A5029663899- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Seismic Waves and Analysis
- Classical Philosophy and Thought
- Magnetic confinement fusion research
- Geophysics and Sensor Technology
- Philosophical Ethics and Theory
- Dust and Plasma Wave Phenomena
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Epistemology, Ethics, and Metaphysics
- Economic Theory and Institutions
- Lightning and Electromagnetic Phenomena
- Particle accelerators and beam dynamics
- Geophysical and Geoelectrical Methods
- Ethics in medical practice
- Political Philosophy and Ethics
- Quantum and Classical Electrodynamics
- History and Developments in Astronomy
- Psychology of Moral and Emotional Judgment
- Radar Systems and Signal Processing
- Scientific Research and Discoveries
University of KwaZulu-Natal
2002-2023
University of Hull
1979-2008
Johns Hopkins University Applied Physics Laboratory
1992
Rhodes University
1960-1973
Cavendish Hospital
1966
The Stare (Scandinavian twin auroral radar experiment) system has been used to measure ionospheric electric fields associated with Pc 5 geomagnetic pulsations. With this system, are derived from the drift velocity of irregularities. spatial resolution is 20 km over a 200,000‐km² grid, and temporal s. It found that oscillating field hydromagnetic line resonance produces poleward moving, bandlike regions aurora, which aligned in east‐west direction. irregularities within these bands...
The Johns Hopkins University/Applied Physics Laboratory HF radar at Goose Bay often sees F‐region drifts or electric fields which are associated with field line resonances in the Earth's magnetosphere. These seen interval from local midnight to morning, and have discrete, latitude‐dependent frequencies approximately 1.3, 1.9, 2.6–2.7, 3.2–3.4 mHz. We show that these compatible MHD waveguide modes, antisunward propagation reflection magnetopause turning points on dipolar lines.
A detailed analysis of HF radar data a ULF pulsation event in the postmidnight sector on January 11, 1989, has been carried out using techniques which allow instantaneous amplitude and phase to be determined as functions geomagnetic latitude, longitude, time. Field line resonances with several different frequencies occur simultaneously at latitudes. These can associated cavity mode 1.3 mHz, 1.9 2.7 3.3 mHz. In addition there is resonance 0.8 mHz does not fit well picture. are constant better...
Recently, the STARE (Scandinavian Twin Auroral Radar Experiment) radar system has been used to measure oscillatory electric fields and latitudinal resonance widths of Pc5 toroidal mode pulsations. In this letter we use these values determine heights‐integrated Pedersen conductivities in regions, quality factors resonances, Joule heating ionosphere by pulsations magnetospheric energy storage resonant waves. We have found that stored a large pulsation is approximately 1% ring current....
A study is presented of a storm time Pc 5 pulsation, observed by GEOS 2 particle detectors and magnetometers at geocentric orbit the STARE auroral radar in ionosphere. These measurements allow comparison phase relationships between magnetic field components, energetic flux, electric ionosphere over substantial region. They also permit wavelength disturbance theory coupling drift mirror wave standing Alfvén developed. The results are compared with this found to support it. In particular, it...
Naturally occurring whistlers provide a powerful ground‐based technique for probing the magnetosphere. The major features of theory whistler propagation in ducts plasmasphere are well understood. details how propagates upward from its source and excites duct it escapes reaches ground not so clear. Recent direction‐finding experiments designed to find point at which signal emerges lower ionosphere; this motion longitude has propagated is inferred. It thus important understand between...
The Nicomachean Ethics, as is well known, distinguishes three types of friendship the goodness, pleasure, and utility. How are these supposed to be related one another? It has often been said that Aristotle regards them focally related1, but W. Fortenbaugh recently argued against this suggested essential connection provided by notion analogy2. seems me, however, neither nor his opponents correct. will central claim paper relates not appeal either analogical or focal homonymy, in terms a...
Moral theories which, like those of Plato, Aristotle and Aquinas, give a central place to the virtues, tend assume that as traits character virtues are mutually compatible so it is possible for one same person possess them all. This assumption—let us call compatibility thesis—does not deny existence painful moral dilemmas: allows may conflict in particular situations when considerations associated with different favour incompatible courses action, but holds these conflicts occur only at...
A new hydromagnetic theory is developed for describing compressional pulsations with large azimuthal wave number. It assumed that there are two plasmas, one hot, in which pressure effects important, and the other cold. The equations derived a general set of magnetic coordinates allow realistic calculations including geometrical magnetosphere. describe three modes coupled by geometry. When number large, fast mode strongly evanescent. This allows an expansion 1/ m order to decouple wave....
We present HF radar observations of Pc5 field line resonances in the post‐midnight Antarctic ionosphere on April 28/29 1997. Simultaneous oscillations were seen solar wind parameters observed by WIND. The spectra both sets data show peaks near 1.3 mHz, 1.9 2.7 mHz and 3.3 mHz. bandpass filtered a complex demodulation technique applied to calculate instantaneous energy flux each band hence power incident front magnetosphere 70 minutes later. magnitude deposited at frequency through Joule...
Several papers have been written about the observed relationship between ground based magnetometer pulsation measurements and simultaneous oscillations of Doppler frequency shifts in ionospherically reflected radio echoes. In this paper we derive mechanisms which relate these observations for vertical incidence case at low to mid latitudes. We investigate effects oscillating electric magnetic fields ionospheric heights on phase path wave, gives rise shifts. identify three main work...
On November 28, 1983, between 1638 UT and 1642 UT, the HILAT satellite moving approximately along noon meridian passed over northeastern Canada encountered dayside high latitude cleft. During passage an upward current sheet bounded to north south by weaker downward sheets was observed. The sheets, particularly sheet, were immersed in a region of fairly intense low energy electron precipitation type commonly observed polar Simultaneous radar measurements made slightly east track which beacon...
Abstract The paper examines a single, apparently simple argument for the existence of incompatibilities between virtues as traits character. This appeals not to empirical truths about human psychology or nature but possibility conflict exercise different in action. There are, example, situations which we can virtue truthfulness only at expense exercising tact, when are asked question straightforward answer will pain our questioner. person who these would give possesses higher degree than...
III—Gratefulness and Gratitude A. D. M. Walker Search for other works by this author on: Oxford Academic Google Scholar Proceedings of the Aristotelian Society, Volume 81, Issue 1, 1 June 1981, Pages 39–56, https://doi.org/10.1093/aristotelian/81.1.39 Published: 08 September 2015