Divertor

In magnetic confinement fusion, a divertor is a device which extracts heat and ash from fusion plasmas by averting direct contact between the confined plasma and the main chamber wall (plasma-wall interactions). A magnetic divertor typically involves creating a separatrix-bounded magnetic topology using special magnetic coils. Particles and heat diffusing outward from the main plasma are diverted and follow the 'open' magnetic field lines to strike dedicated plasma-facing components.

The magnetic divertor concept was first proposed by Lyman Spitzer in 1951 aiming to reduce the impurity levels in stellarators due to sputtering from main chamber walls. It is now recognized as an essential component for heat and particle exhaust in fusion plasmas, with majority of modern day fusion devices capable of establishing a diverted configuration. In tokamaks, high confinement mode plasmas are more readily achieved in diverted configurations.

Divertor physics and optimizing its design as a plasma-wall interface for a power plant is a major research topic in fusion energy.