High temperature superconducting levitation coil for the levitated dipole experiment (LDX)

The Levitated Dipole Experiment (LDX) is an Innovative approach to explore the magnetic confinement of fusion plasmas. A superconducting solenoid (flo ating coil) Is magnetically levitated for up to 8 hours in the center of a 5-meter diameter vacuum vessel. This foil is supported by a Levitating Coil (L-Coil) on top of the vacuum vessel. In the initial machine design, this Levitating Coil was a water-cooled copper solenoid, and was the experiment' s single largest load on the available water system. The main benefit of us ing a high temperature superconducting coil is the ability to apply more au xiliary heating power to the plasma. However, this coil will also be the fi rst high temperature superconducting coil to be used in a US fusion program experiment. The high temperature superconducting L-Coil is a solenoid, usi ng a two-in-hand winding of a commercially available 0.17 mm x 3.1 mm tape by American Superconductor Corporation with a critical current of 62 A st 7 7 K and sell-field. The L-Coil will be operated at 0.9 T and 20 K. The L-Co il has a protection circuit that not only protects it against overheating i n the event of quench, but also against F-Coil collision in the event of a control failure.