Showing papers on "Marx generator published in 2009"

Development of Rectangle-Pulse Marx Generator Based on PFN

Abstract: In this paper, two designs of the rectangle-pulse Marx generator based on pulse-forming network (PFN) for pulse-power application are reported. The PFN is composed of inductors and capacitors. Proposed schemes consist of several identical PFNs that are connected according to Marx generator scheme. PFN Marx generators can output rectangle pulse several hundreds of nanoseconds in duration and several tens of nanoseconds in rising time. The effect of component parameter to the waveform is studied. Prototypes made of four PFNs have been tested. One of the prototypes is designed according to classical Marx mode, while another is designed as an L-C Marx generator in which only one command switch and one isolating switch is needed. In a 500-ns duration, 65-ns rising-time rectangle pulse has been achieved on the matching load.

Scalable, compact, nanosecond pulse generator with a high repetition rate for biomedical applications requiring intense electric fields

Abstract: A high repetition rate, high voltage pulse generator has been developed that scales up the output voltage of a recently reported compact, nanosecond pulse generator that is currently being used in various biomedical applications, including experiments into the mechanisms that drive cellular electropermeabilization and plasma generation for an endodontic disinfection tool [1, 2]. This single-stage, nanosecond architecture is based is composed of a bank of power MOSFETs, a linear network of inductors and capacitors, and a bank of junction recovery diodes; it was reported to feature an output pulse amplitude voltage to input voltage ratio between 5 and 6 [3, 4]. Since commercially available power MOSFETs tend to be limited to 1 kV, the output amplitude of the single-stage pulse generator does not exceed 5 or 6 kV. To combat this limitation, two different architectures have been developed that enable scaling of the output voltage. The first of these increases the voltage input to the pulse-forming network by means of a solid-state Marx bank that employs power MOSFETs arranged in a series-parallel arrangement to handle the high voltage and high current requirements of the switching stage. The second architecture employs a saturating transformer to handle the high current. Each of these has its own advantages: the first architecture has a shorter trigger-to-output delay time and is capable of producing low-jitter pulses with a linear input-output voltage relationship; whereas, the architecture with a saturating core features fewer components and reduced complexity. Prototypes of both architectures have been designed, built, tested, and are currently being used.

Marx generator using power mosfets

Abstract: A compact Marx generator has been developed by using power MOSFETs as the switches. The objective is to develop repetitive, compact, efficient, short-pulse, high-voltage generator for industrial applications. The initial tests were carried out by using 16 switches, achieving output of ∼ 10 kV and ∼ 250 ns in pulse width at repetition rate of ∼ 400 Hz.

Improvement of Edible Mushroom Yield by Electric Stimulations

Abstract: Pulsed high voltage was applied to logs for mushroom culturing to clarify an effect of the pulse high-voltage stimulation on mushroom yield. Inductive energy storage system was employed to construct a pulsed power generator with compact size. Copper thin fuse was used as opening switch to interrupt large circuit current in short time. Four stages Marx generator was used to supply a large current to a secondary energy storage inductor. The output voltage of the inductive energy storage system pulsed power generator was 120 kV with 50 ns pulse width at 5 kV charging voltage to the primary energy storage capacitor. This pulsed high-voltage was applied to sawdust-based block for culturing Lyophyllum decastes and natural logs for culturing Lentinula edodes, Pholiota nameko and Naematoloma sublateritium as an electrical stimulation. The experimental results clearly showed that the yields for four kinds mushroom increased to 1.5-2.1 times larger yield by applying pulse voltage as electrical stimulation.

Development of Miniature Marx Generator using BJT

Abstract: We have developed a small sized all solid-state pulsed power generator for industrial applications and biomedical applications such as an ozonizer and a cell treatment. In this paper, a novel 19 stages Miniature Marx Generator using bipolar junction transistors (BJTs) to produce high voltage and low energy pulses with nano-seconds pulse rise time is described. This pulsed power generator is consisted of a Cockroft-Walton circuit and a Miniature Marx circuit. The Cockroft-Walton circuit charges all capacitors and the charging voltage is about 300 V. The Miniature Marx circuit is consisted of resistors, capacitors, and BJTs as extreme high speed closing switches using avalanche breakdown phenomena. Another set of BJTs are placed in parallel with the load to turning off a load current. The size of Miniature Marx circuit is 72 mm × 95 mm. The pulsed power generator developed here has an output voltage of about −5.2 kV and a pulse duration of 7 ns. The charging energy of primary capacitors is the milli-Joule regime.

