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Title: On the mechanism of acceleration behavior of plasma bullet

Abstract

Two special experiments are designed to study the mechanism of the acceleration behavior of a plasma bullet when it exits a nozzle. First, a T-shape device is used to simulate the air diffusion when a plasma plume exits the nozzle. It is found that adding just 1% of N{sub 2}, O{sub 2}, or air to the main working gas He results in the acceleration of the plasma bullet. Second, materials of different permittivity are added to the left part of the outside of the tube. The experimental results show that the plasma bullet accelerates at the moment when it enters into the right part of the tube where there is no extra material on the outside of the tube. These two experiments confirm that the acceleration behavior of the plasma bullet when it exits the nozzle is due to the air diffusion, hence Penning ionization, and the permittivity change when the bullet exits the nozzle, for example, from a tube with high permittivity to air with low permittivity. Besides, electric field measurements show that the electric field in the bullet head increases when the plasma bullet accelerates. This confirms the electric field driven nature of the plasma bullet propagation.

Authors:
; ;  [1]
  1. State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)
Publication Date:
OSTI Identifier:
22299856
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; AIR; DIFFUSION; ELECTRIC FIELDS; EQUIPMENT; IONIZATION; NOZZLES; PERMITTIVITY; PLASMA; PLUMES; TUBES

