Simulation of Large Magnetic Islands: A Possible Mechanism for a Major Tokamak Disruption

It is known that an internal tokamak disruption leads to a current profile which is flattened inside the surface when the safety factor equals unity. It is shown that such a profile can lead to $m=2\mathrm{}$ magnetic islands which grow to fill a substantial part of the tokamak cross section in a time consistent with the observation of a major disruption.