TY - JOUR
T1 - Bootstrap current fraction scaling for a tokamak reactor design study
AU - Gi, Keii
AU - Nakamura, Makoto
AU - Tobita, Kenji
AU - Ono, Yasushi
N1 - Funding Information:
K. Gi would like to thank Dr. N. Aiba for the discussions related to this study, especially concerning the scan methodology. This work was supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (JSPS) Fellows ( 24-1756 ), JSPS Core-to-Core program No. 22001, and Grant-in-Aid for Scientific Research (A) No. 22246119 .
Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
PY - 2014/11/1
Y1 - 2014/11/1
N2 - We have derived new bootstrap current fraction scalings for systems codes by solving the Hirshman-Sigmar model, which is valid for arbitrary aspect ratios and collision conditions. The bootstrap current density calculation module in the ACCOME code was used with the matrix inversion method without the large aspect ratio assumption. Nine self-consistent MHD equilibria, which cover conventional, advanced and spherical tokamaks with normal or reversed shear, were constructed using numerical calculations in order to compare the bootstrap current fraction values with those of the new model and all six existing models. The Wilson formula successfully predicted the bootstrap current fraction, but it requires current density profile index for the calculation. The new scaling formulas and IPDG accurately estimated the bootstrap current fraction for the normal and weakly reversed shear tokamaks, regardless of the aspect ratio. However, none of the existing models except the Wilson formula can accurately estimate the bootstrap current fraction for the reversed shear tokamaks, which is promising for the advanced tokamak operation mode.
AB - We have derived new bootstrap current fraction scalings for systems codes by solving the Hirshman-Sigmar model, which is valid for arbitrary aspect ratios and collision conditions. The bootstrap current density calculation module in the ACCOME code was used with the matrix inversion method without the large aspect ratio assumption. Nine self-consistent MHD equilibria, which cover conventional, advanced and spherical tokamaks with normal or reversed shear, were constructed using numerical calculations in order to compare the bootstrap current fraction values with those of the new model and all six existing models. The Wilson formula successfully predicted the bootstrap current fraction, but it requires current density profile index for the calculation. The new scaling formulas and IPDG accurately estimated the bootstrap current fraction for the normal and weakly reversed shear tokamaks, regardless of the aspect ratio. However, none of the existing models except the Wilson formula can accurately estimate the bootstrap current fraction for the reversed shear tokamaks, which is promising for the advanced tokamak operation mode.
KW - Bootstrap current fraction
KW - Reactor design
KW - Scaling
KW - Spherical tokamak
KW - Systems codes
KW - Tokamak
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U2 - 10.1016/j.fusengdes.2014.07.009
DO - 10.1016/j.fusengdes.2014.07.009
M3 - Article
AN - SCOPUS:84922489488
SN - 0920-3796
VL - 89
SP - 2709
EP - 2715
JO - Fusion Engineering and Design
JF - Fusion Engineering and Design
IS - 11
ER -