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In this paper, we describe a current generator which consists of the Marx, the current-limited resistors, and the output port and can produce a double-exponential current waveform with the 3 kA, the rise time 10 ns, the pulsewidth 100 ns following the requirement of the IEC 61000-4-25 standard, while the effective impedance of the tested systems does not exceed $2~\Omega $ . A new cavity of Marx is constructed by 12 steel rods which help assembly work more convenient; moreover, the current waveform has less disturbed signal. Because of using the cavity, the charging, trigger, and grounded circuits can be installed out of the Marx. Meanwhile, the cantilever insulated support of Marx also is used. The methods above can help make a compact current generator with a low inductance which can be beneficial to research the electromagnetic coupling laws of system circuit ports and chips.

The gas spark switch is the most used key device in pulsed power systems. As a difficult problem affecting the performance of the gas spark switch, electrode erosion has always been of wide concern and has been studied by scholars. In order to reduce electrode erosion, the erosion resistance of the electrode materials is particularly critical. At present, researchers at home and abroad mainly perform a large number of experiments to compare the erosion resistance of different electrode materials, which require a lot of time and are expensive. Based on the theoretical derivation of the erosion heat conduction process and the analysis of the molten pool movement process, a theoretical prediction model of erosion resistance of electrode materials is established in this paper. The prediction results of this model are consistent with the experimental results of most researchers in the past. In order to further verify the accuracy of this model, this paper selected six electrode materials [stainless steel, brass, RHEAs (Refractory High Entropy Alloys), 90WCu alloy, 70WCu alloy, and 50WCu alloy] tested for 10 000 times under the experimental conditions of a peak current of 30 kA, a single discharge charge transfer of 78 mC, and 2 bars dry air. The final experimental results show that the six electrode materials ranked from weak to strong in erosion resistance: brass, stainless steel, 50WCu, 70WCu, RHEAs, and 90WCu, which is consistent with the prediction results of the model.

To reduce the trigger threshold voltage of the multi-gap gas switch used for linear transformer drivers, a method is proposed by mounting resistors and capacitors in parallel with the switch gaps. Based on the circuit model of the six-gap gas switch, the gap voltage distribution during the triggering process is analyzed. When the multi-gap gas switch is triggered, the voltage distribution between gaps is mainly determined by the stray capacitance between electrodes. In such condition, the trigger voltage is not fully applied on the trigger gap, and as a consequence, a higher trigger voltage is required for obtaining a low jitter. The effects of capacitor parameters on the triggering characteristics of the switch are experimentally investigated. Compared with the original switch design, the results indicate that at a charging voltage of ±80 kV and operating at 60% of the self-breakdown voltage, the trigger voltage is reduced from 110 kV to 75 kV while the 3.2 ns jitter of the switch is preserved.

Cathode material affecting the electrical breakdown time delay and jitter of self-breakdown gas switch has been studied. Experiments have tested the electrical breakdown time delay of four typical cathode materials including stainless steel, brass, W-Cu alloy and graphite under different applied voltage. The gas switch is operated at N2 pressured of 0.1 MPa, in nanosecond pulsed discharge. The breakdown time delay values t d of different cathode materials as the function of the experimental ordinal number are presented. The contourgraph has been used to scan the surface morphology of four cathode electrodes. Comparing the breakdown time delay curve with the section morphology of cathode electrode, it has been preliminarily concluded that the breakdown time delay and jitter are potentially relevant to the surface condition, the surface morphology and physical parameters of cathode material.

The switch used in FLTD primary energy-storing system is chosen as the study object. A self-breakdown experiment of the switches with different gap length has been done at the same breakdown voltage by changing the gap pressure. The influence of the gap length on the switch performance has been researched by observing the change of the breakdown voltage distribution. The experiment result shows that, the self-breakdown voltage dispersion at 6 mm gap is the least. Breakdown voltage distribution with the gap length equal to or less than 6 mm is similar to Gauss distribution function and it is similar to extreme distribution function with the gap length larger than 6 mm. The switch with a long gap whose breakdown voltage distribution loses the symmetry has better static performance at low working ratio. According to the electrode structure used in this paper, the gap length should be chosen between 6 mm and 9 mm to get the best static performance. The reason for the change of breakdown voltage distribution is the alteration of the electric field influencing the electron emission on cathode.

Based on the “QiangGuang-I” facility, a 1-m-long magnetically insulated transmission line (MITL) with a 2-cm anode-cathode gap was designed and experimentally studied. The experimental results show that with the load resistance of 2.07 , current loss along the 1-m-long MITL is negligible, and nearly all of the current loss occurs in the transition from conical disk to coaxial geometry or the output port of the line. At the same time, a 1-D circuit model was developed for the analyses of the MITL on the basis of the transmission-line code. By using this model, the experimental MITL was simulated, and pivotal parameters were estimated. Comparisons indicate that the simulation results agree to 5% within those of the experiments.

Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of the FLTD. In this paper, the breakdown characteristics of the trigger gap and the overvoltage gap are studied experimentally. The reasons for the different breakdown performance of the two gaps are also investigated. The results show that the breakdown delay of the trigger gap is more influenced by the trigger voltage, while the breakdown delay of the overvoltage gap is more influenced by the working coefficient and always higher than that of the trigger gap. The jitter of the trigger gap is more influenced by the trigger voltage and accounts more than 60% of the total switch jitter, while the jitter of the overvoltage gap is hardly changed with the trigger voltage as well as the working coefficient and maintains less than 1.4 ns. It is proved that the discharging product from the trigger gap can effectively reduce the breakdown delay and jitter of the overvoltage gap. Based on that, the effect and improvement of pre-ionization on the two gaps are also studied. It is concluded that the jitter of the trigger gap reduces obviously when the pre-ionization is added, while the pre-ionization almost has no effect on the jitter of the overvoltage gap. The jitter of the overvoltage gap is about two times higher than the trigger gap in the pre-ionizing switch.