Astronomers using the 4-m Daniel K. Inouye Solar Telescope in Hawaii have detected tiny plasma vortices on the Sun\u2019s surface (photosphere) for the first time, revealing a long-suspected process that could transport energy into the million-degree corona.<\/p>\n
The highest-resolution image of the Sun\u2019s 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. Image credit: NSF \/ NSO \/ AURA \/ MPS.<\/p>\n
Using the Inouye Solar Telescope, the solar astronomers captured the highest-resolution images ever taken of the Sun\u2019s photosphere.<\/p>\n
The images revealed whirlpool-like plasma structures only about 20 km (12 miles) across.<\/p>\n
The researchers identified these features as Kelvin-Helmholtz instabilities, vortices that form where layers of plasma moving at different speeds slide past one another, much like waves curling on the ocean.<\/p>\n
\u201cWe 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,\u201d said Dr. David Boboltz, deputy director at the National Solar Observatory.<\/p>\n
Although this phenomenon has been observed on Earth, in planetary atmospheres and in the Sun\u2019s corona, this is the first time it has been confirmed in the Sun\u2019s visible surface layer.<\/p>\n
\u201cAn effect caused by fluid motion, Kelvin-Helmholtz instability occurs when two fluids slide past each other at different velocities creating a \u2018shear\u2019 at the interface, causing small disturbances to grow into striking, wave-like or spiraling, vortices that look like breaking ocean waves,\u201d the scientists said.<\/p>\n
\u201cSince its original formulation by Lord Kelvin and Hermann von Helmholtz around 1870, the phenomenon has been observed and investigated across many areas of physics, including fluid dynamics, meteorology, oceanography, heliosphysics, and astrophysics.\u201d<\/p>\n
\u201cThe 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.\u201d<\/p>\n
According to the team, these microscopic vortices act as hidden engines that can twist and tangle the Sun\u2019s magnetic field lines.<\/p>\n
As those magnetic fields become increasingly stressed, they may release energy that powers solar flares, coronal mass ejections and other eruptions while also heating the Sun\u2019s outer atmosphere.<\/p>\n
The findings suggest that small-scale plasma motions, previously beyond the reach of telescopes, play an outsized role in driving the Sun\u2019s behavior.<\/p>\n
\u201cIt is very exciting to see that the highest-resolution observations of the solar photosphere revealed a new dynamical regime in the form of Kelvin-Helmholtz vortices at the edges of magnetic field concentrations,\u201d said Dr. Matthias Rempel, an astronomer at the High Altitude Observatory.<\/p>\n
\u201cThese observations also provide the highest resolution validation of solar magnetohydrodynamic simulations to date, and the agreement in physical details is impressive.\u201d<\/p>\n