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'MRI' leaks slow motion of sun's interior plasma

According to scientists,'MRI'(Magnetic Resonance Imaging) of the sun's interior plasma motions are providing important clues about how the Sun transfers heat from its deep interior to its surface.

Researchers from NYU's Courant Institute of Mathematical Sciences and its Department of Physics, Princeton University, the Max Planck Institute, and NASA were involved in this research work.

The result has overturned our understanding of how heat is transported outwards by the Sun and it further challenges existing explanations of the formation of sunspots and magnetic field generation, explained the researchers.

"If these motions are indeed that slow in the sun, then the most widely accepted theory concerning the generation of solar magnetic field is broken, leaving us with no compelling theory to explain its generation of magnetic fields and the need to overhaul our understanding of the physics of the sun's interior,"said researchers.

In order to develop their "MRI" of the Sun's plasma flows, the researchers examined high-resolution images of the Sun's surface taken by the Helioseismic and Magnetic Imager (HMI) onboard NASA's Solar Dynamics Observatory. Using a 16-million pixel camera, HMI measures motions on the Sun's surface caused by convection.

Analyzing the precise movement waves on the sun's surface, the researchers were able to calculate its unseen plasma motions.

"These convective motions are currently believed to prop up large-scale circulations in the outer third of the sun that generate magnetic fields," NYU researcher Shravan Hanasoge said.

"However, our results suggest that convective motions in the sun are nearly 100 times smaller than these current theoretical expectations.”

As a result, theories largely rest on what we know about fluid flow and then applying them to the Sun, which is primarily composed of hydrogen, helium, and plasma.

The study has been published in the journal the Proceedings of the National Academy of Sciences.