The Emission Coefficient of the Continuum in an Argon and Nitrogen Plasma at High Temperatures

1977 ◽  
Vol 32 (1) ◽  
pp. 21-27 ◽  
Author(s):  
K. Erhardt ◽  
I. Meyer ◽  
P. Stritzke
Keyword(s):  
Line Intensity ◽  
Electrical Discharge ◽  
Total Pressure ◽  
Nitrogen Plasma ◽  
Continuum Emission ◽  
Emission Coefficient ◽  
Plasma Parameters ◽  
Narrow Temperature Range ◽  
Line Intensities ◽  
The Continuum

Abstract The continuum emission of an argon-and nitrogen plasma developed in an electrical discharge has been investigated in the wavelength range from 3000 Å to 6700 Å. To this purpose the time-and radial dependent plasma parameters such as temperature and the total pressure have been determined in the high conducting stage of the spark by measuring several line intensities. The continuum coefficient was calculated from these data according to the Kramers-Unsöld theory. The comparison of the theoretical and the measured values shows deviations which are discussed. In the case of the argon continuum the ξ-factors for T = 14 000 K agree with the calculated values of Schlüter and the experimental ones of Schulz-Gulde. In the case of the nitrogen plasma the ξ-fac­tors have been determined in the temperature interval from 18 000 K to 45 000 K. Since at these temperatures the particles NII-NIV contribute to the total continuum coefficient, the measured ξ-factors can only be correlated to ξII, ξIII, ... in a narrow temperature range. The measured cor­rection factor ξ for λ = 5050 Å has been applied to determine the temperatures and the pressure of a laser produced spark. The plasma parameters agree with those determined by measuring the line-intensity of the NII-line at 5000 A.

EELS white line intensities calculated for the 3d and 4d metals

1989 ◽  
Vol 47 ◽  
pp. 388-389
Author(s):  
C. C. Ahn ◽  
D. H. Pearson ◽  
P. Rez ◽  
B. Fultz
Keyword(s):  
Experimental Data ◽  
Line Intensity ◽  
Transition Probabilities ◽  
Initial Increase ◽  
White Line ◽  
Hartree Fock ◽  
Line Intensities ◽  
Integrated Intensity ◽  
X Ray Absorption ◽  
The Continuum

Previous experimental measurements of the total white line intensities from L2,3 energy loss spectra of 3d transition metals reported a linear dependence of the white line intensity on 3d occupancy. These results are inconsistent, however, with behavior inferred from relativistic one electron Dirac-Fock calculations, which show an initial increase followed by a decrease of total white line intensity across the 3d series. This inconsistency with experimental data is especially puzzling in light of work by Thole, et al., which successfully calculates x-ray absorption spectra of the lanthanide M4,5 white lines by employing a less rigorous Hartree-Fock calculation with relativistic corrections based on the work of Cowan. When restricted to transitions allowed by dipole selection rules, the calculated spectra of the lanthanide M4,5 white lines show a decreasing intensity as a function of Z that was consistent with the available experimental data.Here we report the results of Dirac-Fock calculations of the L2,3 white lines of the 3d and 4d elements, and compare the results to the experimental work of Pearson et al. In a previous study, similar calculations helped to account for the non-statistical behavior of L3/L2 ratios of the 3d metals. We assumed that all metals had a single 4s electron. Because these calculations provide absolute transition probabilities, to compare the calculated white line intensities to the experimental data, we normalized the calculated intensities to the intensity of the continuum above the L3 edges. The continuum intensity was obtained by Hartree-Slater calculations, and the normalization factor for the white line intensities was the integrated intensity in an energy window of fixed width and position above the L3 edge of each element.

scholarly journals Aperture synthesis CS and 98 GHz continuum observations of protostellar IRAS sources in Taurus

