[en] The results of all most known experiments on the electric conductivity of nonideal plasmas are analyzed. It is shown that the value of conductivity is limited by the plasma frequency

[en] The results of an experimental investigation of the electrical breakdown of air in a discharge gap 10 cm long at atmospheric pressure along the channel of a long laser spark are presented. It was found that the velocity of the breakdown depends on the delay time between the creation of the long laser spark and the application of a voltage pulse to it and equals (0.8-3) x 10⁷ m/sec. The maximum current flowing through the gap also depends on the delay time and equals 1.5-4.5 kA. The dependence of the velocity and current on the delay time are apparently determined by the hydrodynamic evolution of the channel of the long laser spark

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[en] The study of electrical discharges directed by a laser spark has been made necessary by the creation of new types of switches, plasma antennas, and lightning rods, channels for the transport of charged particle beams in inertial thermonuclear fusion devices, and also for modeling the processes in streak lightning. For the most part, previous studies have explored the feasibility of creating such discharges, depending on experimental conditions, and proposed possible mechanisms for the development of discharges, e.g., the stepwise nature of its propagation. A model was proposed in which the discharge front propagates as an ionization wave. This model was based on measurements of the electric potential along the trajectory of a directed discharge. To construct a model and obtain directed discharges with prescribed parameters, one must know the mechanisms of discharge development. In this work, the authors report the results of an electrooptical study of the origin and motion of luminous fronts of ionization waves in an electrical discharge during its initiation, both for a single breakdown site and for a long laser spark with a large number of laser breakdown sites. Results are presented of our study of the stability of a discharge for a current flow of long duration

[en] A longitudinal magnetic field affects the fast ionization-wave structure in a discharge tube surrounded by a metal screen. The field does not alter the wave speed, but the current amplitude is increased. This is explained from a theory for fast-wave propagation in a cylindrical guide containing an axial field. Numerical solutions have been obtained for the stationary nonlinear waves, which are compared with measurements. A theoretical study has been made on the ionization-wave features for large values of the Hall parameter

[en] A study has been made of the characteristics of a glow discharge after perturbation by a nanosecond pulse. There is a pulse in the plasma emission lasting some tens of microseconds. A model is proposed that explains in terms of an excess electron concentration, which reduces the electron temperature and thus reduces the emission intensity

[en] To investigate the effective lifetimes of levels and cross sections of inelastic collisions of excited atoms with atoms in the ground state at sufficiently high pressures (0.4--4.7 kPa), it is suggested to use a nanosecond discharge in weakly ionized plasma. The measured effective lifetimes of the helium 3¹D level are compared with the literature data on associative ionization cross sections and transfer of excitation. The need to take into account the boundedness of levels 3¹P and 3¹D is shown

[en] The basic methods of generation of non-Debye dense plasma and the main results concerning its thermodynamical properties, electrical conductivity and optical pecularities are reviewed. A sensible progress in the investigation of weakly non-ideal plasma properties (number of particles in the Debye sphere zeta approximately 1) is denoted. Attention is mainly concentrated on the particular features of strongly non-ideal plasma (zeta << 1). (author)

[en] The features of the relaxation of a quasi-steady glow discharge after extra excitation by a nanosecond high-voltage pulse are studied experimentally. It is shown that the plasma relaxation is characterized by the existence of a time interval with a low emission intensity--a glow pause. A kinetic model of the helium plasma relaxation is developed. It is shown that the nanosecond discharge that creates extra ionization and metastable atoms enables one to keep the electron temperature at a quasi-steady level within the range 0.05-0.5 eV for several hundred microseconds during the glow pause. The effect of the helium temperature on the glow pause features is investigated

[en] Experimental investigations of dust structures in dc low-pressure glow discharge at temperatures of liquid nitrogen (T = 77 K) and liquid helium (T = 4.2 K) are presented. Super dense dust structures with dust density np ∼ 108-109 cm-3 formed within striations of cryogenic discharges as well as boundary-free worm-like dust structure moved in discharge at 4.2 K were obtained