Now showing items 1-10 of 32

    • An AB initio model for cosmic-ray modulation 

      Engelbrecht, N.E.; Burger, R.A. (IOP Science, 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 Science, 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 ...
    • The charge-sign dependent effect in the solar modulation of cosmic rays 

      Potgieter, M.S. (Elsevier, 2014)
      The centennial anniversary of the discovery of cosmic rays was in 2012. Since this discovery considerable progress has been made on several aspects related to galactic cosmic rays in the heliosphere. It is known that they ...
    • The contribution of millisecond pulsars to the Galactic cosmic-ray lepton spectrum 

      Venter, Christo; Kopp, Andreas; Büsching, Ingo; Harding, Alice K.; Gonthier, Peter L. (Elsevier, 2015)
      Pulsars are believed to be sources of relativistic electrons and positrons. The abundance of detections of γγ-ray millisecond pulsars by Fermi Large Area Telescope coupled with their light curve characteristics that imply ...
    • Cosmic ray modulation in the outer heliosphere: predictions for cosmic ray intensities up to the heliopause along Voyager 1 and 2 trajectories 

      Ferreira, Stephanus Esaias Salomon; Potgieter, Marthinus Steenkamp; Manuel, Rex (Elsevier, 2011)
    • Cosmic rays in the inner heliosphere: insights from observations, theory and models 

      Potgieter, Marthinus Steenkamp (Springer, 2011)
      The global modulation of galactic cosmic rays in the inner heliosphere is determined by four major mechanisms: convection, diffusion, particle drifts (gradient, curvature and current sheet drifts), and adiabatic energy ...
    • Cosmic-ray modulation equations 

      Moraal, Harm (Springer, 2011)
      The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar ...
    • Cosmic-ray positrons from millisecond pulsars 

      Venter, C.; Kopp, A.; Büsching, I.; Harding, A.K.; Gonthier, P.L. (American Astronomical Society, 2015)
      Observations by the Fermi Large Area Telescope of γ-ray millisecond pulsar (MSP) light curves imply copious pair production in their magnetospheres, and not exclusively in those of younger pulsars. Such pair cascades may ...
    • Discovery of the hard spectrum VHE γ-ray source HESS J1641-463 

      Abramowski, A.; Böttcher, M.; Davids, I.D.; Ivascenko, A.; Krüger, P.P.; Pekeur, N.W.; Spanier, F.; Sushch, I.; Venter, C.; Vorster, M. (IOP Publishing, 2014)
      This Letter reports the discovery of a remarkably hard spectrum source, HESS J1641–463, by the High Energy Stereoscopic System (H.E.S.S.) in the very high energy (VHE) domain. HESS J1641–463 remained unnoticed by the usual ...
    • Galactic cosmic rays in the outer heliosphere: theory and models 

      Ferreira, Stephanus Esaias Salomon; Florinski, V.; Pogorelov, N.V. (Springer, 2011)
      We review recent advances in the field of galactic cosmic ray transport in the distant heliosphere. The advent of globalMHD models brought about a better understanding of the three-dimensional structure of the interface ...