Now showing items 1-10 of 15

    • Cosmic ray modulation beyond the heliopause: a hybrid modeling approach 

      Strauss, R.D.; Potgieter, M.S.; Ferreira, S. E. S.; Fichtner, H.; Scherer, K. (IOP Science, 2013)
      Results from a newly developed hybrid cosmic ray (CR) modulation model are presented. In this approach, the transport of CRs is computed by incorporating the plasma flow from a magnetohydrodynamic model for the heliospheric ...
    • Cosmic rays in astrospheres 

      Scherer, K.; Van der Schyff, A.; Ferreira, S.E.S.; Strauss, R.D.; Bomans, D.J. (EDP Sciences, 2015)
      Context: Cosmic rays passing through large astrospheres can be efficiently cooled inside these “cavities” in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front ...
    • 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 ...
    • The effect of a dynamic inner heliosheath thickness on cosmic-ray modulation 

      Manuel, R.; Ferreira, S.E.S.; Potgieter, M.S. (American Astronomical Society, 2015)
      The 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 ...
    • H.E.S.S. reveals a lack of TeV emission from the supernova remnant Puppis A 

      Abramowski, A.; Böttcher, M.; Davids, I.D.; Ivascenko, A.; Krüger, P.P.; Pekeur, N.W.; Spanier, F.; Sushch, I.; Venter, C.; Vorster, M. (EDP Sciences, 2015)
      Context: Puppis A is an interesting ~4 kyr-old supernova remnant (SNR) that shows strong evidence of interaction between the forward shock and a molecular cloud. It has been studied in detail from radio frequencies to ...
    • A local interstellar spectrum for galactic electrons 

      Potgieter, M.S.; Nndanganeni, R.R. (ELSEVIER, 2013)
      A heliopause spectrum at 122 AU from the Sun is presented for galactic electrons over an energy range from 1 MeV to 50 GeV that can be considered the lowest possible local interstellar spectrum (LIS). The focus of this ...
    • Modulation of galactic electrons in the heliosphere during the unusual solar minimum of 2006–2009: a modeling approach 

      Potgieter, M.S.; Vos, E.E.; Munini, R.; Boezio, M.; Di Felice, V. (American Astronomical Society, 2015)
      The last solar minimum activity period, and the consequent minimum modulation conditions for cosmic rays, was unusual. The highest levels of Galactic protons were recorded at Earth in late 2009 in contrast to expectations. ...
    • New modeling of galactic proton modulation during the minimum of solar cycle 23/24 

      Vos, Etienne E.; Potgieter, Marius S. (American Astronomical Society, 2015)
      During the recent prolonged solar minimum of cycle 23/24, the PAMELA detector measured 27-day averaged Galactic proton energy spectra over the energy range that is important for solar modulation. By comparing these spectra ...
    • A new SNR with TeV shell-type morphology: HESS J1731-347 

      Venter, Christo; Vorster, Michael Johannes; Büsching, Ingo; De Jager, Ocker Cornelis (EDP Sciences, 2011)
      Aims. The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731−347 has motivated further observations of the source with the High ...
    • A numerical simulation of cosmic-ray modulation near the heliopause 

      Luo, Xi; Potgieter, Marius; Zhang, Ming; Feng, Xueshang; Pogorelov, N.V. (American Astronomical Society, 2015)
      Based on a hybrid galactic cosmic-ray transport model, which incorporated MHD global heliospheric data into Parker’s cosmic-ray transport equation, we studied the behavior of the transport of galactic cosmic rays and ...