The ITER tokamak is expected to experience disruptions, which are violent MHD instabilities, and which can cause damage to the structures surrounding the plasma. The largest present tokamak, JET, is the main source of information about the effects of disruptions [1]. JET measurements indicate that large forces, of the order of a MN, are generated on the walls enclosing the plasma. In ITER the force will scale up by a factor of 20. It is important to perform computer simulations to verify JET results and examine how they will occur in ITER. Recently 3D time dependent simulations of JET disruption were carried out. It was found that the JET simulations differed from previous ITER simulations [2,3], becuase they were produced by a different MHD instabiliity. Nevertheless the force calculation is in reasonable agreement with the previous simulations. 

The disruption procceds in two stages. In the first stage, the instability, called a "giant sawtooth", causes a rapid loss of confinement of the temperature. In the second stage, the magnetic field heals and the plasma drifts vertically. The plasma has a helical perturbation, which produces an asymmetric wall force. The plasma rotates toroidally, which might cause a resonant amplification of the force on the external conducting structures.

[1] S. N. Gerasimov et al., Nucl. Fusion 54, 073009 (2014)

[2] H. R. Strauss et al., Nucl. Fusion 54, 043017 (2014)

[3] H. R. Strauss, Phys. Plasmas 22, 082509 (2015)