Marx generator

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

Intense nanosecond duration source of 10–250 keV x rays suitable for imaging projectile-induced cavitation in human cadaver tissue

Abstract: The design, fabrication, and performance of a repetitive nanosecond x-ray source having a pumped field-emission x-ray tube are described. A compact Marx generator, 61 cm in length and storing 12 J energy, directly drives the field-emission tube with voltage pulses >380kV and with <4ns rise time from an equivalent generator impedance of 52Ω. The x-ray dose is 520 μSv at a distance of 30.5 cm. A numerical simulation model is used in which the x-ray tube’s cathode width and anode-cathode gap spacing are permitted to change with time, while electron flow between the cathode and anode is space charge limited and nonrelativistic. The x-ray tube model is coupled to an equivalent circuit representation of the Marx generator that includes the capacitance variation with charging voltage of the BaTiO3 capacitors. The capabilities of the x-ray source for flash radiography have been demonstrated by the study of the evolution of cavitation in human cadaver legs induced by high-velocity projectiles.

A New Modular Marx Derived Multilevel Converter

Abstract: A new Modular Marx Multilevel Converter, M3C, is presented. The M3C topology was developed based on the Marx Generator concept and can contribute to technological innovation for sustainability by enabling wind energy off-shore modular multilevel power switching converters with an arbitrary number of levels. This paper solves both the DC capacitor voltage balancing problem and modularity problems of multilevel converters, using a modified cell of a solid-state Marx modulator, previously developed by authors for high voltage pulsed power applications. The paper details the structure and operation of the M3C modules, and their assembling to obtain multilevel converters. Sliding mode control is applied to a M3C leg and the vector leading to automatic capacitor voltage equalization is chosen. Simulation results are presented to show the effectiveness of the proposed M3C topology.

Plasma synthesis jet flow serial connection discharge device based on Marx generator

Abstract: The invention discloses a plasma synthesis jet flow serial connection discharge device based on a Marx generator. The negative pole of a direct current source is grounded, and the positive pole of the direct current source is connected with one end of a charge resistor; the other end of the charge resistor is connected with the positive poles of multiple charge diodes; the negative poles of the multiple charge diodes are connected with one ends of multiple charge capacitors; the other ends of the multiple charge capacitors are connected with the positive poles of multiple discharge diodes; multiple plasma synthesis jet flow exciters are connected to the negative poles of the charge diodes and the negative poles of the discharge diodes in parallel; a discharge resistor is arranged between two discharge diodes; the negative poles of the discharge diodes are grounded; ground electrodes of the plasma synthesis jet flow exciters are grounded; and two ends of a load are connected to the positive pole of the first discharge diode and the negative pole of the last discharge diode in parallel. The plasma synthesis jet flow serial connection discharge device has the following beneficial effects: when the multiple plasma synthesis jet flow exciters are serially connected to synchronously discharge, multi-way superposition pulses are formed at two ends of the load, so that the multi-angle and wide-range flow control can be realized in high-speed flowing field control field, and the high-voltage discharge experimental study can be performed.

Operation of a 500 kV, 4 kA Marx generator at 500 Hz rep-rate

Abstract: A 42 J, 10-stage pulse forming network (PFN) Marx generator capable of producing a 500 kV, 50 ns full-width-half-max (FWHM), ∼5 ns rise time pulse into an open load at a rep-rate of 500 Hz has been designed for use as a pulsed power source for a reflex triode virtual cathode oscillator (vircator). Rayleigh PFNs are used in place of discrete capacitors for each stage of the 10-stage Marx generator. Effort was taken to minimize parasitic inductance such that the quality of the pulse shape is maintained as much as possible. In order to rep-rate the Marx generator, a trigatron-based triggering scheme is used to initiate erection of the Marx generator. A 20 ns risetime, 24 kV solid-state pulse trigger generator capable of operating at high repetition rates is used to drive the trigatron. The required charge rate for a 500 Hz pulse repetition frequency (PRF) for the Marx generator is 24 kW. Repetitive operation requires additional design considerations that would be irrelevant to single pulse firing. Pressurized air is jetted across the spark gaps by means of built-in gas manifolds to remove remaining ionized gas between each pulse and prevent premature erection during the subsequent charging cycle. The built-in gas manifolds were designed using a hydrodynamic simulation to ensure equal flow rate across each of the spark gaps and equal pressure along the length of the tube chamber.