Spherically symmetric high-velocity plasma expansions into background gases

1986 ◽  
Vol 35 (2) ◽  
pp. 239-256 ◽  
Author(s):  
Tai-Ho Tan ◽  
Joseph E. Borovsky
Keyword(s):  
High Velocity ◽  
Spherical Geometry ◽  
Ion Acceleration ◽  
Spherically Symmetric ◽  
Laser Target ◽  
X Ray ◽  
Isothermal Expansion ◽  
Ambient Gases ◽  
Photo Ionization

Spherically symmetric plasmas with high expansion velocities have been produced by irradiating targets with eight beams from the Helios CO2 laser in the presence of gases at various pressures. Attention was given to the properties of the target-emitted ions in order to obtain information about the ion acceleration mechanisms in plasma expansions. Photo-ionization of the ambient gases by the soft X-ray emission from the laser-irradiated targets produced background plasmas, permitting plasma counterstreaming experiments to be performed in spherical geometry. Successful laser-target coupling in the presence of background gases is obtained, modification of the ion acceleration in accordance with isothermal-expansion models is observed, and an absence of collective coupling between collisionless counterstreaming plasmas is found.

Study of innershell photo-ionization-pumped L23M1 transition in Ca for the development of femtosecond X-ray laser

2001 ◽  
Vol 11 (PR2) ◽  
pp. Pr2-225-Pr2-231
Author(s):  
D. Kim ◽  
S. H. Son ◽  
J. H. Kim ◽  
Cs. Toth ◽  
C. P.J. Barty
Keyword(s):  
X Ray ◽  
Photo Ionization

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

scholarly journals Improved Phebus laser performances required for precision laser–target experiments

1998 ◽  
Vol 16 (2) ◽  
pp. 253-265 ◽  
Author(s):  
G. Thiell ◽  
R. Bailly-Salins ◽  
J.L. Bruneau ◽  
G. Coulaud ◽  
P. Estraillier ◽  
...  
Keyword(s):  
Laser Energy ◽  
Incident Beam ◽  
High Energy ◽  
Target Chamber ◽  
Laser Target ◽  
Time Resolved ◽  
X Ray ◽  
Target Experiment ◽  
Pointing Precision ◽  
Energy Shots

The Precision Phebus program, started in 1993, emphasizes a series of laser and target experiment objectives on the two-beam Phebus Nd-phosphate glass laser. Recently, three major objectives that are also very important issues for megajoule-class lasers have been met: First, the balance of the incident beam-to-beam 3ω power is shown to be in the range from 5 to 12% for 3-ns, 3ω-shaped pulses of reproducible high-energy shots; second, the smoothing uniformity of the laser energy deposited on the target, that is, the contrast of the spatial beam modulations, can be kept lower than 5%; and, finally, the tight control of the beam targeting leads to a pointing precision of less than 10 μrd on the target at the target chamber center (TCC) and of 80 μrd on X-ray sources located up to 3 cm from the TCC to improve the space- and time-resolved X-ray shadowgraphy techniques performed for target physics experiments such as implosion and hydrodynamical instability studies.

Reduction of X-ray generation in high-intensity laser ion acceleration

2014 ◽  
Vol 118 (2) ◽  
pp. 247-251 ◽  
Author(s):  
Bastian Aurand ◽  
Stephan Kuschel ◽  
Christian Rödel ◽  
Oliver Jäckel ◽  
Jens Polz ◽  
...  
Keyword(s):  
High Intensity ◽  
Ion Acceleration ◽  
X Ray ◽  
High Intensity Laser ◽  
Intensity Laser

scholarly journals Imprints of a high-velocity wind on the soft X-ray spectrum of PG1211+143

2016 ◽  
Vol 459 (4) ◽  
pp. 4389-4396 ◽  
Author(s):  
K. A. Pounds ◽  
A. Lobban ◽  
J. N. Reeves ◽  
S. Vaughan ◽  
M. Costa
Keyword(s):  
High Velocity ◽  
X Ray

scholarly journals The X-ray view of the Wolf-Rayet stars

1995 ◽  
Vol 163 ◽  
pp. 429-437
Author(s):  
A.M.T. Pollock
Keyword(s):  
High Velocity ◽  
X Ray ◽  
Wide Range ◽  
Colliding Winds

