Direct Numerical Simulation of Near Field Thermal Radiation Based on Wiener Chaos Expansion of Thermal Fluctuating Current

A methodology is proposed, which is capable of determining the near field thermal radiation based on the Wiener chaos expansion. The approach has no explicit constraints on the geometry and temperature distributions of the system and can be easily included with classical electrodynamics simulations. A specific application is made for the near field thermal radiation between two plates and the results are in very good agreement with the classical solutions obtained from Green’s function method. Also, by comparing the resulting solutions with the solutions from Green’s function method, a new point of view for interpreting the results for the near field thermal radiation in terms of a chaos expansion is provided.