A 1-MV, 1-MA, 0.1-Hz linear transformer driver utilizing an internal water transmission line

Abstract: Sandia National Laboratories is investigating linear transformer driver (LTD) architecture as a potential replacement of conventional Marx generator based pulsed power systems. Such systems have traditionally been utilized as the primary driver for z-pinch wire-array experiments, radiography, inertial fusion energy (IFE) concepts, and dynamic materials experiments (i.e. ICE).

Performance of a compact triode vircator and Marx generator system

Abstract: Vircator high power microwave sources are simple, robust, and require no external magnetic field, making them desirable for use in practical compact high power microwave systems. A vircator can be driven directly from the output of a low-impedance Marx generator, eliminating the need for bulky intermediate energy storage components. A compact high power microwave system has been constructed and tested at Texas Tech University utilizing a triode geometry vircator and a compact Marx Generator. The size and performance of this system is compared to a similar system previously developed at Texas Tech. The current triode vircator is housed within a six inch diameter tube which is eleven inches in length. The Marx is contained in an oil tank that is 36 inches long × 12 inches wide × 18 inches tall. Diode voltage and current, and radiated microwave waveforms are presented.

Effects of laser triggering parameters on runtime and jitter of a gas switch

Abstract: Parameters affecting the runtime and jitter of a laser triggered gas switch have been studied. Experiments tested a variety of switch parameters including percentage of selfbreak and switch pressure. The effects of laser beam parameters were also considered, including focal length, laser energy, laser spark length, and laser wavelength. 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 fed into a 7 nF intermediate storage capacitor was used to drive the switch into a 4 ? resistive load. The test switch was pressurized to 306 kPa (30 psig) with SF6 and operated near 1 MV. A New Wave Tempest Nd:YAG laser was used to trigger breakdown of the switch. The laser was focused at the mid-gap between the switch electrodes using lenses with focal lengths between 30 cm and 100 cm. Focused laser energy in the switch ranged from <5 mJ to 80 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.

All solid-state pulsed power generator with semiconductor and magnetic compression switches

Abstract: Conventional pulsed power sources using gas switches suffer from short lifetime, low PRF and expensive maintenance cost. Many all solid-state generator topologies have been developed to replace them. Marx modulator utilizing IGBTs as main switches has many advantages, such as variable pulse length and PRF, snubberless operation, inherent redundancy. However, the relatively slow turn-on speed of IGBT influences the pulse rise time of the Marx modulator. In this paper, a newly developed all solid-state pulsed power generator is proposed. This generator consists of a Marx modulator based on IGBT half bridge modules and a magnetic pulse sharpening circuit, which is employed to compress the rising edge of the Marx output pulse. The pulse sharpening circuit is composed of two magnetic compression switches and one peaking capacitor. The experimental results demonstrated the effectiveness of pulse sharpening. The design of IGBT drive circuits and magnetic switches is introduced in detail in this paper.

Coaxial-type water load for measuring high voltage, high current and short pulse of a compact Marx system for a high power microwave source

Abstract: A coaxial-type water load was used to measure the voltage output from a Marx generator for a high power microwave source. This output had a rise time of 20 ns, a pulse duration of a few hundred ns, and an amplitude up to 500 kV. The design of the coaxial water load showed that it is an ideal resistive divider and can also accurately measure a short pulse. Experiments were performed to test the performance of the Marx generator with the calibrated coaxial water load.

