Negative temperature states for the two-dimensional guiding-centre plasma

Abstract

Theoretical development and numerical simulation of the two-dimensional electrostatic guiding-centre plasma with positive total interaction energy are presented. Equilibrium statistical mechanics predicts that no spatially homogeneous thermal equilibrium state exists for this system. This non-existence is associated with the phenomenon of ‘negative temperatures’. Quasi-stable, spatially inhomogeneous states are shown to form, and are characterized by macroscopic spatially-separated vortex structures.