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In this paper, we derive the scaling laws for different radiating fluids. The studied regimes are relevant for both laboratory astrophysics and High Energy Density Physics. Using Lie groups theory, we obtain scaling laws, the similarity properties and the number of free parameters to rescale experiments. 相似文献
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C. Michaut T. Vinci L. Boireau M. Koenig S. Bouquet A. Benuzzi-Mounaix N. Osaki G. Herpe E. Falize B. Loupias S. Atzeni 《Astrophysics and Space Science》2007,307(1-3):159-164
This paper deals with the radiative shock from both theoretical and numerical points of view. It is based on the whole experimental
results obtained at Laboratoire d'Utilisation des Lasers Intenses (LULI, école Polytechnique). Radiative shocks are high-Mach
number shocks with a strong coupling between radiation and hydrodynamics which leads to a structure governed by a radiative
precursor. These shocks are involved in various astrophysical systems: stellar accretion shocks, pulsating stars, interaction
between supernovae and the interstellar medium. In laboratory, these radiative shocks are generated using high power lasers.
New diagnostics have been implemented to study the geometrical shape of the shock and the front shock density. Data were obtained
varying initial conditions for different laser intensities and temperature. The modeling of these phenomena is mainly performed
through numerical simulations (1D and 2D) and analytical studies. We exhibit results obtained from several radiative hydrodynamics
codes. As a result, it is possible to discuss about the influence of the geometry and physical parameters introduced in the
1D and 2D models. 相似文献
3.
E. Falize C. Michaut C. Cavet S. Bouquet M. Koenig B. Loupias A. Ravasio C. G. Gregory 《Astrophysics and Space Science》2009,322(1-4):71-75
In this paper we study specific classes of radiating shocks which are widely spread in astrophysical environments. We present new analytical solutions available for any exponents of typical power-law cooling function which generalize the five special cases (corresponding to specific values of these exponents) of radiating shocks structure and proceed to the analytical determination of physical quantities. Then an application of the results for the accretion shock in polar is realized. A discussion of the reproducibility of cooling layer in laboratory is proposed using scaling laws. 相似文献
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B. Loupias E. Falize M. Koenig S. Bouquet N. Ozaki A. Benuzzi-Mounaix C. Michaut M. Rabec le Goahec W. Nazarov C. Courtois Y. Aglitskiy A. YA. Faenov T. Pikuz 《Astrophysics and Space Science》2007,307(1-3):103-107
We present experiments performed with the LULI2000 nanosecond laser facility. We generated plasma jets by using specific designed
target. The main measured quantities related to the jet such as its propagation velocity, temperature and emissive radius
evolution are presented. We also performed analytical work, which explains the jet evolution in some cases. 相似文献
5.
��. Falize B. Loupias A. Ravasio C. D. Gregory A. Dizi��re M. Koenig C. Michaut C. Cavet P. Barroso J.-P. Leidinger X. Ribeyre J. Breil H. Takabe Y. Sakawa Y. Kuramitsu T. Morita N. C. Woolsey W. Nazarov S. Pikuz 《Astrophysics and Space Science》2011,336(1):81-85
In this paper, theoretical and experimental laboratory astrophysics results are presented from the POLAR project, the main focus of which is to design and diagnose an exact scaled accretion column using powerful lasers. These measurements allow the testing of the astrophysical models of accretion processes present in magnetic cataclysmic variables. 相似文献
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C. D. Gregory J. Howe B. Loupias S. Myers M. M. Notley Y. Sakawa A. Oya R. Kodama M. Koenig E. Falize S. Bouquet C. Michaut N. C. Woolsey 《Astrophysics and Space Science》2009,322(1-4):37-41
We present the results of experiments in which jets are created through the collision of two laser-produced plasmas. These experiments use a simple ‘v-foil’ target design: two thin foils are placed at an angle of 140° to each other, and irradiated with a high-energy laser. The plasmas from the rear face of these foils collide and drive plasma jets moving with a velocity of ～300 km?s?1. By choosing the foil thickness and material to suit the laser conditions available, it has proven possible to create plasma jets for which the relevant scaling parameters show significant overlap with those of outflows associated with young stellar objects (YSOs). Preliminary results are also shown from experiments to study the effect of an ambient gas on jet propagation. Nominally identical experiments are conducted either in vacuum or in an ambient medium of 5 mbar of nitrogen gas. The gas is seen to increase the jet collimation, and to introduce shock structures at the head of the outflow. 相似文献
7.
C. Michaut E. Falize C. Cavet S. Bouquet M. Koenig T. Vinci A. Reighard R. P. Drake 《Astrophysics and Space Science》2009,322(1-4):77-84
Radiative shocks (RS) occur in astrophysical systems and in high-energy density laboratory experiments. Aided by three dimensionless parameters, we propose a classification of RS into four types, integrating previous work that has focused independently on optical depth and on Mach number. Specific terms, such as a cooling function, a radiative flux, or radiative energy and pressure must be added to the Euler equations in order to model these various kinds of shocks. We examine how these terms correspond to the radiative classification regimes. In astrophysics, observed RS arise generally in optically thin material. Thus, radiation escapes without interaction with the surrounding gas, except perhaps to ionize it, and the energy loss in such shocks can be modeled by a cooling function Λ. In this case only the post-shock region is structured by the radiation cooling. We found the analytical solution for hydrodynamic equations including Λ∝ ρ ε P ζ x θ for arbitrary values of ε, ζ, θ. This is a completely new result. An application of this calculation for the accretion shock in cataclysmic variables of polar type is given in astrophysical terms. We also draw a parallel between RS experiments performed using the LULI2000 laser facility, in France and the Omega laser Facility, in USA. RS developed in these laboratories are more or less optically thick. These high-Mach number RS present a radiative precursor. 相似文献
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B. Loupias C. D. Gregory E. Falize J. Waugh D. Seiichi S. Pikuz Y. Kuramitsu A. Ravasio S. Bouquet C. Michaut P. Barroso M. Rabec le Gloahec W. Nazarov H. Takabe Y. Sakawa N. Woolsey M. Koenig 《Astrophysics and Space Science》2009,322(1-4):25-29
We present experimental results of plasma jet, interacted with an ambient medium, using intense lasers to investigate the complex features of astrophysical jets. This experiment was performed in France at the LULI facility, Ecole Polytechnique, using one long pulse laser to generate the jet and a short pulse laser to probe it by proton radiography. A foam filled cone target was used to generate high velocity plasma jet, and a gas jet nozzle produced the well known ambient medium. Using visible pyrometry and interferometry, we were able to measure the jet velocity and electronic density. We get a panel of measurements at various gas density and time delay. From these measurements, we could underline the growth of a perturbed shape of the jet interaction with the ambient medium. The reason of this last observation is still in debate and will be presented in the article. 相似文献
9.
In this work, we present a classification of laboratory astrophysics experiments. We introduce different invariance concepts
in order to build scaling laws and to determine the astrophysical relevant of laboratory experiments. Finally we present an
analysis of the two-temperature radiating fluid scalability. 相似文献
10.
Cécile Cavet Hung Chinh Nguyen Claire Michaut Emeric Falize Serge Bouquet Laurent Di Menza 《Astrophysics and Space Science》2009,322(1-4):91-95
Vishniac instability has been theoretically studied in supernova remnants where it is supposed to explain the fragmentation of the interstellar medium. However its role is not fully demonstrated in these astrophysical objects. Conditions and assumptions required for the instability growth are explained in detail in the present paper. In addition the HYDRO-MUSCL hydrodynamic code has been used to simulate this instability in order to compare the numerical growth rate with the Vishniac analytical solution. 相似文献
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