| The off-Hugoniot behaviors characterized by magnetically driven quasi-isentropic compression experiment(ICE)and the Equation of State for materials under pressure of TPa are important issues of high energy density physics at extremes.As an emerging dynamic high-pressure loading technique,ICE has been identified to be uniformity,high efficiency,adjustability and repeatability,and with growing promotability and attraction to many fields such as material dynamics,nuclear weapon physics,condensed matter physics in extreme states,thermonuclear fusion,etc.In this dissertation,the CQ/CJ series pulsed power devices developed by the Institute of Fluid Physics,Chinese Academy of Engineering Physics were used as the experimental platform to carry out three type of magnetically driven implosion,compression experiments with cylindrical configurations,which are as follows:metal liner high-velocity implosion experiment,ICE of compact rectangular cylinder configuration with low inductance,and experiment of explosive magnetic flux compression generator(MC-1 generator).A one-dimensional magnetohydrodynamics simulation program SSS-MHD was used throughout the three experimental studies and played an important role in experimental design,parameter selection,data analysis and so on.The main research results of this dissertation are as follows:(1)The original SSS-MHD program was revised and improved,which is embodied in that an approximate calculation method of magnetic field/pressure in planar cavity is presented;the calculation function of the program was extended;the material model was enriched;the accuracy,versatility and reliability of the program were improved.(2)The magnetically driven metal liner high-velocity implosion experiment of small cylindrical liner under pulse current has been successfully carried out on the pulsed power device CQ-3.Imploded by a pulsed load current with a peak 2.1 MA and a rise time 480 ns,the implosion velocity of 2024 Al liner with an initial inner diameter of about 5 mm and a thickness of about 0.5 mm attained 6.57 km/s,and the quasi-isentropic hydrostatic pressure of 2024 A1 of the inner liner reached 19 GPa.The double thin shell(implosion liner and current returning channel)model incorporated with circuit equations can effectively simulate the motion behaviors of liners,and can be used in the physics design of experiments.(3)A compact rectangular cylinder configuration with low inductance was designed and verified experimentally.The results show that the influence of rarefaction wave on the strip-line configuration’s side boundary can be effectively suppressed,and the electromagnetic loading time is extended.Thus,the effective loading current density can be improved by reducing the width of the load configuration.A compact flyer configuration was designed based on the above results and tested on the pulsed power device CQ7.The maximum velocity of 2A12 A1 flyer with initial thickness of 0.2～0.3 mm attained about 8 km/s,driven by a pulsed load current with the peak of 3～3.3 MA and a rise time of 360 ns.(4)The quasi-isentropic compression experiment of DT4 iron material was carried out with CJ-100 MC-1 generator.A hollow sandwich cylindrical target with iron material inside and copper material outside(initial inner radius of 3 mm,total thickness of 2 mm,iron and copper thickness of 1 mm respectively)was driven to a velocity of 6.43 km/s,and a quasi-isentropic hydrostatic pressure of about 206 GPa was obtained in the iron.A solid target filled with LiD was designed to obtained a peak loading pressure of about 350 GPa for the dynamic high pressure metallization experiment,and the experimental results were predicted. |
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