Measurements of heatflux footprints from disruptions

1. Proposed by J.L. Terry, B. Lipschultz, B. LaBombard, R. Granetz • Wmagnetic inside the vessel, WPMI,is typically >> Wthermal and WPMI is typically large, ~0.5 MJ for C-Mod, much larger for ITER • This magnetic energy can play an important role in heating plasma-wetted surfaces if it is 1st converted into plasma energy through the E field of a disruption and resultant Ohmic heating • If that energy is concentrated on material surfaces they may be damaged – (even in C-Mod, although that is not the primary motivation here) • Thus, what is the heatflux footprint through a disruption and how does that change for a mitigated disruption? Measurements of heatflux footprints from disruptions Motivation: C-Mod Ideas Forum: Jan. 10-12, 2011

2. Preliminary experiments, measuring the heatflux to the outer target, with unmitigated disruptions have been carried out. • Qualitatively we saw what we expected, a step at disruption, • then thermal decay. • It is still not clear whether or not we can resolve the heatflux at the thermal quench and current quench Measurements of heatflux footprints from disruptions Background: C-Mod Ideas Forum: Jan. 10-12, 2011

3. Produce downward-going VDEs at reproducible times • Vary stored plasma energy and magnetic energy • Compare unmitigated with mitigated disruptions Measurements of heatflux footprints from disruptions Plan: -This willrequire 2 dedicated runs C-Mod Ideas Forum: Jan. 10-12, 2011