Browsing Faculty of Natural and Agricultural Sciences by Author "Burger, R.A."
Now showing items 1-15 of 15
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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 ... -
Comparison of different analytic heliospheric magnetic field configurations and their significance for the particle injection at the termination shock
Scherer, K.; Burger, R.A.; Fichtner, H.; Effenberger, F.; Wiengarten, T. (EDP Sciences, 2010) -
Cosmic ray diffusion tensor throughout the heliosphere
Pei, C.; Burger, R.A.; Bieber, J.W.; Breech, B.; Clem, J. (American Geophysical Union, 2010)We calculate the cosmic ray diffusion tensor based on a recently developed model of magnetohydrodynamic (MHD) turbulence in the expanding solar wind. Parameters of this MHD model are tuned by using published observations ... -
Cosmic ray modulation with a Fisk-type heliospheric magnetic field and a latitude-dependent solar wind speed
Hitge, M.; Burger, R.A. (Elsevier, 2009)The effect of a latitude-dependent solar wind speed on a Fisk heliospheric magnetic field [Fisk, L. A. Motion of the footpoints of heliospheric magnetic field lines at the Sun: implications for recurrent energetic particle ... -
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 ... -
Effects of various dissipation range onset models on the 26-day variations of low-energy galactic cosmic-ray electrons
Engelbrecht, N.E.; Burger, R.A. (Elsevier, 2010)The effect of various models presented by Leamon et al. (2000) for the dissipation range cutoff wavenumber on the 26-day variations of galactic cosmic-ray electrons in a Fisk-Parker hybrid field is investigated, by means ... -
A Fisk-Parker hybrid heliospheric magnetic field with a solar-cycle dependence
Burger, R.A.; Krüger, T.P.J.; Hitge, M.; Engelbrecht, N.E. (IOP Publishing, 2008)We present a refinement of the Fisk-Parker hybrid field of Burger and Hitge which now includes a region bordering the solar rotational equator where magnetic field footpoint motion occurs only through diffusive reconnection. ... -
A general time-dependent stochastic method for solving Parker's transport equation in spherical coordinates
Pei, C.; Burger, R.A.; Bieber, J.W.; Clem, J. (American Geophysical Union, 2010) -
A generalized Fisk-type HMF: implications of spatially dependent photospheric differential rotation
Steyn, P.J.; Burger, R.A. (IOP Publishing, 2020)The existence of a Fisk-type heliospheric magnetic field (HMF) has been debated ever since Fisk proposed an alternative to the traditional view of the HMF first proposed by Parker. Several modifications of the original ... -
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 ... -
Possible evidence for a Fisk-type heliospheric magnetic field. 1. Analyzing Ulysses/Ket electron observations
Sternal, O.; Engelbrecht, N.E.; Burger, R.A.; Ferreira, S.E.S.; Potgieter, M.S.; Kopp, A. (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 ... -
Reduction of drift effects due to solar wind turbulance
Burger, R.A.; Visser, D.J. (Institution of Physics (IOP), 2010) -
Three-dimensional wavy heliospheric current sheet drifts
Pei, C.; Burger, R.A.; Bieber, J.W.; Clem, J. (IOP publishing, 2012)We present an analytic method to determine the directions of the three-dimensional (3D) heliospheric current sheet (HCS) drift for any tilt angle based on Parker's heliospheric magnetic field and compare it with published ... -
When do particles follow field lines?
Minnie, J.; Burger, R.A.; Matthaeus, W.H.; Bieber, J.W.; Ruffolo, D. (American Geophysical Union, 2009)We examine charged particle transport perpendicular to the large scale magnetic field. We find that the limit of an infinite parallel mean free path of particles diffusing along the large scale magnetic field is a necessary ...