DEVELOPMENT OF H- AND D- ION SOURCES FOR PLASMA-HEATING

The large size of future, and possibly present day, tokamaks requires high neutral atom beam energies for current drive and heating. These injectors must also have a high electrical efficiency and this can be achieved using negative ion sources to create the beam. These large tokamaks, such as ITER or NET require a neutral beam power of around 50-100 MW at beam energy of 1 MeV of D0. This power is achieved by operating several sources in parallel, each one of which would extract a 28-A beam of D- ions of which 57% are converted to D0 in a gas cell neutralizer and can be transmitted to the torus. The injector for one port consists of four units, each of which is a fully independent unit. This article describes the details of the injector unit which is based on volume plasma sources of D- ions.