27 August 2017 to 1 September 2017
RAI Congress Center, Amsterdam, The Netherlands
Europe/Amsterdam timezone

Electrical Field Generation by Hall Effect in High Field No-Insulation REBCO Pancake Coils

31 Aug 2017, 13:45
1h 45m
Posters Area

Posters Area

Poster Presentation of 1h45m G8 - Novel Diagnostics and Other Techniques Thu-Af-Po4.11

Speaker

Prof. So Noguchi (Hokkaido University)

Description

A no-insulation (NI) winding technique is very promising to conduct a practical use of REBCO pancake coils by greatly enhancing the thermal stability. Many applications using the NI technique have been developed or constructed, such as a magnetic separation, a 1.3-GHz NMR, an over 40-T magnet, etc. So far, a lot of measurement data proved a high thermal stability of test magnets through overcurrent experiments. When an NI REBCO magnet transitions into a normal state, an operating current radially bypasses from a joint to another joint across turns. This mechanism enhances a thermal stability of NI REBCO pancake coils, and the bypassing currents avoid the coils from burning out. However, since the bypassing currents flow under a high magnetic field, an electrical field is generated in the circumferential direction, according to the Hall effect. The electrical field generated by the Hall effect is linearly proportional to a current density and a magnetic field. The radial bypass current flows through the stabilizer edges of REBCO tape so that the current density in the radial direction increases under a high magnetic field in the axis direction. Consequently, a high electrical field is generated along the REBCO tape winding. When an NI REBCO magnet is operated under a high background field, the electrical hall-effect field would be not negligible. Therefore, we try to estimate the electrical hall-effect field in simulations, and investigate the influence of the electrical hall-effect field on the stability of NI REBCO magnets. In future, since NI REBCO magnets will be installed into very high background fields, it is necessary to grasp a hall-effect phenomenon not only after quench but also during charging magnets.

Submitters Country Japan

Primary authors

Prof. So Noguchi (Hokkaido University) Prof. Seungyong Hahn (Seoul National University) Prof. Atsushi Ishiyama (Waseda University)

Presentation Materials