On phenomena in ionized gases
Decay of radiation of the sliding surface discharge and the combined
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- 1. Experimental setup and measurements
- 2. Results and discussion
- Ball lightning as a key for the solution of an energy problem by means of muon-catalyzed fusion
- References
- Comparative study on atmospheric-pressure plasma nitriding processes with pulsed-arc jet and barrier discharge
- Characterization of carbon films by microwave-plasma assisted chemical
Decay of radiation of the sliding surface discharge and the combined volume discharge
A. Kuznetsov 1 , I. Mursenkova 1 , I. Znamenskaya 1
1 Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow,Russia The radiation decay of the sliding surface discharge and of the combined volume discharge with plasma electrodes lasting hundreds of nanoseconds in air have been studied experimentally by means of time resolved nanosecond ICCD imaging and streak diagnostics of the discharges development. Investigations were carried out at a voltage of 20-30 kV at air pressure of 2-160 torr. Analysis reveals the differences in the character of the radiation decay of two types of discharges. The radiation decay time of volume discharge decreases with increasing pressure at pressure of 10- 100 torr. The decay time of the diffuse channels of sliding surface discharge is almost constant at pressure below 60 torr and increases at higher pressures.
High efficiency contribution to gas heating during nanosecond discharge is used to control high- speed flow characteristics in aerodynamics [1-2]. In this work, the features of radiation of the sliding surface discharge [2] and the combined volume discharge [3] are investigated with nanosecond resolution using High-speed ICCD
cameras of spectral range 380-880 nm (BIFO Company). The experiments were conducted in the discharge chamber with rectangular channel [2, 3]. Sliding surface discharge of 30×100 mm 2 area consists of diffuse and bright channels moving over a dielectric surface [2]. Combined volume discharge occurs between two sliding surface discharges, which form two plasma electrodes at 24 mm distance between them. 20-30 kV voltage pulses initiated the discharges. The discharge current pulse had amplitude of ~1 kA and duration of ~200 ns. The radiation spectra were recorded using AVASpec- 2048FT spectrometer in the range 174-1100 nm.
The second positive system of molecular nitrogen (C→B) determines the main part of the spectra of the discharges. Volume discharge reveals the diffusive uniform radiation with duration of ~200 ns. Duration of diffuse part of sliding surface discharge close to 200 ns. The radiation of the bright channels lasts several times longer (Fig. 1) and increases with increasing pressure. We have determined the decay time of radiation by processing the dependence of radiation intensity on time for two types of discharges (Fig. 1). Decay times of the radiation of volume discharge and diffuse radiation of the sliding surface discharge are close when pressure less than 100 Tor and have the value of ~40 ns. The radiation decay time of volume discharge decreases weakly when the pressure is rising. The decay time of the diffuse channels of the surface sliding discharge remains nearly constant when pressure is lower than 60 torr but increases significantly at higher pressures. This can be due to kinetic processes that lead to a population of the C 3 П u state of the nitrogen molecule.
Fig. 1. Streak image of sliding surface discharge at pressure 76 torr (left); the decay time of the diffuse channels of surface sliding discharge (1) and the decay time of the volume discharge (2) (right). Voltage is 25 kV.
Russian Foundation for Basic
Research supported this study, project No. 14-08-00777.
[1] D. Bayoda, N. Benard, and E. Moreau. J. Appl. Phys. (2015) 118. [2] I.A. Znamenskaya, D.F. Latfullin, A.E. Lutsky, I.V. Mursenkova, Tech. Phys. Lett. 36 (2010) 795. [3] I. Mursenkova, I. Znamenskaya, I. Ostapenko. Proc. of 31 International Conference on Phenomena in Ionized Gases (2013) 75_1. 10
139 XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Ball lightning as a key for the solution of an energy problem by means of muon-catalyzed fusion
A.G. Oreshko P 1 P , U A.A. Oreshko UP 2 P , T.B. Mavlyudov P 1 P
P 1 P
2 P
Mendeleevo, Moscow region, Russia
The main aim of the work is to develop a method for solving the problem of energy by using muons that are obtained by reacting of a ball lightning with a dense medium. On basis of experi- ments on the interaction of a ball lightning with a dense medium it was shown that in this case there is a generation of muons and muon neutrino, i.e. cascade process is realized, which is similar to the process in extensive air showers. The usage of ball lightning as a source of muons for muon- catalyzed fusion in reactors will improve conditions of operation and allow carrying out the nuclear fusion reaction at a lower temperature without insoluble problems which are characteristic of tradi- tional methods of fusion.
