Production of negative ion plasmas in a Q machine

Sato, Naoyuki

doi:10.1088/0963-0252/3/3/024

Cited by 75 publications

(46 citation statements)

References 7 publications

(2 reference statements)

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“…Negative ions have been detected in the Earth's ionosphere [18], cometary comae [19], and the upper regions of Titan [20]. Moreover, multicomponent plasmas, such as Ar/SF 6 and K/SF 6 plasmas, are generally used to perform basic research on IASWs in dc discharge devices and Q-machines [21][22][23][24][25][26][27][28]. Since the early space observations [29], it has been admitted that the Maxwellian distribution is not always a realistic distribution [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

The collisions of two ion acoustic solitary waves in a magnetized nonextensive plasma

El-Shamy¹,

Tribeche

El-Taibany³

2014

Open Physics

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Abstract:Using the extended Poincaré-Lighthill-Kuo (EPLK) method, the interaction between two ion acoustic solitary waves (IASWs) in a multicomponent magnetized plasma (including Tsallis nonextensive electrons) has been theoretically investigated. The analytical phase shifts of the two solitary waves after interaction are estimated. The proposed model leads to rarefactive solitons only. The effects of colliding angle, ratio of number densities of (positive/negative) ions species to the density of nonextensive electrons, ion-to-electron temperature ratio, mass ratio of the negative-to-positive ions and the electron nonextensive parameter on the phase shifts are investigated numerically. The present results show that these parameters have strong effects on the phase shifts and trajectories of the two IASWs after collision. Evidently, this model is helpful for interpreting the propagation and the oblique collision of IASWs in magnetized multicomponent plasma experiments and space observations.

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Section: Introductionmentioning

confidence: 99%

The collisions of two ion acoustic solitary waves in a magnetized nonextensive plasma

El-Shamy¹,

Tribeche

El-Taibany³

2014

Open Physics

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“…4 Also the electronegative character of fullerenes has been investigated. 5 In spite of the large interest, the available data on negative ion processes is scarce. In particular, more detailed knowledge about negative ion formation mechanisms and the cross sections is needed.…”

Section: Introductionmentioning

confidence: 99%

Electron attachment mass spectrometry as a diagnostics for electronegative gases and plasmas

Stoffels

Tachibana

1998

Review of Scientific Instruments

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. Electron attachment mass spectrometry as a diagnostics for electronegative gases and plasmas. Review of Scientific Instruments, 69(1), 116-122. DOI: 10.1063/1.1148486 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Electron attachment mass spectrometry ͑EAMS͒ has been developed to study mixtures of electronegative gases and plasmas. A quadrupole mass spectrometer ͑QMS͒ has been used to detect negative ions, formed from sampled species by attachment of low energy electrons. Varying the electron energy allows to collect the attachment cross section of the considered species. EAMS appears to be a very powerful technique to study the chemistry of electronegative gases. Unlike ionization mass spectrometry, where cross sections are low at the threshold and rather flat over a broad range of electron energies, attachment resonances are sharp and distinct. Also very limited fragmentation of the parent negative ion occurs, so a given molecule yields only a few different negative ions. This facilitates identification of components in a gas mixture. It is particularly advantageous for detection of large, fragile molecules, which break up after ionization, but can be easily transformed into large negative ions. Moreover, sensitive detection of active species is possible due to their relatively high attachment cross sections. A particularly important application of EAMS is the determination of an effective attachment cross section in a plasma. Recording this cross section allows to decide on the actual negative ion formation mechanism in the plasma environment, where active products of plasma conversion can significantly alter the negative ion production channels and consequently the whole balance of charged particles. Examples of EAMS applications to fluorocarbon gases and low-pressure radio-frequency plasmas are discussed. In a CF 4 discharge conversion of the parent gas into species like C 2 F 6 and C 3 F 8 is easily visualized. The dominant mechanism of negative ion formation in the plasma is electron attachment to these minority species and not to the parent gas. Also larger polymers are readily formed in fluorocarbon plasmas. In a C 2 F 6 discharge molecules with up to ten carbon atoms ͑the mass limit of our apparatus͒ have been detected using EAMS.

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“…The spectral index j is a measure of the slope of the energy spectrum of the supra-thermal particles in the tail of the velocity distribution function. 17 The smaller is the value of j the more supra-thermal particles are in the distribution function tail and harder the energy spectrum. The kappa distribution approaches to Maxwellian as j !…”

Section: Dispersion Relation and Landau Damping Rate Of Ion Acousmentioning

confidence: 99%

“…The plasma produced was considered to be Ar þ ÀSF À 6 , Ar þ -F À , and Ar þ -K À having mass ratios of 0.48, 3.65, and 3.74 respectively, with the presence of electrons as well. [13][14][15][16][17] In the last few years, plasma containing significant concentration of negative ions with electrons and positive ions has gained interest and several authors have investigated the propagation of ionacoustic wave in such a multi-ion plasma. [18][19][20][21] The plasma containing negative ions exists in the D-region of the ionosphere, 22,23 in plasma processing reactors, 24 and in neutral ion beam sources.…”

Section: Introductionmentioning

confidence: 99%

Landau damping of ion acoustic wave in Lorentzian multi-ion plasmas

2011

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The Landau damping rates of ion acoustic wave are studied by using Vlasov-Poisson model for unmagnetized Lorentzian or kappa distributed plasma containing electrons, positively and negatively charged ions. It is found that the damping rate of ion acoustic wave is increased with the decrease of kappa (i.e., the spectral index of Lorentzian distribution) value. The damping rates of the electrostatic wave in multi-ion component plasmas are discussed in detail which depends on electron to ion temperature ratio and ions masses and density ratios. The numerical results are also shown by choosing some typical experimental parameters of multi-ion plasmas.

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Production of negative ion plasmas in a Q machine

Cited by 75 publications

References 7 publications

The collisions of two ion acoustic solitary waves in a magnetized nonextensive plasma

The collisions of two ion acoustic solitary waves in a magnetized nonextensive plasma

Electron attachment mass spectrometry as a diagnostics for electronegative gases and plasmas

Landau damping of ion acoustic wave in Lorentzian multi-ion plasmas

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