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A four-channel scheme of an experiment aimed at obtaining optical and X-ray spectra and images of radiation generated in optical breakdown plasma channels in Bessel beams formed by focusing electromagnetic radiation by means of axicon-type conoid focusing systems is developed.

A powerful pulsed dc converter has been developed for charging battery assemblies on board of hybrid and electric aircraft, which enables full battery capacity charging in cruise mode of the aircraft. This 10-kW modular design converter can operate in a buck–boost mode in a voltage range of 130–300 V with a current limit of 70 A at an output voltage of 150 V. The efficiency of the created converter is ~96–99%, depending on the power consumed in the load. The proposed modular design and multiphase control circuit can be used to create converters with different capacities and high efficiency.

We simulated and experimentally studied the process of the interaction of a barrier discharge with natural gas in a plasma-chemical reactor with a coaxial electrode configuration. The obtained dependences of the hydrocarbon concentration on the average specific energy supplied to the discharge are linear. An explanation of the observed results is proposed.

The efficiency of power transistors in composite high-voltage switches is analyzed. A high-voltage pulse generator capable of generating a periodic voltage signal with a rectangular shape, an amplitude as high as 16 kV, a current greater than 40 A, and a repetition rate of up to 100 kHz has been developed.

The conversion of hydrocarbons during the treatment of a methane–ethane mixture with a barrier discharge in an electrophysical setup was experimentally studied. The theoretical estimation of plasmakinetic processes occurring in a discharge was performed for the developed plasmachemical reactor using the ZDPlasKin algorithm. Experimental results were in agreement with theoretical estimates.

The parameters of a number of high-voltage solid-state switches are studied. Based on the analysis of their work, a high-voltage pulse source with a size of 105 × 260 × 180 mm is assembled to supply cold plasma jets operating at the ac voltage of 220 V, 50 Hz.

The spatiotemporal dynamics of a nanosecond atmospheric-pressure dielectric barrier discharge in 1- to 3-mm-long air gaps was studied experimentally. By using a segmented electrode, data on the time evolution of the discharge in different regions of the discharge gap were obtained. The uniformity of the discharge over the cross section is estimated by analyzing the spatial distribution of its glow.

Rocket and balloon measurement data on atomic-oxygen (λ 63 µm) emission in the upper atmosphere are presented. The data from the longest (1989–2003) period of measurements of the atomic-oxygen (λ 63 µm) emission intensity obtained by spectral instruments on sounding balloons at an altitude of 38 km at midlatitudes have been systematized and analyzed. Regularities in diurnal and seasonal variations in the intensity of this emission, as well as in its relation with solar activity, have been revealed.

A semiconductor rectangular-pulse generator with smoothly controlled output parameters for powering a barrier discharge was developed and investigated. The generator allows the formation of voltage pulses with the smoothly regulated amplitude (0–16 kV) and duration (600 ns–1 ms) across the discharge gap. The pulse rise and fall times can be varied from 40 ns to 1 μs. The generator pulse repetition rate can be smoothly varied from 0 to 50 kHz. The generator can operate in the manual-triggering mode and in the mode of pulse trains with an effective frequency of up to 500 kHz. The generator is intended for initiating and investigating a barrier discharge in millimeter-wide air gaps at the atmospheric pressure.

The results of experimental studies of the process of switching a composite semiconductor switch, which consists of series-connected insulated-gate bipolar transistors with artificially nonuniformly distributed operating parameters are presented.

A compact source of low-temperature plasma for biological and medical applications is proposed, which operates at kilohertz frequencies in the regime of flash-corona discharge with an energy of 0.1 mJ/pulse. The plasma source was tested in application to plasma pretreatment of green salad seeds. Plasma-treated seeds exhibited increased (by about 25%) germination speed as compared to that in the untreated control.

In the given paper, recent results on the development of physical mechanisms and theoretical models of direct laser surface nanostructuring are reviewed. Attention is paid to nanosecond lasers, as they are cheaper and simpler in use than pico- and femtosecond lasers, which is important for the development of further applications. The formation of so-called 'nonresonant' structures, whose period is not directly related to the laser radiation wavelength, is considered. Nanostructuring mechanisms for a number of surface modification processes with and without melting are studied. Corresponding experimental illustrations of nanostructures are given for various materials – polymers, metals, ceramics, and diamond films.

