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Featured researches published by I V Kochetov.
Journal of Physics D | 2007
A. A. Ionin; I V Kochetov; Anatoly P. Napartovich; Nikolay N. Yuryshev
An overview is presented of experimental and theoretical research in the field of physics and engineering of singlet delta oxygen (SDO) production in low-temperature plasma of various electric discharges. Attention is paid mainly to the SDO production with SDO yield adequate for the development of an electric discharge oxygen–iodine laser (DOIL). The review comprises a historical sketch describing the main experimental results on SDO physics in low-temperature plasma obtained since the first detection of SDO in electric discharge in the 1950s and the first attempt to launch a DOIL in the 1970s up to the mid-1980s when several research groups started their activity aimed at DOIL development, stimulated by success in the development of a chemical oxygen–iodine laser (COIL). A detailed analysis of theoretical and experimental research on SDO production in electric discharge from the mid-1980s to the present, when the first DOIL has been launched, is given. Different kinetic models of oxygen low-temperature plasma are compared with the model developed by the authors. The latter comprises electron kinetics based on the accompanying solution of the electron Boltzmann equation, plasma chemistry including reactions of excited molecules and numerous ion–molecular reactions, thermal energy balance and electric circuit equation. The experimental part of the overview is focused on the experimental methods of SDO detection including experiments on the measurements of the Einstein coefficient for SDO transition and experimental procedures of SDO production in self-sustained and non-self-sustained discharges and analysis of different plasma-chemical processes occurring in oxygen low-temperature plasma which brings limitation to the maximum SDO yield and to the lifetime of the SDO in an electric discharge and its afterglow. Quite recently obtained results on gain and output characteristics of DOIL and some projects aimed at the development of high-power DOIL are discussed.
Journal of Physics D | 2003
A. A. Ionin; Yu. M. Klimachev; A. A. Kotkov; I V Kochetov; Anatoly P. Napartovich; L. V. Seleznev; D. V. Sinitsyn; Gordon D. Hager
The possibility of obtaining a high specific input energy in an electron-beam sustained discharge ignited in oxygen gas mixtures O2 :A r :C O (or H2) at the total gas pressures of 10–100 Torr was experimentally demonstrated. The specific input energy per molecular component exceeded ∼ 6k J l −1 atm −1 (150 kJ mol −1 ) as a small amount of carbon monoxide was added into a gas mixture of oxygen and argon. It was theoretically demonstrated that one might expect to obtain a singlet delta oxygen yield of 25% exceeding its threshold value needed for an oxygen–iodine laser operation at room temperature, when maintaining a non-self-sustained discharge in oxygen gas mixtures with molecular additives CO, H2 or D2. The efficiency of singlet delta oxygen production can be as high as 40%.
Plasma Physics Reports | 2003
Nikolai P. Vagin; A. A. Ionin; Yu. M. Klimachev; I V Kochetov; Anatoly P. Napartovich; D. V. Sinitsyn; Nikolai N Yuryshev
Currently, there is no experimental data on the plasma balance in gas mixtures with a high content of singlet delta oxygen O2(1Δg). These data can be obtained by studying the parameters of an electric discharge in singlet oxygen produced by a chemical generator. The O2(1Δg) molecules significantly change the kinetics of electrons and negative ions in plasma. Hence, the discharge conditions at low and high. O2(1Δg) concentrations are very different. Here, the parameters of the positive column of a glow discharge in a gas flow from a chemical singlet-oxygen generator are studied. It is experimentally shown that, at an O2(1Δg) concentration of 50% and at pressures of 1.5 and 2 torr, the electric field required to sustain the discharge is considerably lower than in the case when all of the oxygen molecules are in the ground state. A theoretical model of the glow discharge is proposed whose predictions are in good agreement with the experimental data.
Journal of Physics D | 2009
I V Kochetov; Anatoly P. Napartovich; Nikolay Vagin; Nikolay N. Yuryshev
The pulsed chemical oxygen–iodine laser (COIL) development is aimed at many new applications. Pulsed electric discharge is most effective in turning COIL operation into the pulse mode by instant production of iodine atoms. A numerical model is developed for simulations of the pulsed COIL initiated by an electric discharge. The model comprises a system of kinetic equations for neutral and charged species, electric circuit equation, gas thermal balance equation and the photon balance equation. Reaction rate coefficients for processes involving electrons are found by solving the electron Boltzmann equation, which is re-calculated in a course of computations when plasma parameters changed. The processes accounted for in the Boltzmann equation include excitation and ionization of atoms and molecules, dissociation of molecules, electron attachment processes, electron–ion recombination, electron–electron collisions, second-kind collisions and stepwise excitation of molecules. The last processes are particularly important because of a high singlet oxygen concentration in gas flow from the singlet oxygen chemical generator. Results of numerical simulations are compared with experimental laser pulse waveforms. It is concluded that there is satisfactory agreement between theory and the experiment. The prevailing mechanism of iodine atom formation from the CF3I donor in a very complex kinetic system of the COIL medium under pulse discharge conditions, based on their detailed numerical modelling and by comparing these results both with experimental results of other authors and their own experiments, is established. The dominant iodine atom production mechanism for conditions under study is the electron-impact dissociation of CF3I molecules. It was proved that in the conditions of the experiment the secondary chemical reactions with O atoms play an insignificant role.
