A Measurement of HTS Cable Power Loss in a Sweeping Magnetic Field

Abstract

Short sample HTS power cable composed of multiple 344C-2G strands and designed to energize a fast-cycling dipole magnet was exposed to a sweeping magnetic field in the (2-20) T/s ramping rate. The B-field orientation toward the HTS strands wide surface was varied from to 8 , in steps of 10. The test arrangement allowed measurements of combined hysteresis and eddy current power losses of the cable assembly. For the validity of these measurements, the power losses of a short sample cable composed of multiple LTS wire strands were also performed and compared with the known data. The test arrangement of the power cable is described, and the test results are compared with the projections for the eddy and hysteresis power losses using fine details of the test cable structures.Index Terms-Accelerator magnets, high temperature superconductors, low temperature superconductors, superconductor power cable.

Design, Construction, and Test Arrangement of a Fast-Cycling HTS Accelerator Magnet

“…In the fast-cycling operation the power loss in the conductor is primarily due to the sweeping magnetic field crossing its space. As indicated in [3,4] the effect of the core induced magnetic field can be much reduced with a conductor of a narrow rectangular shape stretching as much as possible from the top to the bottom wall of the cable cavity. The field crossing the conductor space can be then further suppressed by the optimization of the cable cavity width and the cable position in that cavity.…”

“…Each sub-cable consists of twenty 3 m long 344C-2G tapes of 0.2 mm x 4.5 cross-section. As discussed in [3,4] the tapes are paired with their magnetic substrates facing each other and the additional Ni5%W substrates are placed between each pair. The sub-cable design is shown in Fig.…”

“…IN HIGH-ENERGY ACCELERATORS The power losses of the 344-2G HTS sub-cable in a fastcycling magnetic field were measured in [4]. We use these data to project power losses for the test magnet and to extend them for the Proton and Muon synchrotrons of the MAP proposal [6].…”

“…The accelerator and magnet parameters together with the projected power losses are given in Table I. In the HTS cable test [4] the measured power loss was 8 W at 20 T/s cycling rate for a stack of 20 HTS tapes at 8 0 relative to the cycling 0.5 T field. Our studies indicate that in the optimal position of the cable within the core gap (e.g.…”

A Preliminary Consideration of Superconducting Rapid-Cycling Magnets for Muon Acceleration

“…The solution is use a core design where the field crossing conductor is strongly suppressed. As discussed in [5,6,7] to achieve this goal the conductor has to be placed in the center of a wide cable gap, and its width should be no more than 20% of that gap, as illustrated in Fig. 2 The total required cable current to generate 1.8 T field in the 30 mm gap is 60 kA.…”