TCD study sheds light on solar power

FORECASTS OF activity on the sun that can disrupt telecommunications systems on Earth are set to improve, thanks to research carried out at Trinity College Dublin.

Using data from twin satellites that offer three-dimensional views of the sun, scientists tracked how streams of energy from solar storms travel from the sun’s atmosphere to Earth, and they found some surprising results.

Solar storms are enormous eruptions of hot gas from the surface of the sun that can move into the solar system, explained Dr Peter Gallagher, a senior lecturer in astrophysics at Trinity.

“Once launched, they travel at millions of kilometres per hour and contain billions of tonnes of hot solar gas.” When energy from solar storms hits the Earth’s atmosphere, the stream of particles can cause visually arresting displays, including the Northern Lights. But solar storms’ magnetic properties can also interfere with satellites, GPS and telecommunications systems, noted Dr Gallagher.

“We are very dependent on space-based satellites to relay mobile phone and telephone communications, and a storm from the sun can cause them to be completely lost,” he said. “So in Europe we are building up capability to monitor solar activity as you do with the weather on Earth, and make forecasts when solar activity is going to good or bad.” To get a better handle on solar storm eruptions, Dr Gallagher and colleagues at Trinity’s school of physics and the Trinity Centre for High Performance Computing have been analysing images streaming back to Earth from cameras aboard Nasa’s twin satellites.

“Together, the satellites give you a three-dimensional picture of the sun’s atmosphere and the blobs of hot gas that the sun explodes out into space,” explained Dr Gallagher.

“One of the satellites is slightly ahead of the Earth and the other is slightly behind the Earth, so they give you these two eyes in space. Once you get the data from these two different perspectives, you can combine the images together using software and try to reconstruct what the sun’s atmosphere looks like in three dimensions.

“You can tell the direction solar storms are travelling in as they move through space, and that enables you to predict when they are going to hit the earth.”

A key element for the Trinity team, which received funding from Science Foundation Ireland and worked closely with Nasa, was to develop software that could analyse the reams of images coming from the satellites.

This allowed the scientists to generate “a fully three-dimensional reconstruction” of a solar emission from an event on December 12th, 2008 that impacted the Earth several days later, explained Jason Byrne, a PhD student on the project.

However, the results were unexpected, because the solar storms didn’t necessarily travel in straight lines, Dr Gallagher said.

“It was really weird – at first we actually felt we were wrong.

“You would expect when you eject something from a planet or from a star, it should travel straight out from that planet or star,” he said.

“But what we found was that solar storms that were launched near the North Pole got deflected from the North Pole down towards the plane of where the planets orbit.”

The discovery, published in the journal Nature Communications,stands to improve predictions about whether and when solar storms will affect Earth, he added.

“This finding will better enable us to forecast where a solar storm is going to go into the solar system and is it going to hit the Earth, and to better forecast its estimated time of arrival.”