Helium ash exhaust with single-null poloidal divertor in doublet III

The helium ash exhaust function of a divertor has been experimentally demonstrated. Helium atoms accumulate in the divertor region, as the electron density of the main plasma increases. With a helium concentration of approx.1.6% of electron density in the main plasma, neutral helium pressure at the divertor region is as high as 1.0 x 10-4 Torr. This experiment indicates the possibility of helium ash exhaust in an α-particle--heated, diverted tokamak using practical-sized pumping ducts