A control theory approach on the design of a Marx generator network

Abstract: A Marx generator is a well-known type of electrical circuit first described by Erwin Otto Marx in 1924. It has been utilized in numerous applications in pulsed power with resistive or capacitive loads. To-date the vast majority of research on Marx generators designed to drive capacitive loads relied on experimentation and circuit-level modeling to guide their designs. In this paper we describe how the problem of designing a Marx generator to drive a capacitive load is reduced to that of choosing a diagonal gain matrix F that places the eigenvalues of the closed-loop matrix A+BF at specific locations. Here A is the identity matrix and B characterizes the elements of the Marx generator and depends on the number of stages N. Due to the special structure of matrix F, this formulation is a well-known problem in the area of feedback control and is referred to as the structured static state feedback problem. While the problem is difficult to solve in general, due to the specific structures of matrices A and B, various efficient numerical algorithms exist to find solutions in specific cases. In a companion paper by Buchenauer [1] it is shown that if certain conditions hold, then setting the natural frequencies of the circuit to be harmonically related guarantees that all the energy is delivered to the load capacitor after a suitable delay. A theorem formalizing this result is presented. Earlier aspects of this research have been published in two theses [2,3].

Design and performance of an ultra-compact 1.8-kJ, 600-kV pulsed power system

Abstract: A new, high-energy-density Marx generator has been developed for High Power Microwave (HPM) applications. The generator (P/N: MG30-3C-100NF) has been shown to deliver 5 GW to a 25 Ohm load with a peak pulse voltage of 300 kV. A modular close-packing geometry combined with mica-film capacitor technology results in a 1.8 kJ energy storage capacity in a 20 in. diameter × 45 in. cylindrical vessel. The compact architecture accomplishes a high energy per pulse, but also facilitates a relatively low inductance of the system which is characterized by a 90 ns voltage risetime when discharged into a matched resistive load. The system includes an EMI-hardened power electronics suite which includes a solid-state trigger generator, compact HVPS, and a digital pressure regulator. The system requires only pressurized dry air for insulation, operates on an internal prime-power battery pack and is controlled via a fiber-optic remote for ease of use on remote platforms. The system design and pulse characteristics are presented in this paper.

Study of an Ultra-Compact, Repetitive Marx Generator for High-Power Microwave Applications

Abstract: The need for repetitive high-power microwave systems, for instance within the scope of convoy protection, requires the availability of compact, repetitive pulsed-power generators. The development and the first experimental results of an upgraded balanced ISL Marx generator for future repetitive operations at pulse repetition frequencies in the order of 100 Hz are introduced. A key objective is to keep the fundamental modular coaxial concept by reason of its scalability and compactness. Simulation models were developed under the PSpice software package in order to investigate the charging and discharging phases of the Marx generator and also to determine the design criteria for repetitive operations. The charging resistors were replaced by ultracompact inductors for rapid charging, being able to withstand pulsed voltages up to 60 kV and pulsed currents up to 1.4 kA during the discharge phase. An improved type of strontium–titanate high-voltage ceramic capacitor was successfully tested experimentally up to 70 kV. Each new elementary stage of the Marx generator consists of eight 1.1 nF sectors of a cylinder capacitors mounted in parallel, two charging inductors of about 17.8 μH and two halves of spherical spark gaps. The pressurized self-triggered gas switches are arranged along the axis for fast consecutive breakdown thanks to the UV radiation emitted during the breakdown in each gap. The stages are installed in individual fibreglass housings. First experimental results of a 4-stage Marx generator in repetitive operation, driven by a 4 kW capacitor charging power supply up to a maximum voltage of 40 kV, are presented.

Optimizing compact Marx generator networks

Abstract: Compact linear Marx generators are frequently constructed in close-fitting metallic housings. The parasitic capacitance formed between the enclosure and Marx components can substantially exceed the inner-stage capacitance and play an important role in the Marx network performance [1][2]. This capacitance and the inner-stage inductance form the components of a lumped-constant transmission line, which facilitates proper sequential firing of the spark switches. With appropriate component values, these Marx generators can deliver fast rising and nominally flat pulses into resistive loads.

