Collaborations on Long-Pulse Tungsten-Compatible Steady-State Scenarios between DIII-D and KSTAR*

A joint activity has been initiated between the DIII-D and KSTAR programs to develop long-pulse, tungsten-compatible, steady-state scenarios for future tokamaks. This balanced partnership includes shared run-time and a joint team for planning, experiments, and data analysis. For the FY24-25 campaigns, DIII-D has allocated dedicated run days, with a parallel program prepared on KSTAR.

As the first step, the KSTAR team joined DIII-D experiments on-site, successfully conducting experiments on hybrid and high-βp scenarios under KSTAR constraints, such as a new plasma shape on the tungsten divertor, limited ramp-up rate of plasma current for the superconducting magnet, and the maximum available heating and current drives. Concurrently, KSTAR has entered a new experimental phase by commissioning a newly installed lower tungsten divertor during the 2023 campaign, which benefits DIII-D-compatible high-performance lower single null scenarios.

The next step involves joint experiments on KSTAR, focusing on longer pulse operations of KSTAR-compatible hybrid and high-βp scenarios derived from DIII-D. Subsequent campaigns will further investigate these scenarios on both programs. In this presentation, we will introduce recent progress and outcomes from these collaborative activities, highlighting advances and future directions.