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Honorary Associate Professor

Photo of Associate Professor Neil Thomson.

Location
Room 530
Phone numbers
7802 (Office)
64 3 479 7802 (Office Direct Dial)
Email
neil.thomson@otago.ac.nz

Download the vCard for Associate Professor Neil Thomson

Biography

BSc(Hons) & PhD in Physics from Otago.
Post Doc at Max Planck Institut fur Aeronomy, Lindau am Harz (now Max Planck Institut fur Solar System Research).
Space physicist at Physics and Engineering Lab., DSIR, Lower Hutt (now IRL) for ~4 years. Then lecturer - senior lecurer - associate professor, in Physics at Otago.
Study leaves (space physics, 1984-2005) at Stanford and British Antarctic Survey (Sheffield & Cambridge).

The Earth's upper atmosphere intercepts important electromagnetic and fast particle radiation from the Sun and beyond, giving protection for life below. This radiation also ionizes the upper atmosphere allowing long-distance radio communication and providing a way to monitor changes in the incoming radiation. In particular, the lowest edge of this ionization, at heights 50-90 km (depending on time of day etc) forms the upper level of the Earth-ionosphere 'waveguide' (bounded below by the ground). Very Low Frequency (VLF) radio waves, both natural (eg lightning) and man-made, propagate in this waveguide. Their readily measured propagation is very sensitive to the height and sharpness of the waveguide ceiling. These, in turn, are very sensitive to many changes: solar flare x-rays, gamma-ray bursts, fast particle precipitation, cosmic rays, day-dusk-night-dawn, latitude, season, solar cycle etc.

My research interests are centered on measuring and understanding these effects, most recently concentrating on the quiet earth-ionosphere waveguide height and sharpness which provides the reference baseline for all these changes. This involves experimental observations both here and around the word, together with the modeling of the results and their underlying physics.

I also have research interests at greater heights, in the Earth's plasmasphere (~ 10,000 km altitude) which again involve radio propagation both observational and modeling (ray tracing).Find out more about my research.

Publications

Clilverd, M. A., Rodger, C. J., Brundell, J. B., Dalzell, M., Martin, I., Mac Manus, D. H., & Thomson, N. R. (2022, October). Geomagnetically induced currents and harmonic distortion: Monitoring using VLF observations. Verbal presentation at the 18th European Space Weather Week (ESWW), [Hybrid]. Conference Contribution - Verbal presentation and other Conference outputs

Thomson, N. R., Clilverd, M. A., & Rodger, C. J. (2022). Ionospheric D region: VLF-measured electron densities compared with rocket-based FIRI-2018 model. Journal of Geophysical Research: Space Physics, 127, e2022JA030977. doi: 10.1029/2022JA030977 Journal - Research Article

Rodger, C. J., Clilverd, M. A., Belcher, S. R. G., George, H., Cresswell-Moorcock, K., Cook, S., Brundell, J. B., Thomson, N. R., & Ulich, T. (2021, August-September). Towards developing a nowcasting solar flare capability using subionospheric VLF radio: Addressing the ICAO call for global aviation. Verbal presentation at the XXXIV International Union of Radio Science General Assembly and Scientific Symposium (URSI GASS), [Online]. Conference Contribution - Verbal presentation and other Conference outputs

Clilverd, M., Belcher, S., Rodger, C., Cook, S., Thomson, N., Brundell, J., & Raita, T. (2021). Measuring solar flare X-ray flux using ground-based subionospheric VLF networks. Proceedings of the 17th European Space Weather Week (ESWW). Retrieved from http://esww17.iopconfs.org/home Conference Contribution - Published proceedings: Abstract

Belcher, S. R. G., Clilverd, M. A., Rodger, C. J., Cook, S., Thomson, N. R., Brundell, J. B., & Raita, T. (2021). Solar flare X-ray impacts on long subionospheric VLF paths. Space Weather, 19, e2021SW002820. doi: 10.1029/2021SW002820 Journal - Research Article

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