M. Lomaev | Tomsk State University (original) (raw)
Papers by M. Lomaev
Journal of Physics: Conference Series, 2008
Since 2003, an interest to investigation of e-beams generation in gas-filled diodes with high pre... more Since 2003, an interest to investigation of e-beams generation in gas-filled diodes with high pressures has been rekindled. In 2005, the advanced recording methods of electron beams and the use of digital oscilloscopes with wide bandwidth provided the measurements
Surfaces, 2024
Many scientific teams are currently studying the effects of plasma generated by nanosecond diffus... more Many scientific teams are currently studying the effects of plasma generated by nanosecond diffuse discharges on the surfaces of various materials in order to modify their properties. To achieve this, uniform plasma is required to act on the target being treated, which is often an electrode in a discharge system. Previously, the surface treatment uniformity of flat electrodes during a nanosecond discharge in a point-to-plane gap was studied by applying a carbon black layer, and a discharge mode was identified in which there was no erosion on the treated electrode. In this study, it was established that during a nanosecond discharge in air at atmospheric pressure in a non-uniform electric field,
carbon black deposited on the surface of a flat anode can ignite. The conditions and dynamics of carbon black ignition during the nanosecond discharge were determined. It was observed that the carbon black is ignited on the surface and continues to combust in the gap in the form of flame plumes for tens of milliseconds. It was also found that the combustion of carbon black can occur in both diffuse and spark discharges.
2018 20th International Symposium on High-Current Electronics (ISHCE), 2018
The emission spectra of different diamond samples excited by subnanosecond runaway electron beams... more The emission spectra of different diamond samples excited by subnanosecond runaway electron beams (REBs) with an electron energy of up to 200 keV have been experimentally studied. Four diamond samples grown by different methods and one natural diamond were used. REBs were produced by two accelerators based on a gas diode. The effect of the REB parameters as well as the diamond growth method on the emission spectra have been established. The radiation of various bands was observed.
2008 IEEE 35th International Conference on Plasma Science, 2008
ABSTRACT Summary form only given as follows. This paper reports on the pulse sources of spontaneo... more ABSTRACT Summary form only given as follows. This paper reports on the pulse sources of spontaneous UV and VUV radiation with high power, developed on the basis of volume pulse high-current discharges at high specific power of excitation (~100 MW/cm3) and pressures (up to 12 atm) in inert gases and their mixtures with halides. In the experiments, we used a set-up, forming a volume discharge without preionization. The set-up included a primary capacitive store, a pulse transformer, a coaxial line with a wave impedance of 10 or 20 Omega, a peaking spark gap, a gas diode, and a system for working gas mixture preparation and evacuation. First developed set-up presents by itself a source with emitting area of a radiator of greater than 20 cm2. The duration of a generator voltage pulse at a matched load is ~50 ns. The discharge shape was like a truncated cone with a base on the anode. The diameter of the emitting area of the near-cathode discharge plasma was ~6 cm, and ~8 cm near the grid anode; the interelectrode distance was 4.5 cm. The maximum radiating power on Xe2* dimmers at 140-200 nm to the full spatial angle was obtained at the pressure of Xe of 760 torr amounting ~8 MW. The radiation pulse FWHM was of no greater than ~100 ns, and the power density at excitation pulse duration of tens ns was ~2times104 W/cm2. The investigations exhibit that the Xe dimmers radiating power obtained by using the above-mentioned set-up increases with the growth of pressure of Xe until the value of 1 atm. The characteristics of radiant emittance of the volume high-current discharge plasma in inert gases at pressure greater than 1 atm was investigated by using a RADAN-220 pulser with the voltage pulse amplitude of 220 kV and pulse duration at a matched load of ~2 ns. The width of the pulse leading edge was ~0.5 ns. A flat anode and a cathode with a small-curvature radius provided the electric field gain in the near-cathode region. Interelec- - trode distance ranged as 4-16 mm. The most homogeneous discharge was obtained in the high-pressure He. For the first time, a subnanosecond electron beam of fast electrons was registered in He at the pressure of 12 atm. The beam current pulse duration at a half-height was no greater than 100 ps. At Xe pressures greater than 3-4 atm there were observed the discharge contraction channels. At the same time, the high-power radiation of Xe dimmer band was recorded at the pressures less than 12 atm. Though having as a bit decreased radiant energy, the radiating power increased with the growth of Xe pressure, comprising ~1 MW/cm3 at the pressure of 12 atm. In this case, the radiation pulse FWHM was eight ns.