As is known traditional methods of receiving of nuclear fusion reactions have a number of insoluble problems [1]. One of the main problems that have no solutions in the reactors with magnetic confine- ment is anomalous plasma transport on chamber walls. Anomalous transport of plasma is caused by an instability due to the charge separation and the formation of electrical domains – so-called domain instability [2]. Domain instability is a characteristic state of plasma in the presence of strong fields and high temperature. There is no methods in Nature for suppressing this instability. Therefore it is necessary to look for more simple and more efficient methods for successful solving the problem of nuclear fusion. The analysis shows that the energy problem can be solved on the basis of the muon-сatalyzed fusion. The concept of muonic catalytic fusion is one of most promising approaches to nuclear fusion. The only obstacle for muon-сatalyzed fusion
realization is the high cost of muons in existing devices for their obtaining. Existing giant sources of muons require considerable quantity of energy to produce muons. In the experiments it was established that the ball lightning has extremely high penetrating ability, i.e. phenomena of superpassability [3]. This phe- nomenon may be explained by multistage generation of particles due to interaction of high-energy protons of external shell of the ball lightning with dense medium [4]. An interaction of protons with atoms or molecules of dense medium causes appearance of neutral and charged pions. The decay of the pions is accompanied by appearance of either negative muons and muon antineutrinos or positive muons and muon neutrinos. The generation of muons at interaction of the ball lightning with dense medium makes it possible to use of them for nuclear fusion purposes. Only the cycle associated with the usage of negative muons represents the interest. The analysis shows that the cheapest source of muons can be a ball lightning that interacts with the dense low temperature deuterium-tritium plasma. An electric power of facility to produce the ball lightnings "Prometheus" including system of control is equal to 5.4 kW, and its square is 6 m 2 . An inter- esting application is a periodic injection of ball lightnings into the chamber of the reactor of nuclear fu-sion which was preliminary filled of plasma. The proposed method of nuclear fusion has a number of significant advantages compared to the existing me- thods. The method is based on real data obtained by the authors in the experiments on generation of ball lightnings. The suggested method of solution of the fusion problem requires an experimental validation. The cost of creating the demo version of nuclear fu- sion reactor based on muon catalysis is symbolic.
A physical model of the reactor was created. Experi- ments were performed in water steam. May be we should understand the expression P.L.Kapitza "Ball lightning is a small window in the great unknown world" as a hint to the effect that the ball lightning is a unique key to the solution of the problem of obtaining clean energy.
References [1] G.J.Linhart, Quo vadis fusion?
