A source with ion extraction from the plasma volume

The physical basis of an effective new variant of ion source with extraction of ions from the plasma volume, operating in a longitudinal magnetic field developed at the Kurchatov Institute, is described. A thin layer with an electric field is produced in the plasma column of the source without violation of plasma quasineutrality, in order to transport all types of charged particles across the magnetic field toward the extraction slit. This allows high plasma flows to be transported toward the extraction slit with low potential difference ΔU across the layer, and the ion current density in the extracted ion beam can be increased by up to 10–15 times. The induced plasma flow also increases significantly the content of multicharged ions in the beam. A strong dependence of the ion beam current intensity on the potential across the layer provides a means for pulsed modulating or stabilizing the current intensity at the target by special programming or feedback in an inertia-free manner, without changes in the discharge conditions. The ion source operates with various species—gas or sputter materials. An ion current density of 1.5 A/cm 2 was measured in our experiments at ΔU=10 V . The source can be used for accelerators, in semiconductor technology, and for other applications.