NUMERICAL-SIMULATION OF HALO CURRENTS IN TOKAMAKS

The formation of halo currents in a peripheral tokamak plasma is simul ated numerically with the 1.5-dimensional resistive code DINA. Results from numerical calculations of the vertical displacement episode for a tokamak on the scale of the ITER reactor are presented. In the perip heral plasma region, the poloidal and toroidal components of the halo current are estimated for an electron temperature on the order of 50 e V in the case of an uncontrolled upward motion of the plasma column. N umerical calculations incorporating halo currents show that the vertic al velocity of the plasma column decreases during the vertical displac ement episode.