Numerical analysis of laser-driven reservoir dynamics for shockless loading

Journal Article · Sun May 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3575317· OSTI ID:21560228

Mu, Li; Hongping, Zhang; Chengwei, Sun; Jianheng, Zhao; Hong, Yuan ^[1]

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1. Institute of Fluid Physics, Chinese Academy of Engineering Physics, P.O. Box 919-113, Mianyang, Sichuan 621900 (China)

Laser-driven plasma loader for shockless compression provides a new approach to study the rapid compression response of materials not attainable in conventional shock experiments. In this method, the strain rate is varied from {approx}10{sup 6}/s to {approx}10{sup 8}/s, significantly higher than other shockless compression methods. Thus, this loading process is attractive in the research of solid material dynamics and astrophysics. The objective of the current study is to demonstrate the dynamic properties of the jet from the rear surface of the reservoir, and how important parameters such as peak load, rise time, shockless compression depth, and stagnating melt depth in the sample vary with laser intensity, laser pulse length, reservoir thickness, vacuum gap size, and even the sample material. Numerical simulations based on the space-time conservation element and solution element method, together with the bulk ablation model, were used. The dynamics of the reservoir depend on the laser intensity, pulse length, equation of state, as well as the molecular structure of the reservoir. The critical pressure condition at which the reservoir will unload, similar to a gas or weak plasma, is 40-80 GPa before expansion. The momentum distribution bulges downward near the front of the plasma jet, which is an important characteristic that determines shockless compression. The total energy density is the most important parameter, and has great influence on the jet characteristics, and consequently on the shockless compression characteristics. If the reservoir is of a single material irradiated at a given laser condition, the relation of peak load and shockless compression depth is in conflict, and the highest loads correspond to the smallest thickness of sample. The temperature of jet front runs up several electron volts after impacting on the sample, and the heat transfer between the stagnating plasma and the sample is sufficiently significant to induce the melting of the sample surface. However, this diffusion heat wave propagates much more slowly than the stress wave, and has minimal effect on the shockless compression progress at a deeper position.

• OSTI ID: 21560228
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 9; Other Information: DOI: 10.1063/1.3575317; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABLATION
COMPRESSION
CRITICAL PRESSURE
DIFFUSION
ENERGY DENSITY
EQUATIONS OF STATE
HEAT TRANSFER
LASER RADIATION
LOADING
MOLECULAR STRUCTURE
NUMERICAL ANALYSIS
PLASMA JETS
PLASMA PRESSURE
PLASMA SIMULATION
PRESSURE RANGE GIGA PA
PULSE RISE TIME
SPACE-TIME
STRESSES
THERMODYNAMICS
ELECTROMAGNETIC RADIATION
ENERGY TRANSFER
EQUATIONS
MATERIALS HANDLING
MATHEMATICS
PHYSICAL PROPERTIES
PRESSURE RANGE
RADIATIONS
SIMULATION
THERMODYNAMIC PROPERTIES
TIMING PROPERTIES