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

Influence of E-J characteristics of coated conductors and field ramp-up rates on the shielding-current-induced fields of magnets

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

Posters Area

Poster Presentation of 1h45m G5 - Magnetization and Field Quality Thu-Af-Po4.10

Speaker

Yang Li (Kyoto University)

Description

The shielding-current-induced field (SCIF) of coated-conductor magnets has been studied mainly for dc magnets. In dc magnets, E-J characteristics of coated conductors can influence their field stabilities, because shielding currents should decay by the finite resistivity, i.e. E divided by J. In magnets generating time-variant magnetic fields, the field ramp-up/down rates as well as E-J characteristics can influence SCIF. J at an arbitrary point in a coated conductor is associated with E due to the E-J characteristic. Because E is determined by the electromagnetic induction during the field ramp-up/down phase of a magnet, J, as well as the shielding current, should be influenced by the ramp-up or ramp-down rate and E-J characteristics. We carry out numerical electromagnetic field analyses on the SCIF of coated-conductor magnets while varying the field ramp-up/down rates as well as the E-J characteristics of coated conductors. The analyses are conducted on simple axisymmetric coils and the cross-sectional model of a cosine-theta magnet designed for a rotating gantry for carbon cancer therapy. As for the excitation pattern of the magnets, we use simple temporal profiles with repeating ramping-up, flat top, and ramping-down phases for the axisymmetric coils, and temporal profiles simulating the excitation of a magnet for a rotating gantry for the cosine-theta magnet. We look at the influence of the ramp-up/down rates and the E-J characteristics on the current distributions in coated conductors in various phases, i.e. ramp-up/down phases, the flat top phase, and steps of the repeating ramp-up/down phases. Then we discuss their influences on the shielding-current-induced fields.
This work was supported in part by JSPS KAKENHI Grant number 16H02326 and in part by MEXT under the Innovative Nuclear Research and Development Program.

Submitters Country Japan

Primary author

Yang Li (Kyoto University)

Co-authors

Yusuke Sogabe (Kyoto University) Mr Kikuchi Takashi Prof. Naoyuki Amemiya (Kyoto University)

Presentation Materials

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