Browsing Natural and Agricultural Sciences by Author "10060014 - Potgieter, Marthinus Steenkamp (Supervisor)"
Now showing items 1-18 of 18
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Acceleration of cosmic rays in the outer heliosphere
(North-West University (South Africa), Potchefstroom Campus, 2016)Shortly before the Voyager spacecraft crossed the heliospheric termination shock, they encountered narrow, peak-like enhancements in the intensities of low-energy electrons. These enhancements were associated at the time ... -
Aspects of the modulation of cosmic rays in the outer heliosphere
(North-West University, 2006)A time-dependent two-dimensional (2D) modulation model including drifts, the solar wind tennination shock (TS) with diffusive shock acceleration and a heliosheath based on the Parker (1965) transport equation is used to ... -
A comparative study of cosmic ray modulation models
(North-West University, 2015)Until recently, numerical modulation models for the solar modulation of cosmic rays have been based primarily on finite difference approaches; however, models based on the solution of an appropriate set of stochastic ... -
Cosmic ray modulation processes in the heliosphere
(North-West University, 2011)The solar minimum of 2009 has been identified as an exceptional event with regard to cosmic ray (CR)modulation, since conditions in the heliosphere have reached unprecedented quiet levels. This unique minimum has been ... -
Cosmic ray propagation in the galaxy and the heliosphere
(North-West University, 2018)The local interstellar spectra (LIS’s) for cosmic rays (CRs) are still not fully determined over all energy ranges. Numerical modelling, such as with the GALPROP code, can be used to calculate LIS’s for a wide set of CR ... -
Effects of termination shock acceleration on cosmic rays in the heliosphere
(North-West University, 2004)The interest in the role of the solar wind termination shock (TS) and heliosheath in cosmic ray (CR) modulation studies has increased sigm6cantly as the Voyager 1 and 2 spacecraft approach the estimated position of the TS. ... -
Galactic propagation of cosmic rays
(North-West University, 2011)The widely used steady-state, rotational symmetric models (2D models) of cosmic ray (CR) propagation, assume smeared-out sources, which do not necessarily result in the same local CR ux as the real local point sources. ... -
Modeling of electrons in the heliosphere
(North-West University (South Africa), Potchefstroom Campus, 2016)The propagation and modulation of electrons in the heliosphere play an important part in improving our understanding and assessment of the processes of solar modulation. A locally developed, full three-dimensional, ... -
Modeling of galactic cosmic rays in the heliosphere
(2015)The modulation of galactic cosmic ray (GCR) Carbon in a north-south asymmetrical heliosphere is studied, using a two-dimensional numerical model that contains a solar wind termination shock (TS), a heliosheath, as well as ... -
Modelling charge-sign dependent modulation of cosmic rays in the heliosphere
(North-West University (South Africa), 2016)The solar minimum of cycle 23/24 has seen exceptionally quiet levels of solar activity and heliospheric modulation, which resulted in the highest cosmic ray (CR) spectrum ever recorded at Earth in December 2009 by the ... -
Modelling of galactic and jovian electrons in the heliosphere
(North-West University, 2004)A three-dimensional (3D) steady-state electron modulation model based on Parker (1965) transport equation is applied to study the modelling of – 7 MeV galactic and Jovian electrons in the inner heliosphere. The latter ... -
Modelling of galactic cosmic ray electrons in the heliosphere
(North-West University, 2012)The Voyager 1 spacecraft is now about 25 AU beyond the heliospheric termination shock and soon it should encounter the outer boundary of the heliosphere, the heliopause. This is set to be at 120 AU in the modulation model ... -
The modulation of galactic cosmic rays over a solar cycle
(North-West University (South Africa), 2016)This work studied the modulation of galactic cosmic rays in the heliosphere by using a well-established, time dependent numerical modulation model to calculate cosmic ray transport inside the heliosphere over a solar ... -
Shock acceleration as source of the anomalous component of cosmic rays in the heliosphere
(PU vir CHO, 1995)Anomalous cosmic rays are low energy enhancements of the cosmic ray intensities that cannot be explained by standard modulation of galactic cosmic rays entering the heliosphere. Presently it is thought that these anomalous ... -
A study of cosmic ray anisotropies in the heliosphere
(North-West University, 2006)The three-dimensional (3D) steady-state electron modulation model of Ferreira (2002), based on Parker (1965) transport equation, is used to study the modulation of the 7 MeV galactic and Jovian electron anisotropies in ... -
A study of the time-dependent modulation of cosmic rays in the inner heliosphere
(North-West University, 2010)A two-dimensional (2-D) time-dependent cosmic ray modulation model is used to calculate the modulation of cosmic-ray protons and electrons for 11-and 22-year modulation cycles using a compound approach to describe solar ... -
A study of the time-dependent modulation of galactic cosmic rays in the heliosphere
(North-West University, 2005)Time-dependent cosmic ray modulation in the heliosphere is studied by using a two-dimensional time dependent modulation model. To compute realistic cosmic ray modulation a compound approach is used, which combines the ... -
Time–dependent modulation of cosmic rays in the outer heliosphere
(North-West University, 2013)The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a two-dimensional, time-dependent modulation model. The compound approach of Ferreira and Potgieter (2004), ...