Possibility of forming quasi-periodic structures of micron and submicron dimensions on a surface of zirconium dioxide under the action of eximer ArF laser radiation is shown experimentally and theoretically.

A method that controls solid-state insulated gate bipolar transistor (IGBT) switches, allowing one to increase their ON-state duration time from fractions of microseconds up to milliseconds, is proposed. It is shown that the ON-state duration of the switches is limited only by their overheating. The modular design of the high-voltage solid-state switch with a 16-kV operating voltage and 60-A pulse current is experimentally implemented.

The degree of homogeneity of a diffuse dielectric barrier discharge in millimeter air gaps under atmospheric pressure has been analyzed. This analysis is based on the glow-brightness distribution in the discharge gap cross section with allowance for a cylindrical electrode shape. It is shown that the degree of discharge homogeneity depends on both the repetition frequency of voltage pulses applied to the discharge gap and the barrier material.

An experimental technique of passive optical diagnostics of plasma is proposed. The equipment complex designed for its practical implementation is described. The technique is based on the simultaneous recording of self-radiation spectra and images of plasma with the subsequent analysis of the recorded data. This technique can be applied for diagnosing plasmas generated by various means, such as a gas discharge, laser radiation, a shock wave, an explosion, and so on.

The possibility of submicron structure formation on the surface of ZrO2 under excimer nanosecond ArF laser (λ = 193 nm) irradiation is shown. A model for the surface nanostructure formation in the course of laser infusion of solids is proposed.

The generator of sawtooth wave with voltage of 1 kV and frequency of 300 kHz intended to power the pumping region of the electrohydrodynamic flow systems is presented in the work. By varying the storage inductor the range of the operating frequencies can be expanded from dozens of kilohertz to 1 megahertz. The generator also can operate at the resonance frequency, creating a quasi-sinusoidal signal form. The three-phase scheme are implemented. The phase shift can be regulated by the driving generator.

The results of experimental investigations of transient processes and static voltage distribution consideration in composite solid-state switch consisted of series connected insulated gate bipolar transistors (IGBT) under conditions of artificial operational factors distortion are presented. The stability of the series connected transistors assembly with no special balancing circuits or adaptive gate control was shown. In transient, reliable operation of the assembly supported by effect of voltage self-restriction across lagged devices, and due to tolerance of IGBT to short-circuit mode which bounded by the junction power dissipation efficiency. In voltage blocking mode the single transistor overheating does not upsets the balance of the series transistors assembly as a whole, because helps to negative temperature coefficient of IGBT the tendency to self-stabilizing is appear as consequence of dissipation power redistribution. The last require to presence of some operational voltage amplitude margin for a single IGBT in the switch design.

The formation of an electrohydrodynamic flow in atmospheric air by using a high-frequency barrier discharge distributed over the dielectric surface is investigated. The influence of variations in parameters of a fully solid-state pulse generator (with a peak voltage of 0–12 kV, a tunable repetition rate of 10–25 kHz, and a pulse duration of 7 μs) on the current of plasma ion emitter and velocity characteristics of airflow is considered.

The possibility of forming nanostructures on the surface of solids by the action of nanosecond laser pulses causing the material to melt has been shown both theoretically and experimentally. The dependence that the characteristic sizes of the surface nanostructures have on the energy of the laser beam and duration is established. Experimental results on samples of various materials obtained by direct laser nano-structuring using an ArF laser and images of titanium samples with surface nanostructures are presented.

A mobile spectrophotometric complex, intended for simultaneous laboratory and field measurements of the photometric and spectral parameters of radiation of different sources has been designed and produced. Examples of its use for detecting silvery clouds occurring at altitudes of about 82 km, the Polaris aurora, and nightglow of the upper atmosphere in different spectral ranges are given. Images of a solid-fuel rocket launch at the Plesetsk site, taken with the complex at the Zvenigorod station of Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), are presented.

The possibility of increasing the pulse duration of an ArF laser (wavelength 193 nm) by using an artificial forming line with nonlinear chokes is studied. An ArF laser (maximum pulse energy 15 mJ, pulse duration 18 ns, pulse repetition rate 1 KHz) with an all-solid-state pump generator is described.