Atomic and Molecular Pulsed Lasers VII, 2007
Generation time of supeshort avalanche electron beam (SAEB) with respect to discharge current fro... more Generation time of supeshort avalanche electron beam (SAEB) with respect to discharge current front has been established at nanosecond breakdown of air under atmospheric pressure in nonuniform electric field and volume discharge formation. It has been shown that SAEB current maximum is registered at the leading edge of the discharge current before the peak of discharge current of the gas diode capacitance, advancing such peak by ∼100 ps. The amplitude of bias current above 1 kA has been registered. The amplitude of bias current is increased due to capacitor charging, formed by the dense plasma, expanding from the cathode, and the flat metallic anode.
Nanomaterials, 2022
Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from th... more Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from the Earth’s surface attract considerable attention from researchers from all over the world. A significant number of (nano)particles coming from outer space burn up at these altitudes. As a result, vapors of various substances, including metals, are formed at different altitudes. This paper deals with the influence of vapors and particles released from metal electrodes on the color and shape of pulse-periodic discharge in air, nitrogen, argon, and hydrogen. It presents the results of experimental studies. The discharge was implemented under an inhomogeneous electric field and was accompanied by the generation of runaway electrons and the formation of mini-jets. It was established that regardless of the voltage pulse polarity, the electrode material significantly affects the color of spherical- and cylindrical-shaped mini jets formed when bright spots appear on electrodes. Similar jets are ...
IEEE Transactions on Plasma Science, 2010
... 38, NO. 4, APRIL 2010 741 Supershort Avalanche Electron Beams and X-rays in Atmospheric-Press... more ... 38, NO. 4, APRIL 2010 741 Supershort Avalanche Electron Beams and X-rays in Atmospheric-Pressure Air Victor F. Tarasenko, Evgenii Kh. Baksht, Alexander G. Burachenko, Igor D. Kostyrya, Mikhail I. Lomaev, and Dmitri V. Rybka ...
IEEE Transactions on Plasma Science, 2010
ABSTRACT
Technical Physics Letters, 2010
Runaway electron beam parameters and current-voltage characteristics of discharge in helium, hydr... more Runaway electron beam parameters and current-voltage characteristics of discharge in helium, hydrogen, and nitrogen at pressures in the range of several Torr to several hundred Torr have been studied. It is found that the maximum amplitudes of supershort avalanche electron beams (SAEBs) with a pulse full width at half maximum (FWHM) of ~100 ps are achieved in helium, hydrogen, and nitrogen at a pressure of 60, ~30, and ~10 Torr, respectively. It is shown that, as the gas pressure is increased in the indicated range, the breakdown voltage of the gas filled gap decreases, which leads to a decrease in the SAEB current ampli tude. At pressures of helium within 20-60 Torr, hydrogen within 10-30 Torr, and nitrogen within 3-10 Torr, the regime of the runaway electron beam generation changes and, by varying the pressure in the gas filled diode in the indicated intervals, it is possible to smoothly control the current pulse duration (FWHM) from 100 to ~500 ps, while the beam current amplitude increases by a factor of 1.5-3.
Physical Review Accelerators and Beams, 2016
Matter and Radiation at Extremes, 2017
High Voltage, 2017
This study deals with experimental and theoretical simulation data showing the influence of elect... more This study deals with experimental and theoretical simulation data showing the influence of electrode spacing and gas pressure on parameters of a supershort avalanche electron beam (SAEB) formed in SF6 and nitrogen at different rise times and amplitudes of a voltage pulse. Using GIN-55-01, VPG-30-200, and SLEP-150M pulsers, tubular cathodes with a diameter of 6 mm, as well as gaps of 3, 5, and 8 mm, it was shown that the SAEB current amplitude can both increase and decrease depending on an electrode spacing, a waveform and a rise time of the voltage pulse, as well as the pressure of SF6 and nitrogen. It was established as a result of simulation that maximal voltage across the gap during the process of generation of runaway electrons and the thickness of an anode foil have a major effect on the SAEB current pulse amplitude.
Technical Physics, 2007
The dynamics of discharge formation in a two-barrier XeBr excilamp is studied. It is found that t... more The dynamics of discharge formation in a two-barrier XeBr excilamp is studied. It is found that the maximal voltage drop across the lamp and the breakdown voltage of the discharge gap vary with time nonmonotonically upon switching on. This indicates that the discharge goes through several stages before it reaches the steady state. An increase in the lamp capacitance prior to secondary breakdown at the contracted stage of the discharge suggests the formation of a region with a high residual conductivity in the gas-discharge space after primary discharge. It is shown that the use of a keep-alive discharge prevents the arc stage when the excilamp is switched on.