1991 ◽  
Vol 147 ◽  
pp. 353-356
Author(s):  
N. Ohashi ◽  
R. Kawabe ◽  
M. Hayashi ◽  
M. Ishiguro
Keyword(s):  
Molecular Cloud ◽  
Total Mass ◽  
T Tauri Stars ◽  
Continuum Emission ◽  
Beam Size ◽  
Dust Grains ◽  
Dynamical Mass ◽  
T Tauri ◽  
Cloud Cores ◽  
The Continuum

The CS (J = 2 — 1) line and 98 GHz continuum emission have been observed for 11 protostellar IRAS sources in the Taurus molecular cloud with resolutions of 2.6″−8.8″ (360 AU—1200 AU) using the Nobeyama Millimeter Array (NMA). The CS emission is detected only toward embedded sources, while the continuum emission from dust grains is detected only toward visible T Tauri stars except for one embedded source, L1551-IRS5. This suggests that the dust grains around the embedded sources do not centrally concentrate enough to be detected with our sensitivity (∼4 m Jy r.m.s), while dust grains in disks around the T Tauri stars have enough total mass to be detected with the NMA. The molecular cloud cores around the embedded sources are moderately extended and dense enough to be detected in CS, while gas disks around the T Tauri are not detected because the radius of such gas disks may be smaller than 70 (50 K/Tex) AU. These results imply that the total amount of matter within the NMA beam size must increase when the central objects evolve into T Tauri stars from embedded sources, suggesting that the compact and highly dense disks around T Tauri stars are formed by the dynamical mass accretion during the embedded protostar phase.

Micro electrical discharge machining in nitrogen plasma jet

2018 ◽  
Vol 51 ◽  
pp. 198-207 ◽  
Author(s):  
Rimao Zou ◽  
Zuyuan Yu ◽  
Chengyang Yan ◽  
Jianzhong Li ◽  
Xin Liu ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Plasma Jet ◽  
Nitrogen Plasma ◽  
Micro Electrical Discharge Machining

scholarly journals Water maser and radio continuum emission towards IRAS 23139+5939

2007 ◽  
Vol 3 (S242) ◽  
pp. 180-181
Author(s):  
M. A. Trinidad ◽  
S. Curiel ◽  
J. M. Torrelles ◽  
L. F. Rodríguez ◽  
V. Migenes ◽  
...  
Keyword(s):  
Flux Density ◽  
Line Emission ◽  
The Other ◽  
Radio Continuum ◽  
High Mass ◽  
Continuum Emission ◽  
Maser Line ◽  
Water Masers ◽  
Water Maser ◽  
The Continuum

AbstractWe present simultaneous observations of continuum (3.5 and 1.3cm) and water maser line emission (1.3cm) carried out with the VLA-A toward the high-mass object IRAS 23139+5939. We detected two radio continuum sources at 3.5cm separated by 0”5 (~2400 AU), I23139 and I23139S. Based on the observed continuum flux density and the spectral index, we suggest that I23139 is a thermal radio jet associated with a high-mass YSO. On the other hand, based on the spatio-kinematical distribution of the water masers, together with the continuum emission information, we speculate that I23139S is also a jet source powering some of the masers detected in the region.

scholarly journals Correlated modulation between the redshifted Fe Kαline and the continuum emission in NGC 3783

2007 ◽  
Vol 467 (3) ◽  
pp. 1057-1063 ◽  
Author(s):  
F. Tombesi ◽  
B. De Marco ◽  
K. Iwasawa ◽  
M. Cappi ◽  
M. Dadina ◽  
...  
Keyword(s):  
Continuum Emission ◽  
The Continuum

scholarly journals Excitation and analytical characteristics of an ethanol loaded U-shaped arc

2003 ◽  
Vol 68 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Marija Raskovic ◽  
Ivanka Holclajtner-Antunovic ◽  
Mirjana Tripkovic ◽  
Dragan Markovic
Keyword(s):  
Spectral Line ◽  
Electron Number Density ◽  
Ethanol Solution ◽  
Number Density ◽  
Electron Number ◽  
Plasma Parameters ◽  
Line Intensities ◽  
Ethanol Addition ◽  
Plasma Characteristics ◽  
Dc Arc

