Superconducting magnet system for an experimental disk MHD facility

A predesign of a split-pair magnet for a magnetohydrodynamic (MHD) facility for testing a 10-MW open-cycle disk or a 5-MW closed-cycle disk generator is presented. The magnet system consists of a NbTi and a Nb 3Sn section, which provide a magnetic field of 9 T in the active area of the MHD channel. The optimization process, which is based on minimum conductor costs is discussed, and the proposed conductor design is described. Basic solutions for the construction of the magnet, the cryostat and the cooling technique are also presente

Dc and ac behaviour of a normal joint in a superconducting cable

The application of joints which can be disassembled is studied within the framework of the development of high current (25 kA), high power (0.5 kW) cryogenic current supplies (flux pumps).1,2 The behaviour of a scale model with currents up to 5 kA will be presented here.\ud \ud Several means of diminishing the joint resistance have been researched with special attention being paid to detection methods to measure the resistance, and their accuracies.\ud \ud The role of the solder has been investigated. A simple model gives good qualitative understanding of the matter.\ud \ud The presence of ac currents in a cryogenic current supply causes considerably higher losses in the joint because of the non-homogeneous distribution of the current. A good impression of this distribution can be obtained by measuring the field along the joint. The measured results are in good agreement with calculated ones. A useful length of the joint under ac conditions can be defined and is helpful for design purposes