BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Arcs discharges during disruption and fast plasma shutdown by Expl osive Gas Injection DTSTART:20191220T103000 DTEND:20191220T113000 DTSTAMP:20261001T234513Z UID:06576cd56c855772e998e8b5de72811776f697d2bb93cd6ccb165d08 CATEGORIES:Conferences - Seminars DESCRIPTION:Dr. P.V. Savrukhin\, NRC “Kurchatov Institute”\, Moscow\, Russia ITER Domestic Agency\, Moscow\, Russia\nArc discharges are consider ed as a possible mechanism determining transition from relatively slow gro wth of the magnetohydrodynamic (MHD) perturbations to thermal quench (mino r disruption) and subsequent transition to the major disruption with curre nt collapse in the T-10 tokamak with tungsten limiters. The effect of the arc discharges is evaluated using analysis of the fast-scale (0.2–1.5 MH z) electromagnetic oscillations measured by movable magnetic and electric probes located near the plasma boundary at multiple positions inside the v acuum vessel and by postoperational inspection of the in-vessel components . Experiments using a special “arc” probe with castellated surface sti mulating arc discharges indicated that transition to the major disruption is associated with enhanced electron emission from the plasma facing compo nents. The role of the arcs is confirmed in experiments with initiation of the currents in the peripheral plasma using biasing (Ub 0–400 V) betwee n the rail limiter and the movable tungsten electrode. Experiments indicat ed that critical surface current density is required for the arc initiatio n. The radial decay rate and frequencies of the electromagnetic oscillatio ns measured in the T-10 experiments are found to be similar to the ones du ring arc discharges at the laboratory bench. Present experiments in the T- 10 tokamak indicate that arc discharges could determine plasma-wall intera ction during growth of the MHD modes and disruptions in tokamaks with all- metal first-wall.\nPossibilities of the Explosive Gas Injection technique are considered for fast plasma shutdown in the T-10 tokamak.\n  LOCATION:PPB 019 STATUS:CONFIRMED END:VEVENT END:VCALENDAR