Vortices in nature (Video)

Vortices are ubiquitous in nature and they appear in all kinds of fluids.

Ordinary vortices in fluids

A vortex is typically created due to disturbances of the flow in the fluid.

https://images.app.goo.gl/C79XAvnrtCPuRsfz7

A series of vortices in a fluid. The fluid may rotate clockwise or anticlockwise around the vortex center. The vortices may be bigger or smaller.

A series of vortices in a fluid. The fluid may rotate clockwise or anticlockwise around the vortex center. The vortices may be bigger or smaller.

If fluid flows forward, typically, two counter-rotating vortices will be created.

If fluid flows forward, typically, two counter-rotating vortices will be created.

Quantized vortices in superfluids

Gases from vapours of alkali metals can be cooled down to a few nK and they form a state of matter called a Bose-Einstein condensate (BEC). This is a quantum fluid and discrete quantum states are anticipated.

A BEC of cold atoms (Dalibard group, ENS Paris). The atoms are trapped in a harmonic (confining) potential.

A BEC of cold atoms (Dalibard group, ENS Paris). The atoms are trapped in a harmonic (confining) potential.

Flow of the superfluid around the center of the condensate can be sustained if a vortex if formed.

These vortices are quantised, because there are only a discrete number of ways that they may form. The flow velocity around the center of the vortex is quantised.

There is full depletion of fluid at the vortex center.

A superfluid vortex.

A superfluid vortex.