Volume produced H−, D− ion source for proton accelerator and thermo‐nuclear fusion research by sheet plasma

In order to apply a sheet plasma type of volume produced H−, D− ion source to injection of proton accelerators and neutral beam injection of thermo‐nuclear fusion researches, a large sheet plasma of width 20–25 cm and length 30 cm is produced under a discharge current of 175A, a H2 or D2 gas pressure of about 2.5×10−3 Torr and gas flow of (2.0–2.5) Torr l/sec in a magnetic field of (60–110) Gauss.H− of D− ion current is extracted with a current density up to 19 mA/cm2 of 16 mA/cm2, which is uniform within 10% over a large area (over 250 cm2) of the sheet plasma surface, and at an acceleration voltage up to 4.5 kV.The electron current accelerated with the H− or D− ions is negligible beyond a distance of 2 cm from the final acceleration electrode.