Divertor Thermography Interface

Infrared cameras give a 2-D surface-temperature field on the divertor and first wall; the interface turns raw frames into calibrated heat-flux maps.

From frames to heat flux

A single thermocouple gives a point; the divertor needs a field. Infrared thermography cameras image the strike-point region and reconstruct surface temperature across the target, which the twin inverts into a heat-flux map. This map drives detachment control and erosion trending.

The inversion

# surface heat flux from IR temperature history
# solve 1-D transient conduction per pixel:
#   rho*c_p dT/dt = d/dx( k dT/dx )
# with measured surface T(t) as boundary condition
q_surf[px] = invert_conduction(T_ir[px, :], material[px])
heatmap = assemble(q_surf)     # 2-D flux field for control + twin

The inversion is per-pixel transient conduction using the measured surface-temperature history as the boundary condition — it is model-based, so its accuracy depends on the material properties and on emissivity calibration. A layer of redeposited material changes emissivity and biases the reading, which is why calibration drift is tracked continuously.

Consumers

• Detachment control in the divertor/expander interface.
• Erosion and lifetime trending in the twin.
• First-wall protection cross-check with the thermal interface.

Owner: sense-side L2 for frame transport and timestamping; L3 for inversion and heat-flux mapping. Timing: the map updates fast enough for detachment control (tens of ms) but is not on the protection path itself. Design-and-simulation specification, validated against the twin.