where h is the plasma-particle heat transfer coefficient, a is the
surface area of the particle, T∞ is the plasma temperature, Ts is the
particle surface temperature, Ta is the reactor wall temperature,
is the Stephan–Boltzmann constant and ε is the particle emissivity.
This equation represents a simplistic description of the mechanism
occurring in the early stages because the surface vaporises forming
a gaseous shroud that inhibits heat transfer and, consequently, the
mechanism changes.