NUKLEONIKA 2006, 51(1):85-92

Researches on the plasma jet source and injection of hydrogen plasma and neutral gas jets into the Globus-M spherical tokamak are presented. A novel source of dense plasma with high directed velocity is designed, constructed and investigated. This is a double stage system consisting of an intense source utilizing titanium-hydride grains for neutral gas production and a conventional pulsed coaxial accelerator. Optimization of the accelerator parameters, so as to achieve a maximum possible flow velocity with a limited discharge current and a reasonable length of the coaxial electrodes is performed. The calculations are compared with the experiment. A test bed is used for investigation of the intense plasma jet generated by a plasma gun. Plasma jet parameters, among them pressure distribution across the jet, flow velocity, plasma density etc., were measured. Plasma jets with densities of up to 10²² m^-3, total numbers of accelerated particles (1-5) ´ 10¹⁹, and flow velocities of 50-100 km/s were successfully injected into the plasma column of the Globus-M tokamak. Interferometric and Thomson scattering measurements confirmed a deep jet penetration and a fast density rise (<0.5 ms) at all spatial points up to the radius r » 0.3a. The injection did not result in plasma degradation.