Electrical Properties Of High Pressure Liquid Gas Under Strong Laser Loading

The electrical conductivity of materials at high pressure is an important part of the research of electrical properties,which is of great significance to new energy development and planetary science research.High power-laser loading technology can drive materials to achieve ultra-high pressure and high density,and nowadays the diagnosis of mechanical parameters and temperature of it is becoming more and more mature,therefor it is a good choice to utilize this technology to carry out experiments at extreme conditions.However,due to the harsh conditions of the experiment,it is difficult to measure the electrical conductivity of the material directly under high power laser loading.So,it is very important to study and explore the method to diagnose the electrical conductivity of materials at high pressure.In this paper,the research of conductivity of liquid deuterium at high pressure was carried out under SG-II laser device.At first,the traditional diagnostic methods of conductivity under high pressure was analyzed.Then,the conductivity model of low Z materials was established by using the existing diagnosing conditions of the laboratory and the special properties of the material.Finally,the experiment was carried out to measure the electrical conductivity of liquid deuterium.Density,shocked temperature and reflectivity were need for measuring the electrical conductivity.The results show that,deuterium at this range of pressure has an ionization about 67%,electronic conductivity about 2.87 × 105(?m)-1,which means the shocked deuterium reaches a conducting state characteristic of metallic fluid.Apparently,the transition from the insulating molecular state to metallic state of deuterium begins at a lower pressure.We also analyzed the errors of the reflectivity measurement in the experiment,and found that the instability of the probe laser in the measurement time might bring great error to the reflectivity measurement.In order to reduce this error,this paper designed a new system to measure the reflectivity of material more accurately at high pressure under the original diagnosis system of the ninth laser device.