Engineering Development of an HTS Floating Coil for the Mini-RT Project

• Published in: Teion kōgaku Vol. 39; no. 5; p. 193
• Main Authors: YANAGI, Nagato, MITO, Toshiyuki, MORIKAWA, Junji, OGAWA, Yuichi, HAMAGUCHI, Shinji, HISHINUMA, Yoshimitsu, OHKUNI, Kotaro, HORI, Dan, IWAKUMA, Masataka, UEDE, Toshio
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 01.05.2004
• ISSN: 0389-2441; 1880-0408

A magnetically-levitated superconducting coil device, Mini-RT, has been constructed using a high temperature superconductor (HTS) for the purpose of examining a new magnetic confinement scheme of high-beta non-neutral plasmas. The floating coil is wound with silver-sheathed Bi-2223 tapes, and it is operated in the temperature range of 20-40 K. A number of studies and experiments were carried out in order to realize the necessary system. One of them was to demonstrate magnetic levitation using a miniature HTS floating coil having a diameter of 80 mm. The coil was fabricated using Bi-2223/Ag tapes of 12 m and excited by field cooling with liquid nitrogen. The magnetic levitation was examined using a real-time feedback control system with laser displacement gauges. Additionally, a persistent current switch (PCS) has been developed using Bi-2223/Ag tapes of 21 m, and a prototype HTS-PCS was tested in a cryostat. After construction of the floating coil and HTS-PCS for the Mini-RT device was completed, excitation tests were carried out in the cryostat and the basic properties up to the nominal operation condition were examined.