Second derivative Langmuir probe diagnostics of gas discharge plasma at intermediate pressures (review article)

Popov, Tsv K; Dimitrova, M.; Dias, F. M.; Tsaneva, V.; Stelmashenko, Nadia; Blamire, M. G.; Barber, Z. H.

doi:10.1088/1742-6596/44/1/007

Cited by 19 publications

(14 citation statements)

References 15 publications

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“…Within the experiment it was important to construct a discharge tube better suited for spectroscopy than the original design 4,5 (see the explanations below). We planned to make the first cathodes from Ni and to investigate the performance of the tube together with the production of NiH molecule.…”

Section: Introductionmentioning

confidence: 99%

Discharge tube with coaxial geometry for efficient production of metal hydrides

Bozhinova

Kolev

Dimitrova

et al. 2013

Review of Scientific Instruments

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The production of metal hydrides in vapour phase is one of the problems which makes their spectroscopic investigation at high resolution difficult. The molecular densities are usually low and the absorption is often increased by the use of multipass cells or intracavity setups. In this contribution a discharge tube with coaxial geometry is investigated, which is able to produce relatively high densities of NiH (≈10(12) cm(-3)). Additional advantage of the present geometry is that the densities are very homogeneous along the discharge length, 250 mm in our case, which can be made in principle arbitrary long. As a result, reliable absorption was detected even in a single pass experiment. We also present the results of a numerical model which explains the general properties of the plasma in the tube. Based on this understanding, we discuss possible improvements and other applications of this discharge geometry.

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Section: Introductionmentioning

confidence: 99%

Discharge tube with coaxial geometry for efficient production of metal hydrides

Bozhinova

Kolev

Dimitrova

et al. 2013

Review of Scientific Instruments

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“…Among the contact methods of plasma diagnostics, the electric probes are the most reliable diagnostic tools allowing one to measure edge plasma parameters with sufficiently high temporal and spatial resolution. In non-magnetized, low density plasmas Langmuir probes (LPs) allow local measurements of the plasma potential, the charged particles density and the electron energy distribution functions (EEDFs), f (ε) [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Electron energy distribution function, plasma potential and electron density measured by Langmuir probe in tokamak edge plasma

Popov

Ivanova

Ştöckel

et al. 2009

Plasma Phys. Control. Fusion

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The electron energy distribution function (EEDF) at different radial positions is derived from Langmuir probe measurements in the CASTOR tokamak edge plasma using the first derivative method. It is shown that the EEDFs are not Maxwellian but can be approximated as bi-Maxwellians with one dominant, low temperature electron population and one minority composed of hotter electrons. In the limiter shadow the measured EEDFs are Maxwellian. The values of the plasma potential and electron densities at different radial positions are also evaluated. The results presented in this paper demonstrate that the first derivative method allows one to acquire additional plasma parameters using the electron part of the current-voltage characteristics in strongly magnetized tokamak edge plasmas.

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“…A recent theory of the electron probe current collected in the presence of a magnetic field is given in the literature. [22][23][24][25][26][27] It accounts for the radial and parallel diffusion of electrons through the disturbed region and of course is available in the case of a non-local electron kinetic regime, only. This theory is based on the previous work of Swift 28 concerning the disturbance of the plasma produced by the probe and its consequence on the probe characteristic.…”

Section: B Correction Of the Diffusion Through The Probe Disturb Regionmentioning

confidence: 99%

“…In previous works, [22][23][24][25][26][27] considering Equation 5, the authors have shown that according to the diffusion parameter value, the EEDF can be approximated using the first or the second derivative of the collected current. In the present work, we propose a new algorithm to correct the Druyvesteyn method using Arslanbekov theory (Equation (8)), without any approximation according to the w value.…”

Section: B Correction Of the Diffusion Through The Probe Disturb Regionmentioning

confidence: 99%

Time evolution of the electron energy distribution function in pulsed microwave magnetoplasma in H2

Jauberteau

Cortázar

et al. 2016

Physics of Plasmas

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International audienceTime evolution of the Electron Energy Distribution Function(EEDF) is measured in pulsed hydrogen microwave magnetoplasma working at 2.45 GHz. Analysis is performed both in resonance (B = 0.087 T) and off-resonance conditions (B = 0.120 T), at two pressures (0.38 Pa and 0.62 Pa), respectively, and for different incident microwave powers. The important effect of the magnetic field on the electron kinetic is discussed, and a critical analysis of Langmuir probe measurements is given. The Electron Energy Distribution Function is calculated using the Druyvesteyn theory (EEDF) and is corrected using the theory developed by Arslanbekov in the case of magnetized plasma. Three different components are observed in the EEDF, whatever the theory used. They are: (a) a low electron energy component at energy lower than 10 eV, which is ascribed to the electron having inelastic collisions with heavy species (H2, H, ions), (b) a high energy component with a mean energy ranging from 10 to 20 eV, which is generally ascribed to the heating of the plasma by the incident microwave power, and (c) a third component observed between the two other ones, mainly at low pressure and in resonance conditions, has been correlated to the electron rotation in the magnetic field

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Second derivative Langmuir probe diagnostics of gas discharge plasma at intermediate pressures (review article)

Cited by 19 publications

References 15 publications

Discharge tube with coaxial geometry for efficient production of metal hydrides

Discharge tube with coaxial geometry for efficient production of metal hydrides

Electron energy distribution function, plasma potential and electron density measured by Langmuir probe in tokamak edge plasma

Time evolution of the electron energy distribution function in pulsed microwave magnetoplasma in H2

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