Study of the generation and suppression of runaway currents in provoked disruptions in J-TEXT

Runaway currents following disruptions have an important effect on the first wall for the next generation tokamak. The behaviors of runaway currents following intentional provoked disruptions have been investigated in the J-TEXT tokamak. It is found that the runaway current generation following provoked disruptions depends on both the toroidal magnetic field and the plasma current. The conversion efficiency of pre-disruptive plasma currents into runaway currents is in the ranges of 30% to 60% in J-TEXT. The runaway currents can be avoided by the intensive gas puffing of H2 due to the low multiplication factor in J-TEXT.

► The regime of runaway generation in disruptions in J-TEXT has been established.
► The magnetic field threshold for runaway current generation in disruptions is 2.2 T.
► The conversion efficiency of runaway current is in the ranges of 30% to 60%.
► The runaway currents can be avoided by the intensive gas puffing of H2.