High-energy density laboratory astrophysics studies of accretion shocks in magnetic cataclysmic variables

Falize, É.; Ravasio, A.; Loupias, B.; Dizière, A.; Grégory, C.; Michaut, C.; Busschaert, C.; Cavet, Cécile; Kœnig, M.

doi:10.1016/j.hedp.2011.10.001

Cited by 27 publications

(20 citation statements)

References 17 publications

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“…This is the main objective of a laboratory astrophysics project: the POLAR project (Falize et al 2011a). The possibility of producing relevant experiments has been demonstrated on the LULI2000 facility (Falize et al 2012). The experimental way is a complementary approach to increase our understanding of the radiation hydrodynamics of accretion shock.…”

Section: Discussionmentioning

confidence: 99%

Quasi-periodic oscillations in accreting magnetic white dwarfs

Busschaert

Falize

Michaut

et al. 2015

A&A

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Context. Magnetic cataclysmic variables are close binary systems containing a strongly magnetized white dwarf that accretes matter coming from an M-dwarf companion. The high magnetic field strength leads to the formation of an accretion column instead of an accretion disk. High-energy radiation coming from those objects is emitted from the column close to the white dwarf photosphere at the impact region. Its properties depend on the characteristics of the white dwarf and an accurate accretion column model allows the properties of the binary system to be inferred, such as the white dwarf mass, its magnetic field, and the accretion rate. Aims. We study the temporal and spectral behaviour of the accretion region and use the tools we developed to accurately connect the simulation results to the X-ray and optical astronomical observations. Methods. The radiation hydrodynamics code H was adapted to simulate this specific accretion phenomena. Classical approaches were used to model the radiative losses of the two main radiative processes: bremsstrahlung and cyclotron. Synthetic light curves and X-ray spectra were extracted from numerical simulations. A fast Fourier analysis was performed on the simulated light curves. The oscillation frequencies and amplitudes in the X-ray and optical domains are studied to compare those numerical results to observational ones. Different dimensional formulae were developed to complete the numerical evaluations. Results. The complete characterization of the emitting region is described for the two main radiative regimes: when only the bremsstrahlung losses and when both cyclotron and bremsstrahlung losses are considered. The effect of the non-linear cooling instability regime on the accretion column behaviour is analysed. Variation in luminosity on short timescales (∼1 s quasi-periodic oscillations) is an expected consequence of this specific dynamic. The importance of secondary shock instability on the quasi-periodic oscillation phenomenon is discussed. The stabilization effect of the cyclotron process is confirmed by our numerical simulations, as well as the power distribution in the various modes of oscillation.

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Section: Discussionmentioning

confidence: 99%

Quasi-periodic oscillations in accreting magnetic white dwarfs

Busschaert

Falize

Michaut

et al. 2015

A&A

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“…Then we applied this new scheme to a laboratory astrophysics experiment (POLAR) that has been performed on LULI2000 [13] . We illustrate the quality of the radiography technique by looking at the propagation of a high Mach number (M = 5-10) plasma flow.…”

Section: Introductionmentioning

confidence: 99%

Short-pulse laser-driven x-ray radiography

Brambrink

Baton

Kœnig

et al. 2016

High Pow Laser Sci Eng

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We have developed a new radiography setup with a short-pulse laser-driven x-ray source. Using a radiography axis perpendicular to both long-and short-pulse lasers allowed optimizing the incident angle of the short-pulse laser on the x-ray source target. The setup has been tested with various x-ray source target materials and different laser wavelengths. Signal to noise ratios are presented as well as achieved spatial resolutions. The high quality of our technique is illustrated on a plasma flow radiograph obtained during a laboratory astrophysics experiment on POLARs.

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“…In laboratory astrophysics experiments, radiative shocks have been generated by driving a solid density plastic or beryllium piston into a xenon gas cell [4,[11][12][13][14][15][16][17][18] by using a kJ laser to irradiate a pin or foil within a moderate-to high-Z background gas [19,20] or by depositing directly the energy of the laser into gas formed by atomic clusters [8,[21][22][23][24]. For a given shock velocity and a given initial gas pressure, materials with high atomic numbers suit the achievement of the radiative regime, and for this reason, xenon is commonly used as the medium in which the radiative shock propagates.…”

Section: Introductionmentioning

confidence: 99%

Microscopic properties of xenon plasmas for density and temperature regimes of laboratory astrophysics experiments on radiative shocks

et al. 2015

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This work is divided into two parts. In the first one, a study of radiative properties (such as monochromatic and the Rosseland and Planck mean opacities, monochromatic emissivities, and radiative power loss) and of the average ionization and charge state distribution of xenon plasmas in a range of plasma conditions of interest in laboratory astrophysics and extreme ultraviolet lithography is performed. We have made a particular emphasis in the analysis of the validity of the assumption of local thermodynamic equilibrium and the influence of the atomic description in the calculation of the radiative properties. Using the results obtained in this study, in the second part of the work we have analyzed a radiative shock that propagated in xenon generated in an experiment carried out at the Prague Asterix Laser System. In particular, we have addressed the effect of plasma self-absorption in the radiative precursor, the influence of the radiation emitted from the shocked shell and the plasma self-emission in the radiative precursor, the cooling time in the cooling layer, and the possibility of thermal instabilities in the postshock region.

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High-energy density laboratory astrophysics studies of accretion shocks in magnetic cataclysmic variables

Cited by 27 publications

References 17 publications

Quasi-periodic oscillations in accreting magnetic white dwarfs

Quasi-periodic oscillations in accreting magnetic white dwarfs

Short-pulse laser-driven x-ray radiography

Microscopic properties of xenon plasmas for density and temperature regimes of laboratory astrophysics experiments on radiative shocks

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