Lithium Vapor Box Divertor Christopher Jagoe ‘18

Motivation Plasma in tokamak escapes along field lines Heat flux greater than 20 GW/m2 Divertor plates wear out Vapor box uses volumetric cooling Goal: prevent efflux into main body 3 orders of magnitude greater than the surface of the sun

Approach Lithium is hot, expensive, and difficult Water vapor mock-up experiment Parallel development of code (OpenFOAM) DSMC for rarefied gas conditions Kn = mfp/L between 0.01 and 1

Scaling Water vapor in the 0º – 100º range Range of pressure differences much lower Box size will be smaller but not too small Prevent ice from forming

Code Installing (harder than you think) blockMeshDict Boundary conditions Wall, zeroGradient, etc Patching to allow for different densities Courant number, mesh size affects run time

Results Shock pattern discovered Ability to create a pressure driven flow Capability to use more complex geometries Post-processing in Paraview

Impact Next step: comparing code to water vapor If successful, acquiring fundings for NSTX or MAST Reactors can burn cheaper, faster, longer

References Diagram on slide 3 from “The Lithium Vapor Box Divertor” by R. J. Goldston, R. Myers, J. Schwartz, Physica Scripta, 2016