Browsing Research Output by Subject "Turbulence"
Now showing items 1-10 of 25
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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 ... -
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 ... -
A Fisk-Parker hybrid heliospheric magnetic field with a solar-cycle dependence
(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 generalized two-component model of solar wind turbulence and ab initio diffusion mean-free paths and drift lengthscales of cosmic rays
(IOP Publishing, 2016)We extend a two-component model for the evolution of fluctuations in the solar wind plasma so that it is fully three-dimensional (3D) and also coupled self-consistently to the large-scale magnetohydrodynamic equations ... -
The implications of simple estimates of the 2D outerscale based on measurements of magnetic islands for the modulation of galactic cosmic-ray electrons
(IOP Publishing, 2019)The behavior of the 2D turbulence power spectrum at the lowest wavenumbers has a significant effect on the perpendicular diffusion coefficients of charged particles in the heliosphere derived from various scattering theories, ...