Dynamic near-field heat transfer between macroscopic surfaces

TL;DR

This paper models the dynamic near-field heat transfer between macroscopic surfaces using a coupled harmonic oscillator approach, revealing transient heat flux can temporarily exceed steady-state levels by 50%.

Contribution

It introduces a dynamic model for near-field heat transfer based on coupled oscillators, extending beyond traditional steady-state fluctuational electrodynamics.

Findings

Transient heat flux can reach 1.5 times the steady-state value.

The model applies to polar crystal surfaces supporting surface polaritons.

Comparison with standard theory validates the dynamic approach.

Abstract

The dynamic heat transfer between two half-spaces separated by a vacuum gap due to coupling of their surface modes is modelled using the theory that describes the dynamic energy transfer between two coupled harmonic oscillators each separately connected to a heat bath and with the heat baths maintained at different temperatures. The theory is applied for the case when the two surfaces are made up of a polar crystal which supports surface polaritons that can be excited at room temperature and the predicted heat transfer is compared with the steady state heat transfer value calculated from standard fluctuational electrodynamics theory. It is observed that for small time intervals the value of heat flux can reach as high as 1.5 times that of steady state value.