Volume produced H(-), D(-) ion source for proton accelerator and thermo-nuclear fusion research by sheet plasma (1)

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 to approx. 25 cm and length 30 cm is produced under a discharge current of 175 A, a H2 gas pressure of about 2.5 x 10 to the -3 power Torr and gas flow of (2.0 to approx. 2.5) Torr l/sec in a magnetic field of (60 to approx. 110) gauss. Thus, H(-) or D(-) ion current is extracted in a current density up to 19 mA/sq cm or 16 mA/sq cm which is uniform within 10% over a large area (above 250 sq cm) of the sheet plasma surface, and in an acceleration voltage up to 4.5 kV. Then, an electron current accelerated with H(-) or D(-) ions is reduced negligibly beyond a distance of 2 cm from the final acceleration electrode.