P. M. Shchanin

A plasma generator based on nonself-sustained low-pressure glow discharge with a large-volume hollow cathode

The results of studying nonself-sustained glow discharges in an electrode system with a hollow cathode with a volume of 0.25 m3 are presented. A high-current (up to 35 A) nonself-sustained glow discharge at low pressures (0.3–1.0 Pa) is initiated and sustained with the help of an auxiliary cold-hollow-cathode arc discharge. When the current of a nonself-sustained glow discharge increases from 2 to 35 A, its burning voltage changes from 40 to 300 V. These values are much lower than the voltage for a self-sustained glow discharge in the same electrode system. At a discharge current of 30 A, the electron concentration at the center of the hollow cathode is ne ∼ 1010–1011 cm−3 and the electron temperature is Te ≈ 2 eV. The discharge considered can be used in the system for modification of materials and products.

Emission properties of a plasma cathode based on a glow discharge for generating nanosecond electron beams

The emission properties of a plasma cathode based on a nanosecond pulsed glow discharge with currents of up to 200A at a pressure of 5×10−2 Pa are studied experimentally. Stable ignition and burning of the discharge are ensured if the current in the auxiliary pulsed discharge is 25–30% of that in the main discharge and its pulse duration exceeds that of the main discharge by more than an order of magnitude. Emission current pulses from the cathode with amplitudes of up to 140A fully reproduce the discharge current and are determined by the transparency of the grid anode.

Low-threshold gas lasers pumped by plasma-cathode accelerators

The lasing on the electronic transitions of xenon and neon is studied. It is demonstrated that plasma-cathode accelerators serve as effective sources for the pumping of low-threshold lasers (W < 100 W/cm3). The laser energy in xenon at the wavelength λ = 1.73 μm is 5 J at an efficiency of 2%, and the laser energy in neon at the wavelengths λ = 585.3 nm is 0.5 J at an efficiency of 0.3%. The repetitively pulsed mode of the xenon and neon lasers carried out at a repetition rate of 50 Hz. The radiation energy of a wide-aperture laser with an active volume of 600 l is 100 (0) J for a wavelength of 1.73 (2.03) μm at an efficiency of 2% (1%).

An arc generator of a broad plasma stream

The design and basic parameters of an arc plasma generator based on a combined cathode are described. The cathode consists of a hot tungsten filament located in the hollow cathode. A plasma stream with a cross section of 150×10 cm2 and a density of ∼1010 cm−3 at a pressure of 0.1–1 Pa is generated at a discharge current of up to 60 A without a cathode spot. The plasma generator can be utilized for final cleaning and activation of surfaces of materials and articles before depositing functional coatings on them and in plasma-assisted deposition by using either vacuum arc or magnetron discharges.

Arcing and breakdown in near-electrode plasma

In this paper we shall discuss the peculiarities of the arc discharge in large interelectrode gaps and the breakdown of the near-electrode plasma sheath depending on the surface condition.

Electron-beam-pumped broad-aperture lasers

The results of an experimental study of the laser action on XeCl*, KrF*, and N2 molecules and by the atomic transitions of xenon and neon are presented. Laser radiation energies of 110, 90, 3, 100, 50, and 0.5 J have been obtained at (lambda) equals 308, 249, 358, 1730, 2030, and 585 nm, respectively. The experiments were carried out on two accelerators producing radially convergent electron beams, that pumped laser chambers 20 mm in diameter with a beam current of FWHM duration 0.3, 30, and 100 microsecond(s) .