Development of a Repetitive Wave Erection Marx Generator

Abstract: A repetitive ten-stage wave erection Marx generator is developed to investigate the electrical characteristics of such compact devices and potentially provide an economical approach to realize the miniaturization of intense electron beam accelerators. Compact design has been made for the generator in order to achieve a proper stray capacitance of the spark gap electrode with respect to the ground in each stage because these proper grounded stray capacitances are critical for obtaining a good wave erection process. This generator is initially resistively isolated for single-shot tests and then changed to inductively isolated for repetitive operation. In single-shot experiments, the generator is tested to be able to deliver a high-voltage pulse of 210 kV and a rise time of about 5 ns on a 90-Ω dummy load at a charging voltage of 40 kV. This result agrees basically with that of the PSpice circuit simulation, which adopts a self-breakdown spark gap model. The preliminary experimental results of repetitive operation show that at a charging voltage of 30 kV, the generator can operate at 8.5 Hz without gas blow-off from the internal spark gaps, producing an output pulse of 150 kV and a rise time of less than 20 ns. Differences in the output pulse waveforms between resistively and inductively isolated configurations are analyzed.

Linear Transformer Driver (LTD) development at Sandia national laboratory

Abstract: Most of the modern high-current high-voltage pulsed power generators require several stages of pulse conditioning (pulse forming) to convert the multi-microsecond pulses of the Marx generator output to the 40–300 ns pulse required by a number of applications including x-ray radiography, pulsed high current linear accelerators, Z-pinch, Isentropic Compression (ICE), and Inertial Fusion Energy (IFE) drivers. This makes the devices large, cumbersome to operate, and expensive. Sandia, in collaboration with a number of other institutions, is developing a new paradigm in pulsed power technology; the Linear Transformer Driver (LTD) technology. This technological approach can provide very compact devices that can deliver very fast high current and high voltage pulses. The output pulse rise time and width can be easily tailored to the specific application needs. Trains of a large number of high current pulses can be produced with variable inter-pulse separation from nanoseconds to milliseconds. Most importantly, these devices can be rep-rated to frequencies only limited by the capacitor specifications (usually is 10Hz). Their footprint as compared with current day pulsed power accelerators is considerably smaller since LTD do not require large oil and de-ionized water tanks. This makes them ideally fit for applications that require portability. In the present paper we present Sandia Laboratory's broad spectrum of developmental effort to design construct and extensively validate the LTD pulsed power technology.

A compact high power microwave (hpm) source

Abstract: A compact high power microwave (HPM) source is reported. It generates short pulses by direct excitation of an antenna with a 300 kV Marx generator. Oil insulation is used to protect capacitor banks from breakdown, while discharge gaps are designed to work in air. The Marx generator risetime is less than 50 ns. The disk-cone antenna is also oil-insulated and operates in the self-breakdown regime. Radiated pulse has the duration about 2 ns and the spectrum from 800 MHz to 2 GHz. The HPM source is used for studying the vulnerability of computers and different electronic components. (4 pages)

Development of a Repetitive Wave Erection Marx Generator

Abstract: A repetitive ten-stage wave erection Marx generator is developed to investigate the electrical characteristics of such compact devices and potentially provide an economical approach to realize the miniaturization of intense electron beam accelerators. Compact design has been made for the generator in order to achieve a proper stray capacitance of the spark gap electrode with respect to the ground in each stage because these proper grounded stray capacitances are critical for obtaining a good wave erection process. This generator is initially resistively isolated for single-shot tests and then changed to inductively isolated for repetitive operation. In single-shot experiments, the generator is tested to be able to deliver a high-voltage pulse of 210 kV and a rise time of about 5 ns on a 90-Omega dummy load at a charging voltage of 40 kV. This result agrees basically with that of the PSpice circuit simulation, which adopts a self-breakdown spark gap model. The preliminary experimental results of repetitive operation show that at a charging voltage of 30 kV, the generator can operate at 8.5 Hz without gas blow-off from the internal spark gaps, producing an output pulse of 150 kV and a rise time of less than 20 ns. Differences in the output pulse waveforms between resistively and inductively isolated configurations are analyzed.

Compact Marx generators modified for fast risetime

Abstract: Traditionally, the 1.6-MV Marx generator offered by APELC operates at a charge voltage of 40 kV, an erected voltage of 1.6 MV, a stored energy of 260 J, and an output pulse rise time between 6-8 ns. APELC has developed a pulse conditioning system (PCS) that can be retrofitted into the existing MV Marx generator housing to improve output pulse rise time at a minimal cost of stored energy. The performance characteristics of the newly developed PCS driven by a slightly modified version of APELC's MV Marx generator will be provided. APELC has also retrofitted its staple 15-stage, 33-J, Marx generator with a scaled version of the same PCS. Preliminary results of the scaled version of the PCS are presented as well.

