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PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-8718
DTSTART:20240408T170000Z
DTEND:20240408T181500Z
DTSTAMP:20260413T223352Z
LAST-MODIFIED:20240403T163253Z
LOCATION:1227 Engineering Dr
SUMMARY:“Controlling plasma-material interactions with real-time pow
 dered material injection”\, Plasma Physics (Physics/ECE/NE 922) Semi
 nar\, Florian Effenberg\, PPPL
DESCRIPTION:In the DIII-D tokamak\, coatings up to 10 nm thick were gr
 own on plasma-facing components (PFCs) at 1 nm/s using boron (B) and s
 ilicon (Si) injections in both powder and pellet forms during L-mode a
 nd H-mode discharges. Utilizing the impurity powder dropper (IPD) and 
 the impurity granule injector (IGI)\, materials were injected at rates
  of 1-200 mg/s\, with varying sizes and speeds\, enhancing wall condit
 ions akin to glow discharge boronization by reducing impurity influxes
  and significantly increasing the density-to-gas fueling ratio. Post-m
 ortem analysis confirmed the formation of B-C layers with average surf
 ace composition B:C∼1. Si pellet injection at a rate of 1-15 mg/s yi
 elded Si-rich layers on the divertor tiles of at least 1 nm in thickne
 ss. The in-situ growth of thin films in real-time demonstrates the cap
 ability of surface material replenishment during long-pulse plasma ope
 ration or steady-state devices without ramp-down of the magnetic field
 s. <br>
\n<br>
\nConcurrently\, B and BN powder injections into the SA
 S-VW divertor demonstrated significant effects on heat flux and W eros
 ion control without adversely affecting H-mode performance. Specifical
 ly\, B injections at rates up to 25 mg/s resulted in a notable decreas
 e in W deposition. In contrast\, BN injections led to substantial X-po
 int radiation\, prominently reducing heat fluxes and W erosion through
  detachment. These outcomes underline the efficacy of powder injection
  techniques in managing plasma-material interactions\, particularly in
  high-Z environments\, highlighting their potential in next-step long-
 pulse devices.<br>
\n
URL:https://www.physics.wisc.edu/events/?id=8718
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