On the role of atomic momentum and molecules in self-consistent 1D scrape-off layer simulation of MAST-U, using DIV1D

In this paper, the 1D physics-based dynamic Scrape-Off-Layer (SOL) model DIV1D is extended to include molecular interactions and the effects of finite atomic flow velocity parallel to the magnetic field lines. The addition of molecular interactions, atomic flow, and geometric settings in DIV1D leads to qualitative agreement with stationary 1D profiles obtained by mapping 2D SOLPS-ITER simulations for the parallel heat flux, electron temperature, electron density, plasma flow velocity, atomic density, atomic flow velocity and molecular density. Steady-state simulations of DIV1D show higher levels of particle, momentum and heat losses through collisional-radiative interactions between ions and molecules, compared to ions and atoms, in the divertor. Density ramp simulations show that DIV1D is now capable of dynamically transitioning between different SOLPS-ITER equilibria for MAST-U, capturing behaviour throughout the target particle flux rollover into deeply detached regimes.