Exponential Tails in Two-Dimensional Rayleigh-Bénard Convection

In this letter we investigate the probability density function (PdF) of the temperature field by numerical simulations of Rayleigh-Benard convection in two spatial dimensions. The PdF of the temperature shows exponential tails, consistently with previous laboratory experiments and numerical simulations. A new theoretical explanation for the exponential tail of the PdF is offered.