Cybele: A large size ion source of modular construction for the Tore-Supra diagnostic injector

Abstract

A 70keV 40A hydrogen beam injector has been developed at Cadarache for plasma diagnostic purpose (MSE and charge exchange) on the Tore-Supra tokamak. This injector routinely operates with a large size ion source (the so-called Pagoda ion source) which does not completely fulfill all the requirements necessary for the present experiments. As a consequence, the development of a new ion source (called Cybele) has been underway whose objectives are a high accelerated proton fraction (>80%), current density of 160mA∕cm2, and uniform illumination of the extraction surface (within ±5%) for long shot operation (from 1to100s). The main particularity of Cybele is the modular construction; it is composed of five, vertically juxtaposed modules, geometrically arranged to fit the curved extraction surface of the injector, which ensures the geometrical focusing of the neutral beam 7m downstream, at the entrance to the tokamak. Cybele will be tested first for positive-ion production for the Tore-Supra injector and later ...