AC Losses in JT-60SA TF Magnet During Commissioning: Experimental Analysis and Modeling

During the integrated commissioning of JT-60SA tokamak, the Toroidal Field (TF) magnet has experienced fast current discharges which have induced AC losses in its winding packs (WP) and in its casings. Using the thermo-hydraulic sensors network installed at the inlet and outlet of the TF coils, we have performed enthalpy balances to estimate the transient heat loads generated by AC losses. In parallel, we have modeled the hysteresis and coupling losses produced in the WP and the eddy currents losses produced in the casings by such events. We then assess and discuss the consistency between these experimental and first theoretical analyses from the energy balance point of view.