Predicting equatorial plasma bubbles with SWARM

A map of the Earth with the locations of plasma bubble events superimposed on it.
Map of Equatorial Plasma Bubble (EPB) events across the Earth. Most bubbles occur over the Atlantic in a region called the ‘South Atlantic Anomaly’. Here high energy particles and gamma rays penetrate deep into our atmosphere and influence the creation of bubbles.
Sachin Reddy/University College London/Mullard Space Science Laboratory

Changes in atmospheric density after sunset can cause hot pockets of gas called ‘plasma bubbles’ to form over the Earth’s equator, resulting in communication disruptions between satellites and the Earth. New AI models are now helping scientists to predict plasma bubble events and create a forecast. The work was presented this week at the National Astronomy Meeting (NAM 2022) by Sachin Reddy, a PhD student at University College London.

Shortly after sunset, pockets of super-heated gas called ‘plasma bubbles’ form in the upper atmosphere and stretch into space (up to 900km above the Earth’s surface). These bubbles start small and grow rapidly – from the size of a football pitch to that of a small country in just a couple of hours. As the bubbles grow bigger, they can prevent satellites from communicating with the Earth by blocking and warping their radio signals.

To predict plasma bubbles, a team of researchers has collated 8 years of data from the SWARM satellite mission. The spacecraft has an automatic bubble detector on-board called the Ionospheric Bubble Index. This compares changes in the density of electrons and the magnetic field strength to check if bubbles are present: a strong correlation between the two indicates the presence of a plasma bubble.

The satellite flies at an altitude of 460km (about 30x higher than a commercial plane) through the middle of most plasma bubbles. The model combines the data collection from SWARM with a machine learning approach to make predictions on the likelihood of a plasma bubble event occurring at any time.

The results show that the number of plasma bubble events varies from season to season, just like the weather, and that the number of events increases with solar activity. Despite this, the model finds location to be a far more crucial element in predicting plasma bubbles than the time of year, with most events occurring over a region in the Atlantic called the South Atlantic Anomaly. The AI model predicts events with an accuracy of 91% across different tests.

Reddy says: “Just like the weather forecast on earth, we need to be able to forecast bubbles to prevent major disruptions to satellite services. Our aim is to be able to say something like: “At 8pm tomorrow there is a 30% chance of a bubble appearing over the Horn of Africa.” This kind of information is extremely useful for spacecraft operators and for people who depend on satellite data every day, just like you and me.”

Media contacts

Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7292 3979
Mob: +44 (0)7802 877 699

Ms Cait Cullen
Royal Astronomical Society

Science contacts

Sachin Reddy
Mullard Space Science Laboratory
University College London

Notes for editors

About NAM 2022

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About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

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About the Science and Technology Facilities Council

The Science and Technology Facilities Council (STFC) is part of UK Research and Innovation – the UK body which works in partnership with universities, research organisations, businesses, charities, and government to create the best possible environment for research and innovation to flourish. STFC funds and supports research in particle and nuclear physics, astronomy, gravitational research and astrophysics, and space science and also operates a network of five national laboratories, including the Rutherford Appleton Laboratory and the Daresbury Laboratory, as well as supporting UK research at a number of international research facilities including CERN, FERMILAB, the ESO telescopes in Chile and many more.

STFC's Astronomy and Space Science programme provides support for a wide range of facilities, research groups and individuals in order to investigate some of the highest priority questions in astrophysics, cosmology and solar system science. STFC's astronomy and space science programme is delivered through grant funding for research activities, and also through support of technical activities at STFC's UK Astronomy Technology Centre and RAL Space at the Rutherford Appleton Laboratory. STFC also supports UK astronomy through the international European Southern Observatory and the Square Kilometre Array Organisation.

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About the University of Warwick

The University of Warwick is one of the world’s leading research institutions, ranked in the UK’s top 10 and world top 80 universities. Since its foundation in 1965 Warwick has established a reputation of scientific excellence, through the Faculty of Science, Engineering and Medicine (which includes WMG and the Warwick Medical School).

Submitted by Robert Massey on Fri, 15/07/2022 - 14:30