This project will use optical imaging of the aurora together with radar observations of the ionosphere to investigate extreme heating of the neutral upper atmosphere caused by auroral processes. The understanding gained will benefit atmospheric modelling for climate predications and could improve predictions of drag on spacecraft and space debris.
The flow of the solar wind past the Earth transfers a significant amount of energy into the upper atmosphere (sometimes even greater than the solar irradiance) via electric currents and auroral particle precipitation. Part of the energy is visible as the aurora, but most ends up as heat. This heating is currently poorly quantified and poorly understood, but it has important impacts such as atmospheric expansion (which affects spacecraft orbits) and complex influences on the lower atmosphere which are important for climate forecasting. The electric fields responsible for the heating are highly variable near aurora, in both time and space. Large-scale measurements of the average electric field lead to a significant underestimate of the total heating and even greater underestimate of the peak heating. Recent work in Southampton has used optical observations to determine the ionospheric electric field and thermospheric neutral temperature above Svalbard in the high Arctic, both at much higher resolution than previous measurements. We found extreme changes in temperature (100s of K) and very rapid rates of both heating and cooling, which are difficult to explain using current understanding even after accounting for the high resolution of the observations. This project will use measurements of the aurora and ionosphere made by new state-of-the-art instruments installed in northern Norway. The spatial variation in the electric field around aurora will be investigated and compared with 2D measurements of the neutral temperature. The findings will advance theories for auroral electrodynamics and the deposition of energy in the atmosphere as heat.
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted in Physics & Astronomy. Specific training will include:
- Attendance at a national introductory summer school in solar-terrestrial physics.
- An opportunity to join fieldwork in northern Norway and Svalbard, in order to calibrate and maintain the optical instruments; training will be provided in Arctic safety and operation of the instrumentation.
- Postgraduate lectures and research seminar series provided in Physics & Astronomy.
- Presentation and communication skills will be honed through participation in weekly group meetings, a journal club, and presentation of findings at national and international conferences.
- Training in public engagement will be provided by the Physics & Astronomy public engagement officers.
Krcelic, P., et al. (2023), Fine-scale electric fields and Joule heating from observations of the aurora. J. Geophys. Res, doi:10.1029/2022JA030628.
Price, D. J., et al. (2019), High-resolution optical observations of neutral heating associated with the electrodynamics of an auroral arc. J. Geophys Res., doi:10.1029/2019JA027345