A fully automatic optical system for determining the volume emission coefficient of radiation throughout plasmas

Lapworth, K G; Allnutt, L A

doi:10.1088/0022-3735/10/7/017

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…Previous attempts of two-view reconstructions have achieved varying degrees of success, for example [1][2][3][4][5][6]. A simple method of reconstruction from two orthogonal views has been developed in [1].…”

Section: Introductionmentioning

confidence: 99%

“…This allowed one to reduce the problem of reconstruction to Abel inversion formulas. This method was employed in [2] to determine the temperature distribution in argon RF discharge plasma. Two different algorithms were used in [3] for reconstructing the JET x-ray emissivity from two views: the first was based on Cormack's analytic solution and the second was based on the finite element approach.…”

Section: Introductionmentioning

confidence: 99%

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Two-view tomography

Denisova¹

2000

J. Phys. D: Appl. Phys.

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Computed tomography is a useful tool for gas and plasma diagnostics. Unfortunately, viewing access in many tomographic experiments, such as in plasma physics, is strongly limited, which leads to a highly underdetermined inversion problem. A promising approach to this problem is the maximum entropy (ME) method. An application of the ME concept to the problem of two-view tomography is considered in this paper. It is shown that if additional prior information of the source is available it can be effectively incorporated into the maximum entropy algorithm. The crucial role of prior information is illustrated by several numerical examples.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Two-view tomography

Denisova¹

2000

J. Phys. D: Appl. Phys.

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“…4 In previous years, extensive studies were conducted on the simplified case, where only two mutually perpendicular directions were used for tomography measurements. 5,6 This approximation includes only the first two terms in the Fourier transform of the Radon integral, making it difficult to depict the entire angular distribution of plasma parameters. The Radon technique was described in literature using a four-axis industrial robot to study RF capacitively and inductively coupled plasmas.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the supersonic flowing microwave discharge using two dimensional plasma tomography

Nikolić

Samolov

Cuckov

et al. 2013

Journal of Applied Physics

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A tomographic numerical method based on the two-dimensional Radon formula for a cylindrical cavity has been employed for obtaining spatial distributions of the argon excited levels. The spectroscopy measurements were taken at different positions and directions to observe populations of excited species in the plasmoid region and the corresponding excitation temperatures. Excited argon states are concentrated near the tube walls, thus, confirming the assumption that the post discharge plasma is dominantly sustained by travelling surface wave. An automated optical measurement system has been developed for reconstruction of local plasma parameters of the plasmoid structure formed in an argon supersonic flowing microwave discharge. The system carries out angle and distance measurements using a rotating, flat mirror, as well as two high precision stepper motors operated by a microcontroller-based system and several sensors for precise feedback control. V

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“…A simple method of reconstruction from two orthogonal views has been developed in [5] where prior information about a small departure from axial symmetry allowed the source function to be presented in the form of the leading terms in a Fourier expansion. This method was used in [6] to determine the temperature distribution in argon radiofrequency discharge plasma. In [7] the prior information on the source function was presented as a combination of axially symmetrical and nonsymmetrical functions.…”

Section: Introductionmentioning

confidence: 99%

X-ray absorption tomography of a high-pressure metal-halide lamp with a bent arc due to Lorentz-forces

Denisova

Haverlag

Ridderhof

et al. 2008

J. Phys. D: Appl. Phys.

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Due to its practical importance x-ray absorption (XRA) tomography is becoming a widely applied technique for reconstruction of gas temperature distribution in high intensity discharge lamps. Most of the previous papers have dealt with the cylindrically symmetric plasmas that normally occur when lamps are burned vertically. In this work, a XRA tomographic diagnostic is applied for the first time to a high-pressure metal-halide lamp with a bent arc. X-ray lamp-off and lamp-on measurements have been made for two orthogonal directions. The maximum entropy-based algorithm was applied for the reconstruction of local absorption coefficients which are directly related to the local values of mercury density and plasma temperature. For correct reconstruction of the temperature profile at the edges a new numerical strategy based on the adaptive regularization parameter is developed. This strategy allows use of the measured value of the wall temperature as a reference point to obtain a quantitative temperature distribution.

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A fully automatic optical system for determining the volume emission coefficient of radiation throughout plasmas

Cited by 6 publications

References 8 publications

Two-view tomography

Two-view tomography

Characterization of the supersonic flowing microwave discharge using two dimensional plasma tomography

X-ray absorption tomography of a high-pressure metal-halide lamp with a bent arc due to Lorentz-forces

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