Nukleonika, 54 (4) (2009) 305-309. [2] A.G.Oreshko, Proc. 41 st EPS Conf. on Plasma Physics, Berlin (2014), P2.144. [3] A.G.Oreshko, Journ.of Plasma Physics, 71 (3) (2015) 18 p. [4] A.G.Oreshko, A.A.Oreshko, Proc. 43 th EPS
Conf. on Plasma Physics, Leuven (2016), P2.110 . Topic number: 18 140
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Negative ion mobility and ion-molecule reactions in O 2
with a trace amount of moisture
Y. Okuyama 1 P , K. Arai 2 , S. Suzuki P 2
, H. Itoh 2
P 1 P National Institute of Technology, Tomakomai College, Hokkaido, Japan
P
P Chiba Institute of Technology, Chiba, Japan
The mobility of negative ions was measured in O 2 while varying the H 2 O concentration using a high-pressure ion drift tube with a point-plane gap acts as a negative ion detector. The H 2 O concentration was monitored during the mobility measurement with a trace moisture analyser. Decreasing mobility were observed with increasing the H 2 O concentration between 15 to 17000 ppb as 2.39, 2.31, 2.21 and 2.15 cm 2 /V·s. The mobility 2.39 cm 2 /V·s is considered as O 4 ˉ, and then O 4 ˉ was converted to O 2 ˉ·(H
2 O), O
2 ˉ·(H
2 O) 2 and O 2 ˉ·(H 2 O) 3 by ion-molecule reactions. Thus, decreasing mobility could be interpreted as the variations of ion species by ion-molecule reactions which were reproduced by solving the continue equations using the modified rate coefficients.
1. Introduction We have been measured negative ion mobility in O 2 at high-pressures using a high-pressure ion drift tube with a point-plate gap acts as an ion detector [1, 2]. At such high-pressures, the negative ion mobility is strongly affected by impurities although the concentrations of impurities are lower than a few ppm. In this paper, we describe the results of ion mobility measurement and ion-molecule reactions in O 2 with a trace amount of moisture. 2. Experimental set up The measurement method used for negative ion mobility had already been described in previous papers [1, 2]. During the measurements, H 2 O concentrations were monitored by a trace moisture analyzer (HALO-H 2 O: Tiger Optics) whose principle is based on a cavity ring-down spectroscopy [3] using a light of which wave length is 1392.53 nm. 3. Results and discussions Figure 1 shows the obtained mobilities and the corresponding relative intensities of ions calculated using the rate coefficients in zero dimension. The mobility 2.39 cm 2 /V·s was observed in the range of H 2 O concentration between 15 to 450 ppb which is considered as O 4 ˉ. After that, the mobility is decreased to 2.31, 2.21 cm 2 /V·s considered as O 2 ˉ·(H 2 O) and O
2 ˉ·(H
2 O) 2 in the H 2 O concentration 450 to 4600, 4600 to 17000 ppb, respectively. The mobility 2.15 cm 2 /V·s considered as O 2 ˉ·(H
2 O) 3 is also observed at the range of H 2 O concentration between 12500 to 17000 ppb. We considered the sequential progress of negative ions in O 2 with a little amount of moisture as shown in fig. 2. O 2 ˉ having a mobility 2.17 cm 2 /V·s [4] was never observed in our experiment because measurements were carried out around atmospheric pressure. In fig. 1 (b), the rate coefficients k 1 , k 2 and
k 3 reported by others [5-8] were used for the calculation. In contrast, other rate coefficients k 4 , k 5
and k 6 were modified to fit in experiments because some of them were not sufficiently to convince us. The result is shown in fig.1 (b) as an example.
Acknowledgement This work was supported by JSPS KAKENHI GRANT Number 16K18065. 4. References [1] Y. Okuyama et al., J. Phys. D, 45, (2012) 195202 [2]
578−584 (in Japanese) [3]
H. Abe and K. Yamada, Sens. Actuators A, 165 (2011) 230-238 [4]
R. M. Snuggs et al., Phys. Rev. A, 3 (1971) 477 [5]
1870 -1883 (1966) [6]
L G McKnight and J Sawina, Phys. Rev. A, 4, 1043 (1971) [7]
J. D. Payzant and P. Kebarle, J. Chem. Phys, 56, 3482 - 3487 (1972) [8]
D. A. Parkes, Trans. Faraday Soc, 67, 711 (1971) ultrahigh-purity O 2 2 2 2 high-purity O 450 ppb 4600 ppb
ultrahigh-purity O added with H O 2.8
2.6 2.4
2.2 100
80 60 40 20 10 2 H O concentration (ppb) Re lat iv e i
nt en sit y of io ns (%
) 100
1000 10000
0 0 M ob ili
ty μ (c m /V
s) 2 Fig. 1 Observed mobilities and their relative ion intensities against H 2 O concentration. O 4 ˉ O 2 ˉ•(H 2 O) O 2 ˉ•(H
2 O) 2 O 2 ˉ•(H 2 O) 3
(a) (b) Fig. 2 Reactions of ions in O 2 with H 2 O.
