Interaction of High Temperature Plasma Flowing from Long Cusp Trap with Solid Materials

Abstract

Process of interaction of intense plasma fluxes up to 10 MW/cm2 with solid targets was studied experimentally. It was shown that a dense plasma layer arises near target surface and protects the target from direct effect of an incoming high temperature plasma. Spatial distribution and temporal behavior of the shielding layer depend on the target materials. For a high Z materials (tungsten, copper, stainless steel) dense plasma layer is localized near the surface during all time of the interaction. For a low Z materials (graphite, boron nitrid, plexiglass, aluminium) low dense plasma cloud – “corona” rapidly expands toward incoming plasma flow along the magnetic field lines. The experiments demonstrated effective shielding of the different materials surface from excessive evaporation. Bulk energy of incoming plasma is converted into SXR radiation in near surface layer for a high Z materials and, partially, into target plasma heating for a low Z materials. Measured parameters of plasma shield are used as a benchmark in developing numerical codes to predict a real damage for ITER divertor plates due to hard disruptions.