The effect of the ethanol load on the discharge and analytical parameters of an argon stabilized U-shaped DC arc has been recorded. Measurements of the radial distribution of the apparent temperatures and the electron number density of the DC plasma showed that ethanol addition causes a decrease in both plasma parameters. The changes in the plasma characteristics, as well as in transport and atomisation processes of the analyte cause a general change in the spectral line intensities, which depends on the physical characteristics of the analyte and the quantity of ethanol loaded into the plasma. Improved detection limits were obtained for V and Mn when a 10%(v/v) water?ethanol solution was nebulized into the plasma.

scholarly journals Spectroscopic Analysis of DC-Nitrogen Plasma Produced using Copper Electrodes

2021 ◽  
pp. 3560-3569
Author(s):  
Ala F. Ahmed ◽  
Ali A. Yousef
Keyword(s):  
Debye Length ◽  
Target Material ◽  
Optical Emission ◽  
Nitrogen Plasma ◽  
Molecular Spectra ◽  
Stark Broadening ◽  
Plasma Parameters ◽  
Working Pressure ◽  
Copper Electrodes ◽  
Copper Material

      This study shows the effects of copper material electrode, applied voltage, and different pressure values on electrical discharge plasma. The purpose of the work is the application of the spectral analysis method to obtain accurate results of nitrogen plasma parameters. By using the optical emission spectroscopy (OES), many N2 molecular spectra peaks appeared in the range from 300 to 480 nm. Also, some additional peaks were recorded, corresponding to atomic and ionic lines for nitrogen, target material, and hydrogen, in all samples. The electron density (ne) was calculated from the measurement of Stark broadening effect, which was found to decrease with increasing pressure from 0.1 mbar to 0.8 mbar. The higher emission intensities occurred at 0.2 mbar working pressure and were reduced with higher pressure. The vibrational temperature (Tvib) for N2 increased from 0.17 to 0.33 eV with increasing the pressure from 0.15 mbar to 0.2 mbar, then decreased to 0.25 eV with increasing the pressure to 0.8 mbar. Other plasma parameters were studied, which are electron temperature (Te), plasma frequency of electron ( ), and Debye length (λD).

scholarly journals Planet formation in action: resolved gas and dust images of a transitional disk and its cavity

2013 ◽  
Vol 8 (S299) ◽  
pp. 90-93
Author(s):  
Nienke van der Marel ◽  
Ewine F. van Dishoeck ◽  
Simon Bruderer ◽  
Til Birnstiel ◽  
Paola Pinilla ◽  
...  
Keyword(s):  
Planet Formation ◽  
Early Stage ◽  
Continuum Emission ◽  
Dust Trapping ◽  
Spatially Resolved ◽  
First Results ◽  
Disk Evolution ◽  
Gas Cavity ◽  
Dust Distribution ◽  
The Continuum

AbstractPlanet formation and clearing of protoplanetary disks is one of the long standing problems in disk evolution theory. The best test of clearing scenarios is observing systems that are most likely to be actively forming planets: the transitional disks with large inner dust cavities. We present the first results of our ALMA (Atacama Large Millimeter/submillimeter Array) Cycle 0 program using Band 9, imaging the Herbig Ae star Oph IRS 48 in CO 6−5 and the submillimeter continuum in the extended configuration. The resulting ~0.2″ spatial resolution completely resolves the cavity of this disk in the gas and the dust. The gas cavity of IRS 48 is half as large as the dust cavity, ruling out grain growth and photoevaporation as the primary cause of the truncation. On the other hand, the continuum emission reveals an unexpected large azimuthal asymmetry and steep edges in the dust distribution along the ring, suggestive of dust trapping. We will discuss the implications of the combined gas and dust distribution for planet formation at a very early stage. This is one of the first transition disks with spatially resolved gas inside the cavity, demonstrating the superb capabilities of the Band 9 receivers.

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