Browsing by Subject "Turbulence"
Now showing items 1-10 of 33
-
An ab initio approach to the heliospheric modulation of galactic cosmic rays
(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 approach to the historical modulation of cosmic rays
(North-West University (South Africa), 2021)The relationship between observed cosmic-ray intensities and the heliospheric magnetic field during the early space age is generally considered to be anomalous, relative to their relationship observed at later times. ... -
Correlation of long-term cosmic-ray modulation with solar activity parameters
(IOP Publishing, 2019)In this work, we analyze the long-term cosmic-ray modulation observed by the Hermanus neutron monitor, which is the detector with the longest cosmic-ray record, from 1957 July. For our study we use the force-field approximation ... -
Cosmic-ray acceleration and escape from post-adiabatic supernova remnants
(EDP Sciences, 2020)Context. Supernova remnants are known to accelerate cosmic rays on account of their nonthermal emission of radio waves, X-rays, and gamma rays. Although there are many models for the acceleration of cosmic rays in supernova ... -
Cosmic-ray modulation: an ab initio approach
(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 ... -
Current sheets, magnetic islands, and associated particle acceleration in the solar wind as observed by Ulysses near the ecliptic plane
(IOP Publishing, 2019)Recent studies of particle acceleration in the heliosphere have revealed a new mechanism that can locally energize particles up to several MeV nucleon–1. Stream–stream interactions, as well as the heliospheric current sheet ... -
Determining pitch-angle diffusion coefficients from test particle simulations
(IOP Publishing, 2016)The transport and acceleration of charged particles in turbulent media are topics of great interest in space physics and interstellar astrophysics. These processes are dominated by the scattering of particles off magnetic ... -
Diffusion in pulsar wind nebulae: an investigation using magnetohydrodynamic and particle transport models
(Oxford Univ Press, 2016)We study the transport of high-energy particles in pulsar wind nebulae (PWN) using three-dimensional magnetohydrodynamic (MHD) and test-particle simulations, as well as a Fokker–Planck particle transport model. The latter ... -
The effect of the heliospheric current sheet on cosmic-ray modulation
(North-West University (South Africa), Potchefstroom Campus, 2015)The heliospheric current sheet is a dominant feature of the heliosphere. As solar activity increases, the tilt angle of the current sheet increases, and so does the region swept out by this structure, to cover most of ... -
Effects of various dissipation range onset models on the 26-day variations of low-energy galactic cosmic-ray electrons
(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 ...