Time-resolved optical resonant absorption spectroscopy of Cr metallic vapor in air using a broadband LED light source

Horváth, Balint; Lamara, T.

doi:10.1088/0963-0252/22/4/045006

Cited by 14 publications

(7 citation statements)

References 10 publications

(28 reference statements)

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“…A simple method, known as the line equivalent width method, has been used to solve this problem [21]. This method is described in other publications [22,23]. The area, W, below the previously obtained fractional absorption, shown in figure 3(c), is independent of the line profile [24]:…”

Section: Measurement Of the Density Of Crmentioning

confidence: 99%

Optical absorption spectroscopy of metallic (Cr) vapor in a vacuum arc

Wang

Liu

et al. 2018

J. Phys. D: Appl. Phys.

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The measurement of the metallic vapor density in a vacuum arc is crucial to acquire a better understanding of both the anodic activity and the dielectric recovery process in vacuum interrupters. The objective of this study was to measure the chromium vapor density and its axial distribution within the gap between the chromium contacts. Optical absorption spectroscopy (OAS) with a broadband light-source is adopted for this investigation. The results show that when the vacuum arc burns in the diffuse mode, the metallic vapor density maxima occur near the electrodes during the arcing period. At the peak current, the vapor density near the electrodes can be as high as 2.5 × 1018 m−3. With the decrease of the arc current, the metallic vapor density near the electrodes decreases as well, while the vapor density in the center of the gap remains nearly constant during the arcing period. At current zero, the metallic vapor in the gap has a nearly uniform distribution of about 3 × 1017 m−3. When the vacuum arc burns in the high-current mode, the metallic vapor density near the anode is lower than that in other areas until the vacuum arc becomes diffuse. Then, the evaporation process of the anodic molten region starts to play an important role and the metallic vapor density near the anode increases. At current zero, the metallic vapor has a density of about 4 × 1018 m−3 near the anode, which is much higher than anywhere else. Because the metallic vapor density at current zero is too low to cause a Townsend avalanche, extra factors are needed for initiating the breakdown in the post-arc phase. These factors could include a residual plasma within the gap and the behavior of the liquid metal in the molten anodic region.

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Section: Measurement Of the Density Of Crmentioning

confidence: 99%

Optical absorption spectroscopy of metallic (Cr) vapor in a vacuum arc

Wang

Liu

et al. 2018

J. Phys. D: Appl. Phys.

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“…Lafferty believed that the temperature of particles inside the vacuum arc was not completely equal and might be in a state of non-thermodynamic equilibrium [6]. The experimental research on the microscopic parameters of vacuum arc mainly includes probe [7,8], spectroscopy [9][10][11][12][13][14][15][16][17][18][19], interferometry [20,21] and mass spectrometry, etc. Kutzner and Glinkowski used sinusoidal wave with frequency of 100 Hz as probe scanning signal to diagnose the parameters of low-current vacuum arc plasma [7].…”

Section: Introductionmentioning

confidence: 99%

Experimental study on dynamic characteristics of charged particles in vacuum arc

Liu,

Yuan,

Liu

et al. 2023

Meas. Sci. Technol.

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The vacuum arc is essentially a process of evaporation, collision and ionization of metal materials to keep burning. Electron temperature and density are important parameters to describe vacuum arc plasma transport. This paper was based on the theory of continuous spectral radiation, combined with the principle of two-colorimetric temperature measurement, and realized 2D calculation and observation of electron temperature and density. The experimental platform for vacuum arc breaking and an optical image acquisition system were established to achieve synchronous acquisition of two wavelengths of arc by imaging separation method. On the basis of partial local thermodynamic equilibrium hypothesis, and obtained the 2D dynamic distribution of the electron temperature and density. The results showed that electron density decayed along the radial direction and the density near anode was lower in the axial direction. The 2D distribution trend of electron temperature was opposite to the density. Electron temperature had a little change and the electron density expands outward in different arcing times. With the increase of current amplitude, the peak value of electron density increased, and the electron density in the arc gap also increased. The measured results could reflect the formation and movement of microscopic particles at the initial diffusion stage.

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“…Evaluation of the ground state density of neutral species (Cu and Cr atoms) can be performed by optical absorption spectroscopy (OAS) [17][18][19][20][21]. The absorption measurement setup typically consists of a light source, optical system for beam adjustment and a spectrograph for registration of absorption spectra.…”

Section: Introductionmentioning

confidence: 99%

“…Usually, broadband light sources are applied since they provide enough power in the visible spectral region and, thus, allow for a choice of various wavelength ranges of interest. The measurements are of feasible complexity as long as they are performed after the current zero crossing, when the emission from arc plasma is negligibly small [17][18][19][20]. Investigations in the active phase, however, require much more effort, e.g., arrangement of a second optical path for registration of plasma radiation from the probed region only [21].…”

Section: Introductionmentioning

confidence: 99%

Properties of Vacuum Arcs Generated by Switching RMF Contacts at Different Ignition Positions

et al. 2020

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The influence of initiation behavior of the drawn arc on the arc motion, on arc characteristics during the active phase, as well as on the post-arc parameters, was studied. The study was focused on arc dynamics, determination of the anode surface temperature after current interruption, and diagnostics of metal vapor density after current zero crossing. Different optical diagnostics, namely high-speed camera video enhanced by narrow-band optical filters, near infrared spectroscopy, and optical absorption spectroscopy was applied. The initiation behavior of the drawn arc had a clear influence on arc parameters. Higher local electrode temperature occurs in case of the electrodes with ignition point near the outer electrode boundary. This further causes an enhanced density of chromium vapor, even in cases with lower arc duration. The results of this study are important for design development of switching RMF contacts for future green energy applications.

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Time-resolved optical resonant absorption spectroscopy of Cr metallic vapor in air using a broadband LED light source

Cited by 14 publications

References 10 publications

Optical absorption spectroscopy of metallic (Cr) vapor in a vacuum arc

Optical absorption spectroscopy of metallic (Cr) vapor in a vacuum arc

Experimental study on dynamic characteristics of charged particles in vacuum arc

Properties of Vacuum Arcs Generated by Switching RMF Contacts at Different Ignition Positions

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