IAEA Fusion Energy Conference 2010

Proceedings of the 23rd IAEA Fusion Energy Conference
Daejeon, 11-16 October 2010

Organized by the International Atomic Energy Agency
and hosted by the Government of the Republic of Korea


(ITR/P1-36) 3D Effect of Ferromagnetic Materials on Alpha Particle Power Loads on First Wall Structures and Equilibrium on ITER

K. Shinohara1), T. Kurki-Suonio2), D. Spong3), O. Asunta2), K. Tani1), E. Strumberger4), S. Briguglio5), S. Günter4), T. Koskela2), G. Kramer6), S. Putvinski7), K. Hamamatsu1), ITPA Topical Group on Energetic Particles
1) Japan Atomic Energy Agency, Naka, Ibaraki, Japan
2) Aalto university, Assn. Euratom-Tekes, P.O. Box 4100, FI-02015 Aalto, Finland
3) Oak Ridge National Laboratory, Fusion Energy Theory Group, Oak Ridge, USA
4) Max-Planck-Institut-für-Plasmaphysik, EURATOM-Association, Garching, Germany
5) ENEA, Frascati, Italy
6) Princeton Plasma Physics Laboratory, Princeton University, USA
7) ITER Organization, CS 90 046, 13067 Saint Paul-lez-Durance Cedex, France

Abstract.  Within the ITPA Topical Group on Energetic Particles, we have investigated the impact that various mechanisms breaking the tokamak axisymmetry can have on the fusion alpha particle confinement in ITER as well as on the wall power loads due to these alphas. In addition to the well known TF ripple, the 3D effect of ferromagnetic materials and ELM mitigation coils are included in these mechanism. First, the validity of using a 2D equilibrium was investigated: a 3D equilibrium was reconstructed using the VMEC code, and it was verified that no 3D equilibrium reconstruction is needed but it is sufficient to add the vacuum field perturbations onto an axisymmetric equilibrium. Then the alpha particle confinement was studied using two independent codes, ASCOT, and F3D OFMC, all of which assume MHD quiescent background plasma and no anomalous diffusion. The distribution of the peak power load was found to depend on the first wall shape. We also made the first attempt to accommodate the effect of fast ion related MHD on the wall loads in ITER using the HMGC and ASCOT codes. The power flux to the wall was found to increase due to the redistribution of fast ion by the MHD. Furthermore, the effect of the ELM mitigation field on the fast ion confinement was addressed by simulating NBI ions with the F3D OFMC code. The loss power fraction of NBI ions was found to increase from 0.3% without the ELM mitigation field to 5-6% with the ELM mitigation field.

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