Researchers sprayed liquid trimethylaluminium in the upper atmosphere using rockets and observe his movement. So scientists have studied turbulence that occur in the upper layers of the mesosphere and lower layers of the thermosphere at an altitude of about 100 kilometers. The study of such effects, may help physicists to understand how exactly is the mixing of gases in the atmosphere. Article published in the journal JGR: Space Physics.
Swirls, which were examined by scientists, appear due to the instability of Kelvin-Helmholtz. It occurs between two contacting media with sufficient velocity difference. Under these conditions, the profile of currents, a point of inflection where the second derivative of speed with respect to the coordinate becomes zero, and according to the criterion of Rayleigh instability occurs. This phenomenon is very often seen in everyday life: it is the instability of Kelvin-Helmholtz leads to the appearance of waves on the water surface in the wind. The same effects occur continuously in the atmosphere, not only on our planet: the characteristic twist can be seen on the border of the Great red spot on Jupiter.
Rafael Mesquita (Mesquita Rafael) from Clemson University have observed instability of a Kelvin-Helmholtz in the Earth’s atmosphere at the altitude of 102 km. For this, he and his colleagues used data collected during a research launch rockets in 2018. Then for the multidimensional study of the upper atmosphere, scientists launched three missiles, two of them with an interval of 30 minutes, sprayed into the atmosphere of liquid trimethylaluminium, and immediately after that a third rocket was thrown into the air, 220 pounds of water. In their work the authors discuss the results of only the first two runs, analysis of data on emission of water third missile will be presented in a separate article.
The movement released into the atmosphere gases scientists have followed from two points: from the observation point on the earth, and c aircraft, which provided NASA. There is also a authors were lidars, by which they could monitor the temperature of the released gases into the atmosphere. This approach has subsequently enabled the physicists to precisely reconstruct the trajectory of the gases in each moment of time and conduct a numerical assessment of what is happening in the atmosphere phenomena. At the same time, researchers monitored the magnetosphere of the Earth in the vicinity of the launch to ensure that the perturbations of the atmosphere are not caused by a magnetic storm and associated streams of charged particles. The second launch was the most successful: physics saw the characteristic instability of Kelvin-Helmholtz turbulence under weak geomagnetic activity.