Injection of neutral particles from negative ions


Negative ion Neutral Beam Injection (NNBI) is a heating system for fusion plasmas.

How does it work?

Charged particles are accelerated and subsequently neutralized to allow the particle beam to pass the confinement field produced by the magnets that hold the plasma, a charged gas, inside the reactor. The beam of neutral particles produced by the NBI transfers kinetic energy to the hydrogen isotopes magnetically confined in the reactor, heating the temperature to the point where the fusion reactions are able to start. In the experimental ITER fusion reactor the temperature to be reached is 150 million degrees Centigrade.

Two prototypes were designed to develop the ITER heating system in Padua at Consorzio RFX:

  • SPIDER, the most powerful negative ion source in the world
  • MITICA, the full scale ITER neutral injector