scholarly journals Characterization of laser-driven Radiative shock of Astrophysical interests

2015 ◽  
Vol 11 (A29A) ◽  
Author(s):  
U. Chaulagain ◽  
C. Stehlé ◽  
J. Larour ◽  
M. Kozlová ◽  
F. Suzuki-Vidal ◽  
...  
Keyword(s):  
Shock Waves ◽  
Shock Structure ◽  
Experimental Results ◽  
Radiative Shock ◽  
X Ray ◽  
Laser Facility ◽  
Post Shock

AbstractWe highlight the recent experimental results on laser-driven radiative shock waves of astrophysical interests using kJ PALS laser facility. The generated shock is probed instantaneously by X-ray laser (λ = 21.2 nm) showing an unambiguous shock structure that includes both the post-shock and the precursor.

scholarly journals Target Design for XUV Probing of Radiative Shock Experiments

2020 ◽  
Vol 6 (1) ◽  
pp. 30-41
Author(s):  
U. Chaulagain ◽  
C. Stehlé ◽  
P. Barroso ◽  
M. Kozlova ◽  
J. Nejdl ◽  
...  
Keyword(s):  
Laboratory Astrophysics ◽  
The Novel ◽  
Radiative Shock ◽  
Radiative Shocks ◽  
Numerical Studies ◽  
Laser Facility ◽  
Post Shock ◽  
Technical Specifications ◽  
Novel Design ◽  
Target Design

Radiative shocks are strong shocks characterized by plasma at a high temperature emitting an important fraction of its energy as radiation. Radiative shocks are commonly found in many astrophysical systems and are templates of radiative hydrodynamic flows, which can be studied experimentally using high-power lasers. This is not only important in the context of laboratory astrophysics but also to benchmark numerical studies. We present details on the design of experiments on radiative shocks in xenon gas performed at the kJ scale PALS laser facility. It includes technical specifications for the tube targets design and numerical studies with the 1-D radiative hydrodynamics code MULTI. Emphasis is given to the technical feasibility of an XUV imaging diagnostic with a 21 nm (~58 eV) probing beam, which allows to probe simultaneously the post-shock and the precursor region ahead of the shock. The novel design of the target together with the improved X-ray optics and XUV source allow to show both the dense post-shock structure and the precursor of the radiative shock.

scholarly journals Hard x-ray transmission curved crystal spectrometers (10–100 keV) for laser fusion experiments at the ShenGuang-III laser facility

2016 ◽  
Vol 4 ◽  
Author(s):  
Ming-hai Yu ◽  
Guang-yue Hu ◽  
Ning An ◽  
Feng Qian ◽  
Yu-chi Wu ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Optical Design ◽  
Experimental Results ◽  
Laser Fusion ◽  
Recording Medium ◽  
High Quality ◽  
X Ray ◽  
Laser Facility ◽  
Working Distance ◽  
Spectral Ranges

Two transmission curved crystal spectrometers are designed to measure the hard x-ray emission in the laser fusion experiment of Compton radiography of implosion target on ShenGuang-III laser facility in China. Cylindrically curved ${\it\alpha}$ -quartz (10–11) crystals with curvature radii of 150 and 300 mm are used to cover spectral ranges of 10–56 and 17–100 keV, respectively. The distance between the crystal and the x-ray source can be changed over a broad distance from 200 to 1500 mm. The optical design, including the integral reflectivity of the curved crystal, the sensitivity, and the spectral resolution of the spectrometers, is discussed. We also provide mechanic design details and experimental results using a Mo anode x-ray source. High-quality spectra were obtained. We confirmed that the spectral resolution can be improved by increasing the working distance, which is the distance between the recording medium and the Rowland circle.

scholarly journals Laboratory radiative accretion shocks on GEKKO XII laser facility for POLAR project

2018 ◽  
Vol 6 ◽  
Author(s):  
L. Van Box Som ◽  
É. Falize ◽  
M. Koenig ◽  
Y. Sakawa ◽  
B. Albertazzi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Laser Energy ◽  
High Energy ◽  
Experimental Results ◽  
Material Structure ◽  
Reverse Shock ◽  
Before And After ◽  
Laser Facility ◽  
Post Shock ◽  
Accretion Shocks

A new target design is presented to model high-energy radiative accretion shocks in polars. In this paper, we present the experimental results obtained on the GEKKO XII laser facility for the POLAR project. The experimental results are compared with 2D FCI2 simulations to characterize the dynamics and the structure of plasma flow before and after the collision. The good agreement between simulations and experimental data confirms the formation of a reverse shock where cooling losses start modifying the post-shock region. With the multi-material structure of the target, a hydrodynamic collimation is exhibited and a radiative structure coupled with the reverse shock is highlighted in both experimental data and simulations. The flexibility of the laser energy produced on GEKKO XII allowed us to produce high-velocity flows and study new and interesting radiation hydrodynamic regimes between those obtained on the LULI2000 and Orion laser facilities.

scholarly journals Analysis of microscopic properties of radiative shock experiments performed at the Orion laser facility

2018 ◽  
Vol 6 ◽  
Author(s):  
R. Rodríguez ◽  
G. Espinosa ◽  
J. M. Gil ◽  
F. Suzuki-Vidal ◽  
T. Clayson ◽  
...  
Keyword(s):  
Spectroscopic Properties ◽  
Radiation Hydrodynamics ◽  
Post Processing ◽  
Radiative Shock ◽  
Hydrodynamic Simulations ◽  
Shock Region ◽  
Laser Facility ◽  
Post Shock ◽  
Charge State Distributions ◽  
Thermodynamic Regime

In this work we have conducted a study on the radiative and spectroscopic properties of the radiative precursor and the post-shock region from experiments with radiative shocks in xenon performed at the Orion laser facility. The study is based on post-processing of radiation-hydrodynamics simulations of the experiment. In particular, we have analyzed the thermodynamic regime of the plasma, the charge state distributions, the monochromatic opacities and emissivities, and the specific intensities for plasma conditions of both regions. The study of the intensities is a useful tool to estimate ranges of electron temperatures present in the xenon plasma in these experiments and the analysis performed of the microscopic properties commented above helps to better understand the intensity spectra. Finally, a theoretical analysis of the possibility of the onset of isobaric thermal instabilities in the post-shock has been made, concluding that the instabilities obtained in the radiative-hydrodynamic simulations could be thermal ones due to strong radiative cooling.

Growth Mechanism and Characterization of Porous CuS Microspheres

2012 ◽  
Vol 568 ◽  
pp. 348-351
Author(s):  
Shuang Xu ◽  
Nuan Song ◽  
Chang Li Qiu ◽  
Yao Ping Zhang ◽  
Jian Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Mechanism ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this paper, a facile method was presented to fabricate CuS porous microspheres, which were formed by the intergrowth of CuS polycrystalline nanoslices. The obtained sample has been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electronic diffraction (SAED), and scanning electron microscopy (SEM). On the basis of the experimental results, we proposed a self-assemble mechanism to elucidate the formation of CuS nanoslice structure.

Precursor photo-ionization model for magnetically-driven transverse shock waves

1977 ◽  
Vol 17 (1) ◽  
pp. 69-84 ◽  
Author(s):  
B. P. Leonard
Keyword(s):  
Magnetic Field ◽  
Shock Waves ◽  
Transverse Field ◽  
Shock Structure ◽  
Ionization Mechanism ◽  
Previous Theory ◽  
Shock Speed ◽  
Post Shock ◽  
Ionization Model ◽  
Wave Normal

