Experimental Studies Of Equation-of-State Driven By High Power Lasers——The Research Of Absolute Measurement Of High Pressure Equation-of-State Of Aluminum

The equation of state (EOS) of matter at high pressure is a very important parameter for weapon designing, and it is one of the most important content in the forward science of inertial confinement fusion (ICF). It is also of great importance to the study of many phenomena in astrophysics, planetary physics, geophysics, high- density plasma and material science. With the foundation and upgrading of many high power laser facilities, a new method of using high power laser driving shock wave to study the materials EQS has been found under the laboratory conditions. Facing with the fact of nuclear test forbidding, performing laser EQS experimental research under the laboratory conditions shows more important and is the developing direction for this subject. Hugoniot data at pressure of TPa region have been obtained for some materials in laser EQS experiment. However, most of those EQS data were derived from a sample relative to the EQS of a standard material in a method called impedance-match, so their accuracy were strongly depend on the accuracy of the standard material抯 EQS data. Often, there are not the corresponding standard material抯 EQS data at pressure of TPa region, therefore the scientists working on EQS always make the effort to solve the problem of carrying out absolute measurement for laser EQS at pressure of TPa region. All of us know that double-foil driven by high power laser have two main applications in experimental EQS studies, the first one is to use it as pressure multiplier (pressure enhancement effect), the second one is to use it as a method for absolute measurement. But, there are two key conditions to be satisfied. The first one is that the symmetric impact should be achieved between the flyer and the target, which needs the flyer to recover its initial state before the impact. The second one is V ABSTRACT that there is widely stable range of shock wave propagation in the target, which is convenient for fabricating target and improving experimental measurement accuracy. Though some scientists have done some researches on the flyer states and the target response recently, we haven抰 seen any reliable reference. So, researching the method for absolute measurement of laser EOS by using the double-foil target was the study aim in this paper. Using the principle of theory coupling with experiment, we studied the physical process of laser directly driving an aluminum flyer impact an aluminum target. And gave the physical profiles of the accelerated flyer state and the shock wave propagation properties in the target. Also we did experimental researches on the EOS absolute measurement, and acquired some novel results. Firstly, numerical simulations were done for the model of laser directly driving an aluminum flyer impact an aluminum target. The effects of several parameters on the state of the accelerated flyer and the characteristics of shock wave propagation in the target were studied in detail, and the physical data and physical profilers were obtained more generally, which made us understand the whole physical process more profoundly. Simulation results showed that laser intensity and duration (FWHM), flyer thickness, impact distance, flyer and target抯 material, etc., have obvious effect on the flyer state and the shock wave characteristic in the target. If the parameters of laser...