Preventing a Tokamak from Overheating

Good news!

"Now, on one of the key European tokamak experiments ... have demonstrated a new and potentially efficient way to shed excess heat ...

The EPFL team realized they could boost the useful, heat-removing radiation by reconfiguring the confinement field to include a second X-point along the divertor funnel. Experiments at the TCV vindicated this concept, which they call the X-point target radiator (XPTR). What’s more, conditions for filling the XPTR with plasma turned out to be easy to achieve and control. ..."

From the abstract:

"Fusion plasma regimes with a strongly radiating magnetic 𝑋 point are promising candidates to tackle the outstanding power exhaust challenge in reactor-scale devices.

In this Letter, we report on a new type of 𝑋-point radiator, the XPTR (𝑋-point target radiator), produced by a secondary 𝑋 point placed well away from the confined plasma. This XPTR features strongly facilitated detachment access and significantly reduced sensitivity of the radiative front position near the secondary 𝑋 point. Consistent with a reduced analytical model, the physical origin of 𝑋-point radiation is rooted in its magnetic geometry, irrespective of whether the field lines are closed or open. The results presented open up a class of novel power exhaust concepts where radiative edge cooling can be robustly avoided during divertor detachment."

Physics - Preventing a Tokamak from Overheating "Fusion reactor experiments in Switzerland have demonstrated a new way to remove unwanted heat from a magnetically confined plasma."

X Point Target Radiator Regime in Tokamak Divertor Plasmas (no public access)