STUDIES OF THE ABLATED PLASMA FROM EXPERIMENTAL PLASMA GUN DISRUPTION SIMULATIONS

Extensive simulations of tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense plasma shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1-40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 10-100 MJ/m(2). A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma, Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of similar to 1 mm. Time-resolved data with 40-200 ns resolution was also recorded, The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface.