The performance capabilities of the PINK, a plasma generator with a thermionic cathode mounted in the cavity of a hollow cathode, depending for its operation on a non-self-sustained low-pressure gas discharge have been investigated. It has been shown that when a single-filament tungsten cathode 2 mm in diameter is used and the peak filament current is equal to or higher than 100 A, the self-magnetic field of the filament current significantly affects the discharge current and voltage waveforms. This effect is due to changes in the time and space distributions of the emission current density from the hot cathode. When the electron mean free path is close to the characteristic dimensions of the thermionic cathode, the synthesized plasma density distribution is nonuniform and the cathode is etched nonuniformly. The cathode lifetime in this case is 8–12 h. Using a cathode consisting of several parallel-connected tungsten filaments ∼0.8 mm in diameter moderates the effect of the self-magnetic field of the filament current and nearly doubles the cathode lifetime. The use of this type of cathode together with a discharge igniting electrode reduces the minimum operating pressure in the plasma generator to about one third of that required for the generator operation with a single-filament cathode (to 0.04 Pa).
Generation of plasma in a pulsed non-self-sustained glow discharge with a hollow cathode with an area of ≥2 m2 at gas pressures of 0.4–1 Pa was studied experimentally. At an auxiliary arc-discharge current of 100 A and a main discharge voltage of 240 V, a pulse-periodic glow discharge with a current amplitude of 370 A, pulse duration of 340 μs, and repetition rate of 1 kHz was obtained. The possibility of creating a uniform gas-discharge plasma with a density of up to 1012 cm−3 and an electron temperature of 1 eV in a volume of >0.2 m3 was demonstrated. Such plasma can be efficiently used to treat material surfaces and generate pulsed ion beams with a current density of up to 15 mA/cm2.
1 May 2015 in Russian Journal of General Chemistry
In the paper the principles of generation of low temperature capacitively coupled in a vacuum chamber of a large size with the use of original low-pressure arc discharges are considered. The designs...
The paper considers a plasma source based on a low-pressure (≈1 Pa) high-current (up to 450 A) non-self-sustained glow discharge with a hollow cathode of volume ≈0.2 m3. The research data are presented on the ignition stability of the discharge, on its main parameters, and on the radial and azimuthal plasma inhomogeneity varying with the pressure, discharge voltage and current, and anode-to-cathode area ratio at a plasma density of ≈1018 m−3 and an ionization degree of ≈1%. The beam plasma formations synthesized in such an electrode system of non-self-sustained glow discharge with a hollow cathode are interesting both from a scientific and technical point of view.
Self-sustained glow discharge with a hollow cathode was studied at high discharge currents (up to 30 A). Using a grid analyzer placed on the side flange of the hollow cathode, the ion and electron...