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A high-pressure CO2 laser with a discharge initiated by a subnanosecond electron beam formed in the laser operating medium under pressure 5 atm. Radiation energy of 40 mJ in active volume of ~ 4 cm3 at radiation duration of 20 ns has been obtained. Laser operation at pulse repetition rate (p.r.r.) of up to 5 Hz has been demonstrated. Specific energy input of ~0,07 J/cm3. atm have been realized in laser operating gas mixture CO2:N2:He = 1:1:6 under pressure of 5 atm on the course of a pulsed non-sustained discharge with pre-ionization.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

It has been shown that a volume discharge is forming in a non-uniform electric field at a short voltage pulse rise and pulse nanosecond duration without preionization in different gases under pressures above atmospheric (helium 6 atm, nitrogen 3 atm).

It has been shown that the use of gas diodes with cathode electric field enhancement and voltage pulses having a short leading edge allow to form high-current subnanosecond electron beams. An electron beam appears at voltage pulse leading edge with duration at FWHM not more than 0.3 ns. On the beam current termination the discharge is usually continued in a quasi-stationary mode having a volume character. With a diode filled in with air under atmospheric pressure, beam current amplitude over 240 A at a pulse duration at FWHM of 0.2 ns and current density of 40 A/cm 2 was obtained. It has been also shown that at a smal l gas diode inductance the subnanosecond electron beams are formed in various gases in a wide pressure range (up to 6 atm in helium, and up to 4 atm in nitrogen). It has been established that with the new method an electron beam is formed due to critical field reached between an anode and plasma propagating from a cathode. Key words: e-beam, running electrons, gas diode, volume discharge

Atmosphere pressure CO2-laser with e-beam initiated disch arge formed in laser operating mixture has been created. Energy of radiation as 18 mJ in active volume of ~6 cm3 has been obtained. Laser operation at pulse repetition rate of up to 5 Hz was demonstrated. Specific energy input as ~0.1 J/cm3 was realized in gas mixture CO2:N2:He = 1:1:4 under atmosphere pressure in the process of a pulsed non-self-sustained discharge with ionized amplification. This method of discharge initiation is rather promising for creation of short-pulse high-pressure lasers.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The formation of a beam of runaway electrons in a diode filled with helium at a pressure from 0.1 to 760 Torr was studied under conditions of a pulsed (4 ns) high (200 kV) voltage applied to the discharge gap. The experimental data results indicate that the electron beam is generated either at a large strength of electric field, when the fraction of runaway electrons is large, or in the field of low strength, where intensive electron multiplication takes place. In the latter case, cathode plasma propagates to anode at high velocity, at that with electrical field distribution in gas diode area the critical value of E/p is reached either due to geometric quotient leading to formation of nanosecond and subnanosecond electron beams. The electron beams obtained in the helium-filled diode had the current amplitude of up to 200 A (corresponding to the current density above 20 A/cm2) at electron energy of ~130 keV.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper reports on experimental study of subnanosecond e-beam formed in air under atmospheric pressure. An electron beam with amplitude of ~ 170 A with duration at FWHM ~0.3 ns has been obtained. Based on beam temporal characteristics and discharge spatial characteristics, the critical fields were supposed to be reached at plasma approach to anode. Simultaneously, the sharp high-energy pulse of e-beam current is generated. Of critical importance is cathode type and plasma protrusions occurred on the cathode. It is shown that in order to get maximum e-beam in gas diode, the discharge in gas diode should be volume.

Properties of plasma produced in volume nanosecond high-pressure discharge and its formation conditions under elevated pressure in air, nitrogen, krypton, argon, neon and gas mixtures Ar-N2, Ar-Xe, CO2-N2-He in the gap with the cathode having small curvature radius have been investigated. Time-amplitude characteristics and radiation spectra of plasma in different gases in the range of 230-600 nm were defined. Lasing in the gas mixture Ar-Xe at active length of 1.5 cm has been achieved by excitation through volume nanosecond high-pressure discharge. Comparison of spectral radiation in nitrogen, krypton, argon, and neon under pumping of mentioned gases by volume discharge in non-uniform electric field, by nanosecond e-beam, and by volume pulsed discharge in the uniform electric field with high initial voltage was made. Lasing has also been obtained in the gas mixture CO2-N2-He under pumping by e-beam initiated discharge. The electron beam was formed in a gas diode filled the same gas mixture.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Investigation of the modes of thin metal and ceramic films (0,3-1 μm) removal from the glass and stainless steel substrate by IR and UV laser radiation has been performed. It is presented that the efficient film destruction and removal occurs due to laser induced thermal strength under laser fluxes of ~0.5 J/cm2 not sufficient for phase transformation.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Formation of microscopic size colored dots on titanium foil surface by pulsed IR-laser irradiation was studied. It was found that the dot on titanium surface changes its color from yellow to blue as the exposure is increased. According to our numerical calculation, the colored dot formation is accompanying with titanium surface melting and partial evaporation. At pulse-periodical irradiation mode it can result in foil break-through.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The interaction of pulsed periodical CO2-(λ~10.6 ´m), and Xe-(λ~1.73 μm) lasers radiation with surfaces of polymers has been studied. Correlation between parameters of surface erosion (area of crater and amount of evaporated material versus laser focus position and number of pulses) was investigated using teflon (polytetrafluoroethylene-PTFE) and vinypros (plasticized semi-transparent polyvinylchloride) sample. Monitoring of erosion track on surfaces was performed through optical microscopy. It has been shown that at pulsed periodical CO2-radiation interaction with teflon and vinypros the sputtering of polymers with formation of submicron-size particles occurs. Dependencies of particle sizes, form and sputtering velocity on laser pulse duration and target temperature have been obtained.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The complex of experimental installations for studying of laser radiation interaction with surface of metals has been established. At titanium surface irradiating depending on the accumulated laser radiation energy, the surface color might be changed from bright yellow to red and deep-blue colors. The presented results testify to the possibility to use the change of titanium surface color at heating by laser irradiation in the open air to obtain dot raster images. Presently, form the world data available on interaction of laser radiation with metal and dielectric surfaces and development of experimental diagnostics techniques by itself it is allowed to raise a reverse question, i.e., restoration of laser radiation energy spatial distribution through surface imprint. Using imprints, it is also possible to make an express diagnostics of multi-layer surface coatings. With this in mind, we have made the detailed morphology of imprint of the pulsed HF-laser interaction with carbon steel surface through atomic force microscope.