2009 IEEE International Conference on Plasma Science - Abstracts, 2009
ABSTRACT
SPIE Proceedings, 2009
A windowless excilamp, a xenon excilamp with the high specific power of radiation and an air-cool... more A windowless excilamp, a xenon excilamp with the high specific power of radiation and an air-cooling KrCl excilamp for microelectronic applications are described. The excilamps have the total radiating surface up to 900 cm 2. The VUV specific average power of a windowless excilamp is 3 mW/cm 2 and 5 mW/cm 2 for argon (λ ~ 126 nm) and krypton (λ ~146 nm) accordingly at distance of 3 cm from the emitting surface. The xenon excilamp (λ ~ 172 nm) has 50 W of the average total VUV power and 120 mW/cm 2 of density and the large-aperture air-cooling KrCl (λ ~222 nm) excilamp has 30 mW/cm 2 of the radiation density and the radiation homogeneity 12 %.
Instruments and Experimental Techniques, 2007
The design and test results of the collector assembly intended for recording electron beams of su... more The design and test results of the collector assembly intended for recording electron beams of subnanosecond duration are presented. The collector assembly features a passband of up to 12 GHz and is capable of transmitting slightly-distorted voltage pulses with a half-height duration longer than ~50 ps. The collector assembly was used to detect current pulses of a subnanosecond-duration electron beam generated in a gas-filled diode.
Journal of Applied Physics, 2011
This paper presents the results of the experimental studies of a pulsed discharge in atmospheric ... more This paper presents the results of the experimental studies of a pulsed discharge in atmospheric pressure air in an inhomogeneous electric field for various parameters of voltage pulses. It is shown that in a wide range of experimental conditions, including those with a positive electrode of small curvature radius, a diffuse discharge is ignited in the gap. In particular, a diffuse discharge is ignited at a pulse repetition frequency of 1 kHz and a voltage pulse amplitude of 25and25 and 25and40 kV across a high-resistance load. With voltage pulses of $ 220 kV in amplitude and low repetition frequencies, an extended ($70 cm) diffuse discharge is observed in gaps of 13-40 mm. It is confirmed that the diffuse form of discharges in an inhomogeneous electric field at increased pressures is attributed to the generation of runaway electrons and x-rays. V
Journal of Physics: Conference Series, 2008
Since 2003, an interest to investigation of e-beams generation in gas-filled diodes with high pre... more Since 2003, an interest to investigation of e-beams generation in gas-filled diodes with high pressures has been rekindled. In 2005, the advanced recording methods of electron beams and the use of digital oscilloscopes with wide bandwidth provided the measurements
Surfaces, 2024
Many scientific teams are currently studying the effects of plasma generated by nanosecond diffus... more Many scientific teams are currently studying the effects of plasma generated by nanosecond diffuse discharges on the surfaces of various materials in order to modify their properties. To achieve this, uniform plasma is required to act on the target being treated, which is often an electrode in a discharge system. Previously, the surface treatment uniformity of flat electrodes during a nanosecond discharge in a point-to-plane gap was studied by applying a carbon black layer, and a discharge mode was identified in which there was no erosion on the treated electrode. In this study, it was established that during a nanosecond discharge in air at atmospheric pressure in a non-uniform electric field,
carbon black deposited on the surface of a flat anode can ignite. The conditions and dynamics of carbon black ignition during the nanosecond discharge were determined. It was observed that the carbon black is ignited on the surface and continues to combust in the gap in the form of flame plumes for tens of milliseconds. It was also found that the combustion of carbon black can occur in both diffuse and spark discharges.
2018 20th International Symposium on High-Current Electronics (ISHCE), 2018
The emission spectra of different diamond samples excited by subnanosecond runaway electron beams... more The emission spectra of different diamond samples excited by subnanosecond runaway electron beams (REBs) with an electron energy of up to 200 keV have been experimentally studied. Four diamond samples grown by different methods and one natural diamond were used. REBs were produced by two accelerators based on a gas diode. The effect of the REB parameters as well as the diamond growth method on the emission spectra have been established. The radiation of various bands was observed.
