Investigation On The Equation Of State And Ionization Equilibrium For Warm Dense Plasma

The equation of state and ionization equilibrium of warm dense matter is widely encountered in the high-energy-density physics researches,such as inertial confinement fusion and wire-array Z-pinch.In this thesis,three global equation of state models are reviewed.The performance of different models under shock compression is studied.The equation of state for aluminum in warm dense matter regime is established based on partially ionized model with several important non-ideal effects taken into consideration.A non-deal Saha equation is deduced to calculate the ionization equilibrium.The property of equation of state ionization equilibrium in warm dense matter regime are studied.The magnetohydrodynamic calculation with“cold start”conditions for electrical explosion of metal wire is carried out with database of equation of state and ionization equilibrium obtained by above models.The accuracy of the equation of state and ionization equilibrium models is verified by comparing the simulated results with relevant experimental data.In order to describe the parameters of aluminum in multiphase region,the Mie-Grüneisen equation of state,Tillotson equation of state and Multi-Branch Analytical equation of state are studied Three fitting methods,which are Zero-Kelvin fitting,room temperature fitting and Hugoniot fitting are applied in the Mie-Grüneisen equation of state The performance of different equation of states under shock compression is analyzed.The Hugoniot curves,release isentrope curves and phase diagrams are calculated and compared with relevant experimental data.The above models can predict the thermodynamic behavior of aluminum under shock compression.In order to obtain parameters of equation of state and ionization equilibrium for aluminum in warm dense regime,an equation of state and ionization equilibrium for dense plasma based on partially ionized plasma model is constructed.The important non-ideal effects,such as the coulomb interaction between charged particles,excluded volume effect due to high density and polarization effect induced by interaction between atoms and charged particle are considered.The data of equation of state for aluminum plasma and the particle composition with density ranging from 1.0×10^-4 g/cm³ to 3.0 g/cm³ and temperature ranging from 1.0×10⁴ to 3.0×10⁴ K are calculated.The results are compared and analyzed with other models and related experimental data.According to the variation of key parameters such as free energy and ionization energy in the non-ideal Saha equation,the phenomenon that the average ionization degree of aluminum plasma increases rapidly with the density in critical density region is analyzed.The experimental setup for electrical explosion of metal wire is introduced briefly.The experimental setup consists of three parts:a high-voltage pulsed-current generator,a trigger circuit and a vacuum system.The pulsed-current generate nanosecond current with1?2k A in magnitude.The physical process of electrical explosion of metal wire is numerically simulated using the parameters of equation of state and ionization equilibrium of warm dense plasma.The calculation results of magnetohydrodynamics are compared with experimental results,which verifies the accuracy of the equation of state and ionization equilibrium model for warm dense plasma.