Citation Formats

Wu, S., Lu, X., E-mail: luxinpei@hotmail.com, and Pan, Y. On the mechanism of acceleration behavior of plasma bullet. United States: N. p., 2014. Web. doi:10.1063/1.4890490.
Wu, S., Lu, X., E-mail: luxinpei@hotmail.com, & Pan, Y. On the mechanism of acceleration behavior of plasma bullet. United States. doi:10.1063/1.4890490.
Wu, S., Lu, X., E-mail: luxinpei@hotmail.com, and Pan, Y. Tue . "On the mechanism of acceleration behavior of plasma bullet". United States. doi:10.1063/1.4890490.
@article{osti_22299856,
title = {On the mechanism of acceleration behavior of plasma bullet},
author = {Wu, S. and Lu, X., E-mail: luxinpei@hotmail.com and Pan, Y.},
abstractNote = {Two special experiments are designed to study the mechanism of the acceleration behavior of a plasma bullet when it exits a nozzle. First, a T-shape device is used to simulate the air diffusion when a plasma plume exits the nozzle. It is found that adding just 1% of N{sub 2}, O{sub 2}, or air to the main working gas He results in the acceleration of the plasma bullet. Second, materials of different permittivity are added to the left part of the outside of the tube. The experimental results show that the plasma bullet accelerates at the moment when it enters into the right part of the tube where there is no extra material on the outside of the tube. These two experiments confirm that the acceleration behavior of the plasma bullet when it exits the nozzle is due to the air diffusion, hence Penning ionization, and the permittivity change when the bullet exits the nozzle, for example, from a tube with high permittivity to air with low permittivity. Besides, electric field measurements show that the electric field in the bullet head increases when the plasma bullet accelerates. This confirms the electric field driven nature of the plasma bullet propagation.},
doi = {10.1063/1.4890490},
journal = {Physics of Plasmas},
number = 7,
volume = 21,
place = {United States},
year = {Tue Jul 15 00:00:00 EDT 2014},
month = {Tue Jul 15 00:00:00 EDT 2014}
}
  • An electron spin resonance investigation of the reactions of HS{sup {sm bullet}} and S{sup {sm bullet}{minus}} produced from H{sub 2}S, HS{sup {minus}}, and S{sup 2{minus}} in glassy matrices at low temperatures is presented. Co-60 irradiation of 8 M NaClO{sub 4}, 12 M LiCl, and alkali-metal hydroxide glasses at 77 K results in the formation of O{sup {sm bullet}{minus}}, Cl{sub 2}{sup {sm bullet}{minus}}, and e{sup {minus}}. Upon annealing to about 150 K O{sup {sm bullet}{minus}} or Cl{sub 2}{sup {sm bullet}{minus}} reacts with the solutes H{sub 2}S, HS{sup {minus}}, or S{sup 2{minus}} to form HS{sup {sm bullet}} and S{sup {sm bullet}{minus}} radicals.more » In the presence of molecular oxygen HS{sup {sm bullet}} and S{sup {sm bullet}{minus}} each react to form sulfur dioxide anion radical, SO{sub 2}{sup {sm bullet}{minus}}. {sup 17}O isotopic studies verify the source of the oxygen in SO{sub 2}{sup {sm bullet}{minus}} is the molecular oxygen dissolved in the matrices. In the absence of molecular oxygen, competing processes are clearly observed; i.e., HS{sup {sm bullet}} and S{sup {sm bullet}{minus}} attack H{sub 2}S and HS{sup {minus}} to form dimer radicals HSSH{sup {sm bullet}{minus}} and HSS{sup {sm bullet}2{minus}}. At low pH the authors find that HS{sup {sm bullet}} attacks H{sub 2}S to form HSS{sup {sm bullet}}. Mechanisms for the formation of these species are proposed, and hyperfine couplings and g values are reported. Ab initio molecular orbital calculations are performed to aid their understanding of the electronic structure of the various radical species formed and the energetics of their reactions.« less
  • The reaction of Fe(C{sub 5}Me{sub 5}){sub 2} donor (D) and 2,5-disubstituted-7,7,8,8-tetracyano-p-quinodimethane, TCNQR{sub 2} (R = Cl, Br, I, Me, OMe, OPh) acceptor (A), results in the formation of 1:1 electron-transfer complexes of (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+}(TCNQR{sub 2}){sup {sm bullet}{minus}} composition. The structure of (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+}(TCNQI{sub 2}){sup {sm bullet}{minus}} belongs to the centrosymmetric P2{sub 1}/n space group (a = 11.131 (2) {angstrom}, b = 32.929 (5) {angstrom}, c = 8.728 (1) {angstrom}, {beta} = 105.06 (1){degree}, Z = 4, V = 3,089 {angstrom}{sup 3}, R = 3.4%; R{sub w} = 3.1% at {minus}100{degree}C). The unitmore » cell comprises {hor ellipsis}D{sup {sm bullet}+}A{sup {sm bullet}{minus}}D{sup {sm bullet}+}A{sup {sm bullet}{minus}}D{sup {sm bullet}+}A{sup {sm bullet}{minus}}{hor ellipsis} chains along a with the intrachain Fe{sup III}{hor ellipsis}Fe{sup III} distance of 11.131 {angstrom} and the interchain Fe{sup III}{hor ellipsis}Fe{sup III} separations less than the intrachain spacing of 8.728 (in-registry) and 9.778 {angstrom} (out-of-registry). The structure of ((Co(C{sub 5}Me{sub 5}){sub 2}){sup +}){sub 2}(TCNQI{sub 2}){sup 2{minus}} belongs to the centrosymmetric P{anti 1} space group (a = 9.537 (3) {angstrom}, b = 9.880 (2) {angstrom}, c = 12.728 (1) {angstrom}, {alpha} = 85.24 (1){degree}, {beta} = 86.25 (1){degree}, {gamma} = 81.39 (2){degree}, Z = 1, V = 1,180 {angstrom}{sup 3}, R = 5.4%; R{sub w} = 5.5% at {minus}70{degree}C).« less
