Experiments on pure electron plasmas have found that the decay of 2D turbulence can lead to spontaneous formation of “vortex crystals,” which are symmetric arrays of strong vortices within a background of weaker vorticity. In this paper we show that these vortex crystals can be described as regional maximum fluid entropy states. The theory explains the observed patterns of the vortex crystals as well as the vorticity distribution of the background.

• Received 29 September 1997

DOI:https://doi.org/10.1103/PhysRevLett.80.4434