Session KP01 - Poster Session III.
POSTER session, Tuesday afternoon, March 23
Exhibit Hall, GWCC
The MH3D++ unstructured mesh version of the MH3D code was used for tokamak disruption simulations. (H. Strauss et. al), IAEA-F1-CN-69/TH3/4, Yokohama (1998) We have studied the effect of 3D pressure perturbations caused by pellet injection on MHD stability. The pellet pressure perturbation can trigger ballooning like modes, which might explain recent experimental results (D.G.Whyte et. al), Phys. Rev. Lett. 81, 4392 (1998). It is found that pellets on the high magnetic field side require a higher beta for instability, as well as leading to more localized instabilities. We have also studied kink instabilities in the thermal quench phase of tokamak disruptions. We used a thin resistive wall boundary condition, and included an ITER relevant model of runaway electrons formed by avalanching. We will present calculations of halo current and runaway electron toroidal asymmetry due to nonlinear external kink modes. The MH3D++ code has been extended to have the capability of using a 3D mesh in configuration space, suitable for stellarator equilibrium and stability studies. Equilibria can be initialized with VMEC output or generated from initial data. Examples of stellarator computations will be presented.