“…D v , which can be determined statistically (at least, in the mean), specifies the dislocation point (or vortex) density-the mean number of dislocation lines piercing unit area of a plane (Berry, 1978). These statistics have been thoroughly studied for quasimonochromatic paraxial waves (Baranova et al, 1981), monochromatic waves in two dimensions Freund and Freilikher, 1997;Freund and Shvartsman, 1994;Freund et al, 1993;Freund and Wilkinson, 1998;Shvartsman and Freund, 1994b), isotropic random waves (Berry and Dennis, 2000), and random waves subject to the Aharonov-Bohm effect (Houston et al, 2017) among others, with novel extensions to the statistics of knotted nodal lines by Dennis (2014, 2016).…”