2023 – High power, maximum q_par detachment

High power, maximum q_par detachment

2023 Research Campaign, Divertor Science and Innovation

Purpose of Experiment

The wall of a tokamak divertor will be subject to high power and heat fluxes in a future reactor. If the peak flux is too high, it risks damage to the wall material. Past experiments in existing machines have predicted a high heat flux and narrow heat profile in reactors, but more recent experiments indicate that new effects seen at higher pressure might change how the peaks scale, easing the heat-flux challenge. Understanding how the plasma parameter profiles in and near the divertor change with changing inputs like plasma current, magnetic field, and heating power is essential for designing a reactor.

Experimental Approach

Data from this experiment will test whether the peak heat flux continues to increase strongly with increasing pressure, or whether it begins to saturate. This will be tested at both a low and high plasma current, to help understand what physical processes effect the saturation. The experiment will consist of scans of plasma density—from low to high density—at two values of plasma current, which controls the heat flux width. We will scan heating power to vary the divertor pressure and see how the peak values change with pressure. We intend to push the plasma current and heating power to the highest possible values, both to make the divertor more reactor-relevant and to continue to push DIII-D in preparation or future heating upgrades.

See more details, including project leads, at U.S. Department of Energy, Office of Scientific and Technical Information (OSTI).

Share your thoughts on replacement of DIII-D's graphite wall with this form and on June 12-13 at a virtual community workshop!