Electron cyclotron resonance negative ion source

Production and control of electron cyclotron resonance (ECR) plasmas for ne gative ion sources have been studied. A new production method using permane nt magnets is proposed as one possibility for a large diameter high density uniform microwave plasma. The microwave power is launched by an annular sl ot antenna into the circumference of a chamber with a line-cusp or a ring-c usp type permanent magnets, where magnetic field can be applied in a local region and plasmas can be efficiently produced if the ECR condition is sati sfied. In this article, we report the structure of the ECR negative ion sou rce, the characteristics of the ECR plasmas, and comparison of the ECR plas mas with dc discharge plasmas from the viewpoint of a negative ion source f or neutral beam injector. H- volume production is confirmed in ECR plasmas although the effect of the magnetic filter for controlling plasma parameter s is different from that in dc discharge plasmas. (C) 2000 American Institu te of Physics. [S0034-6748(00)63102-7].