Overview

Project Highlights:

  • Identifying storm-related geomagnetically-induced currents (GICs) using a global network of ground-based magnetometers.
  • Investigating the coupling between different solar wind drivers, and the local time and latitude of the magnetic perturbations.
  • Exploring the impact of GICs on linked power networks spanning many tens of degrees of latitude.

Geomagnetically-induced currents (GICs) are induced at the Earth’s surface due to rapid changes in the geomagnetic topology caused by the interaction of the planetary magnetic field with the solar wind. These currents have been shown to have a damaging impact on a range of modern infrastructure from power grid stability and oil pipeline corrosion to railway signalling failures, with observed disruption from the equator to high latitudes (e.g. Canon et al., 2015). Estimates have placed the UK GDP loss caused by the disruption from a once-in-a-century space weather event between £0.9 and 15.9 billion (depending on the level of investment in instrumentation and forecasting capabilities)

GICs are driven by extreme solar wind events, and as such their occurrence is strongly influenced by the solar activity cycle. Cycle 24 was considered to be relatively weak, but still contained eight major storms (KP 8- or above), including the much-studied St Patrick’s Day storm of 2015. Solar cycle 25 began in 2019 and has been predicted to be of the same magnitude as the previous cycle. While there is a link between solar activity and GICs, there are several mechanisms by which GICs are induced, and the variables characterising the location and intensity of the GICs are not well-understood.

A variety of studies have focussed on the measurements of GICs in power grids both at high latitudes and the equatorial region, however these have largely been case-studies of the intense storms of the last solar cycle, as well as theoretical predictions for extreme events (see Figure 1). In this project we will be investigating the full range of event magnitudes (looking at the temporal evolution, intensity and spatial extent), and putting these into the global context using global field-aligned current data taken by a constellation of orbiting satellites, and chains of ground-based magnetometers.

Left, network map of the National Grid GB high voltage power grid. Right, simulated currents in the power grid for an extreme space weather event (red indicates currents going into the ground, blue indicates currents going into the UK’s power grid), from Beggan et al., 2013.

Methodology

The student will begin by familiarising themselves with a recommended programming language (IDL or python) and the processing and visualisation of ground-based magnetometer and AMPERE field-aligned current data sets. The student will then download several years of magnetometer data at 1 Hz resolution, and write an algorithm to identify periods of rapid changes in the local magnetic field. The location and local time of these events will be compared with the simultaneous global conditions such as the location, structure and intensity of field-aligned currents from AMPERE data, the ring current strength and intensity and the solar wind parameters prior to the storm. Events with strong magnetic perturbations spanning many degrees of latitude are of particular interest on continents such as South America where the connected power grids may be impacted by both high latitude substorm-related GICs, and equatorial ring current-driven GICs.

The student will be required to publish their work in appropriate scientific journals, and will be encouraged to present their work at both national and international conferences. The student will also be required to collaborate with international colleagues and may have the opportunity for collaborative research visits.

Training and Skills

The student will be required to learn a programming language both for data analysis and visualisation purposes. They will be trained in appropriate scientific techniques, and, through the Radio and Space Plasma Physics Group, will receive broad training in space physics and the plasma environment of the Earth and the other planets. The student will be part of the regular speaking programme run by the research group and will be expected to present their work twice per year. Furthermore, they will be encouraged to join the student Journal Club meetings, as well as Earth Club meetings, which will give them insight into analysing and critiquing papers in their research field, and the chance to see how their work fits into the wider research of the group.

Timeline

Year 1: Familiarisation with computer programming techniques, data analysis techniques, downloading appropriate magnetometer data (AMPERE data has already been downloaded) and development of algorithms to automatically identify rapid changes in magnetic field intensity. Statistical studies of the location, duration and local time of the space weather events.

Year 2: Statistical study of the intensity and structure of the AMPERE field-aligned currents relative to the space weather events identified from the magnetometer data.

Year 3: Select case studies for further investigation, particularly focussing on events with signatures spanning a range of latitudes, hence initiated by multiple drivers.

Partners and collaboration (including CASE)

The primary partners in this research are the providers of the magnetometer data that will be used to determine the potential GIC events. The majority of the data will be available via the SuperMAG website, PI. Dr. Jesper Gjerloev, with whom Dr Imber (and more broadly our research group) have a long-standing collaboration. Furthermore, Prof. Hermann Opgenoorth (University of UMĖA, and honorary Prof. at University of Leicester) will be a key collaborator, having studied these events from the Scandinavian perspective for many years. We have existing collaborations with the MET office, who are responsible for the UK space weather prediction capability.

Further Details

Dr Suzie Imber

Department of Physics and Astronomy

University of Leicester

Leicester, LE1 7RH

Email: suzie.imber@leicester.ac.uk