Spectacular auroras caused by “head-on” blow to Earth’s magnetic field could damage critical infrastructure, warns new research.
Interplanetary shocks that strike Earth’s magnetic field cause more powerful ground-level electric currents – threatening pipelines and submarine cables, say scientists.
Auroras have inspired myths and portents for thousands of years – but only now, with modern technology dependent on electricity, are their true power being appreciated.
The new study, published in the journal Frontiers in Astronomy and Space Sciences, shows that the same forces that cause auroras also cause currents that can damage infrastructure that conducts electricity, such as pipelines.
Researchers showed that the impact angle of interplanetary shocks is key to the currents’ strength, offering an opportunity to forecast dangerous shocks and shield critical infrastructure.
Study lead author Dr. Denny Oliveira, of NASA’s Goddard Space Flight Center in Maryland, said: “Auroras and geomagnetically induced currents are caused by similar space weather drivers.
“The aurora is a visual warning that indicates that electric currents in space can generate these geomagnetically induced currents on the ground.”
“The auroral region can greatly expand during severe geomagnetic storms.
“Usually, its southernmost boundary is around latitudes of 70 degrees, but during extreme events, it can go down to 40 degrees or even further, which certainly occurred during the May 2024 storm – the most severe storm in the past two decades.”
He explained that auroras are caused by two processes: either particles ejected from the sun reach Earth’s magnetic field and cause a geomagnetic storm, or interplanetary shocks compress Earth’s magnetic field.
Dr. Oliveira says the shocks also generate geomagnetically induced currents, which can damage infrastructure that conducts electricity.
He warned that more powerful interplanetary shocks mean more powerful currents and auroras — but frequent, less powerful shocks could also do damage.
Dr. Oliveira said: “Arguably, the most intense deleterious effects on power infrastructure occurred in March 1989 following a severe geomagnetic storm.
“The Hydro-Quebec system in Canada was shut down for nearly nine hours, leaving millions of people with no electricity.
“But weaker, more frequent events such as interplanetary shocks can pose threats to ground conductors over time.
“Our work shows that considerable geoelectric currents occur quite frequently aftershocks, and they deserve attention.”
He says shocks that hit the Earth head-on, rather than at an angle, are thought to induce stronger geomagnetically induced currents because they compress the magnetic field more.
The research team investigated how geomagnetically induced currents are affected by shocks at different angles and times of day.
They cross-referenced a database of interplanetary shocks with readings of geomagnetically induced currents from a natural gas pipeline in Mäntsälä, Finland, which is generally in the auroral region during active times.
To calculate the properties of the shocks, such as angle and speed, they used interplanetary magnetic field and solar wind data.
The shocks were divided into three groups: highly inclined shocks, moderately inclined shocks, and nearly frontal shocks.
The researchers found that more frontal shocks cause higher peaks in geomagnetically induced currents both immediately after the shock and during the following sub-storm.
Particularly intense peaks took place around magnetic midnight when the north pole would have been between the sun and Mäntsälä. Localized substorms at the time also cause “striking” auroral brightening.
Dr. Oliveira said: “Moderate currents occur shortly after the perturbation impact when Mäntsälä is around dusk local time, whereas more intense currents occur around midnight local time.”
Because the angles of the shocks can be predicted up to two hours before impact, the research team says the information could allow protections to be set in place for electricity grids and other vulnerable infrastructure before the strongest and most head-on shocks strike.
Dr. Oliveira said: “One thing power infrastructure operators could do to safeguard their equipment is to manage a few specific electric circuits when a shock alert is issued.
“This would prevent geomagnetically induced currents reducing the lifetime of the equipment.”
However, the team didn’t find strong correlations between the angle of a shock and the time it takes for it to hit and then induce a current.
Dr. Oliveira says that may be because more recordings of currents at different latitudes are needed to investigate.
He added: “Current data was collected only at a particular location, namely the Mäntsälä natural gas pipeline system.
“Although Mäntsälä is at a critical location, it does not provide a worldwide picture.
“In addition, the Mäntsälä data is missing several days in the period investigated, which forced us to discard many events in our shock database.
“It would be nice to have worldwide power companies make their data accessible to scientists for studies.”
Produced in association with SWNS Talker
