May 6-8

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Author: Brendan C Lyons
Requested Type: Poster
Submitted: 2024-04-12 15:06:04

Co-authors: J.H. Kim, S.J. Lee, J.W. Kim, N.M. Ferraro, S.C. Jardin

Contact Info:
General Atomics
PO Box 85608
SAN DIEGO, CA   92186-5
United States

Abstract Text:
Future tokamaks will require disruption mitigation systems (DMS) to prevent machine damage during the uncontrolled loss of plasma confinement. Massive impurity injection, particularly shattered pellet injection (SPI), is the leading candidate for a DMS. Validated, predictive models are needed to project these systems to future devices, which require models for the macroscopic plasma evolution as well as the injected impurity dynamics. To simulate these conditions, the M3D-C1 extended-magnetohydrodynamics (MHD) code has traditionally been coupled to a coronal non-equilibrium model for impurity ionization and radiation, which is formally valid only in the low-collisionality limit. We present an upgrade to this impurity model by coupling M3D-C1 to the full ADAS model. This provides a density-dependent, collisional-radiative model for ionization and radiation and greatly expands the number of impurities that can be considered by M3D-C1. We also present results of shattered-pellet injection (SPI) simulations of several realistic scenarios on the KSTAR tokamak. The results are validated against data for single and dual-symmetric injection of neon-doped pellets as well as dual, time-staggered injection with a pure-deuterium pellet followed by a neon-doped pellet. We explore the effects of the localization of the plasma source, equilibrium plasma rotation, and coronal versus collisional-radiative impurities on these results. Agreement and discrepancies between the simulations and density/radiation measurements, both in time scale and magnitude, will be discussed.

This work is supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences under Awards DE-FC02-04ER54698 and DE-FG02-95ER54309. Contributing to the ITER DMS Task Force.

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