In an article recently featured on the cover of the Proceedings of the National Academy of Sciences (PNAS), a team of researchers from the University of Oxford (Robert J. Ewart, Michael L. Nastac, Alexander A. Schekochihin) and from GoLP/IPFN (Pablo B, Thales S, Luís OS) uncovered how collisionless plasmas relax to equilibrium under the action of turbulence.

While collisional plasmas achieve Maxwellian distributions through particle collisions, the study shows that in collisionless plasmas, turbulent dynamics alone drive relaxation toward universal, but non-Maxwellian, equilibria featuring power-law energy distributions. Theoretical predictions were confirmed through large-scale numerical simulations performed by the GoLP team, which captured the turbulent cascade and the progressive erosion of phase-space conservation over time. These results reveal that turbulence can induce a gradual loss of memory of the plasma’s initial state, leading to the emergence of universal equilibria determined by the nature of the turbulent mixing.

This work advances fundamental understanding of turbulence, entropy growth, and relaxation in collisionless plasmas, with important implications for both astrophysical and laboratory plasma environments.