Scientists have solved a longstanding mystery about the Sun that could help astronomers predict space weather and solar storms.
The team of boffins from the University of Sydney, University of Colorado, and the Southwest Research Institute in Boulder believe they have worked out how the Sun's internal magnetic dynamo, also known as its solar dynamo, actually works.
A solar dynamo is a naturally occurring electric generator in the Sun's interior producing electric currents and a magnetic field.
It is widely accepted that the solar dynamo is responsible for generating and maintaining the magnetic fields of the Sun in the solar convection zone and neighboring layers.
The convection zone consists of a 200,000-kilometer-deep ocean of super-hot rolling, turbulent fluid plasma taking up the outer 30% of the star’s diameter.
Up until now, experts believed that the largest swirls take up the convection zone, imagined as giant circular convection cells.
But the mystery had baffled scientists for years as they have never found these cells – a long-standing problem known as the ‘Convective Conundrum’.
Mathematician Dr Geoffrey Vasil said: "There is a reason for this. Rather than circular cells, the flow breaks up into tall spinning cigar-shaped columns ‘just’ 30,000 kilometers across. This is caused by a much stronger influence of the Sun’s rotation than previously thought.
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"You can balance a skinny pencil on its point if you spin it fast enough. Skinny cells of solar fluid spinning in the convection zone can behave similarly.
"We don’t know very much about the inside of the Sun, but it is hugely important if we want to understand solar weather that can directly impact Earth. Strong rotation is known to completely change the properties of magnetic dynamos, of which the Sun is one."
Collaborators Professor Keith Julien of the University of Colorado and Dr Nicholas Featherstone at Southwest Research Institute in Boulder said: “This predicted rapid rotation inside the Sun suppresses what otherwise would be larger-scale flows, creating more variegated dynamics for the outer third of the solar depth.
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Dr. Vasil added: "By properly accounting for rotation, our new model of the Sun fits observed data and could dramatically improve our understanding of the Sun’s electromagnetic behavior.
"The next solar max is in the middle of this decade, yet we still don’t know enough about the Sun to predict if these cyclical events will produce a dangerous storm.
"While a solar storm hitting Earth is very unlikely, like an earthquake, it will eventually happen, and we need to be prepared.”
"Better knowledge of the internal dynamism of our home star could help planners avoid disaster if they have enough warning to shut down equipment before a blast of energetic particles does the job instead.
"We cannot explain how sunspots form. Nor can we discern what sunspot groups are most prone to violent rupture. Policymakers need to know how often it might be necessary to endure a days-long emergency shutdown to avoid a severe catastrophe."
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