The effect of air pressure(12.5,25,50,and 100 kPa)on the gen eration of runaway electron beams in a non-uniform electric field when applying voltage pulses(~35 kV)with a rise time of?200 ns has been studied.The result...The effect of air pressure(12.5,25,50,and 100 kPa)on the gen eration of runaway electron beams in a non-uniform electric field when applying voltage pulses(~35 kV)with a rise time of?200 ns has been studied.The results show that the discharge has various stages:streamer,diffuse,and spark.Initially,a wide streamer develops in the gap and a diffuse discharge is formed.A spark is formed u 100 ns after the breakdown.The current pulse of a supershort avalanche electron beam(SAEB)was measured with a collector at various pressures of air.Experiments show that there are two modes of generation of run away electrons.At an air pressure of 25-100 kPa,a single SAEB current pulse with a full width at half-maximum(FWHM)of 120-140 ps is observed.At the air pressure of 12.5 kPa,two current pulses of the electron beam are observed.FWHM of the first and second current pulses are ul40ps and u300 ps,respectively.The current pulse amplitude of the second electron beam is higher than that of the first one,but the electron energy is less.展开更多
The paper presents research data on positive and negative coronas inatmospheric pressure air in a highly inhomogeneous electric field. Thedata show that irrespective of the polarity of pointed electrodes placed ina hi...The paper presents research data on positive and negative coronas inatmospheric pressure air in a highly inhomogeneous electric field. Thedata show that irrespective of the polarity of pointed electrodes placed ina high electric field (200 kV/cm), this type of discharge develops via ballstreamers even if the gap voltage rises slowly (0.2 kV/ms). The start voltageof first positive streamers, compared to negative ones, is higher andthe amplitude and the frequency of their current pulses are much lower:about two times and more than two orders of magnitude, respectively.The higher frequency of current pulses from negative streamers provideshigher average currents and larger luminous areas of negative coronascompared to positive ones. Positive and negative cylindrical streamersfrom a pointed to a plane electrode are detected and successive dischargetransitions at both polarities are identified.展开更多
The conditions for the formation of spark channels with a bead structure in an inhomogeneous electric field at different polarities of voltage pulses are studied.Voltage pulses with an amplitude of up to 150 kV and a ...The conditions for the formation of spark channels with a bead structure in an inhomogeneous electric field at different polarities of voltage pulses are studied.Voltage pulses with an amplitude of up to 150 kV and a rise time of≈1.5μs were applied across a 45-mm point-to-plane gap.Under these conditions,spark channels consisting of bright and dim regions(bead structure)were observed.It is shown that when current is limited,an increase in the rise time and the gap length does not affect the formation of the bead structure.It was found that an increase in the amplitude of voltage pulses leads to an increase in the length of beads.The appearance of the bead structure is more likely at negative polarity of the pointed electrode.The formation of spark channels was studied with a four-channel ICCD camera.展开更多
In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an in...In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an incident wave amplitude of up to 30 kV, FWHM of around 4 ns, and rise time of around 2.5 ns were applied to the gap in an inhomogeneous electric field. The ST3PS steel specimens exposed to this type of discharge revealed changes in their defect subsystem, suggesting that the runaway electron preionized diffuse discharge provides surface hardening of the steel.展开更多
Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure a...Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.展开更多
Diffuse and volume discharges are currently used widely in various fields.This work compares the properties of diffuse and volume discharges,as well as considers the conditions for their formation at high pressures.Th...Diffuse and volume discharges are currently used widely in various fields.This work compares the properties of diffuse and volume discharges,as well as considers the conditions for their formation at high pressures.The main attention is paid to a diffuse discharge(DD).It has been shown that the ignition of a diffuse discharges is preceded by the development of a wide streamers.In the case of a volume discharge,the streamers usually have a small diameter and an ionisation waves emerging from it passes into the spark leader with subsequent discharge constriction.There are images and emission spectra of diffuse discharges in air and nitrogen in the paper.It has been confirmed that a diffuse discharges initiated by a nanosecond voltage pulse in a point-to-plane gaps has a uniform effect on the surface of a flat electrode.It was found that thin tracks of luminous particles are observed against the background of the DD plasma glow.They are asso-ciated with sputtering of the pointed electrode material due to the large field enhance-ment on the macro-and microinhomogeneities.展开更多
The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device...The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device(ICCD)and a streak-camera were used.Electrical parameters were measured with high resolution(10 GHz).An original method of measuring a displacement current caused by a streamer was applied.As was expected,positive streamer branches in nitrogen at low voltages and/or elevated pressures while a large-diameter streamer is formed in air.However,at high voltages or negative polarity,the large-diameter streamer is formed both in nitrogen and air in the entire pressure range.It was found that runaway electrons(REs)are generated in the very first picoseconds of gas ionisation near the pointed cathode.It was assumed that REs can be generated near the pointed anode and produce bremsstrahlung radiation due to a sharply inhomogeneous distribution of electrical potential.It was found that in the final stage of negative streamer development in air and nitrogen,the gas between the streamer front and the opposite electrode is ionised almost simultaneously in the entire volume when the streamer diameter is almost equal to the interelectrode gap.展开更多
文摘The effect of air pressure(12.5,25,50,and 100 kPa)on the gen eration of runaway electron beams in a non-uniform electric field when applying voltage pulses(~35 kV)with a rise time of?200 ns has been studied.The results show that the discharge has various stages:streamer,diffuse,and spark.Initially,a wide streamer develops in the gap and a diffuse discharge is formed.A spark is formed u 100 ns after the breakdown.The current pulse of a supershort avalanche electron beam(SAEB)was measured with a collector at various pressures of air.Experiments show that there are two modes of generation of run away electrons.At an air pressure of 25-100 kPa,a single SAEB current pulse with a full width at half-maximum(FWHM)of 120-140 ps is observed.At the air pressure of 12.5 kPa,two current pulses of the electron beam are observed.FWHM of the first and second current pulses are ul40ps and u300 ps,respectively.The current pulse amplitude of the second electron beam is higher than that of the first one,but the electron energy is less.
