Source
With Source you can add one or more radiative heat sources as parallel source, point source, and small element source. You can specify the Source for the Radiation module in the Properties panel, after selecting the module in the Flow Analysis tree.
Parallel Source
A parallel source specifies a uniform planar radiative heat flux. Flux Direction Vector and Power Density are specified under parallel source.
Point Source
A point source specifies an isotropic radiative heat flux emitted from a point. Position Vector of the source and Total Power are specified under point source.