Marco La Mantia (Charles University) gives a webinar on ‘Flow visualization in superfluid helium-4 (with particles)’.

The contribution of this experimental technique to our understanding of turbulent flows of superfluid helium-4 is reviewed and special emphasis is given to recent results obtained in Prague. Specifically, it is shown that flow visualization data can be employed to estimate (i) the mean distance between quantized vortices, especially in conditions that cannot be accessed by the standard second sound attenuation technique, and (ii) the strength of macroscopic vortical structures, especially in the absence of Eulerian data, which is often the case for flows of superfluid helium-4.