Single-null-divertor.

A magnetic field configuration in a tokamak that allows the removal of impurities from the plasma in the lower part of the vacuum vessel by a divertor. By installing an additional poloidal magnetic coil on the bottom of the chamber, the magnetic lines of the last closed magnetic surface, called the separatrix, are crossed. The particles located at the separatrix are then guided beyond the crossing point, called the X-point, and from there on to the divertor. Underneath are vacuum pumps that take care of their removal from the plasma. In this way, the purity of the plasma is maintained.