Ever since the earliest work, X-ray observations have been central in the chequered development of the study of interacting high-velocity winds in binaries. This review assesses how confidently the observations of Wolf-Rayet stars may be interpreted as the result of colliding winds, drawing attention to the wide range of X-ray luminosities even among the relatively bright binaries. Although the data do not generally conform to the simplest binary models, some suggestions are made to reconcile theory and observation.

scholarly journals Possible X-Ray Flares in a Recurrent Nova

1990 ◽  
Vol 122 ◽  
pp. 427-428
Author(s):  
Izumi Hachisu ◽  
Hiroshi Itoh
Keyword(s):  
Dynamical Evolution ◽  
Spectral Shape ◽  
Spherically Symmetric ◽  
X Rays ◽  
X Ray ◽  
Wind Region ◽  
Recurrent Nova ◽  
Red Giant ◽  
Hydrodynamic Code

Abstract:The dynamical evolution and nonequilibrium X-ray emission of recurrent nova remnants have been investigated by using a spherically symmetric hydrodynamic code. We assume that the nova ejecta expand into a wind from a red-giant companion. The wind material is blast-shocked, and emits copious X-rays. The blast shock soon breaks out of the wind region and the X-ray emission declines drastically. The blast shock eventually catches up with the relatively slow ejecta of the previous outbursts. The X-ray emission may then be rejuvenated in both luminosity and spectral shape.

scholarly journals Microstructure, Mechanical Properties and Wear Behavior of High-Velocity Oxygen-Fuel (HVOF) Sprayed (Cr3C2-NiCr+Al) Composite Coating on Ductile Cast Iron

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 840 ◽  
Author(s):  
Marzanna Ksiazek ◽  
Lukasz Boron ◽  
Adam Tchorz
Keyword(s):  
Cast Iron ◽  
Electron Microscope ◽  
High Velocity ◽  
Bending Strength ◽  
Wear Behavior ◽  
Ductile Cast Iron ◽  
Wear Behaviour ◽  
Wear Properties ◽  
Alloy Matrix ◽  
X Ray

In the present work Cr3C2-NiCr powder containing Al particles was deposited on ductile cast iron with high-velocity oxy-fuel (HVOF) thermal spray coating technique. An investigation was conducted to determine the role of Al particles in the Cr3C2-NiCr coating produced with HVOF technique on microstructure, mechanical and wear properties in a system Cr2C3-NiCr coating/ductile cast iron. The microstructure of the HVOF-sprayed Cr3C2-NiCr+Al coating was characterized by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). Microstructure analysis reveals the formation of coating with low porosity, good adhesion to the substrate and dense structure with irregularly shaped particles of Al arranged in strips and finely fragmented Cr3C2 particles embedded in a nanocrystalline Ni-Cr alloy matrix. In addition, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (Cr3C2-NiCr+Al)/ductile cast iron as well as microhardness and wear resistance of the coating. It was found that the addition of Al particles significantly increased resistance to cracking and wear behaviour in the studied system.

The AGN dependence on cluster mass

2018 ◽  
Vol 14 (S342) ◽  
pp. 145-148
Author(s):  
Elias Koulouridis ◽  
Keyword(s):  
Galaxy Clusters ◽  
High Velocity ◽  
High Redshift ◽  
High Mass ◽  
X Ray ◽  
Cluster Galaxies ◽  
Cluster Mass ◽  
Bona Fide ◽  
Low Mass ◽  
Velocity Dispersions

AbstractWe present the results of a study of the AGN density in a homogeneous and well studied sample of 167 bona-fide X-ray galaxy clusters (0.1<z<0.5). Our aim is to study the AGN activity in 167 XXL X-ray galaxy clusters as a function of the cluster mass and the location of the AGN in the cluster. We report a significant AGN excess in our low-mass cluster sub-sample between 0.5r500 and 2r500. In contrast, the high-mass sub-sample presents no AGN excess. The AGN excess in poor clusters indicates AGN triggering, supporting previous studies that reported enhanced galaxy merging in the cluster outskirts. This effect is probably prevented by high velocity dispersions in high-mass clusters. Comparing also with previous studies of massive or high-redshift clusters, we conclude that the AGN fraction in cluster galaxies anti-correlates strongly with cluster mass.

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