High-density plasma production for neutralizing negative ion beam

Abstract

An electron cyclotron resonance (ECR) plasma production method using electron cyclotron wave is presented. This method is not subjected to any cutoff-density scaling, and is capable of generating dense plasmas far beyond the critical density of an ordinary wave. It has been demonstrated that a plasma density more than 1013 cm−3 (argon) is obtained with a low frequency (2.45 GHz) and low power (11 kW) microwave. The experimental results and the application to plasma neutralizer are described. The experimental verification of superpermeability of Nb membrane in a plasma environment is in progress to develop a plasma neutralizer with Nb-membrane wall. The design parameters of Nb-membrane pump are presented.