Scientists using the U.S. National Science Foundation Daniel K. Inouye Solar Telescope have made a major breakthrough in solar physics, discovering Kelvin-Helmholtz Instability on the surface of the Sun — a finding that could help explain explosive solar activity and other solar phenomena.
SUMMARY: The U.S. National Science Foundation National Solar Observatory (NSF NSO) announced today a major breakthrough in solar physics. Using the world’s most powerful solar telescope, the NSF Daniel K. Inouye Solar Telescope near the summit of Maui’s Haleakalā, combined with computer simulations, an international team of scientists from the NSO, NSF NCAR High Altitude Observatory (HAO), and the Max Planck Institute for Solar System Research (MPS) found the signature of Kelvin-Helmholtz instability (KHI), tiny swirling patterns like small whirlpools, on the Sun’s surface. Researchers suggest that KHI might be a key reason why the Sun’s outer atmosphere gets so hot, and why magnetic energy builds up and moves around on the Sun. Magnetic energy fuels solar flares and eruptions—the kind of solar activity that can send bursts of energy toward Earth and affect satellites, power grids, and other technology. The discovery opens a new window into the fundamental physics of the Sun and other stars while underscoring the unmatched capabilities of the Inouye Solar Telescope.
Boulder, Colorado — August 5, 2026 — The U.S. National Science Foundation National Solar Observatory (NSF NSO) today announced a groundbreaking discovery in the field of solar physics that could fundamentally change how we understand the physical mechanisms driving solar activity and its impacts on life on Earth.
NSF Inouye Solar Telescope Captures First High-Resolution View of Kelvin-Helmholtz Instability in the Solar Photosphere
A team of international researchers from the NSO, the NSF NCAR High Altitude Observatory (HAO), and the German Max Planck Institut für Sonnensystemforschung (MPS) has discovered Kelvin-Helmholtz instability (KHI) in the form of small, swirling, whirlpool-like patterns on the surface of the sun (the photosphere). The research, published in the journal Nature, is based on data collected with the world’s largest solar telescope, the NSF Daniel K. Inouye Solar Telescope, built and operated by NSO on the island of Maui, HI. The time-lapse video and images released today reveal a solar landscape unlike any that had been seen before, uncovering small-scale and dynamic swirls everywhere at the edges of magnetic areas. This allowed for the unambiguous identification of KHI in the photosphere, providing the first experimental confirmation of a phenomenon that has long been predicted by theory but could only be revealed by the Inouye Solar Telescope’s high spatial resolution.
“We believe that the discovery of Kelvin-Helmholtz instability in the solar photosphere, backed up by analysis of numerical simulations, is a major step forward in our understanding of the dynamics and evolution of solar and stellar plasma, and will serve as a basis for future discoveries.“ — Dr. David Boboltz, Deputy Director at the National Solar Observatory.
Kelvin-Helmholtz Instability Explained
An effect caused by fluid motion, KHI occurs when two fluids slide past each other at different velocities creating a “shear” at the interface—causing small disturbances to grow into striking, wave-like or spiraling, vortices that look like breaking ocean waves. Since its original formulation by Lord Kelvin and Hermann von Helmholtz around 1870, KHI has been observed and investigated across many areas of physics, including fluid dynamics, meteorology, oceanography, heliosphysics, and astrophysics. The instability is observed at a variety of scales from small lake and ocean waves (in windy conditions) and cloud formations on Earth, to the atmospheres of gas giants like Jupiter and Saturn, and the interaction of the solar wind with planetary magnetospheres within our solar system.
A close-up view from the Inouye Solar Telescope image highlighting a region of the solar photosphere. The enlarged inset reveals the fine-scale magnetic structures and dark striations associated with the Kelvin-Helmholtz instability at a scale of tens of kilometers. Credit: NSF/NSO/AURA/MPS
NSF/NSO/AURA/MPS
Hawai‘i-scale: The highest-resolution image of the Sun's surface (photosphere) ever captured, taken at 416 nm by the Inouye Solar Telescope. It reveals deformed boundaries of magnetic elements and ultra-fine scale stripes, both associated with Kelvin-Helmholtz instability. Credit: NSF/NSO/AURA/MPS
NSF/NSO/AURA/MPS
Vortices as a Driver of the Sun’s Explosive Events
The swirling vortices of magnetic solar plasma have become an area of increased interest for solar physicists. They could be an effective source of free magnetic energy, which powers major solar activity—including explosive events from tiny nano-flares to massive flares, jets, and coronal mass ejections. These are the main contributors to space weather, and can severely disrupt our modern technological infrastructure, including power grids, satellites, GPS navigation, and global communications.
The leading theory on how the Sun builds up magnetic energy is called “flux braiding.” As magnetic field lines twist around each other—like braiding hair—they create a tense, unstable setup. When that tension gets rapidly released, the tangled magnetic lines “snap”, cross over each other, and reconnect in new shapes (a process called “magnetic reconnection”). This sudden rearrangement releases a burst of energy as the system settles into a calmer, lower-energy state.
What scientists don’t fully understand yet is what causes the twisting and braiding to happen in the first place. This new discovery—those small swirling patterns (from the Kelvin-Helmholtz instability)—might be part of the answer. Since the swirls seem to be happening constantly and everywhere on the Sun’s surface where there is a strong enough magnetic field, they could be the everyday “engine” that keeps twisting the magnetic field lines and setting the whole process in motion.
