Title :
KSTAR Magnetic Field Measurement During the Commissioning and Remanent Field Evaluation
Author :
Yonekawa, Hirofumi ; Kim, Y.O. ; Lee, Hyun Jung ; Yoon, S.W. ; Hahn, S.H. ; Lee, K.S. ; Lee, D.K. ; Park, Soo Hwan ; Chu, Yong ; Bang, E.N. ; Park, K.R. ; Oh, Y.K. ; Bak, J.S. ; Leuer, J.A.
Author_Institution :
Nat. Fusion Res. Inst., Daejeon, South Korea
fDate :
6/1/2009 12:00:00 AM
Abstract :
An in situ measurement of the magnetic field generated by the assembled superconducting magnet coils was held by using precision Hall sensors during the commissioning of the Korea Superconducting Tokamak Advanced Research (KSTAR) device. This was done in order to investigate the magnetic influence of Incoloy 908, which is the jacket material for the cable-in-conduit conductors (CICCs) of the Nb3Sn coils. After the PF coils were discharged from 1 kA the vertical remanent field at the plasma center was more than 10 G, while the TF coils were not energized. The vertical magnetic field generated by the PF coils had a discrepancy of up to 50 G between measurement and the calculation assuming no magnetic influence of Incoloy 908. Thus, non-negligible ferromagnetism was identified and attributed to Incoloy 908. In contrast, most of the hysteresis observed in the magnetic measurements was eliminated when the Incoloy 908 of the TF windings was saturated by the TF coil charging.
Keywords :
Tokamak devices; ferromagnetic materials; fusion reactor materials; iron alloys; magnetic field measurement; magnetic hysteresis; nickel alloys; niobium alloys; remanence; superconducting cables; superconducting coils; superconducting magnets; superconducting materials; tin alloys; CICC; FeNi-Nb3Sn; Incoloy 908; KSTAR commissioning; KSTAR magnetic field measurement; Korea superconducting tokamak advanced research device; cable-in-conduit conductors; ferromagnetism; hysteresis; plasma center; poloidal field coils; precision Hall sensors; remanent field evaluation; superconducting magnet coils; toroidal field coil charging; toroidal field windings; vertical remanent field; ${rm Nb}_{3}{rm Sn}$; Incoloy 908; remanent magnetic field; superconducting magnet coil;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2009.2018486
