Trimethyl-aluminum gas clouds released by the first of three rockets launched as part of NASA’s “Super Soaker” campaign. The curling waves of the Kelvin-Helmholtz instability – appearing briefly in the center of the image before dissipating – may explain how gases mix in what were previously considered stable layers of the atmosphere. Credit: NASA/Super Soaker/Rafael Mesquita
Glowing vapor clouds released from NASA research rockets launched in Alaska in January 2018 trace curling waves high in Earth’s atmosphere, at the very boundary of space, revealing fluid flow structures known as Kelvin-Helmholtz instability.
From a NASA news release on August 4, 2020:
The “surfer waves” in this image, forming high above the Alaskan sky, illuminate the invisible currents in the upper atmosphere. They were measured by trimethyl-aluminum gas released during a sounding rocket launch from Poker Flat, Alaska, on Jan. 26, 2018. Scientists photograph the gas, which is not harmful to humans [Editor’s note: not harmful at those altitudes and in that application] after it instantaneously ignites when exposed to oxygen. The findings were published in JGR: Space Physics.
Such curling waves are a product of the Kelvin-Helmholtz instability, which occurs when streams of gas or liquid pass by each other at ...