“We are only at the beginning of recognizing the wide-reaching impact the discovery of Kelvin-Helmholtz instability has on our understanding of the connection between the magnetized plasma motion and the energy transport and release into the upper solar atmosphere.” — Dr. Friedrich Wöger, Senior Scientist at the National Solar Observatory.
Inouye Observations, Simulations, and Theory Align
In their Nature paper, the team analyzed and compared the high-resolution Inouye observations with computer simulations of the solar photosphere created with a highly specialized code built and maintained by international teams including HAO and MPS (MPS/University of Chicago Radiative MHD, or “MURaM”). These computer simulations provided by HAO are built using basic physics equations that describe what’s happening in the Sun’s atmosphere, and are an important tool in the interpretation of scientific data. The simulations allow the scientists to “see” things that are hard or impossible to measure directly by observation, giving insight into processes that would otherwise stay hidden.
In the case of this work, the scientists found dozens of vortex-like structures along the edges of magnetic areas both in the observations and simulations, with strikingly similar characteristics and dynamics. For example, the average distance between vortices, known as the “instability wavelength,” ranged between 50–65 km in both cases. The study shows that the Sun’s constantly bubbling surface, or granulation, interacts with magnetic structures to create areas where neighboring layers move at different speeds, providing the conditions necessary to trigger KHI.
“It is very exciting to see that the highest-resolution observations of the solar photosphere revealed a new dynamical regime in the form of KH vortices at the edges of magnetic field concentrations. These observations also provide the highest resolution validation of solar magnetohydrodynamic simulations to date, and the agreement in physical details is impressive.” — Dr. Matthias Rempel, Senior Scientist at the High Altitude Observatory.
The team’s advanced analyses of the Inouye observations and the computer simulations, combined with their agreement with analytical theory, led to the conclusion that the swirling vortices, and the fast-moving, finest-scale dark stripes (“striations”), found in both the observations and simulations are without a doubt produced by KHI.
Implications for the Solar Atmosphere and Coronal Heating Mystery
”Kelvin-Helmholtz instability is likely a mechanism that contributes to the heating of the outer atmosphere and is part of the solution of the longstanding enigma of why stars have a million degrees Kelvin hot corona.” — Dr. Thomas Rimmele, Chief Technologist at the National Solar Observatory.
The data also shows that this swirling effect (KHI) efficiently mixes magnetized and non-magnetized plasma on the Sun’s surface, enhancing the spreading out or diffusion of magnetic fields throughout the solar atmosphere. The diffusion resulting from the KHI is a key factor scientists use when building models to predict how magnetic activity changes over time—not just for our Sun, but for other stars too.
”The Sun’s magnetic field is generated by dynamo processes that act like giant cosmic engines that turn the star’s rotational energy into magnetic fields. However, because the solar magnetic cycle is only 11 years, a remarkably rapid timescale in cosmic terms, the generated magnetic flux must dissipate efficiently. Current models struggle to explain this rapid diffusion. The Kelvin-Helmholtz instability we discovered in the solar photosphere can act as a key source of this missing magnetic diffusion.” — Dr. David Kuridze, Astronomer at the National Solar Observatory.
Looking Ahead
Scientists are now moving towards the next phase of analysis, which includes using computer programs that can automatically spot and study these swirling patterns — aided by the high resolution data from the Inouye Solar Telescope. This next phase of research will help in two main ways: it’ll show scientists more about how much energy these KHIs can carry up into the Sun’s higher atmosphere, where it helps heat things up, and it’ll also help scientists figure out just how much they affect the way magnetic fields spread out in the lower parts of the Sun’s atmosphere.
“To understand the dynamic space weather that affects Earth, we have to see the small-scale processes driving it. For decades, seeing these vortices at such tiny scales remained elusive. By pairing a massive four-meter mirror with state-of-the-art optics and instruments, the NSF Inouye Solar Telescope delivers the resolving power needed to reveal these ultrafine details for the first time, enabling discoveries that were once beyond our reach.” — Dr. Jacqueline Keane, NSF Program Director for the National Solar Observatory
The paper describing this study, titled “Ubiquitous Kelvin-Helmholtz Instabilities Driving Plasma Mixing on the Sun,” is now available in Nature.
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About the NSF National Solar Observatory
The mission of the U.S. National Science Foundation National Solar Observatory (NSF NSO) is to advance knowledge of the Sun, both as an astronomical object and as the dominant external influence on Earth, by providing forefront observational opportunities to the research community.
NSO built and operates the world’s most extensive collection of ground-based optical and infrared solar telescopes and auxiliary instrumentation— including the NSF-NOAA GONG network of six stations around the world, and the world’s largest solar telescope, the NSF Daniel K. Inouye Solar Telescope—allowing solar physicists to probe all aspects of the Sun, from the deep solar interior to the photosphere, chromosphere, the outer corona, and out into the interplanetary medium. These assets also provide data for heliospheric modeling, space weather forecasting, and stellar astrophysics research, putting our Sun in the context of other stars and their environments.
Besides the operation of cutting-edge facilities, the mission includes the continued development of advanced instrumentation both in-house and through partnerships, conducting solar research, and educational and public outreach. NSO is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with NSF. For more information, visit nso.edu.
Contact
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