Quantum Sensing of the Geomagnetic Space Weather Environment

On 13 March 1989, the largest magnetic storm of the last century caused widespread effects on power systems around the world including a blackout of the Hydro-Québec system in Canada. In the space of 93 seconds, its power grid collapsed leaving residents without electricity for 9 hours. In the UK, two large power transformers were severely damaged and required expensive repairs. In the intervening 30 years, society has become much more reliant on continuous power supply, global navigation satellite systems (GNSS), broadband internet, mobile phone communication and other services which can be badly affected by so-called space weather, specifically the effects generated by rapid variations of the magnetic field on the order of seconds to minutes. It is anticipated that a more severe event than the March 1989 storm in the contemporary UK could cause economic damage on the order of billions of pounds per day.

Measuring changes of the geomagnetic during a storm is of critical national importance and can help understand the hazards posed from space weather. While present day scientific-level instruments that measure the magnetic field (called fluxgate magnetometers) at UK geomagnetic observatories are very sensitive, they are not quite sufficient for the task of making absolute rapid, high-accuracy and noise-free measurements of the magnetic field. We wish to build and deploy a new type of sensor known as an optically pumped magnetometer. This uses cutting-edge quantum technology, developed in the last decade, to measure the vibrations of Caesium (Cs) atoms inside a glass cell which are able to detect small changes of the Earth's magnetic field. As a bonus, the new magnetometers reduce the size, weight and power requirements of a sensor while increasing its accuracy over 100-fold compared to current instrumentation.

To test the new optically pumped magnetometer we will run it in parallel with the scientific instruments at the Eskdalemuir geomagnetic observatory in the Scottish borders for six months. This location has had a world-leading observatory in operation since 1904 and is one of the magnetically cleanest sites in the UK. Once the performance has been assessed a further five OPM sensors will be built, integrated into a bespoke communications and power supply and deployed to remote sites across the UK to augment the BGS space weather monitoring network. In conjunction with the existing geomagnetic instruments, we will achieve a world first with the densest national network of magnetometers. This will surpass the World Meteorological Organisation (WMO) recommendation of no more than 200 km between magnetic stations.

The project will bring together the technical skills of the University of Strathclyde's Physics Department to build the sensor, along with RAL Space's electronic system experience to optimise its performance. The British Geological Survey Geomagnetism team have ample experience in deploying and running long term installations and validating the accuracy of magnetic instruments. This is a cross-disciplinary project with the potential to bring technical, scientific, social and economic benefit in the form of a new high accuracy magnetometer than the can be deployed across the UK (and the world) in order to study the effects of hazardous space weather.