T _cs degradation of ITER TF samples due to fast current discharges

Abstract Direct current tests performed in the past on conductor samples of toroidal field (TF) ITER coils revealed degradation sharing temperature, T cs . The progresses with repetitive electromagnetic loading, and also thermal cycles between 4.5 K room temperature. This feature was observed short SULTAN test facility (EPFL-SPC, Switzerland) as well TF Insert Coil CSMC (Naka, Japan). We present three independent observations suggesting that initiation sample quench followed by a fast discharge, which normally complements every I c both CSMC, enhances rate. exact mechanism this contribution to remains unidentified.