  Turbulence in classical fluids is characterized by persistent structures that
emerge from the chaotic landscape. We investigate the analogous process in
fully kinetic plasma turbulence by using high-resolution, direct numerical
simulations in two spatial dimensions. We observe the formation of long-living
vortices with a profile typical of macroscopic, magnetically dominated
force-free states. Inspired by the Harris pinch model for inhomogeneous
equilibria, we describe these metastable solutions with a self-consistent
kinetic model in a cylindrical coordinate system centered on a representative
vortex, starting from an explicit form of the particle velocity distribution
function. Such new equilibria can be simplified to a Gold-Hoyle solution of the
modified force-free state. Turbulence is mediated by the long-living
structures, accompanied by transients in which such vortices merge and form
self-similarly new metastable equilibria. This process can be relevant to the
comprehension of various astrophysical phenomena, going from the formation of
plasmoids in the vicinity of massive compact objects to the emergence of
coherent structures in the heliosphere.
