  Weakly collisional and collisionless plasmas are typically far from local
thermodynamic equilibrium (LTE), and understanding energy conversion in such
systems is a forefront research problem. The standard approach is to
investigate changes in internal (thermal) energy and density, but this omits
energy conversion that changes any higher order moments of the phase space
density. In this study, we calculate from first principles the energy
conversion associated with all higher moments of the phase space density for
systems not in LTE. Particle-in-cell simulations of collisionless magnetic
reconnection reveal that energy conversion associated with higher order moments
can be locally significant. The results may be useful in numerous plasma
settings, such as reconnection, turbulence, shocks, and wave-particle
interactions in heliospheric, planetary, and astrophysical plasmas.
