Solving a solar puzzle could help save Earth from planet-wide blackouts

Could solar storms knock out the global internet? Yes, but we don’t know when or how it could happen. Mathematician Dr. Geoffrey Vasil has offered a new understanding of the Sun’s convection zone to help.

Scientists from the University of Sydney and the United States have solved a long-standing mystery about the Sun that could help astronomers predict space weather and help us prepare for potentially devastating geomagnetic storms if they were to strike the Earth.

The Sun’s internal magnetic field is directly responsible for space weather – high-energy particle fluxes from the Sun that can be triggered by solar flares, sunspots, or coronal mass ejections that produce geomagnetic storms. Yet it is not clear exactly how these events occur and it has been impossible to predict when these events will occur.

Now, a new study led by Dr Geoffrey Vasil of the University of Sydney’s School of Mathematics & Statistics could provide a solid theoretical framework to help improve our understanding of the Sun’s internal magnetic dynamo that contributes to near space weather. of the earth.

The Sun is made up of several distinct regions. The convection zone is one of the largest – a 200,000 kilometer deep ocean of super hot, turbulent, rolling fluid plasma occupying the outer 30 percent of the star’s diameter.

The existing solar theory suggests that the largest eddies and eddies occupy the convection zone, imagined as giant circular convection cells.

However, these cells were never found, a long-standing problem known as “Convective Conundrum”.

Dr Vasil said there was a reason for this. Rather than circular cells, the flow breaks up into tall, cigar-shaped columns rotating “only” 30,000 kilometers in diameter. This, he said, is caused by a much stronger influence of the Sun’s rotation than previously thought.

“You can balance a thin pencil on its tip if you spin it fast enough,” said Dr. Vasil, an expert in fluid dynamics. “The thin cells of the solar fluid rotating in the convection zone can behave in the same way.”

The results were published in the Proceedings of the National Academy of Sciences.

“We don’t know much about the interior of the Sun, but it is extremely important if we are to understand solar weather which can have a direct impact on Earth,” said Dr Vasil.

“Strong rotation is known to completely change the properties of magnetic dynamos, of which the Sun is a part.”

Dr Vasil and colleagues, Professor Keith Julien of the University of Colorado and Dr Nicholas Featherstone of the Southwest Research Institute in Boulder, claim that this predicted rapid rotation inside the Sun suppresses what would otherwise be fluxes at more large scale, creating a more varied dynamic for the outer third of the solar depth.

“By correctly accounting for the rotation, our new model of the Sun matches the observed data and could significantly improve our understanding of the electromagnetic behavior of the Sun,” said Dr. Vasil, lead author of the study.

In the most extreme cases, solar geomagnetic storms can flood Earth with pulses of radiation capable of searing our sophisticated global electronics and communications infrastructure.

A huge geomagnetic storm like this hit Earth in 1859, known as the Carrington event, but that was before our global dependence on electronics. The nascent telegraph system from Melbourne to New York was affected.

“A similar event today could destroy billions of dollars of global infrastructure and take months, if not years, to repair,” said Dr Vasil.

A solar coronal mass ejection in August 2012

A small-scale event in 1989 caused massive blackouts in Canada in what some initially thought could be a nuclear attack. In 2012, a solar storm of similar magnitude to the Carrington event passed through Earth without impact, missing our orbit around the Sun by just nine days.

“The next solar max is in the middle of this decade, but we still don’t know enough about the Sun to predict whether these cyclical events will produce a dangerous storm,” Dr. Vasil said.

“Although a solar storm hitting Earth is very unlikely, like an earthquake, it will eventually happen and we need to be prepared.”

Solar storms emerging from within the Sun can take from hours to days to reach Earth. Dr Vasil said that a better understanding of the internal dynamism of our home star could help planners avoid disaster if they are savvy enough to shut down equipment before an energetic particle explosion does the job. in place.

“We cannot explain how sunspots are formed. We also cannot discern which groups of sunspots are most prone to violent rupture. Policymakers need to know how often it may be necessary to undergo a shutdown. emergency of several days to avoid a serious disaster, ”he said.

The theoretical model of Dr Vasil and his colleagues will now have to be tested by observation in order to further improve the modeling of the internal processes of the Sun. To do this, scientists will use a technique known as helioseismology, to listen inside the star’s beating heart.

“We hope that our findings will inspire further observations and research into the driving forces of the Sun,” he said.

This could involve the unprecedented launch of polar-orbiting observation satellites outside the elliptical plane of the solar system.