The newest, sharpest image ever taken of the Sun doesn’t just look striking, it confirms something solar physicists have suspected for decades but never actually seen. Captured by the NSF Daniel K. Inouye Solar Telescope in Hawai’i, the world’s largest solar telescope, the image reveals flower-like structures spanning roughly the radius of Earth, with details as fine as a single city. And at the edges of those structures, researchers found exactly what they were looking for: swirls.

The phenomenon is called Kelvin-Helmholtz instability (KHI), a well-known process that occurs whenever two fluids or gases flow past each other at different speeds, creating waves and eventually spiraling vortices. It shows up in clouds on Earth, in the bands of Jupiter and Saturn, and at the boundary of Earth’s magnetosphere. On the Sun, it had long been theorized to occur in the solar photosphere, where streams of magnetic plasma flow past one another, but no instrument had ever had the resolution to actually catch it happening, until now.

Using the Inouye telescope’s FastCam imager, built jointly by the National Solar Observatory and Germany’s Max Planck Institute for Solar System Research, an international team captured time-lapse footage showing small-scale, dynamic swirls at the edges of magnetic regions across the Sun’s surface. Combined with numerical simulations, the observations gave researchers their first unambiguous confirmation of KHI happening on a star.

Why does it matter? These swirling vortices may be a missing piece in one of solar physics’ most stubborn puzzles: why the Sun’s outer atmosphere, the corona, is over a hundred times hotter than the surface below it. KHI is a known mechanism for mixing plasma and building up magnetic energy, the same magnetic energy that eventually powers solar flares and coronal mass ejections capable of disrupting satellites and power grids on Earth. Researchers now suspect these tiny whirlpools may help explain how energy and magnetic fields move around and build up on the Sun, feeding directly into the space weather that reaches us.

The finding also demonstrates just how much remains hidden in the Sun’s surface dynamics at scales we’ve only just become able to resolve. As the Inouye telescope continues observing, researchers expect KHI to become a foundational piece of how we model the Sun’s atmosphere going forward.

Original paper: Ubiquitous Kelvin–Helmholtz instabilities driving plasma mixing on the Sun

Image Credit: NSF, NSO, AURA, MPS, Inouye Tel.