Edge momentum transport within an extended MHD code*

Edge plasma flows with large shear are correlated with the occurrence of Quiescent H-mode (QH-mode) [1] as opposed to operation with edge localized modes (ELMs). Prior NIMROD MHD simulations of QH-mode [2] use implicit sources that maintain the flow profiles. However, these implicit sources complicate the MHD-induced transport analysis and a higher-fidelity model is needed. This work studies the forces and nonlinear flow evolution within the context of extended MHD. Our simulations are initialized with a reconstructed DIII-D state where the flow is measured by both main-ion and Carbon impurity charge-exchange recombination spectroscopy. We then study the evolution with MHD with Braginskii-like closures coupled to a fluid-neutral model. Progress towards including a drift-kinetic closure [3] for the force density from the neoclassical stress and ion-orbit loss is discussed.

[1] KH Burrell et al., Phys. Plasmas 12, 056121 (2005)
[2] JR King et al., Phys. Plasmas 24, 055902 (2017); JR King et al., Nucl. Fusion 57 022002 (2017)
[3] ED Held et al., Phys. Plasmas 22, 032511 (2015)