关键词: 等离子体反冲/
冲击压强/
激光加载/
激光干涉
English Abstract
Plasma recoil induced by laser radiated solid target
Zhou Lei1,2,Li Xiao-Ya2,
Zhu Wen-Jun2,
Wang Jia-Xiang3,
Tang Chang-Jian1
1.Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064, China;
2.Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China;
3.State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
Fund Project:Project supported by the Science and Technology Foundation of State Key Laboratory of Shock Wave and Detonation Physics, China (Grant Nos. 077110, 77160).Received Date:16 April 2015
Accepted Date:17 January 2016
Published Online:05 April 2016
Abstract:Based on the theory of conservation of momentum, a theoretical method of calculating the shock pressure induced by laser loading via diagnosing plasma recoil momentum is presented. When a high-power laser irradiates a solid target surface, the plasma jet with high velocity induced by laser has a recoil effect on the target. Then the plasma recoil momentum induced by laser irradiating solid target can be calculated by the distribution of electron plasma. At the same time, the subcritical electron plasma density could be measured by interferometry and the supercritical plasma density could be fitted into exponential function form. So the variation of shock wave pressure could be calculated via diagnosing plasma recoil momentum. This method does not consider the relationship between D and u, nor uses the window material nor needs the steady shock propagation. It is a useful method of studying the material property under high strain rate and isentropic compression. Numerical simulation results using one-dimensional radiation hydro code called MULTI for laser intensities ranging from 51012 W/cm2 to 51013 W/cm2 are presented. The electron temperature is nearly equal to the ion temperature for the laser pulse duration 2 ns but much greater than the ion temperature for = 1 ns. This means for that ns pulse duration, the difference between electron and ion temperature could be ignored in general. And in order to fit the shock pressure value more exactly, the density of ablation surface nabl = n0exp(-1) is used in the simulations. The simulation results indicate that the value of calculating shock pressure obtained via diagnosing plasma recoil momentum is similar to the shock pressure calculated by MULTI simulation for ns pulse duration. And the value of calculating shock pressure is also similar to the experimental value for pulse duration = 5 ns. From the simulation results, it is obvious that the method of calculating the shock pressure via diagnosing plasma recoil momentum is effective and feasible.
Keywords: plasma recoil/
shock pressure/
laser loading/
laser interference
