Toroidal studies of fast crash with Hall effects in tokamak

Both linear and nonlinear evolution of m/n=1/1 resistive kink mode is performed by a three-dimensional, fully toroidal, non-reduced and Hall-MHD code CLT. It is found that the hall terms can increase the linear growth rate of resistive kink mode when the thermal conductivity is small. However, they can greatly decrease the linear growth rate when the thermal conductivity exceeds the threshold. A transition from a ‘Y-type’ reconnection layer to a ‘X-type’ layer and a nonlinear enhanced growth rate are observed in Hall-MHD simulations, which are consistent with previous cylindrical simulations and theoretical analysis. This can be a good candidate to explain the fast crashes observed in tokamaks.