The National Science Foundation’s National Solar Observatory (NSF NSO) announced on August 5, 2026, a discovery that could change solar physics. Using the Daniel K. Inouye Solar Telescope, the most powerful in the world, an international team found the signature of the Kelvin-Helmholtz instability (KHI) on the Sun’s surface.
The patterns, small vortex-like swirls, were seen in the photosphere — the visible layer of the star. The research, published in the journal Nature, is the result of collaboration between NSO, the High Altitude Observatory (HAO) of NCAR, and the Max Planck Institute for Solar System Research (MPS) in Germany.
The telescope, installed atop Haleakalā in Hawaii, allowed the first experimental confirmation of a phenomenon predicted over a century ago. The Kelvin-Helmholtz instability occurs when two fluids slide over each other at different speeds, creating shear at the interface and generating vortices that resemble breaking waves.
Since the original formulation by Lord Kelvin and Hermann von Helmholtz around 1870, KHI has been observed in various contexts — from clouds on Earth to the atmospheres of Jupiter and Saturn. Now, for the first time, it has been unequivocally identified in the solar photosphere, thanks to the high spatial resolution of Inouye.
Scientists believe these vortices could be the key to understanding why the Sun’s outer atmosphere is so hot and how magnetic energy accumulates and moves. This energy powers solar flares, which can affect satellites, power grids, and communication systems on Earth.
The main theory for the accumulation of magnetic energy is ‘flux braiding’ — the intertwining of magnetic field lines, like braided hair. When tension is released rapidly, magnetic reconnection occurs, triggering eruptions. But what initiates the braiding was still a mystery.
The new discovery suggests that KHI swirls, which appear constantly at the edges of magnetic regions, may be the ‘engine’ that twists field lines and initiates the process. ‘We are only at the beginning of recognizing the impact of the discovery of the Kelvin-Helmholtz instability on the connection between the movement of magnetized plasma and the transport and release of energy in the upper solar atmosphere,’ said Dr. Friedrich Wöger, senior scientist at NSO.
The team compared Inouye’s observations with computer simulations of the photosphere, using the MURaM code, developed by teams at HAO and MPS. The simulations, based on fundamental physical equations, allow visualizing processes that cannot be measured directly.
The results were remarkable: dozens of vortex-like structures appeared in both observations and simulations, with nearly identical characteristics and dynamics. For example, the average distance between vortices — the ‘instability wavelength’ — varied between 50 and 65 km in both cases.
‘It is very exciting to see that the highest-resolution observations of the photosphere have revealed a new dynamic regime in the form of KH vortices at the edges of magnetic field concentrations,’ said Dr. Matthias Rempel, senior scientist at HAO. ‘These observations also provide the highest-resolution validation of solar magnetohydrodynamic simulations to date, and the agreement in physical details is impressive.’
The discovery opens a new window into the fundamental physics of the Sun and other stars. Dr. David Boboltz, deputy director of NSO, highlighted: ‘We believe that the discovery of the Kelvin-Helmholtz instability in the solar photosphere, supported by the analysis of numerical simulations, is a major step in our understanding of the dynamics and evolution of solar and stellar plasma, and will serve as a basis for future discoveries.’
The study also underscores the unique capabilities of the Inouye Telescope, which continues to reveal unprecedented details of the Sun. Understanding these processes is essential for predicting space weather and protecting our technological infrastructure.
The research was released by NSF NSO, which operates the telescope in Hawaii. Scientists hope the new data will help unravel the mysteries of solar activity and its impacts on Earth.