Browsing Faculty of Natural Sciences@PUK by Title
Now showing items 223-242 of 1399
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Cosmic ray diffusion tensor throughout the heliosphere
(American Geophysical Union, 2010) -
Cosmic ray flux at the Earth in a variable heliosphere
(Elsevier, 2008) -
Cosmic ray modulation beyond the heliopause: a hybrid modeling approach
(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 ray modulation with a Fisk-type heliospheric magnetic field and a latitude-dependent solar wind speed
(Elsevier Science Limited, 2009) -
Cosmic rays in astrospheres
(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 ... -
Cosmic rays in the dynamic heliosheath
(Elsevier, 2008) -
Cosmic rays in the dynamic heliosphere
(Elsevier, 2009) -
Cosmic rays in the inner heliosphere: insights from observations, theory and models
(Springer, 2011)The global modulation of galactic cosmic rays in the inner heliosphere is determined by four major mechanisms: convection, diffusion, particle drifts (gradient, curvature and current sheet drifts), and adiabatic energy ... -
The cosmic-ray ground-level enhancement of 1989 September 29
(IOP Publishing, 2014)The ground-level enhancement (GLE) of 1989 September 29 is one of the largest of 71 solar energetic particle events observed by neutron monitors on Earth. It was smaller than the record-breaking GLE 5 of 1956 February 23, ... -
Cosmic-ray modulation equations
(Springer, 2011)The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar ... -
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 ... -
A cosmic-ray positron anisotropy due to two middle-aged, nearby pulsars?
(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 Cosmic-ray Positron Anisotropy due to Two Middle-Aged,Nearby Pulsars?
(IOP Publishing Limited, 2008) -
Cosmic-ray positrons from millisecond pulsars
(American Astronomical Society, 2015)Observations by the Fermi Large Area Telescope of γ-ray millisecond pulsar (MSP) light curves imply copious pair production in their magnetospheres, and not exclusively in those of younger pulsars. Such pair cascades may ... -
Cosmic-ray yield and response functions in the atmosphere
(American Geophysical Union, 2012)Since the middle 1950s, neutron monitors have provided a continuous record of the intensity of secondary atmospheric particles produced by the primary cosmic radiation above the atmosphere. The number of counts due to ... -
The cost of environmental impact assessment (EIA) in South Africa
(World Scientific Publishing Co., 2009)The wide adoption of EIA internationally is implicitly or explicitly based on the assumption that the benefits of EIA outweigh the costs. However, there has been surprisingly little empirical research conducted on the ... -
Cr(VI) and conductivity as Indicators of surface water pollution from ferrochrome production in South Africa: four case studies
(Springer Verlag, 2015)South Africa is one of the largest ferrochromium (FeCr) producers. Most FeCr is exported to developed countries. Therefore the impact of this industry is of national and international importance. Cr(VI) and conductivity ... -
Cr(VI) formation during ozonation of Cr–containing materials in aqueous suspension: implications for water treatment
(South African Water Research Commission, 2012)Ozonation, or advanced oxidation processes (utilising ozone decomposition products as oxidants) are widely used in industrial wastewater and drinking water treatment plants. In these applications the use of ozone is based ... -
Cr(VI) generation during flaring of CO-rich off-gas from closed ferrochromium submerged arc furnaces
(Springer Verlag, 2015)Ferrochromium (FeCr) is the only source of new Cr units used in stainless steel production, which is a vital modern day alloy, making FeCr equally important. Small amounts of Cr(VI) are unintentionally formed during several ...
