PLASMA DRIVEN SUPERPERMEATION AND ITS POSSIBLE APPLICATIONS TO ION SOURCES AND NEUTRAL BEAM INJECTORS

A metal-membrane of macroscopic thickness can, under certain condition s, become superpermeable to hydrogen particles whose energy (kinetic, internal, or chemical) exceeds 1 eV. Such a membrane can transfer the energetic hydrogen almost like an opening of the same area. Superperme able membranes can also compress the permeating gas by orders of magni tude and clean it from any impurities. Due to these characteristics su perpermeable membranes could be employed in ion sources and neutral be am injectors: (a) for pumping and recycling hydrogen from ion sources, (b) for pumping hydrogen gas from the extraction area and recycling t he gas into the ion source, (c) for pumping deuterium or hydrogen in t he plasma neutralizer of a negative ion based neutral beam injector. W e will describe the possible use of superpermeable membranes in these devices, the experiments which we effected demonstrating this new tech nique, and projects for its future use. (C) 1998 American Institute of Physics.