Wall forces produced during ITER disruptions

Abstract

Nonlinear simulations with the M3D code [W. Park et al., Phys. Plasmas 6, 1796 (1999)] are performed of disruptions produced by large scale magnetohydrodynamic instabilities. The toroidally asymmetric wall forces produced during a disruption are calculated in an ITER [T. Hender et al., Nucl. Fusion 47, S128 (2007)] model. The disruption is produced by a vertical displacement event and a kink mode. Expressions are derived for the wall force, including the sideways force, using a thin conducting wall model. The scaling of wall force with γτw is obtained, where γ is the kink growth rate and τw is the wall penetration time. The largest force occurs with γτw≈1. A theory is developed of the wall force produced by kink modes. The theory is in qualitative agreement with the simulations and Joint European Torus [V. Riccardo et al., Nucl. Fusion 49, 055012 (2009)] experiments. In particular, the theory and simulations give dependence of the sideways on γτw, correlation of sideways force with sideways plasma displacement, and correlation of toroidally varying plasma current with toroidally varying vertical displacement.