Now showing items 1-10 of 12

    • 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 ...
    • Cosmic-ray modulation: an ab initio approach 

      Engelbrecht, N.E.; Burger, R.A. (Springer Verlag, 2014)
      A better understanding of cosmic-ray modulation in the heliosphere can only be gained through a proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays. We present an ab initio model ...
    • A cosmic-ray positron anisotropy due to two middle-aged, nearby pulsars? 

      Büsching, I.; De Jager, O.C.; Potgieter, M.S.; Venter, C. (IOP Publishing, 2008)
      Geminga and B0656+14 are the closest pulsars with characteristic ages in the range of 100 kyr to 1 Myr. They both have spin-down powers of the order 3 × 1034 ergs s–1 at present. The winds of these pulsars had most probably ...
    • A generalized diffusion tensor for fully anisotropic diffusion of energetic particles in the heliospheric magnetic field 

      Effenberger, F.; Strauss, R.D.; Fichtner, H.; Scherer, K.; Barra, S.; Kleimann, J. (IOP publishing, 2012)
      The spatial diffusion of cosmic rays in turbulent magnetic fields can, in the most general case, be fully anisotropic, i.e., one has to distinguish three diffusion axes in a local, field-aligned frame. We reexamine the ...
    • Modeling drift along the heliospheric wavy neutral sheet 

      Burger, R.A. (IOP Publishing, 2012)
      Drift along the wavy heliospheric neutral sheet is believed to play an important role in cosmic-ray modulation and can explain the peaked versus flat intensity profiles during consecutive solar magnetic epochs. Modulation ...
    • Modeling the modulation of galactic and jovian electrons by stochastic processes 

      Kopp, Andreas; Potgieter, Marthinus Steenkamp; Strauss, Roelf Du Toit; Büsching, Ingo (IOP Publishing, 2011)
      We present a newly developed numerical modulation model to study the transport of galactic and Jovian electrons in the heliosphere. The model employs stochastic differential equations (SDEs) to solve the corresponding ...
    • Possible evidence for a fisk-type heliospheric magnetic field, 1: analyzing Ulysses/Ket electron observations 

      Burger, Renier Adriaan; Engelbrecht, Nicholas Eugene; Ferreira, Stephanus Esaias Salomon; Potgieter, Marthinus Steenkamp; Sternal, O.; Fichtner, H.; Heber, B.; Kopp, A.; Scherer, K. (IOP Publishing, 2011)
      The propagation of energetic charged particles in the heliospheric magnetic field is one of the fundamental problems in heliophysics. In particular, the structure of the heliospheric magnetic field remains an unsolved ...
    • Spectral analysis and interpretation of the Y-ray emission from the Starburst NGC 253* 

      Abramowski, A.; Büsching, I.; Casanova, S.; Pekeur, N.W.; Sheidaei, F.; Venter, C.; Vorster, M. (IOP publishers, 2012)
      Very high energy (VHE; E ≥ 100 GeV) and high-energy (HE; 100 MeV ≤ E ≤ 100 GeV) data from γ-ray observations performed with the H.E.S.S. telescope array and the Fermi-LAT instrument, respectively, are analyzed in order to ...
    • A stochastic approach to galactic proton propagation: influence of the spiral arm structure 

      Kopp, A.; Büsching, I.; Potgieter, M.S.; Strauss, R.D. (Elsevier, 2014)
      A 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 ...