2008 IEEE 35th International Conference on Plasma Science, 2008
ABSTRACT Summary form only given as follows. This paper reports on the pulse sources of spontaneo... more ABSTRACT Summary form only given as follows. This paper reports on the pulse sources of spontaneous UV and VUV radiation with high power, developed on the basis of volume pulse high-current discharges at high specific power of excitation (~100 MW/cm3) and pressures (up to 12 atm) in inert gases and their mixtures with halides. In the experiments, we used a set-up, forming a volume discharge without preionization. The set-up included a primary capacitive store, a pulse transformer, a coaxial line with a wave impedance of 10 or 20 Omega, a peaking spark gap, a gas diode, and a system for working gas mixture preparation and evacuation. First developed set-up presents by itself a source with emitting area of a radiator of greater than 20 cm2. The duration of a generator voltage pulse at a matched load is ~50 ns. The discharge shape was like a truncated cone with a base on the anode. The diameter of the emitting area of the near-cathode discharge plasma was ~6 cm, and ~8 cm near the grid anode; the interelectrode distance was 4.5 cm. The maximum radiating power on Xe2* dimmers at 140-200 nm to the full spatial angle was obtained at the pressure of Xe of 760 torr amounting ~8 MW. The radiation pulse FWHM was of no greater than ~100 ns, and the power density at excitation pulse duration of tens ns was ~2times104 W/cm2. The investigations exhibit that the Xe dimmers radiating power obtained by using the above-mentioned set-up increases with the growth of pressure of Xe until the value of 1 atm. The characteristics of radiant emittance of the volume high-current discharge plasma in inert gases at pressure greater than 1 atm was investigated by using a RADAN-220 pulser with the voltage pulse amplitude of 220 kV and pulse duration at a matched load of ~2 ns. The width of the pulse leading edge was ~0.5 ns. A flat anode and a cathode with a small-curvature radius provided the electric field gain in the near-cathode region. Interelec- - trode distance ranged as 4-16 mm. The most homogeneous discharge was obtained in the high-pressure He. For the first time, a subnanosecond electron beam of fast electrons was registered in He at the pressure of 12 atm. The beam current pulse duration at a half-height was no greater than 100 ps. At Xe pressures greater than 3-4 atm there were observed the discharge contraction channels. At the same time, the high-power radiation of Xe dimmer band was recorded at the pressures less than 12 atm. Though having as a bit decreased radiant energy, the radiating power increased with the growth of Xe pressure, comprising ~1 MW/cm3 at the pressure of 12 atm. In this case, the radiation pulse FWHM was eight ns.
Atomic and Molecular Pulsed Lasers VII, 2007
Generation time of supeshort avalanche electron beam (SAEB) with respect to discharge current fro... more Generation time of supeshort avalanche electron beam (SAEB) with respect to discharge current front has been established at nanosecond breakdown of air under atmospheric pressure in nonuniform electric field and volume discharge formation. It has been shown that SAEB current maximum is registered at the leading edge of the discharge current before the peak of discharge current of the gas diode capacitance, advancing such peak by ∼100 ps. The amplitude of bias current above 1 kA has been registered. The amplitude of bias current is increased due to capacitor charging, formed by the dense plasma, expanding from the cathode, and the flat metallic anode.
Nanomaterials, 2022
Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from th... more Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from the Earth’s surface attract considerable attention from researchers from all over the world. A significant number of (nano)particles coming from outer space burn up at these altitudes. As a result, vapors of various substances, including metals, are formed at different altitudes. This paper deals with the influence of vapors and particles released from metal electrodes on the color and shape of pulse-periodic discharge in air, nitrogen, argon, and hydrogen. It presents the results of experimental studies. The discharge was implemented under an inhomogeneous electric field and was accompanied by the generation of runaway electrons and the formation of mini-jets. It was established that regardless of the voltage pulse polarity, the electrode material significantly affects the color of spherical- and cylindrical-shaped mini jets formed when bright spots appear on electrodes. Similar jets are ...
IEEE Transactions on Plasma Science, 2010
... 38, NO. 4, APRIL 2010 741 Supershort Avalanche Electron Beams and X-rays in Atmospheric-Press... more ... 38, NO. 4, APRIL 2010 741 Supershort Avalanche Electron Beams and X-rays in Atmospheric-Pressure Air Victor F. Tarasenko, Evgenii Kh. Baksht, Alexander G. Burachenko, Igor D. Kostyrya, Mikhail I. Lomaev, and Dmitri V. Rybka ...
