THE USE OF AN ELECTROTHERMAL PLASMA GUN TO SIMULATE THE EXTREMELY HIGH HEAT-FLUX CONDITIONS OF A TOKAMAK DISRUPTION

Disruption damage conditions for future large tokamaks like ITER are n early impossible to simulate on current tokamaks. The electrothermal p lasma source SIRENS has been designed, constructed, and operated to pr oduce high density(> 10(25)/m(3)), low temperature (1-3 eV) plasma for med by the ablation of the insulator with currents of up to 100 kA (10 0 mu s pulse length) and energies up to 15 kJ. The source heat fluence (variable from 0.2 to 7 MJ/m(2)) is adequate for simulation of the th ermal quench phase of plasma disruption in future fusion tokamaks. Dif ferent materials have been exposed to the high heat flux in SIRENS, wh ere comparative erosion behavior was obtained. Vapor shield phenomena has been characterized for different materials, and the energy transmi ssion factor through the shielding layer is obtained. The device is al so equipped with a magnet capable of producing a parallel magnetic fie ld (up to 16 T) over a 8 msec pulse length. The magnetic field is prod uced to decrease the turbulent energy transport through the vapor shie ld, which provides further reduction of surface erosion (magnetic vapo r shield effect).