New research shows that the angle at which these solar shocks hit Earth is crucial to protect infrastructure.
For thousands of years, humans have gazed at the vibrant auroras, dancing in the night sky. But these beautiful displays are more than just a pretty sight. They’re a warning sign of a hidden danger – geomagnetically induced currents.
Auroras are caused by particles from the sun slamming into Earth’s magnetic field. These same forces may compress the magnetic field, resulting in tremendous flow currents that may reach the ground.
New research shows that the angle at which these solar shocks hit Earth is crucial to protect infrastructure.
“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,” explained Denny Oliveira of NASA’s Goddard Space Flight Center, and lead author of this new study.
Head-on shocks
Earth’s dazzling auroras stem from two processes: solar storms unleashed by the sun and magnetic field compressions induced by interplanetary shocks. These shocks occur when a fast solar wind overtakes a slower stream, thereby creating a shock wave.
Both can cause dangerous currents to flow through the Earth, potentially damaging electrical infrastructure. Bigger events bring bigger threats, but even minor shocks pose a risk.
“The auroral region can greatly expand during severe geomagnetic storms,” Oliveira added. “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.”
Researchers found that head-on shocks are likely to create the strongest geomagnetically induced currents, leading to “powerful ground-level electric currents, threatening pipelines and submarine cables.”
This is because head-on shocks can compress the magnetic field more.
How the angle was found
The researchers examined how the angle and timing of solar shocks influence geomagnetically induced currents. To understand the connection, the researchers looked at two sets of data.
One was a collection of recorded interplanetary shocks, while the other was readings of electrical currents taken from a natural gas pipeline in Mäntsälä, Finland. This pipeline is located in a region that frequently sees auroras during times of strong solar activity.
They used interplanetary magnetic field and solar wind data to calculate the angle and speed of each shock. And then divided them into three categories: highly inclined, moderately inclined, and nearly frontal.
Research showed a clear link between shock angle and current strength. The more head-on a solar shock hits, the stronger the jolt of electricity that travels to the ground. This electrical surge typically occurs in two bursts: one right after the initial impact, and another during a following substorm – a smaller geomagnetic disturbance. Surprisingly, these peak surges were strongest at midnight, when Mäntsälä’s north pole faced the sun directly.
The study authors state that scientists can predict the angle of a shock up to two hours before it hits. This may provide time to take precautions, like reducing power on certain lines.
Source: IE
