What To Know
- It is a bit like listening to the echoes in a cave to deduce the size and shape of the cave itself.
- This model revealed that variations in the flow of plasma (the extremely hot, ionized gas that makes up the Sun) in the outermost 5 to 10 percent of its surface closely matched the magnetic fields that we can observe from Earth.
- Keaton Burns, a researcher involved in the study, explains that visible phenomena like the solar corona (the outer layer visible during solar eclipses), sunspots (dark areas on the surface), and solar flares (sudden bursts of radiation) are all related to the Sun’s magnetic field.
Scientists have made a discovery that could revolutionize our understanding of solar phenomena and improve predictions of solar storms. Complex computer simulations reveal that the Sun’s magnetic field originates from plasma instabilities in the outer layers of the Sun’s surface rather than from deep within as previously thought.
The mystery of solar magnetism
THE Suna gigantic ball of plasma, creates powerful magnetic fields through the swirling motions of its charged ions. The convection zone where these motions occur comprises the upper third of the Sun’s radius and extends from the surface to about 200,000 kilometers below. Since the magnetic field lines cannot cross, they sometimes knot together before suddenly breaking, triggering solar flares or coronal mass ejections (CME). When they head toward Earth, these CMEs can cause geomagnetic storms. However, the exact origin of solar magnetism has remained a mystery. Researchers have previously tried to understand it using 3D computer simulations, but these models, which require millions of hours on supercomputing facilities, were often too simplistic.
Helioseismology: a new approach
For this new study, researchers turned to a method called helioseismology. This field of science uses vibrations observed on the surface of the Sun to understand what is happening inside our star. It is a bit like listening to the echoes in a cave to deduce the size and shape of the cave itself. Using sophisticated algorithms based on these vibrations, researchers created a computer model of the Sun. This model revealed that variations in the flow of plasma (the extremely hot, ionized gas that makes up the Sun) in the outermost 5 to 10 percent of its surface closely matched the magnetic fields that we can observe from Earth. This plasma flow is comparable to water currents swirling in a river. These movements create powerful magnetic fields. Traditionally, these magnetic fields were thought to come from deeper layers. However, when the researchers incorporated the effects of the deeper layers into their simulation, the resulting image was blurry and did not match the actual observations. In other words, the magnetic fields we observe appear to be generated much closer to the surface than previously thought.
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What implications and perspectives?
Keaton Burns, a researcher involved in the study, explains that visible phenomena like the solar corona (the outer layer visible during solar eclipses), sunspots (dark areas on the surface), and solar flares (sudden bursts of radiation) are all related to the Sun’s magnetic field. By developing their model further, the researchers hope to be able to predict solar storms more accurately. This could give us a better chance of preparing and protecting our infrastructure, such as satellites, power grids and communications, from their potentially devastating effects. In short, this discovery could not only deepen our understanding of our star, but also improve our ability to defend ourselves against the hazards of space. Details of the study are published in the journal Nature.
