabedle Donald (North-West University, 2006)
      A time-dependent two-dimensional (2D) modulation model including drifts, the solar wind tennination shock (TS) with diffusive shock acceleration and a heliosheath based on the Parker (1965) transport equation is used to ...
    • A calibration neutron monitor for long-term cosmic ray modulation studies 

      Krüger, Helena (North-West University, 2006)
      The propagation of high-energy cosmic rays is influenced by the time-varying heliospheric magnetic field embedded in the solar wind, and by the geomagnetic field. To penetrate through this geomagnetic field, they must ...
    • A calibration neutron monitor: statistical accuracy and environmental sensitivity 

      Krüger, Helena; Moraal, Harm (Elsevier, 2010)
      This paper is a follow-on of that of Krüger et al. [Krüger, H., Moraal, H., Bieber, J.W., Clem, J.M., Evenson, P.A., Pyle, K.R., Duldig, M.L., Humble, J.E. A calibration neutron monitor: energy response and instrumental ...
    • Challenges to cosmic ray modeling: from beyond the solar wind termination shock 

      Potgieter, M.S. (Elsevier, 2008)
      Voyager 1 crossed the solar wind termination shock on December 16, 2004 at a distance of 94 AU from the Sun, to become the first spacecraft to explore the termination shock region and to enter the heliosheath, the final ...
    • Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with H.E.S.S. 

      Abdalla, H.; Barnard, M.; Böttcher, M.; Davids, I.D.; Garrigoux, T.; Ivascenko, A.; Krüger, P.P.; Pekeur, N.W.; Richter, S.; Seyffert, A.S.; Spanier, F.; Sushch, I.; Van der Walt, D.J.; Van Rensburg, C.; Venter, C.; Wadiasingh, Z.; Zacharias, M.; H.E.S.S. Collaboration (EDP Sciences, 2018)
      The diffuse very high-energy (VHE; >100 GeV) γ-ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal ...