| In this dissertation, the background and the significance of plasma erosion opening switch (POS) research were outlined, and an overview about POS research in the world was stated. The trend of the future POS research is also discussed. Since the ambiguity still exits widely not only in POS fundamental theory and experiment, but also in engineering design up to now, the POS was investigated more deeply both in theory and experiment in the dissertation.Theoretically, the POS conducting phase, opening phase and power flow phase were investigated via analytical method and numerical simulation, respectively.For conducting phase, the scaling laws in different POS conduction regimes, i.e. magneto-hydrodynamics (MHD), electron magneto-hydrodynamics (EMHD) and bipolar (BP) were derived from 1D analytical model in coaxial geometry firstly, which could predict the relations between the conduction current, conduction time and the initial plasma density, cathode radius, and axial length of plasma. Upon this, a 2D snowplow numerical code was used to simulate the conduction phase in the MHD regime based on the parameters of the practical test-bed in our experiments. Sequence of snowplow fronts and the radial position where the opening will occur were obtained. The conduction time at different peak conduction current was predicted, and the results were consistent with the experimental data.For opening phase, two kinds of opening mechanism, i.e. Hall erosion and electrostatic erosion, were roughly derived and discussed qualitatively. Then the gap formation process was examined with the aid of particle-in-cell (PIC) simulation. It was shown that Hall erosion and electrostatic erosion will both affect the gap formation process. While the latter one that is introduced by magnetic field expulsion will dominate the opening process. With such a modified point of view, the present experimental observation could be explained better.For power flow phase, the coupling characteristics between the POS and the inductive load were studied by PIC code based on the practical test-bed parameters in our experiment. The simulation reproduced the power flow process from the POS to the load explicitly, accompanying with energetic electrons and ions flow. The POS voltage and load current obtained from the simulation were in good agreement with the experimental results.Experimentally, a 100 kA test-bed and corresponding electric and plasma diagnostics apparatus for POS investigation were established. The POS performance in variousconditions and its capability to drive a wire-array load were studied extensively. A novel high sensitivity interferometer that has widely applicable perspectives in pulsed power technology was developed. Afterward, the plasma gun was tested with the implementation of this interferometer.To investigate the plasma injector of the POS, the current variation and the time-integral plasma luminosity photograph during the discharge process of the plasma gun were acquired. In the experiments, a removable stainless steel plate was placed in the distance of 70 mm from the gun nozzle to mimic the cathode-plasma interaction in POS. With such a configuration, quasi-2D line-integrated electron density distribution and the .average injection velocity of plasma were obtained with the interferometer, which are helpful for the 2D snowplow simulation and the optimization of the design for the plasma gun.In the experiments, the POS performance was investigated with different initial injection plasma parameters, including variety of Marx-plasma guns time delay, plasma guns working voltage (21 kV, 24 kV and 27 kV) and the number of the guns (1, 2,4 and 8). Different Marx discharging voltage (120 kV, 200 kV and 280 kV) and different POS cathode radii (1 cm and 2 cm) were also adopted. It is concluded that, the conduction current and the conduction time increase with increasing Marx-plasma gun time delay, plasma guns working voltage and the number of the guns. The rise time of the load current decreases and voltage multiplication fa... |
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