Auroras have fascinated people for centuries, but their stunning displays come with hidden dangers.
These natural light shows are caused by the same space weather events that can create electric currents capable of damaging power infrastructure like pipelines and grids.
Scientists have now discovered that the angle at which these space weather shocks hit Earth can determine how strong these damaging currents are.
This finding, published in Frontiers in Astronomy and Space Sciences, could help predict and protect against these harmful shocks.
Dr. Denny Oliveira from NASA’s Goddard Space Flight Center, the lead author of the study, explained, “Auroras and geomagnetically induced currents are caused by similar space weather events.
The aurora is a visual warning that electric currents in space can generate harmful currents on the ground.”
Auroras occur when particles from the sun reach Earth’s magnetic field, causing a geomagnetic storm, or when interplanetary shocks compress Earth’s magnetic field.
These shocks can also create geomagnetically induced currents, which damage electrical infrastructure. Stronger shocks mean more powerful currents and brighter auroras, but even frequent, less powerful shocks can cause significant damage over time.
One of the most severe impacts on power infrastructure happened in March 1989. A major geomagnetic storm caused the Hydro-Quebec power system in Canada to shut down for nearly nine hours, leaving millions without electricity.
“But weaker, more frequent events can also threaten power systems over time,” said Oliveira. “Our study shows that significant geoelectric currents occur often after shocks and deserve attention.”
The researchers found that shocks hitting Earth head-on cause stronger geomagnetically induced currents because they compress the magnetic field more.
To understand how shock angles affect these currents, they studied interplanetary shocks and compared them with current readings from a natural gas pipeline in Mäntsälä, Finland, an area often within the auroral zone during active periods.
Using data on the interplanetary magnetic field and solar wind, the shocks were categorized into three groups: highly inclined, moderately inclined, and nearly frontal shocks.
The findings revealed that nearly frontal shocks cause the highest peaks in currents immediately after the shock and during the following substorm, especially around magnetic midnight.
“Moderate currents occur shortly after the shock when Mäntsälä is around dusk, while more intense currents happen around midnight,” said Oliveira.
This information could be used to protect power grids by predicting shock angles up to two hours before impact. “Power grid operators could manage specific electric circuits when a shock alert is issued to prevent geomagnetically induced currents from damaging equipment,” suggested Oliveira.
However, the study found no strong link between the shock angle and the time it takes for currents to form. This may be due to the limited data available, which only came from the Mäntsälä pipeline system. More data from different locations worldwide is needed for a complete understanding.
Oliveira emphasized, “It would be helpful if power companies worldwide made their data accessible to scientists for studies like this.”
By understanding and predicting these space weather shocks, we can better protect our critical infrastructure from their damaging effects.