A compact, low jitter, fast rise time, gas-switched pulse generator system with high pulse repetition rate capability

Abstract: We present the experimental results of an ongoing research effort focused on the development and refinement of a compact, low jitter, fast rise time, command triggered, high peak power, high pulse repetition rate (PRR), gas-switched pulse generator system. The main component of the system is a gas-switched Marx-like pulse generator module designed for applications including UWB radar, microwave sources, and triggering large scale multi-module pulsed power systems of all types. The pulse generator system, comprised of a single or multiple Marx modules, is command triggered by a single or multiple TTL level pulses generated by a timing and control system implemented using LabVIEW software and a PXI-based hardware system. The TTL trigger pulses fire all solid-state high voltage trigger pulsers that close the first stage switches in the Marx modules using a novel method to reduce jitter. The control system also accepts user input to set the desired output conditions, adjusts the charge voltage of a high voltage capacitor charging power supply, inhibits capacitor charging during firing of the pulse generators, and can control the system in a closed-loop fashion to maintain relative timing and output characteristics during timing drifts and changing environmental conditions. The individual Marx stages are compact and stackable and utilize field enhanced spark gap switches. The stage capacitors are charged in parallel through mutually coupled inductors in series with resistors. This charging scheme allows for high PRR operation limited only by the stage switch recovery time and the power of the available capacitor charging power supply. The stage switches are optically coupled to aid in Marx output voltage formation and to minimize system jitter. The Marx generator is housed in a lightweight aluminum pressure vessel and is operated in a low pressure dry air environment. The design exhibits a low inductance which varies depending on the number of stages used. Using a five stage prototype, we have generated output voltages of ∼100 kV with a rise time of ≪4 ns. The output pulse width is variable and is dependent on the value of the Marx stage capacitors used and the load resistance. The pulse generator system has been operated in a burst mode at a PRR in excess of 1 kHz with good output voltage regulation. The total jitter of the Marx generator system, i.e. from the application of the trigger pulse to arrival of the output pulse, was measured and found to be ≪1 ns.

A 250KV-300PS-350HZ Marx generator as source for an UWB radiation system

Abstract: This paper aims at presenting the design and realisation of an autonomous, ultra wideband (UWB) radiation source consisting of a high gain broadband antenna driven by a subnanosecond pulsed power source.

Pulse Breakdown Strengths of Liquid, Gel and Solid Insulating Materials Using Closely Spaced Spherical Electrodes

Abstract: In this paper an evaluation of a number of different insulating materials, under pulse breakdown conditions, is described. The experimental setup used an 8 stage Marx generator in order to generate a high potential difference (in the range 80–220 kV) between two spherical electrodes which were spaced 1.5–3.5 mm apart. The breakdown voltage of each of the materials was recorded and the data was then post-processed in order to determine the breakdown strength of each of the samples.

A Marx generator driven impulse radiating antenna

Abstract: APELC has developed an Impulse Radiating Antenna (IRA) that consists of a TEM-horn-fed parabolic reflector that is directly driven by a 22-J, 400-kV Marx generator. The system is based on standard Marx generator designs offered by APELC. The Marx generator output couples directly to the TEM horn via a transition from a coaxial geometry that approximates a standard coaxial-to-parallel plate transition. Primary design considerations that facilitate achievement of high instantaneous radiated power include appropriate Marx generator rise time, transition design, and TEM horn focal point positioning. Data collected over the course of the system design is presented.

Optimization of an FCG-Based High-Power Microwave System Using Nonexplosive Pulsed Power

Abstract: This paper presents a nonexplosive pulsed-power system that replicates the output current waveform of a flux compression generator (FCG). The primary purpose of this system is to efficiently test the power conditioning components of an explosively driven HPM system, while drastically reducing the time between tests which are inherent with explosive experiments. The power conditioning system (PCS) of the HPM system includes an energy-storage inductor, an electroexplosive opening switch (fuse), and a peaking gap and serves to match the FCG output characteristics with the HPM diode load requirements. A secondary purpose of the nonexplosive test bed is to provide data points which could be directly compared with those from explosively driven experiments. For this reason, a reflex-triode virtual cathode oscillator (vircator) was connected to the output of the nonexplosive system, and the results of which were compared with similar testing done with an FCG and a compact Marx generator. Since the behavior of the fuse is known to play a critical role in the performance of the PCS, a study was performed on the effect of different fuse designs on the overall performance of the PCS. Specifically, the quality of the electrical connection between the fuse wire array and the rest of the system was tested. Fuse design experiments were conducted with the nonexplosive test bed firing into a water resistor dummy load, which showed a 13% increase in peak load voltage and more than an 11% increase in energy transfer for fuses with improved wire-electrode connection strength. Some basic rules about fuse design, as well as conclusions on the performance of the PCS when driving an HPM load, are given.

A novel and non-invasive pulsed electric field technique for industrial food processing

Abstract: A novel and non-invasive pulsed electric field (PEF) technology for use in the food processing industry is under development at both Loughborough University (UK) and the University of Pau (France). The technology uses an antenna coupled to a high-voltage pulsed generator to produce short duration pulses of very intense electric field strength. In the Loughborough scheme, a Tesla transformer charges an oil-filled pulse forming line to more than 500 kV, and electric fields are generated by a pulsed antenna with a rise time of 1 ns with a figure of merit of about 130 kV. In the Pau scheme, a gas pressurised pulse forming unit, comprising a peaking stage and a crowbar switch, is incorporated into the last stage of a ten-stage Marx generator. When a Valentine travelling wave antenna is attached, the overall system is capable of generating electric fields with a rise time of 300 ps with a figure of merit of 450 kV. During the common research programme, the combination of a Tesla transformer and an ultrafast Marx generator technology will bring complementary improvements in the design of intense pulsed electric field generators and allow measurements to be made over the wide radiated field frequency spectrum, essential for the present research. The novel non-invasive PEF technology offers considerable promise and in principle opens the possibility to process for the first time solid foodstuff such as meat. A possible major potential application also exists in the wine industry, with the possibility of accelerated ageing after bottling. The many aspects of commercial implications of the successful development of the novel technique will be highlighted. An essential requirement arising in the common research programme is the measurement of intense fast transient electric fields. Field measurements are conventionally performed using D-dot probes and special purpose antennae, but since these methods are unsuitable for the present application both Loughborough and Pau are developing fast electro-optic sensors based on the Kerr effect for measurements in water and the Pockels' effect for measurements in air. These techniques offer several advantages over conventional sensors, such as high bandwidth, miniaturisation, non-invasion and complete immunity to electromagnetic perturbing influence from the high-voltage generators, which together make them extremely suitable for innovative electric field treatment applications. However, some precautions have to be implemented to ensure reliable measurements and the paper will present the major principles involved in the design of dedicated experimental arrangements. Preliminary results will be presented and evaluated from the experimental research programmes underway at the two Universities. (4 pages)

Experimental results on design aspects of a compact repetitive Marx generator

Abstract: This paper presents the experimental results of a repetitive Marx generator being developed at BARC. Effect of lead inductance, sparkgaps' alignment, charging inductor, ground inductor and shielding has been studied. Two types of configurations have been adopted in order to reduce the erected Marx inductance and results are compared. In this Marx generator plus-minus charging scheme was adopted for both test setups. Each setup comprised of 2-stage Marx with 4 series capacitors (each rated for 0.15 microfarad, 40nH, 50kV) while discharging giving 0.375 microfarads capacitance. In one of the scheme Type-I, all spark gaps were aligned in line of sight arrangements and successive discharge path were assembled in a zigzag manner so that the induced magnetic field gets cancelled out and effective inductance is reduced. This scheme was terminated to an aqueous load and critical matched condition was achieved at 12 ohm. This scheme had effective capacitance of 0.0375 microfarads, wave shape in lower voltage i.e. 10–15kV charging level. During experiments effect of load was also seen which gave half the open voltage to matched load [z=√(L/C)] and in critical damping condition voltage was 0.7 times of open circuit voltage. These data will be used for developing a 6-stage 1.2 kJ Marx generator for 20 pps burst output. Presently testing is limited to 2pps due to charging power supply limitations. Thus the results can be summarized as follows: (i) line of sight and ultra violet triggering is not effective for a distance of 200mm, (ii) cancellation of induced magnetic field is not effective at 5kA current peak at 100mm distance, (iii) longer length leads in smaller diameter is preferable over larger diameter with smaller length assembly with zigzag leads for giving shorter pulse, higher current and faster rise time.

