Fast ion beam–plasma interaction system

• Published in: Review of scientific instruments 1979-07, Vol.50 (7), p.862-866
• Main Authors: Breun, R. A., Ferron, J. R.
• Format: Article
• Language: English
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1135940

A device has been constructed for the study of the interaction between a fast ion beam and a target plasma of separately controllable parameters. The beam of either hydrogen or helium ions has an energy of 1–4 keV and a total current of 0.5–2 A. The beam energy and beam current can be varied separately. The ion source plasma is created by a pulsed (0.2–10‐ms pulse length) discharge in neutral gas at up to 3×10−3 Torr. The neutrals are pulsed into the source chamber, allowing the neutral pressure in the target region to remain less than 5×10−5 Torr at a 2‐Hz repetition rate. The creation of the source plasma can be described by a simple set of equations which predict optimum source design parameters. The target plasma is also produced by a pulsed discharge. Between the target and source chambers the beam is neutralized by electrons drawn from a set of hot filaments. Currently under study is an unstable wave in a field‐free plasma excited when the beam velocity is nearly equal to the target electron thermal velocity (v beam≈3.5×107 cm/s, T e =0.5 eV).