Nasa is developing a forecasting system that would enable grid operators to prevent blackouts caused by solar storms.
The space agency has recently opened six test sites around the USA that compare computer simulations of detected space weather events with the actual impact on the ground.
Geomagnetic storms, caused by the interference of powerful solar flares with the Earth’s magnetosphere, have wreaked havoc with power grids and telecommunication systems in the past.
In March 1989 a powerful coronal mass ejection (CME), a release of matter from the upper layers of the Sun, triggered a geomagnetic storm on Earth, which knocked out power to the Canadian province of Quebec for nine hours.
The most severe solar storm ever recorded, the 1859 Carrington Event, disrupted telegraph services across Europe and North America, and saw some telegraph operators receiving electrical shocks from the equipment.
In today's wired and interconnected world, such an incident could have far-reaching consequences.
However, Nasa says that with an advanced warning, infrastructure operators would be able to take measures to minimise or even mitigate the impact. To be able to provide such a warning is the goal of the Solar Shield project, overseen by researchers from Nasa’s Goddard Space Flight Center in Maryland.
"We really want to create models that accurately show incoming space weather," said Antti Pulkkinen, a research astrophysicist at Goddard, and the lead of the Solar Shield project. "That way, space weather forecasters can provide the grid operators the information they need to know what's happening when they start seeing weird fluctuations in the power grid."
The problem is that although solar flares hit Earth often, they only cause problems when they attack the planet’s magnetosphere at a certain angle.
"One of the problems we need to solve is predicting the direction of the magnetic field embedded in a CME," said Pulkkinen. "They only generate major storms within the magnetosphere if they're pointed opposite Earth's magnetic field when they hit - otherwise, it may give an initial punch and then just kind of fizzle."
When a solar flare with a magnetic field oriented in the opposite direction than the Earth’s magnetosphere hits the Earth, the magnetosphere starts shaking, changing the strength and direction of the magnetic field all over the planet. These changing magnetic fields can induce electric currents on the ground, which have an affinity for long metallic structures such as oil pipelines, telecommunication lines or power lines.
Travelling on these metallic structures, the geomagnetically induced currents (GIC) can cross vast distances.
On a power line, the GIC could damage transformers and cause voltage to collapse.
But the operators can protect the grid, for example, by injecting reserve power into the system to stabilise the voltage. To do that, however, they need to know at least 20 minutes in advanced.
The Nasa team studies images from coronographs and instruments from Nasa’s Advanced Composition Explorer satellite to learn about the direction of the incoming CMEs. This data is run through computer models, which provide estimates of when, where and at what speed and strength the solar flare will strike the Earth. The calculations are then compared with measurements taken from six power substations across the US, in turn enabling the scientists to fine-tune the models.
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