k 1 k 3_1 k 2 k 4_1 k 4_2 k 2_2 k 5_1 k 5_2 k 6_1 k 6_2 141
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Comparative study on atmospheric-pressure plasma nitriding processes with pulsed-arc jet and barrier discharge R. Ichiki 1 , K. Kitamura 1 , A. Maeda 1 , R. Sannomiya 1 , K. Yamanouchi 1 , S. Chiba 1 , M. Kono 1
2 , S. Akamine 1 , S. Kanazawa 1
1 Faculty of Engineering, Oita University, Oita, Japan 2 Fukuoka Industrial Technology Center, Kitakyushu, Japan
We have demonstrated nitrogen atom diffusion into steel surface using the atmospheric-pressure the atmospheric-pressure pulsed-arc (PA) jet and the dielectric barrier discharge (DBD). The elementary processes occurring in the two kinds of atmospheric-pressure plasmas proved to differ considerably; that is, the PA jet nitriding involves NH radicals as key radicals, while NH is not essential in the DBD nitriding.
Plasma nitriding is one of the case hardening technologies for upgrading the mechanical properties of steel surface by nitrogen atom (N) diffusion. In industry, low-pressure plasmas are utilized for plasma nitriding. On the other hand, our group has developed atmospheric pressure plasma methods for nitriding to offer novel material processing to industry. For the present, we achieved nitriding with the pulsed-arc (PA) plasma jet [1] and the dielectric barrier discharge (DBD) [2]. In this paper, we discuss the chemical and physical differences of the two nitriding methods to understand the elementary process and technological potential of them.
The pulsed-arc is ignited inside the cylindrical electrode, where the pulsed voltage of 5 kV and several
s is applied to the inner electrode at 21 kpps. The operating gas is N 2 /H 2 mixture at the flow ratio of 99:1. The afterglow (jet plume) is sprayed onto the steel sample at 530 ○ C.
2.2. DBD nitriding One of the planer electrodes is the sample electrode to be treated. The opposite electrode is fitted with an alumina barrier of 2.5 mm in thickness. The discharge gap is 1 mm. The ac voltage of 5.7 kV and 12.8 kHz is applied to the sample electrode to ignite DBD. The operating gas is N 2 /H 2 mixture at the flow ratio of 9:1. The treatment temperature is 530
○ C.
3. Results and discussions We have achieved to diffuse N atoms into steel surfaces by the both experimental procedures. Here, the thickness of the hardened layer, several 10 m, is
similar to the conventional nitriding of industrial use. Fig. 1 shows the comparison of optical emission spectra from the two plasmas during the treatment. In the PA jet, the emission of NH is dominant, implying that NH radicals are actively produced. Besides, the NH emission is found to decrease with increasing H 2
demonstrated that the diffusion amount of N into the steel is decreased by increasing H 2 . These facts indicates that NH is the key radical in the PA jet nitriding. On the other hand, we see that in the DBD, no NH peak appears, while N 2 2nd positive band is dominant. In addition, we have succeeded in DBD nitriding even without H 2 addition. These facts indicate that NH is not essential in the DBD nitriding. In addition, the N atom emission is not observed, implying that the active production of N is unlikely. We regard the dissociative adsorption of excited N 2 as a possible scenario of N diffusion. This work was supported by JSPS KAKENHI Grant Number 15K17482.
[1] H. Nagamatsu et al., Surf. Coat. Technol. 225 (2013) 26. [2] K. Kitamura et al., Proc. 21st Intl. Conf. Gas Discharge their Appl. (2016) 429.
14 Fig. 1 Optical emission spectra of plasmas. 142
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