A 193-nm electric-discharge ArF laser pumped by an all-solid-state generator based on a semiconductor switch and a system of magnetic compression of high-voltage pulses is studied. The laser emits 18-ns, 15 mJ pulses at a pulse repetition rate of 1 kHz.

In recent years, nanostructures in solids have begun to receive more attention from researchers as important objects having very promising applications in various fields of science and technology. Ordered and disordered ensembles of nanoparticles represent new artificial materials with a broad range of applications due to their unique properties. The nanostructured surfaces improve the electrical, thermal, and electron-emission properties of materials and lead to better compatibility of tissues with implants used in orthopedics and dentistry. They also find application in selective nanocatalysis, microelectronics, nanophotonics, spectroscopy, and high-power optics; ensure superhigh data recording density; and are used in developing light-emitting silicon-base devices. This implies a need for developing the physical foundations of new effective methods for the formation of two- and three-dimensional structures with characteristic sizes less than one micrometer both at the surface and in the bulk of solids and for studying the mechanisms of nanostructure formation, which can be of various natures. In this study, the possibility of forming nanostructures at solid surfaces by laser pulses leading to the melting of the material surface is evaluated. The action of a laser pulse with a certain energy density and duration on a solid surface can lead to the melting of the surface layer. Let us consider the process of its solidification due to subsequent heat removal in the depth of the solid phase. In this case, the liquid turns out to be in the supercooled state and a considerable temperature difference across the liquid‐solid interface is established. Depending on the degree of supercooling, the subsequent nucleation of the crystal phase can have either a fluctuational [1] or a spontaneous [2] character (Fig. 1). The variation of the thermodynamic potential during the formation of a new phase center (nucleus) consisting of n atoms can be described as follows

A generator designed to excite a copper vapor laser is described. A high-voltage switch used in the generator circuit is based on ten IGBT transistors connected in series and operates jointly with two sections of magnetic pulse compression. A Kulon LT-10Cu sealed-off and self-heated gas-discharge tube with an average consumed power of 1.4 kW is used as an active element. The maximum power emitted by the active element is 13 W, at which the amplitude of the current flowing through this element is 180 A, the pulse duration at the base is 100 ns, and the pulse repetition rate is 17 kHz.

The paper describes the mechanism for formationof periodic nanostructures on the surface of solidsunder the action of intense laser radiation. Themodel based on a nonlinear relaxation oftemperature-induced stresses. The solid deformedby laser radiation is considered in a form of threesimultaneously coexisting phases. The system ofequations, which describes these phases, is reducedto the generalized Ginzburg–Landau equation thathas a periodic solution. For estimation thecalculation of the step of the periodic structurearising on the silicon surface under the action of alaser pulse is done.

High voltage switch unit on a base of isolated gate bipolar transistors (IGBT) with operating voltage of 4.5 kV and capability of pulse width control is developed and investigated. The start-stop circuit of IGBT gates control lets the switch to be open for near unlimited periods of time up to be continually open at constant nanosecond delay time.

The simple theoretical model of heating side walls by laser plasma in the laser drilling of high aspect ratio microvias in metals and semiconductors is proposed. According to this model the recommendations are given on how to avoid the undesirable effect of melting side walls by laser plasma, strongly deteriorating microdrilling quality. The obtained results constitute a physical basis for the development of clean laser microdrilling. Particular estimations are given for the laser drilling of silicon wafers.

A complex of instruments implementing a new optical method of plasma diagnostics in electrophysical setups equipped with plasmatrons is described. The proposed method is based on the simultaneous monitoring of the intrinsic emission spectra and the images of plasma, followed by the joint analysis of these data. An analysis of the information gained using the new instrumentation complex provides a basis for the solution of various practical problems, including optimization of the working regimes of plasmachemical reactors and determination of the spatial arrangement of plasmatrons in newly designed systems.

The results of theoretical investigations of heat and mass transfer processes in structures with open pores are presented. The results of calculations of the thermal and thermal-strain characteristics of laser mirrors utilizing powder and metal-fiber structures are also presented. These were made to optimize the design of power optics components. The proposed method of predicting the characteristics of laser reflectors utilizing porous materials can be used to determine the optimal type of structure and the parameters needed to ensure dissipation of the unavoidable heat fluxes with permissible distortions of the mirror surface.

