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A device inside the vacuum vessel of a tokamak or stellarator that allows the continuous removal of impurities and helium from the fusion plasma. In a tokamak, there is usually one divertor at the bottom of the vacuum vessel (single-null configuration), but there may also be a second divertor at the top of the vacuum vessel (double-null configuration). Stellarators use an island divertor configuration, where magnetic islands are created at the edges of the plasma to allow impurities to be drawn towards the divertor plates. The divertor consists of plates made of very resistant materials with a high melting point (e.g. tungsten), as it is subjected to a much higher heat load than the rest of the vacuum vessel. Behind the plates are vacuum pumps that remove impurities. These are fed to the divertor by a magnetic field, shaped in cross-section like an elongated letter D with two “legs” that point precisely at the divertor plates.