IEEE Transactions on Plasma Science, 2010
ABSTRACT
Technical Physics Letters, 2010
Runaway electron beam parameters and current-voltage characteristics of discharge in helium, hydr... more Runaway electron beam parameters and current-voltage characteristics of discharge in helium, hydrogen, and nitrogen at pressures in the range of several Torr to several hundred Torr have been studied. It is found that the maximum amplitudes of supershort avalanche electron beams (SAEBs) with a pulse full width at half maximum (FWHM) of ~100 ps are achieved in helium, hydrogen, and nitrogen at a pressure of 60, ~30, and ~10 Torr, respectively. It is shown that, as the gas pressure is increased in the indicated range, the breakdown voltage of the gas filled gap decreases, which leads to a decrease in the SAEB current ampli tude. At pressures of helium within 20-60 Torr, hydrogen within 10-30 Torr, and nitrogen within 3-10 Torr, the regime of the runaway electron beam generation changes and, by varying the pressure in the gas filled diode in the indicated intervals, it is possible to smoothly control the current pulse duration (FWHM) from 100 to ~500 ps, while the beam current amplitude increases by a factor of 1.5-3.
Physical Review Accelerators and Beams, 2016
Matter and Radiation at Extremes, 2017
High Voltage, 2017
This study deals with experimental and theoretical simulation data showing the influence of elect... more This study deals with experimental and theoretical simulation data showing the influence of electrode spacing and gas pressure on parameters of a supershort avalanche electron beam (SAEB) formed in SF6 and nitrogen at different rise times and amplitudes of a voltage pulse. Using GIN-55-01, VPG-30-200, and SLEP-150M pulsers, tubular cathodes with a diameter of 6 mm, as well as gaps of 3, 5, and 8 mm, it was shown that the SAEB current amplitude can both increase and decrease depending on an electrode spacing, a waveform and a rise time of the voltage pulse, as well as the pressure of SF6 and nitrogen. It was established as a result of simulation that maximal voltage across the gap during the process of generation of runaway electrons and the thickness of an anode foil have a major effect on the SAEB current pulse amplitude.
Technical Physics, 2007
The dynamics of discharge formation in a two-barrier XeBr excilamp is studied. It is found that t... more The dynamics of discharge formation in a two-barrier XeBr excilamp is studied. It is found that the maximal voltage drop across the lamp and the breakdown voltage of the discharge gap vary with time nonmonotonically upon switching on. This indicates that the discharge goes through several stages before it reaches the steady state. An increase in the lamp capacitance prior to secondary breakdown at the contracted stage of the discharge suggests the formation of a region with a high residual conductivity in the gas-discharge space after primary discharge. It is shown that the use of a keep-alive discharge prevents the arc stage when the excilamp is switched on.
2009 IEEE International Conference on Plasma Science - Abstracts, 2009
ABSTRACT
SPIE Proceedings, 2009
A windowless excilamp, a xenon excilamp with the high specific power of radiation and an air-cool... more A windowless excilamp, a xenon excilamp with the high specific power of radiation and an air-cooling KrCl excilamp for microelectronic applications are described. The excilamps have the total radiating surface up to 900 cm 2. The VUV specific average power of a windowless excilamp is 3 mW/cm 2 and 5 mW/cm 2 for argon (λ ~ 126 nm) and krypton (λ ~146 nm) accordingly at distance of 3 cm from the emitting surface. The xenon excilamp (λ ~ 172 nm) has 50 W of the average total VUV power and 120 mW/cm 2 of density and the large-aperture air-cooling KrCl (λ ~222 nm) excilamp has 30 mW/cm 2 of the radiation density and the radiation homogeneity 12 %.
Instruments and Experimental Techniques, 2007
The design and test results of the collector assembly intended for recording electron beams of su... more The design and test results of the collector assembly intended for recording electron beams of subnanosecond duration are presented. The collector assembly features a passband of up to 12 GHz and is capable of transmitting slightly-distorted voltage pulses with a half-height duration longer than ~50 ps. The collector assembly was used to detect current pulses of a subnanosecond-duration electron beam generated in a gas-filled diode.
Journal of Applied Physics, 2011
This paper presents the results of the experimental studies of a pulsed discharge in atmospheric ... more This paper presents the results of the experimental studies of a pulsed discharge in atmospheric pressure air in an inhomogeneous electric field for various parameters of voltage pulses. It is shown that in a wide range of experimental conditions, including those with a positive electrode of small curvature radius, a diffuse discharge is ignited in the gap. In particular, a diffuse discharge is ignited at a pulse repetition frequency of 1 kHz and a voltage pulse amplitude of 25and25 and 25and40 kV across a high-resistance load. With voltage pulses of $ 220 kV in amplitude and low repetition frequencies, an extended ($70 cm) diffuse discharge is observed in gaps of 13-40 mm. It is confirmed that the diffuse form of discharges in an inhomogeneous electric field at increased pressures is attributed to the generation of runaway electrons and x-rays. V