WAVE Group

Post 3: Working on very low frequency (VLF) radio wave data from Antarctica with Dr M A Clilverd


We make observations of very low frequency (3-30 kHz) radio waves in Antarctica as a means of studying the physics of the ionosphere and magnetosphere. VLF waves travel in the whistler mode along geomagnetic field aligned paths through the plasma of the magnetosphere from the northern hemisphere to Antarctica, and in the spherical waveguide formed by the Earth and the ionosphere. By measuring the characteristics of the received signals - amplitude, phase, group travel time, dispersion, Doppler shift and direction of arrival - we can infer wave-particle interactions, particle precipitation, large scale plasma drifts, temporal and spatial density variations, and the effects of electromagnetic pollution. We then try to understand how these effects in the magnetospheric and ionospheric plasma are related to external influences such as the interaction of the solar wind with the magnetosphere. In order to carry out this programme we make analogue and digital recordings of VLF signals, some of which originate in lightning discharges or from VLF communications and navigational transmitters, and some of which are generated spontaneously by plasma instabilities. Data are stored in Antarctica on digital audio tape, and are returned to Cambridge annually in May.


The project for Drs Clilverd and Watkins will involve the comparison of a global model of lightning activity with data recorded at Halley, Antarctica. The comparison will be used to identify areas of strength and weakness in the model and should illuminate the underlying physics behind recent long-term trend results. Additional comparisons with regional lightning activity levels determined from satellite will also be undertaken with a view to interpreting El Nino signatures in the Halley data.


No specialised knowledge of the VLF research project is required. The necessary training and equipment will be provided. However, experience of working with scientific data and with using computers would be an asset.


The appointment will be for 10 weeks.