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The preparation and measurement of the magnetoelastic properties of bonded Terfenol-D and Pr0.15Tb0.3Dy0.55Fe2 composites are reported. The experiments were carried out in various conditions, including compaction pressure and binder proportion in order to optimize the preparation method. The typical conditions are with the compaction pressure between 48 and 80 MPa and a weight ratio of binder to powder of 4:100. Large magnetostrictions of 1186×10−6 at 450 KA/m for the Terfenol-D composite with an applied compressive stress of 10 MPa and 900×10−6 at 900 KA/m for the Pr0.15Tb0.3Dy0.55Fe2 composite have been obtained with the following conditions: particle size of 165 μm, weight ratio of binder to powder of 4:100, and a compaction pressure of 80 MPa.

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Production of runaway electrons during disruptions has been observed in the HT-7 Tokamak. The runaway current plateaus, which can carry part of the pre-disruptive current, are observed in lower-hybrid current drive (LHCD) limiter discharges. It is found that the runaway current can mitigate the disruptions effectively. We can use gas puffing to increase the line-averaged density to restrain the runaway electrons and rebuild the plasmas after the disruptions. Detailed observations are presented on the runaway electrons generated following disruptions in the HT-7 tokamak discharges. The results indicate that the magnetic oscillations play a significant role in the loss of runaway electrons in disruptions. There are two important preconditions to rebuild plasmas by runaway electrons after the disruptions. One of them are weak magnetic oscillations; another one are LHWs (lower-hybrid waves).