2024 – Radiation front stability and staged divertor validation: Sensitivity of detachment front to leg length, PSOL and shaping

Radiation front stability and staged divertor validation: Sensitivity of detachment front to leg length, PSOL and shaping

2024 Research Campaign, Divertor Science and Innovation

Purpose of Experiment

This experiment will examine the impact of increasing the outer leg length on the radiation front stability during detachment. Understanding the compatibility of retaining high confinement scenarios with deep divertor dissipation required for any tokamak scenario operation. Deep detachment is likely required for future machines but is often coupled with confinement degradation through intense radiation within the confined plasma near the X-point. While some scenarios actively control this X-point radiator, this experiment seeks to see how to best avoid the radiation collapse toward the X-point by increasing the outer leg length over a range of injected powers that will control the upstream X-point temperature and parallel Te gradient.

Experimental Approach

Use nitrogen seeding in smaller volume plasmas with extended outer divertor leg. Scan injected power in seeded detached plasmas. Scan strike point location to vary total field gradient along the outer leg.

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