  • The reaction of Fe{sup II}({eta}{sup 5}-C{sub 5}Me{sub 4}H){sub 2} with cyano acceptors A (A = TCNE (tetracyanoethylene), TCNQ (7,7,8,8-tetracyano-p-quanodimethane), n-C{sub 4}(CN){sub 6} (n-hexacyanobutadiene), C{sub 6}(CN){sub 6} (tris(dicyanomethylene)cyclopropane), DDQ (2,3-dichloro-5,6-dicyanobenzoquinone), TCNQF{sub 4} (perfluoro-7,7,8,8-tetracyano-p-quinodimethane) results in formation of 1:1 charge-transfer salts of (Fe{sup III})(C{sub 5}Me{sub 4}H){sub 2}){sup {sm bullet}+}(A){sup {sm bullet}{minus}} composition. The TCNE and TCNQ complexes have been structurally characterized. The high-temperature magnetic susceptibility for polycrystalline samples of these complexes can be fit by the Curie-Qeiss law, {chi} = C(T-{theta}){sup {minus}1}, with {theta} = +0.5 {plus minus} 2.2 K, and {mu}{sub eff} ranges from 2.71 to 3.97 {mu}{sub B}, suggesting thatmore » the polycrystalline samples measured had varying degrees of orientation. The 7.0 K EPR spectrum of the radical cation exhibits an axially symmetric powder pattern with g{sub {parallel}} = 4.11 and g{sub {perpendicular}} = 1.42, and the EPR parameters are essentially identical with those reported for ferrocenium and decamethylferrocenium. No EPR spectrum is observed at 78 K. Akin to the (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+} salts, these salts have {sup 57}Fe Moessbauer spectra consistent with complete charge transfer; however, unlike the case for the former complexes, quadrupole splittings of 0.30 and 0.220 mm/s are observed at 4.8 and 298 K, respectively. The absence of strong interionic magnetic coupling for the (Fe(C{sub 5}Me{sub 4}H){sub 2}){sup {sm bullet}+} salts contrasts with the behavior of the (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+} salts. 26 refs., 13 figs., 8 tabs.« less
  • The reactions of the hydroxyl radical with 2-(methylthio)ethanoic acid and 2,2[prime]-thiodiethanoic acid have been investigated in H[sub 2]O and D[sub 2]O. The initial step is a formation of an OH adduct at the sulfur moiety (absorption maximum at [lambda] = 340 nm) with absolute rate constants of k[sub OH+2[minus]MTEA] = 8.7 X 10[sup 9] M[sup [minus]1] s[sup [minus]1] and k[sub OH+2.2[prime][minus]TDEA] = 9.1 X 10[sup 9] M[sup [minus]1] s[sup [minus]1]. The subsequent decay pathways of these adducts strongly depend on pH but do not lead to the respective intermolecularly S. S-bonded dimeric radical cations even at high concentrations of solutemore » ([approximately] 10[sup [minus]2] M) and protons ([approximately] 10[sup [minus]1] M). The S.S-bonded radical cations are typically formed upon oxidation of unsubstituted thioethers. Instead, very high radiation chemical yields of CO[sub 2] (G = 3.5-6.0) and of [alpha]-(alkylthio)-alkyl radicals are observed over the entire investigated pH region (1.0-7.5). Mechanistically, the formation of CO[sub 2] and the associated reaction kinetics including solvent kinetic isotope effects suggest the occurrence of an intramolecular electron transfer from the carboxyl group to the oxidized sulfur function followed by homolytic carbon-carboxyl bond breakage into carbon dioxide and the [alpha]-(alkylthio)alkyl radical. The OH radical-induced decarboxylation can receive part of its driving force from the resonance stabilization of the R-S-CH[sub 2][center dot] radical resulting from CO[sub 2] cleavage. 41 refs., 3 figs., 2 tabs.« less
  • An atmospheric pressure plasma jet source driven by pulsed wave of several tens of kilohertz and by sinusoidal wave was designed and characterized. A newly designed jet consists of a sharpened tungsten pin electrode covered with a cone type Teflon layer confined in a Pyrex tube. This structure provides an efficient ignition since the electric field is concentrated on the end of electrode. Using the electrical and optical characterization, the properties of plasma bullet were explored. For the Ar plasma jet driven by a pulsed wave at low duty cycles, the volume, the speed, and the luminosity of the plasmamore » bullet became larger, and the striation behavior was observed.« less