Journal of Physics D | 2009
A. A. Ionin; Yu. M. Klimachev; A. Yu. Kozlov; A. A. Kotkov; I V Kochetov; Anatoly P. Napartovich; Oleg A. Rulev; L. V. Seleznev; D. V. Sinitsyn; Nikolay Vagin; Nikolay N. Yuryshev
The influence of nitrogen oxides NO and NO2 on the specific input energy (SIE) and the time behaviour of singlet delta oxygen (SDO) luminescence excited by a pulsed e-beam sustained discharge in oxygen were experimentally and theoretically studied. NO and NO2 addition into oxygen results in a small increase and decrease in the SIE, respectively, the latter being connected with a large energy of electron affinity to NO2. The addition of 0.1–0.3% nitrogen oxides was experimentally and theoretically demonstrated to result in a notable enhancement of the SDO lifetime, which is related to a decrease in the atomic oxygen concentration in afterglow. It was experimentally demonstrated that to get a high SDO concentration at the gas pressure 30–60u2009Torr for a time interval of less than ~0.5u2009s one needs to add not less than 0.2% nitrogen oxides into oxygen. The temperature dependence of the relaxation constant for SDO quenching by unexcited oxygen was estimated by using experimental data on the time behaviour of SDO luminescence.
Journal of Physics D | 2011
I V Kochetov; Anatoly P. Napartovich; Nikolay Vagin; Nikolay N. Yuryshev
A pulsed electric discharge is the most effective means to turn chemical oxygen–iodine laser (COIL) operation into the pulse mode by fast production of iodine atoms. Experimental studies and numerical simulations are performed on a pulsed COIL initiated by an electric discharge in a mixture CF3Iu2009:u2009N2u2009:u2009O2(3X)u2009:u2009O2(au20091Δg) flowing out of a chemical singlet oxygen generator. A transverse pulsed discharge is realized at various iodide pressures. The model comprises a system of kinetic equations for neutral and charged species, the electric circuit equation, the gas thermal balance equation and the photon balance equation. Reaction rate coefficients for processes involving electrons are repeatedly re-calculated by the electron Boltzmann equation solver when the plasma parameters are changed. The processes accounted for in the Boltzmann equation include direct and stepwise excitation and ionization of atoms and molecules, dissociation of molecules, electron attachment processes, electron–ion recombination, electron–electron collisions and second-kind collisions. The last processes are particularly important because of a high singlet oxygen concentration in gas flow from the singlet oxygen chemical generator. A conclusion is drawn about satisfactory agreement between the theory and the experiment.
Plasma Physics Reports | 2000
Nikolai P. Vagin; A. A. Deryugin; A. A. Ionin; Yu. M. Klimachev; I V Kochetov; Anatoly P. Napartovich; D. V. Sinitsin; Nikolai N Yuryshev
The breakdown of oxygen in a dc electric field is studied. A high concentration of oxygen molecules in the a1Δg excited state is obtained in a purely chemical reactor. A decrease in the breakdown voltage at degrees of excitation exceeding 50% is observed. The theoretical decrement in the breakdown voltage obtained by solving the Boltzmann equation is in good agreement with the experimental data.
XVII International Symposium on Gas Flow and Chemical Lasers and High Power Lasers | 2008
A. A. Ionin; Yu. M. Klimachev; A. A. Kotkov; A. Yu. Kozlov; I V Kochetov; Anatoly P. Napartovich; Oleg A. Rulev; L. V. Seleznev; D. V. Sinitsyn; Nikolay Vagin; Nikolay N. Yuryshev
Experimental and theoretical study of influence of nitrogen oxides NO and NO2 admixtures in oxygen containing gas mixture excited by pulsed electron-beam sustained discharge on input energy and time behavior of singlet delta oxygen (SDO) luminescence was carried out. Temperature dependence of the constant of SDO relaxation by unexcited molecular oxygen was estimated.
Quantum Electronics | 2017
Nikolai P. Vagin; I V Kochetov; Anatoly P. Napartovich; Nikolai N Yuryshev
Based on the measured absorption coefficient for the atomic iodine transition in the mixtures of iodides with helium we have determined the fractions of the excited atomic iodine produced by dissociation of CH3I, CF3I, i-C3F7I, C2F5I and C2H5I molecules in a self-sustained pulsed discharge. In the 1: (3 – 15) mixtures of iodides with helium at the pressure 133 – 400 Pa these fractions amount to 0.29 for CF3I and CH3I, 0.2 for i-C3F7I, and 0.31 for C2F5I and C2H5I. The accuracy of determining the excited iodine fraction is 10%. The numerical modelling is carried out for the mixtures containing CF3I. The calculated values of the excited iodine fraction for the mixture with CF3I agree well with the experimental data.
Proceedings of SPIE, the International Society for Optical Engineering | 2008
A. A. Ionin; Yu. M. Klimachev; A. Yu. Kozlov; A. A. Kotkov; I V Kochetov; Anatoly P. Napartovich; Oleg A. Rulev; L. V. Seleznev; D. V. Sinitsyn; Nikolay Vagin; Nikolay N. Yuryshev
Influence of nitrogen oxides NO and NO2 on specific input energy (SIE) and time behavior of singlet delta oxygen (SDO) luminescence excited by pulsed e-beam sustained discharge in oxygen was experimentally and theoretically studied. NO and NO2 addition into oxygen results in small increase and decrease of SIE, respectively, the latter being connected with large energy of electron affinity to NO2. The addition of 0.1-0.3% nitrogen oxides was experimentally and theoretically demonstrated to result in notable enhancement of SDO lifetime, which is related to a decrease of atomic oxygen concentration in afterglow. There was experimentally demonstrated that for getting high SDO concentration at gas pressure 30-60 Torr for the time interval less than ~0.5 s one needs to add not less than 0.2% nitrogen oxides into oxygen. Temperature dependence of relaxation constant for SDO quenching by unexcited oxygen was estimated by using experimental data on time behavior of SDO luminescence.