Spectral Analysis of a Quiescent Filament

1994 ◽  
Vol 144 ◽  
pp. 361-363
Author(s):  
P. Kotrč ◽  
P. Heinzel ◽  
A. V. Gorshkov ◽  
E. V. Kononovich ◽  
Yu. A. Kupryakov ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Cloud Model ◽  
Spectral Lines ◽  
Plasma Parameters ◽  
Preliminary Results ◽  
Quiescent Filament

AbstractWe have determined principal plasma parameters in a filament by applying the appropriate cloud model to several observed spectral lines. Then we compared them to prominence models from the recent numerical NLTE modelling of Gouttebrozeet al. (1993) (referred to as GHV). Some preliminary results of such an attempt are described and related problems are briefly discussed.

Measurement of plasma parameters of a quasistationary plasma accelerator from self-absorbed spectral lines

1992 ◽  
Vol 56 (3) ◽  
pp. 281-286
Author(s):  
Ya. F. Volkov ◽  
V. V. Marinin ◽  
N. I. Mitina ◽  
M. A. Tiarov ◽  
S. A. Trubchaninov
Keyword(s):  
Plasma Accelerator ◽  
Spectral Lines ◽  
Plasma Parameters

scholarly journals Studies of plasma interactions with tungsten targets in PF-1000U facility

Nukleonika ◽  
2016 ◽  
Vol 61 (2) ◽  
pp. 149-153
Author(s):  
Maryna S. Ladygina ◽  
Elzbieta Skladnik-Sadowska ◽  
Dobromil R. Zaloga ◽  
Marek J. Sadowski ◽  
Monika Kubkowska ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Optical Emission ◽  
Target Surface ◽  
Sample Surface ◽  
Optical Microscope ◽  
High Plasma ◽  
Spectral Lines ◽  
Optical Measurements ◽  
Plasma Stream ◽  
Plasma Parameters

Abstract This paper presents results of experimental studies of tungsten samples of 99.95% purity, which were irradiated by intense plasma-ion streams. The behaviour of tungsten, and particularly its structural change induced by high plasma loads, is of great importance for fusion technology. The reported measurements were performed within a modified PF-1000U plasma-focus facility operated at the IFPiLM in Warsaw, Poland. The working gas was pure deuterium. In order to determine the main plasma parameters and to study the behaviour of impurities at different instants of the plasma discharge, the optical emission spectroscopy was used. The dependence of plasma parameters on the initial charging voltage (16, 19 and 21 kV) was studied. Detailed optical measurements were performed during interactions of a plasma stream with the tungsten samples placed at the z-axis of the facility, at a distance of 6 cm from the electrode outlets. The recorded spectra showed distinct WI and WII spectral lines. Investigation of a target surface morphology, after its irradiation by intense plasma streams, was performed by means of an optical microscope. The observations revealed that some amounts of the electrodes material (mainly copper) were deposited upon the irradiated sample surface. In all the cases, melted zones were observed upon the irradiated target surface, and in experiments performed at the highest charging voltage there were formed some cracks.

scholarly journals The temperature characteristics of plasma induced by femtosecond laser radiation

2019 ◽  
Vol 220 ◽  
pp. 03034
Author(s):  
Sergei Arakelyan ◽  
Svetlana Zhirnova ◽  
Arkady Galkin ◽  
Dmitriy Kochuev ◽  
Elena Shamanskaya ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Electron Concentration ◽  
Relative Intensity ◽  
Collision Frequency ◽  
Plasma Temperature ◽  
Spectral Lines ◽  
Femtosecond Laser Radiation ◽  
Plasma Parameters ◽  
Atoms And Molecules

In this work, the plasma temperature in an argon and nitrogen medium is measured at various pressure values. Such data can be used to calculate plasma parameters: electron concentration, collision frequency with atoms and molecules, etc. Two approaches are used to measure temperature: using a pyrometer and measuring the relative intensity of spectral lines.

scholarly journals Investigations concerning plasma parameters and population inversion in laser-produced counterstreaming plasmas

1991 ◽  
Vol 9 (2) ◽  
pp. 501-515 ◽  
Author(s):  
P. Glas ◽  
M. Schnürer
Keyword(s):  
Computational Analysis ◽  
Nuclear Charge ◽  
Gain Coefficient ◽  
Spectral Lines ◽  
Interaction Zone ◽  
Electron Number ◽  
Plasma Parameters ◽  
X Ray ◽  
Spatial Intensity Distribution ◽  
Resonance Transitions

We investigated the case where two laser-produced plasmas collide nearly head on. Special attention was devoted to the fundamentals necessary to realize a coherent X-ray source. A gas-dynamic computational analysis was performed to understand the evolution of the density, the temperature, and the velocity of merging plasmas. The spatial intensity distribution of selected spectral lines reveals that the interaction of plasmas of different nuclear charge and charge state is not strictly collision dominated. Using spectral line intensity ratios, we determined electron temperatures and electron number densities, as well as the intensity inversion on the 4–1 to 3–1 resonance transitions of [He]-like Al. Inversion occurs in the vicinity of the targets if identical materials are used (Al–Al) and is possibly indicated in the interaction zone for different ones (Al–Cu), too. The inversion factors (and the gain coefficient) for the 4–3 transition of [He]-like Al at about 130 Å were estimated.

