The ESTHER code is an open-source, one-dimensional, Lagrangian, radiative hydrodynamics code developed since 2004 at CEA [1,2]. It allows studying the evolution of a stacking of various media (metals, dielectrics), transiting from the solid to the plasma phase, under the effect of an intense, pulsed irradiation. This pulse may be a laser, X-rays, electrons, ions or a combination of these. The code simulates the energy deposition resulting from these pulses, the hydrodynamic evolution of fluid or solid materials, thermal conduction, radiative transfer, mechanical response of materials, and many other mechanisms.
The software is used for a very broad spectrum of applications, in very different operating regimes and for very different experimental equipments:
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‘cold’ regime, for the study of laser-induced shocks (mechanical damage, plasticity), for nanosecond pulses and moderate intensities ($I < 10^{12}, \mathrm{W/cm^2}$);
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‘WDM’ (Warm-Dense-Matter) regime, for simulating the dynamics of a medium moving from the solid phase to the plasma phase, in the femtosecond or nanosecond regime;
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plasma/‘hot’ regime, for the study of systems subjected to high-intensity lasers, where radiation effects need to be taken into account to simulate plasma evolution.
ESTHER is a code in permanent development: new features and models are regularly implemented, and since 2023, modernization work has been underway to improve its robustness and ease of use and development. Finally, since summer 2024, ESTHER has been available open-source on Gitlab. (subject to invitation, contact: mathurin.lagree@cea.fr or ludovic.lecherbourg@cea.fr)
![Left: illustration of the use of ESTHER in the ‘cold’ regime. [A] Consecutive images of the spalling of an aluminum sample following a laser shock. [B] Spatial stress profile in the aluminum sample, simulated with ESTHER, at the instant when, under tensile stress, the material ruptures and a spall is formed. [C] Experimental (red) and simulated (blue) free surface velocity profile of the aluminum sample. An arrow indicates the time for which the spall is created. Right: illustration of the use of ESTHER in the ‘WDM’ regime: study of the response of gold and its solid phases fcc and bcc following X-ray irradiation at the LCLS (Linac Coherent Light Source), and comparison with ESTHER (solid lines) [D] mass fraction of the two phases and [E] total mass density as a function of time.](https://www-lmce.cea.fr/images/plasma_physics/figure_esther.png)
Figure : ESTHER simulations in 'cold' and 'WDM' regimes
Left: illustration of the use of ESTHER in the ‘cold’ regime. [A] Consecutive images of the spalling of an aluminum sample following a laser shock. [B] Spatial stress profile in the aluminum sample, simulated with ESTHER, at the instant when, under tensile stress, the material ruptures and a spall is formed. [C] Experimental (red) and simulated (blue) free surface velocity profile of the aluminum sample. An arrow indicates the time for which the spall is created. Right: illustration of the use of ESTHER in the ‘WDM’ regime: study of the response of gold and its solid phases fcc and bcc following X-ray irradiation at the LCLS (Linac Coherent Light Source), and comparison with ESTHER (solid lines) [D] mass fraction of the two phases and [E] total mass density as a function of time.
Publications
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J.P. Colombier, P. Combis, F. Bonneau, R. Le Harzic, E. Audouard, “Hydrodynamic simulations of metal ablation by femtosecond laser irradiation,” Phys. Rev. B 71, 165406 (2005) DOI
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S. Bardy, B. Aubert, T. Bergara, L. Berthe, P. Combis, D. Hébert, E. Lescoute, Y. Rouchausse L. Videau, “Development of a numerical code for laser-induced shock waves applications,” Optics & Laser Technology 124, 105983 (2020) DOI