文摘The paper presents research data on positive and negative coronas inatmospheric pressure air in a highly inhomogeneous electric field. Thedata show that irrespective of the polarity of pointed electrodes placed ina high electric field (200 kV/cm), this type of discharge develops via ballstreamers even if the gap voltage rises slowly (0.2 kV/ms). The start voltageof first positive streamers, compared to negative ones, is higher andthe amplitude and the frequency of their current pulses are much lower:about two times and more than two orders of magnitude, respectively.The higher frequency of current pulses from negative streamers provideshigher average currents and larger luminous areas of negative coronascompared to positive ones. Positive and negative cylindrical streamersfrom a pointed to a plane electrode are detected and successive dischargetransitions at both polarities are identified.
基金The work is performed in the framework of the State task for HCEI SB RAS,project#13.1.4.
文摘The conditions for the formation of spark channels with a bead structure in an inhomogeneous electric field at different polarities of voltage pulses are studied.Voltage pulses with an amplitude of up to 150 kV and a rise time of≈1.5μs were applied across a 45-mm point-to-plane gap.Under these conditions,spark channels consisting of bright and dim regions(bead structure)were observed.It is shown that when current is limited,an increase in the rise time and the gap length does not affect the formation of the bead structure.It was found that an increase in the amplitude of voltage pulses leads to an increase in the length of beads.The appearance of the bead structure is more likely at negative polarity of the pointed electrode.The formation of spark channels was studied with a four-channel ICCD camera.
文摘In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an incident wave amplitude of up to 30 kV, FWHM of around 4 ns, and rise time of around 2.5 ns were applied to the gap in an inhomogeneous electric field. The ST3PS steel specimens exposed to this type of discharge revealed changes in their defect subsystem, suggesting that the runaway electron preionized diffuse discharge provides surface hardening of the steel.
基金funded by the Ministry of Science and Higher Education of the Russian Federation within Agreement no.075-15-2021-1026 of November 15,2021.
文摘Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.
基金Ministry of Education and Science of the Russian Federation,Grant/Award Number:FWRM-2021-0014National Natural Science Foundation of China,Grant/Award Number:52261145695。
文摘Diffuse and volume discharges are currently used widely in various fields.This work compares the properties of diffuse and volume discharges,as well as considers the conditions for their formation at high pressures.The main attention is paid to a diffuse discharge(DD).It has been shown that the ignition of a diffuse discharges is preceded by the development of a wide streamers.In the case of a volume discharge,the streamers usually have a small diameter and an ionisation waves emerging from it passes into the spark leader with subsequent discharge constriction.There are images and emission spectra of diffuse discharges in air and nitrogen in the paper.It has been confirmed that a diffuse discharges initiated by a nanosecond voltage pulse in a point-to-plane gaps has a uniform effect on the surface of a flat electrode.It was found that thin tracks of luminous particles are observed against the background of the DD plasma glow.They are asso-ciated with sputtering of the pointed electrode material due to the large field enhance-ment on the macro-and microinhomogeneities.
基金National Key Research and Development Plan of China,Grant/Award Number:2021YFE0114700Ministry of Science and Higher Education of the Russian Federation,Grant/Award Number:075-15-2021-1026。
文摘The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device(ICCD)and a streak-camera were used.Electrical parameters were measured with high resolution(10 GHz).An original method of measuring a displacement current caused by a streamer was applied.As was expected,positive streamer branches in nitrogen at low voltages and/or elevated pressures while a large-diameter streamer is formed in air.However,at high voltages or negative polarity,the large-diameter streamer is formed both in nitrogen and air in the entire pressure range.It was found that runaway electrons(REs)are generated in the very first picoseconds of gas ionisation near the pointed cathode.It was assumed that REs can be generated near the pointed anode and produce bremsstrahlung radiation due to a sharply inhomogeneous distribution of electrical potential.It was found that in the final stage of negative streamer development in air and nitrogen,the gas between the streamer front and the opposite electrode is ionised almost simultaneously in the entire volume when the streamer diameter is almost equal to the interelectrode gap.
