Thermal resistance of individual phases on platform

Above the J-tube air section, the thermal network only needs to consider one of the separated power cores as the thermal influence of the hang off itself is considered negligible. The thermal network for a single power core is defined by a sub set of the thermal network designed for the J tube air section, with only $T_1$ and $T_2$, because due to the separation of the power cores, the amour layer is no longer present i.e. no need for $T_3$. The heat transfer on the external surface of the power core is solved using the same approach as for the external surface of the J tube.