Discussion of energy recovery on negative ion based neutral beam injectors and conceptual study of a purely electrostatic energy recovery system
An Energy Recovery System for negative ion based neutral beam injectors is discussed. In this purely electrostatic system the residual positive and negative ions are electrostatically separated, the electrostatic deflector is made of baffles (in order to reduce the gas pressure and trap the secondary electrons by an electric field), the positive ions are dumped at full energy and the negative ions are decelerated and collected on a composite electrode, acting as an electrostatic trap for secondary electrons. This system might be cheap and simple to operate, since no additional power supplies would be required. Narrow beams, with a width of around 0.1 m, are preferred for electrostatic deflection, for differential pumping and also with respect to current density limitations. Calculations show that current density limits should appear only at the level of 150 A./m2 of decelerated ions, in the case of 1 MeV D(-) beams with 0.1 m width. The unneutralised D(-) ion current may be recovered with an efficiency of about 90% provided the problem of recycled gas evacuation is carefully handled.
Bibliographic Reference: Report: EUR-CEA-FC-1392 EN (1990) 35 pp.
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199011264 / Last updated on: 1994-12-01
Original language: en
Available languages: en