An analysis is made of the thermoelastic action of high-power pulse-periodic laser radiation on the surface of a solid. The analysis is made using relationships, similar to Duhamel integrals, between the characteristics of the thermally stressed state on exposure to cw and arbitrarily time-varying laser radiation. Calculations are made of the dependences of the maximum laser radiation intensities causing impermissible elastic distortions of the surface, plastic flow of the material resulting in residual stresses, fatigue failure and melting of the surface layer.

An investigation was made of the properties of electronic I?III and I?IV intermetallic compounds as potential materials for coating of reflection elements to be used in power optics. It was found that the use of intermetallic compounds reduced considerably the scattering losses. The maximum unevenness of polished optical surfaces was 4 nm.

A system of stability parameters of optical components is introduced for cw and pulse-periodic laser systems. It is shown that there are many phenomena that govern the damage threshold of an optical surface irradiated with high-power pulse-periodic laser radiation. It is shown that in the case of components for power optics systems with an optical damage threshold amounting to a few hundreds of kilowatts per square centimeter the mechanisms of brittle and fatigue damage of the optical surfaces become important in the case of pulse-periodic illumination.

An investigation is made of the feasibility of using phase diffraction gratings as laser beam couplers for monitoring the main radiation parameters.

The simple theoretical model of laser plasma heating side walls in laser drilling high aspect ratio microvias in metals and semiconductors is proposed. On this basis the recommendations are given how to avoid the undesirable effect of laser plasma melting side walls, strongly deteriorating microdrilling quality. Obtained results constitute a physical foundation for development of optimized laser drilling and cutting. Particular estimations are given for laser drilling silicon wafers.The simple theoretical model of laser plasma heating side walls in laser drilling high aspect ratio microvias in metals and semiconductors is proposed. On this basis the recommendations are given how to avoid the undesirable effect of laser plasma melting side walls, strongly deteriorating microdrilling quality. Obtained results constitute a physical foundation for development of optimized laser drilling and cutting. Particular estimations are given for laser drilling silicon wafers.

The present paper describes an all-solid-state high voltage nanosecond pulse generator for pumping a copper vapor laser. The main feature of this device is using a high voltage switch composed of a stack of insulated gate bipolar transistors (IGBT), what makes it compacter and more cost effective than traditional systems based on thyratrons and vacuum tubes. A fast transformer circuit provides highly synchronous on/off control of the IGBT stack. Two-stage magnetic pulse compressor is used to enhance the system efficiency.The developed laser pumping system generates current pulses with amplitude of 230 A and rise time of 30 ns at pulse repetition rate of 15 kHz. Average laser output power of 13 W was obtained under these pumping conditions.

In the given paper recent results of authors on development of physical mechanisms and theoretical models of direct laser surface nanostructuring are reviewed. The attention is paid to nanosecond lasers, as they are cheaper and simpler in use compared to pico-, and femtosecond lasers, which is important for the development of further applications. The formation of so-called “non-resonant” structures, whose period is not directly related to laser radiation wavelength, is considered. Nanostructuring mechanisms for a number of surface modification processes with melting and without melting are studied. Corresponding experimental illustrations of nanostructures are given for various materials – polymers, metals, ceramics and diamond film.In the given paper recent results of authors on development of physical mechanisms and theoretical models of direct laser surface nanostructuring are reviewed. The attention is paid to nanosecond lasers, as they are cheaper and simpler in use compared to pico-, and femtosecond lasers, which is important for the development of further applications. The formation of so-called “non-resonant” structures, whose period is not directly related to laser radiation wavelength, is considered. Nanostructuring mechanisms for a number of surface modification processes with melting and without melting are studied. Corresponding experimental illustrations of nanostructures are given for various materials – polymers, metals, ceramics and diamond film.

A theoretical proposal is made and an experimental demonstration is reported of the desirability of using structures with open pores in the construction of cooled laser mirrors with a separating layer a few microns thick. The aim is to increase the optical damage threshold of the mirror surfaces. It is reported that the thermal deformation of a water-cooled mirror at the center of the illuminated zone ~50 mm in diameter is ~λ /30, where λ =10.6 μ for a maximum steady-state heat flux of ~500 W/cm2. The maximum rate of heat removal per unit surface area is about 2.5 kW/cm2.