Monitoring cosmic ray intens ties in Antarctica - an appropriate scientific activity
HarmMoraal North-West University
The previous SANAP mission statement justified our scientific role in Antarctica as
"to increase understanding of the natural environment and life in the Antarctic and Southern Ocean through appropriate (emphasis) science and technology." In this presentation I will show that monitoring experiments - sometimes brushed off as being insufficiently 'cutting edge', 'innovative' or 'strategic' in nature, are in fact appropriate for their purpose, and that they do deliver world-class scientific results.
As primary example I will use the 20 January 2005 so-called Ground Level Enhancement observed by the Sanae neutron monitor, to show how this made an almost unique contribution to the theory of cosmic-ray acceleration on the sun. As secondary example I will talk about pilot and planned experiments to extract the 1 OBe isotope, as indicator of the cosmic-ray intensity in the past, out of shallow ice layers.
Once again, this is an appropriate, affordable experiment, because it uses the specific nature of the ice wall in the vicinity of Sanae, which is difficult to find in other locations.
SANAP PI Symposium Final Programme & Abstracts 8
Polar Space weather studies during IPY2007: First results from South African Antarctic experiments.
Ben D.L. Opperman1.2, Pierre J. Cilliers1, Peter R. Sutcliffe1•3
, Lindsay Magnus1•3 ,
Cathryn N. Mitchell4 and Lucilla Alfonsi5
1Hermanus Magnetic Observatory, Hermanus, South Africa, 2Department of Physics and Electronics, Rhodes University, Grahamstown, South Africa. 3 School of Physics, University of KwaZulu-Nata/, Durban, South Africa. 4Department of Electrical and Radio Engineering, University of Bath, Bath, U.K., 5Istituto Nazionale di Geojisica e Vu/canologia(INGV), Rome, Italy.
The ionosphere significantly affects radio propagation, affecting satellite navigation and communications systems and making it an important polar space weather parameter to monitor. Periods of high geomagnetic disturbances, caused by high sunspot activity, solar flares or solar coronal mass ejections are especially significant as rapid changes in the ionosphere incapacitates GPS navigation and HF communication systems, critical life-dependent systems in polar regions. The HMO, in collaboration with other research partners, manages and operates several ionospheric measurement instruments at SANAE IV (71.67°S, 2.84°W), located in the auroral oval, to facilitate our understanding of ionospheric dynamics and behaviour.
These instruments include the SHARE radar used for monitoring ionospheric convection, i.e. the noon-midnight-oval edge motion of ionospheric plasma over the polar cap due to the ExB drift effected by the electric field resulting from the interplanetary magnetic field (IMF) coupling with the earth's magnetosphere; an ionospheric scintillation monitor (ISM) observing rapid, small scale structural changes in the ionosphere; total field magnetometer used for monitoring changes in the magnetic field and predicting auroral and sub storm onsets and a dual frequency GPS receiver used for monitoring the Total Electron Content of the ionosphere. First results from the IPY 2007 campaign are presented illustrating the correlation between measurements and investigating possible driving forces of the ionospheric behaviour.
The application of these instruments to observe other phenomena like field resonance PC5 Ultra Low Frequency pulsations and polar night-time ionospheric plasma transport mechanisms are also illustrated.
SANAP PI Symposium Final Programme & Abstracts 9