In recent years, turbulence research was invigorated by the application of statistical mechanics methods, with increasing evidence pointing to the transition to turbulence as a directed percolation process. In this junior research group, this process is studied on the level of individual particles using complex plasmas.
A complex plasma is a conducting gas containing micrometer-sized particles that strongly interact with each other. Complex plasmas show many effects typically seen in ordinary fluids, for instance wave or droplet formation, but in contrast to ordinary fluids, the motion of the constituents of the system can be observed in real time. In order to do so, the microparticles are illuminated with a laser, and their motion is recorded by a fast camera. These observations are possible due to the relatively large size of the microparticles – but this large size also results in a strong influence of gravity on the microparticles. Therefore, often experiments under microgravity conditions are necessary.
As the dynamics of individual particles is accessible with complex plasmas, they are ideal to study how collective effects such as turbulence. In this project, we aim to understand how the interaction between the particles leads to the formation of turbulent cascades, and to directly observe the percolation process during the spread of turbulence. We will compare these results with the onset of other collective effects, such as collective motion in droplets and bubbles.