The transfer of solar wind energy into the Earth’s Upper Atmosphere via high-frequency electromagnetic waves

Theme: Natural & Biological Hazards

Primary Supervisor:

Colin Forsyth

Space and Climate Physics, UCL

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Secondary Supervisor:

Jonathan Holmes

Geography, UCL

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Additional Supervisor(s):

Project Description:

Earth’s magnetic field is highly dynamic and fluctuates on a wide spectrum of timescales, from milliseconds to millions of years. By examining characteristic periodicities of these fluctuations alone, many geophysical phenomena can be identified. In this project we wish to investigate the causes of very rapid changes of the magnetic field between 10s and 100Hz, where processes within the Earth’s magnetosphere and ionosphere produce rapid changes of the magnetic field, transferring vast amounts of energy (~1015J) into the upper atmosphere.

In particular, periodic but irregular fluctuations in Earth’s nightside field enable the determination of how the energy flows within the external magnetic field during large geomagnetic storms and their related sub-storm processes. The pulsations that are generated can give us scientific information (by proxy) about sub-storm processes, which in turn allows us to start assessing their impact on the development of induced currents in high-voltage power systems that can occur during these storms.

Magnetic field measurements can be made both on the ground and in space to probe this energy transfer. The British Geological Survey amongst others have sophisticated ground instrumentation that are very sensitive to small variations (400 km). Data from a new European Space Agency mission Swarm will also be used. Finally, multiple reflections of the energy from lightning flashes also allow us to study the ionosphere and magnetosphere. A detailed understanding of their long-term behaviour and how they relate to large-scale energy transfer remains unknown.

Policy Impact of Research:

The UK National Risk Register lists Space Weather as medium-high likelihood, medium impact civil emergency. This work will impact the UK policy and economy in terms of understanding the risk from external field variations during geomagnetic storms. These include disruptions to satellite-based assets, GPS signals, power systems aircraft communication systems.

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