  The statistics of power fluctuations are studied in simulations of
two-dimensional turbulence in both inverse (energy) and direct (enstrophy)
cascade regimes from both Lagrangian and Eulerian perspectives. The probability
density function (PDF) of the appropriately defined dimensionless power is
strongly non-gaussian with asymmetric exponential tails. This distribution can
be modeled by the distribution of the product of correlated normal variables
allowing a derivation of the asymptotics of the tails. The PDF of the
dimensionless power is shown to exhibit an empirical Fluctuation Relation. An
expression for the entropy production rate is deduced from the asymptotic form
of the power PDF and is found to agree very well with the measured entropy
rate.