Repetitive auto-triggered Marx generator as the driver of an ultrawideband source

Abstract: Traditional uses of the Marx generator have been limited to energy storage and delivering systems, such as charging capacitors or pulse forming lines. However, low energy, compact, high peak power Marx generators can be used as repetitive drivers for many applications. This paper presents the design, the realisation and experimental tests of a repetitive auto-triggered Marx generator expected to be the driver of a broadband radiation system. This whole system consists of a pulsed power source, i.e. a pulse forming line charged by a Marx bank and an UWB antenna array. Design of the Marx generator were planned to reach a voltage level of up to 400kV, a 200Hz repetition rate and a good reproducibility. In this way, the generator is supplied with a high voltage pulsed power supply; charging and discharging circuits were made of home-designed inductors. Furthermore, we focus on the first stage of this Marx generator in which a new simple auto-triggered spark-gap was integrated. The Marx is then combined to a forming line and a peaking spark gap to deliver rectangular output pulses with rise-times closed to 250ps.

Ignition of a Deuterium Micro-Detonation with a Gigavolt Super Marx Generator

Abstract: The Centurion–Halite experiment demonstrated the feasibility of igniting a deuterium–tritium micro-explosion with an energy of not more than a few megajoule, and the Mike test, the feasibility of a pure deuterium explosion with an energy of more than 106 MJ. In both cases the ignition energy was supplied by a fission bomb explosive. While an energy of a few megajoule, to be released in the time required of less than 10−9 s, can be supplied by lasers and intense particle beams, this is not enough to ignite a pure deuterium explosion. Because the deuterium–tritium reaction depends on the availability of lithium, the non-fission ignition of a pure deuterium fusion reaction would be highly desirable. It is shown that this goal can conceivably be reached with a “Super Marx Generator”, where a large number of “ordinary” Marx generators charge (magnetically insulated) fast high voltage capacitors of a second stage Marx generator, called a “Super Marx Generator”, ultimately reaching gigavolt potentials with an energy output in excess of 100 MJ. An intense 107 Ampere-GeV proton beam drawn from a “Super Marx Generator” can ignite a deuterium thermonuclear detonation wave in a compressed deuterium cylinder, where the strong magnetic field of the proton beam entraps the charged fusion reaction products inside the cylinder. In solving the stand-off problem, the stiffness of a GeV proton beam permits to place the deuterium target at a comparatively large distance from the wall of a cavity confining the deuterium micro-explosion.

Compact 200-Hz pulse repetition GW Marx generator system

Abstract: The compact, wave-erection, GW-class Marx generator has been previously reported for use in 5 ns to sub-ns risetime pulsed power applications. This generator topology has recently been adapted for high Pulse Repetition Frequency (PRF) applications and is the basis for a new high-PRF pulsed power system. The 33-J generator is capable of delivering a 300-kV pulse into a matched 50-Ohm load, or 600 kV into an open circuit. The high-PRF system includes an 8 kJ/sec TDK-Lambda high-voltage power supply and an APELC trigger and control unit. The APELC trigger unit contains a 150-mJ thyratron-based pulser and facilitates the synchronous pulse charging of the Marx generator. Additionally, the trigger unit provides analog output signals of the thyratron and Marx charging signals and features LED diagnostics and fault indicators on the front panel. Applications of the high-PRF system include sourcing of High Power Antennas. Design considerations, system architecture, and experimental results of the high-PRF pulsed power system are presented in this paper.