Marx generator

About: Marx generator is a research topic. Over the lifetime, 1276 publications have been published within this topic receiving 8970 citations.

Electrical modeling of mercury for optimal machine design and performance estimation

Abstract: Mercury is a new pulsed-power generator at NRL, having been transferred from FZK (Forschungszentrum Karlsruhe, Germany) where it was known as KALIFHELIA [R. J. Commisso et al., 2003; P. Hoppe et al., 2001]. Mercury is an MIVA (magnetically-insulated inductive voltage adder) designed to produce 50-ns pulses with load voltages up to 6 MV at a current of 360 kA and deliver 100-kJ of energy to the load [J. Fockler et al., 1993]. The inductive and resistive components connecting the Marx bank and the intermediate stores have been reconfigured to fit into one "machine tank" and to improve energy transfer, allowing for a reduced Marx charge voltage. A detailed circuit model was developed for Mercury based on an earlier model for KALIF-HELIA and updated to include new information and data from FZK. Circuit element values for the MIVA and the load were determined through PIC simulations. Good agreement between measured and calculated current and voltage peaks was found using the model fed by voltage signals measured upstream of the MIVA on KALIF-HELIA. Detailed modeling has shown that the original design parameters of the machine can be met at NRL.

Effects of Laser Triggering Parameters on Runtime and Jitter of a Gas Switch

Abstract: The University of Missouri has studied parameters affecting the runtime and jitter of a laser triggered gas switch. Experiments tested a variety of switch parameters including percentage of self-break and charge voltage. The effects of laser beam parameters were also considered, including focal length, laser energy and laser spark length. Experiments were performed on the Tiger pulsed power machine. Measurements were taken on a spark gap switch built from the trigger section of a Rimfire switch. A Marx bank consisting of 32, 3.1 uF, capacitors that feeds into a 7 nF intermediate storage capacitor drives the switch into a 4 Omega resistive load. The test switch was pressurized with SF6 and operated near 1 MV, at a switch pressure of 30 psig. A 30 mJ, 266 nm, Nd:YAG laser was used to trigger breakdown of the switch. The laser was focused at the midgap between the electrodes using lenses with focal lengths between 30 cm and 100 cm. Focused laser energy in the switch ranged from <5 mJ to 20 mJ. The effects of switch and laser beam parameters on the runtime and jitter of a laser triggered gas switch are presented. The end goal of the research is to determine optimal conditions for improved switch performance.

PWM Voltage Droop Compensation for Bipolar Solid-State Marx Generator Topologies

Abstract: This paper presents a novel technique for the voltage droop compensation of long pulses in solid-state bipolar high-voltage Marx generators. Considering the modularity of Marx generators the compensation consists in adding one extra stage to perform as a pulsewidth modulation circuit. This stage voltage is added to the output positive or negative pulses, and an output $L_{f}C_{f}$ filter is included to smooth the voltage pulse waveform. A five-stage laboratory prototype of this circuit has been assembled using 1200-V Insulated Gate Bipolar Transistors and diodes with 1000-V dc input voltage. The circuit was operated at 50-Hz bipolar pulse rate, giving 4-kV bipolar pulses, into a resistive load, with 100- $\mu \text{s}$ pulsewidth and 9.5-ms relaxation time. The circuit was able to compensate 10% of bipolar pulse voltage droop.

Study on a Marx generator with high-voltage silicon-stacks instead of isolating inductances

Abstract: Marx generator is a voltage boosting device for power pulse compression, in which its capacitors are charged in parallel and discharged in series. To get a higher voltage boost ratio, high-voltage silicon stacks have been applied to substitute the isolated inductances in this study. Experiments with two isolation modes in the Marx generator have been carried out. Experimental results reveal that the high-voltage silicon stacks with the parameters of 50 kV/1 kA used in the Marx generator can increase the voltage step-up ratio to 168.6:1, up from 141:1 and 162.9:1 when isolating inductances and silicon-stacks with parameters of 50 kV/3 kA are applied, respectively. Moreover, the silicon stack-isolating-type Marx generator can almost eliminate the pre-pulse existing on the load if the isolated inductances employed. Therefore, it is crucial to choose appropriate high-voltage silicon stacks as the isolating devices in the Marx generator designed in this study.

406‐nm laser on the C→B band of N2

Abstract: Intense visible laser emission on the 0‐3 transition of the N2 (C→B) band at 405.9 nm has been observed by exciting Ar/5–10% N2( pTOTAL ≈2000 Torr) gas mixtures with a long‐pulse (∼0.5 μs) electron beam of cylindrical symmetry. The experimental apparatus consists of a coaxial diode of 50 cm length and 250 cm3 anode volume driven by a low inductance, ∼250‐kV Marx generator. Lasing on the violet line occurs following bottlenecking of the 0‐1 and 0‐2 ultraviolet laser transitions. With ∼0.8% output coupling at 406 nm, a maximum output energy of 2.2 mJ in a 200‐ns FWHM pulse has been obtained in the violet which is comparable to that extracted (for optimum mirror transmission) on the 358‐ and 380‐nm UV laser lines.