Shock waves produced by magnetic compression are called transverse when the magnetic field contains no component in the direction of the shock wave normal. It is experimentally well known that very strong shocks of this type show classical MHD behaviour in terms of both jump conditions and structure. It is also known that relatively slow transverse shocks can be of an ionizing gasdynamic type with no jump in the imbedded transverse field. Since there are fundamental differences in both the structure and the jump relationships of these two types of shock waves, it is of interest to investigate the transition behaviour in the intermediate shock speed regime. A previously widely accepted model due to Kulikovskii & Lyubimov and Chu assumes no precursor ionization and requires significantly large values of the magnetic Prandtl number, Pm, within the shock structure. That model is shown to be physically inappropriate because experimentally observed transition speeds and corresponding post-shock temperatures imply negligibly small shock Pm values. Also in that model, MHD conditions are approached only asymptotically at large shock speeds. The present precursor ionization model assumes effectively zero Pm values throughout transition and into the low-speed MHD regime. As distinct from the previous theory, this model predicts the attainment of full MHD conditions at and above a well-defined finite shock speed. The assumption of a characteristic post-shock temperature model for the ionization mechanism allows unique jump relations to be formulated independently of other transport mechanisms. Results include computed values of various jump ratios and the electric field as functions of shock speed throughout gasdynamic, transition, and MHD regimes. The solutions form a one-parameter family depending on the relative combination of upstream magnetic field and density (e.g. the Alfvén velocity). Shock structure phase plane trajectories are computed at a number of typical shock speeds throughout transition.

scholarly journals Shock Damage Analysis in Serial Femtosecond Crystallography Data Collected at MHz X-ray Free-Electron Lasers

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1145
Author(s):  
Alexander Gorel ◽  
Marie Luise Grünbein ◽  
Richard Bean ◽  
Johan Bielecki ◽  
Mario Hilpert ◽  
...  
Keyword(s):  
Shock Waves ◽  
Free Electron ◽  
Liquid Jets ◽  
Erroneous Conclusion ◽  
X Ray ◽  
Laser Facility ◽  
Jet Behavior ◽  
Supersonic Shock ◽  
Serial Femtosecond Crystallography ◽  
Do So

Serial femtosecond crystallography (SFX) data were recorded at the European X-ray free-electron laser facility (EuXFEL) with protein microcrystals delivered via a microscopic liquid jet. An XFEL beam striking such a jet may launch supersonic shock waves up the jet, compromising the oncoming sample. To investigate this efficiently, we employed a novel XFEL pulse pattern to nominally expose the sample to between zero and four shock waves before being probed. Analyzing hit rate, indexing rate, and resolution for diffraction data recorded at MHz pulse rates, we found no evidence of damage. Notably, however, this conclusion could only be drawn after careful identification and assimilation of numerous interrelated experimental factors, which we describe in detail. Failure to do so would have led to an erroneous conclusion. Femtosecond photography of the sample-carrying jet revealed critically different jet behavior from that of all homogeneous liquid jets studied to date in this manner.

scholarly journals Spatial and temporal characteristics of X-ray emission from hot plasma driven by a relativistic femtosecond laser pulse

2009 ◽  
Vol 27 (1) ◽  
pp. 19-26 ◽  
Author(s):  
W. Hong ◽  
Y. He ◽  
T. Wen ◽  
H. Du ◽  
J. Teng ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Intensity ◽  
Laser Fusion ◽  
X Rays ◽  
X Ray ◽  
Hot Plasma ◽  
Laser Facility ◽  
Jet Structure ◽  
Spatial And Temporal Characteristics

AbstractWe present the temporal and spatial characterization of X-ray sources (at ~1 keV) driven by a 200 TW, 30 fs, 800 nm laser pulse on SILEX-I laser facility at Research Center of Laser Fusion. For laser copper foil interaction with laser intensity between 6 × 1018 W/cm2and 3 × 1019 W/cm2, the X-ray images show cone-like jet structures. While the yield of X-rays is strongly dependent on the laser intensity, the plasma expansion length is weakly dependent on the laser intensity, and the open angle of the cone-like jet is not correlated to the laser intensity. The formation of the jet structure is attributed to the plasma transverse confine by the self-induced quasi-static magnetic field. An X-ray pedestal 4 ns preceding the main pulse was observed. The correlation between X-ray pedestal and collimated proton beam generation was found.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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