Plasma and Fusion Research

Volume 11, 2403023 (2016)

Regular Articles

Fokker-Planck Simulation Study of Hot-Tail Effect on Runaway Electron Generation in ITER Disruptions
Hideo NUGA, Akinobu MATSUYAMA1), Masatoshi YAGI1) and Atsushi FUKUYAMA
Kyoto University, Kyoto-Daigaku-Katsura, Nisikyo-Ward, Kyoto 615-8540, Japan
1)
Japan Atomic Energy Agency, 2-166 Omotedate-Obuchi, Rokkasho 039-3212, Japan
(Received 30 November 2015 / Accepted 1 February 2016 / Published 17 March 2016)

Abstract

A Fokker-Planck code TASK/FP, which calculates the evolution of the relativistic momentum distribution function of electrons and the induced toroidal electric field, has been applied to the study of runaway electron (RE) generation in ITER disruptions. The hot-tail effect on the RE generation is investigated. Hot tail is formed during the thermal quench ahead of the Dreicer generation, which have an impact on the subsequent current and the electric field evolution. The hot-tail affects the RE current density profile even in the secondary RE dominant case. In spite of the small ratio of the primary electrons, they are multiplied significantly by the avalanche effect. Consequently, the hot-tail effect plays an important role in determining the total RE current density profile after the current quench.

Keywords

runaway electron, disruption, ITER, hot-tail effect, thermal quench

DOI: 10.1585/pfr.11.2403023

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References

  • [1] T.C. Hender et al., Nucl. Fusion 47, S128 (2007).
  • [2] H. Smith and E. Verwichte, Phys. Plasmas 15, 072502 (2008).
  • [3] T. Fehér, H. Smith, T. Fülöp et al., Plasma Phys. Control. Fusion 53, 035014 (2011).
  • [4] H. Nuga, A. Matsuyama et al., J. Plasma Fusion Res. 10, 1203006 (2015).
  • [5] C.F.F. Karney and N.J. Fisch, Phys. Fluids 28, 116 (1985).
  • [6] C. Karney, Computer Physics Reports 4, 183 (1986).
  • [7] J. Wesson, Tokamaks Third edition, (Clarendon, Oxford, 2004) p.737.
  • [8] M.N. Rosenbluth and S.V. Putvinski, Nucl. Fusion 37, 1355 (1997).
  • [9] S. Chiu, M. Rosenbluth et al., Nucl. Fusion 38, 1711 (1998).
  • [10] J.W. Conner and R.J. Hastie, Nucl. Fusion 15, 415 (1975).
  • [11] R.M. Kulsrud et al., Phys. Rev. Lett. 31, 690 (1973).
  • [12] R. Aymar, P. Barabaschi and Y. Shimomura, Plasma Phys. Control. Fusion 44, 519 (2002).