Theory Weekly Highlights for January 2020

January 31, 2020

A new module, IMAS HCD, has been developed in OMFIT to provide an interface to the IMAS Heating and Current Drive (HCD) Python workflow that was developed by ITER. Notably, the IMAS HCD workflow can model the power deposition and current drive of EC, IC, and NBI actuators, and account for their interaction through Fokker Plank calculations. All physics components exchange data via ITER IMAS data structures, which allow seamless switching of physics codes with different fidelity and numerical complexity for solving the same physics quantities. In this scheme, OMFIT enables loading the experimental data of different devices into IMAS, and provides a convenient user interface to facilitate setting up and executing the HCD workflow, as well as visualizing and comparing simulation results. The ability of OMFIT to interface with the IMAS HCD Python workflow has been enabled by the OMAS numerical library.

January 17, 2020

Phil Snyder, Yueqiang Liu, Chris Holland, Steffi Diem, Mattias Knolker, and Brendan Lyons attended the final meeting of the Community Planning Process workshop series in Houston TX from January 13 through January 17 2020.

January 10, 2020

A recent study investigated the effects of a wide electric sheath at the divertor targets on the ionization and emission of tungsten impurities, which play key roles in predicting and monitoring the erosion of tungsten divertor in tokamak. High-Z impurities like tungsten ionize within the Chodura sheath region in attached plasma conditions. To accurately model ionization and emission of impurities within the sheath region, the modification of the electron distribution in the sheath region must be taken account of. It was shown that the SXB coefficient for neutral tungsten used to monitor in-situ tungsten gross erosion is significantly reduced in high-density attached divertor plasma conditions ne > 5×1013 cm-3 because of the ionization of neutral tungsten well within the sheath region. This work has been published in Contributions to Plasma Physics as “Effects of the Chodura sheath on tungsten ionization and emission in tokamak divertors” by J. Guterl et al.

These highlights are reports of research work in progress and are accordingly subject to change or modification