Studies of the aurora and geomagnetically induced currents have revealed that the angle of an interplanetary impact relative to the Earth’s magnetic field has a significant effect on the strength of the currents that impact electrical infrastructure. Direct impacts tend to induce stronger currents, which can lead to widespread power outages. Predicting these impacts can help mitigate the risk to critical infrastructure.
Scientists have found that an interplanetary shock hitting Earth’s magnetic field head-on could make electrical currents on the ground more powerful, threatening pipelines and undersea cables.
The aurora is caused by particles from the Sun striking the Earth’s magnetic field, which also causes geomagnetically induced currents at ground level that can damage infrastructure that conducts electricity. Scientists studying these currents to protect critical infrastructure have conducted the first study to compare real-time measurements of interplanetary shock waves and geomagnetically induced currents, showing that the angle of shock wave impact is key to predicting potential damage to infrastructure, with shock waves that strike the magnetic field at an angle generating weaker currents.
Impact of interplanetary shock waves on infrastructure
The Northern Lights have been the subject of myth and omens for thousands of years, but it wasn’t until modern technology that relies on electricity that we realized their true power: The same forces that create the Northern Lights also create electrical currents, which can damage infrastructure that carries electricity, like pipelines. The forefront of astronomy and space science They demonstrate that the angle of impact of an interplanetary shock wave is key to the strength of ocean currents, providing an opportunity to predict dangerous shock waves and protect critical infrastructure.
“Auroras and geomagnetically induced currents are caused by similar space weather factors,” National Aeronautics and Space Administration (NASA)“Auroras are a visual warning that currents in space can generate geomagnetically induced currents on the ground,” said John F. Kennedy, a researcher at the Goddard Space Flight Center and lead author of the paper.
“The auroral field can expand greatly during severe geomagnetic storms,” he added. “Usually its southern boundary is around 70 degrees latitude, but in extreme cases it can go down to 40 degrees or even more. This certainly happened during the May 2024 storm, the most intense storm in the last 20 years.”
Light, color, action
Auroras are caused by two processes: particles emitted from the Sun reaching the Earth’s magnetic field and causing a geomagnetic storm, or interplanetary shock waves compressing the Earth’s magnetic field. These shock waves also generate geomagnetically induced currents that can damage infrastructure that conducts electricity. The more powerful the interplanetary shock waves, the stronger the currents and auroras, but even less powerful and more frequent shock waves can cause damage.
“Perhaps the most significant negative impact on power infrastructure occurred after a severe geomagnetic storm in March 1989, which shut down the Quebec hydroelectric system in Canada for nearly nine hours, leaving millions of people without electricity,” Oliveira says. “But weaker, more frequent phenomena like interplanetary shock waves can pose a threat to ground conductors over time. Our study shows that significant earth currents occur quite frequently after shock waves, making them worth paying attention to.”
An impact that hits Earth head-on, rather than at an angle, is thought to compress the magnetic field more and thus create stronger geomagnetically induced currents. Scientists have investigated how impacts at different angles and times of day affect geomagnetically induced currents.
To do so, the researchers took a database of interplanetary shock waves and cross-referenced them with measurements of geomagnetically induced currents from a natural gas pipeline in Mantsala, Finland, which is typically in the auroral region during active periods. To calculate the shock wave’s properties, such as angle and speed, the researchers used data on the interplanetary magnetic field and solar wind. The shock waves were divided into three groups: highly oblique shocks, moderately oblique shocks, and nearly frontal shocks.
Angle of attack
They found that the more frontal shocks there were, the higher the peaks of geomagnetically induced currents, both immediately after the shocks and during the substorms that followed. A particularly strong peak occurred around magnetic midnight, when the North Pole was between the Sun and Mantsara. Localized substorms at this time also produce a pronounced auroral glow.
“Mantsala experiences moderate currents just after the disturbance hits at dusk local time, but stronger currents form around midnight local time,” Oliveira said.
The angle of these quakes can be predicted up to two hours before they occur, meaning this information could allow protection measures to be put in place for power grids and other vulnerable infrastructure before the most powerful, frontal quakes hit.
“One thing that power infrastructure operators can do to protect their equipment is to manage some specific electrical circuits when a shock alarm is triggered,” Oliveira suggests, “this will prevent geomagnetically induced currents from shortening the lifespan of the equipment.”
However, the scientists did not find a strong correlation between the angle of the impact and the time it took for it to strike and induce an electric current, which may be because they need more recordings of the current at different latitudes to investigate this aspect.
“The current data was collected only at a specific location, namely the Mantzara natural gas pipeline system,” Oliveira warned. “Although Mantzara is in an important location, it is not representative of the global situation. Furthermore, the Mantzara data had gaps of several days during the study period, which forced us to exclude many events from the shocks database. We would encourage utilities around the world to provide scientists with their data for study.”
Reference: “First direct observation of the effect of the impact angle of an interplanetary shock wave on real geomagnetically induced currents: the case of the Finnish natural gas pipeline system” by Denny M. Oliveira, Eftihia Zesta, and Sérgio Vidal Luengo, May 7, 2024, The forefront of astronomy and space science.
DOI: 10.3389/fspas.2024.1392697