Chebyshev Spectra Resistance to Trend of Random Noise

2018 ◽  
Vol 17 (03) ◽  
pp. 1850028 ◽  
Author(s):  
Boris M. Grafov ◽  
Alexey L. Kluev ◽  
Tatyana B. Kabanova ◽  
Alexey D. Davydov
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Fourier Analysis ◽  
Random Process ◽  
Chebyshev Polynomials ◽  
Random Noise ◽  
Spectral Lines ◽  
Spectral Approach ◽  
Experimental Conditions ◽  
Strong Trend

Spectral analysis of random noise in the space of discrete Chebyshev polynomials is an alternative to spectral Fourier analysis. The importance of Chebyshev spectral approach is associated with the fact that the discrete Chebyshev transformation of the [Formula: see text]-th order eliminates automatically the polynomial trend of the ([Formula: see text]−1) order. Using the method of artificial trend, it was found that, under the real experimental conditions, the intensity of Chebyshev spectral lines with numbers higher than 1 is resistant to a strong trend of random process. This effect is observed when we use both the arithmetic averaging and the median. The Chebyshev spectral approach is a powerful tool for spectral analysis of random time series with a strong trend.

scholarly journals Spectral analysis of the O(He)-type central stars of the planetary nebulae K 1-27 and LoTr 4

2011 ◽  
Vol 7 (S283) ◽  
pp. 482-483
Author(s):  
Nicole Reindl ◽  
Ellen Ringat ◽  
Thomas Rauch ◽  
Klaus Werner ◽  
Jeffrey. W. Kruk
Keyword(s):  
Spectral Analysis ◽  
Planetary Nebulae ◽  
Agb Stars ◽  
Evolutionary Sequence ◽  
Preliminary Results ◽  
Pure Helium ◽  
R Coronae Borealis Stars ◽  
Central Stars

AbstractThe four known O(He) stars are the only amongst the hottest post-AGB stars whose atmospheres are composed of almost pure helium. Thus, their evolution deviates from the hydrogen-deficient post-AGB evolutionary sequence of carbon-dominated stars like e.g. PG 1159 stars. The origin of the O(He) stars is still not explained. They might be either post-early AGB stars or the progeny of R Coronae Borealis stars. We present preliminary results of a non-LTE spectral analysis based on FUSE and HST/COS observations.

scholarly journals A NIR spectrum of a hot Jupiter from the ground: Preliminary results

2010 ◽  
Vol 6 (S276) ◽  
pp. 158-162
Author(s):  
Avi M. Mandell ◽  
L. Drake Deming ◽  
Geoffrey A. Blake ◽  
Heather A. Knutson ◽  
Michael J. Mumma ◽  
...  
Keyword(s):  
High Resolution ◽  
Nir Spectroscopy ◽  
Spectral Lines ◽  
Temperature Structure ◽  
High Resolution Data ◽  
Preliminary Results ◽  
Line Intensities ◽  
Eclipse Observations ◽  
Absorbing Layer ◽  
Atmospheric Transmittance

AbstractHigh resolution NIR spectroscopy offers an excellent complement to the expanding dataset of transit and secondary eclipse observations of exo-planets with Spitzer that have provided the bulk of our understanding of the atmospheres and internal structure of these objects. High-resolution data can quantify the vertical temperature structure by isolating specific spectral lines formed at various depths. The presence of an opaque absorbing layer can also be inferred - and its pressure level determined quantitatively - via its effect on spectral line intensities.We have analyzed data for a single secondary eclipse of the bright transiting exo-planet host star HD189733 at L-band wavelengths (3–4 μm) using the NIRSPEC instrument on Keck-II. We utilize a sophisticated first-order telluric absorption modeling technique that, combined with a calibration star, has already been proven to remove the effects of varying atmospheric transmittance and allow us to reach unprecedented S/N. We are conducting validation of the final data reduction products and developing high-resolution atmospheric models for comparison, but we have already been able to rule out emission from methane as reported by Swainet al. (2010). We present preliminary results and discuss future plans for analysis and observations.

scholarly journals High-precision measurement of velocity profiles in laser-created chlorine plasma

1995 ◽  
Vol 13 (4) ◽  
pp. 503-510 ◽  
Author(s):  
O. Renner ◽  
E. Krouský ◽  
T. Mißalla ◽  
E. Förster ◽  
G. Hölzer
Keyword(s):  
Spectral Lines ◽  
Plasma Parameters ◽  
High Precision Measurement ◽  
One Dimensional ◽  
Electron Temperature Gradient ◽  
Spatially Resolved ◽  
Doppler Shifts ◽  
Velocity Gradients ◽  
Marquardt Algorithm ◽  
The One

A vertical dispersion variant of the Johann spectrometer has been used to record the highresolution X-ray spectra of the chlorine He-like resonance line group emitted from lowradiance plasma. The emission profiles were measured at two observation angles and decomposed into single spectral lines by using a fit based on the Levenberg-Marquardt algorithm. The results of computerized analysis of the one-dimensional (1-D) spatially resolved spectra were used to evaluate the distribution of the main plasma parameters. The electron temperature gradient 7.5·104 eV cm-1 was computed by modeling the measured spectra with the collisional-radiative package RATION. The blowoff maximum velocities 4.2–6.1·107 cm s-1 and the velocity gradients 0.9–1.6·109 s-1 were determined from the Doppler shifts of individual spectral lines within their different spatial extent.

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