Pulsed Power Research Research Articles

Analysis and Design of a Pulsed Power Generator for a Low-Energy Magnetic Pulse Welding System

Magnetic pulse welding (MPW) is a joining method that uses Lorentz force generated from an electromagnetic field. This method not only has the advantage of not causing thermal deformation of the material and no by-products compared to the method of joining by melting by heat but also enables the joining of dissimilar metals rather than the joining of the same metal. Joining dissimilar metals can reduce the weight of mechanical devices and apply them to various fields. Recent research on MPW has focused on the characteristics of bonding according to the material or structure of metal rather than on pulse power research that generates the main factor of operation. However, in the operation of MPW, a Lorentz force is generated by the induced current caused by the electromotive force created in the flyer tube and the external magnetic field in the actuator. Therefore, it is necessary to analyze and optimize the pulse power to improve reliability and to miniaturize the system to expand the MPW utilization range. In this paper, we analyzed MPW operation according to a section of the pulse power output waveform. A condition for obtaining the maximum current in the flyer tube was proposed, and a plateau-shaped waveform was derived as an ideal output waveform capable of maintaining the Lorentz force. Through analysis, the proposed pulse power device is designed as a pulse-forming network (PFN) that generates a plateau output waveform. The design specification is that the circuit of PFN (type E) is designed so that the output waveform is pulse width 10 (μs) and the maximum output current is 100 (kA), and it is verified by simulation.

Commissioning Experiments at the Naval Postgraduate School Pulsed Power and EM Launch Laboratory

A new laboratory for pulsed power and electromagnetic (EM) launch research has been built and commissioned at the Naval Postgraduate School, Monterey, CA, USA. This facility is comprised of new, compact pulsed power modules that are 18 kJ each, as well as 1.1-MJ modules from the previous Electric Launch Facility at Kirkcudbright, Scotland. A total of 20 MJ of capacitive energy is stored to deliver pulsed, mega-ampere currents to loads, such as medium- and minor-caliber EM launchers, high-current test fixtures, and magnetic pulse generators. This equipment was recently commissioned with new instrumentation and data acquisition systems. A 5-m-long, medium caliber launcher was fired to commission the new facility, pulsed power, controls, and instrumentation. Circuit simulations compare favorably with experiments, exhibiting error on the order of 1%.

A Review of Diverse Academic Research in Nanosecond Pulsed Power and Plasma Science

This article was invited in order to summarize for the special edition of a Plenary Review presentation at the IEEE ICOPS/PPC meeting, June 23 2019 by M. Gundersen. It is a review of research conducted into primarily academic environments in nanosecond pulsed power, applications of the pulsed power research to bioelectrics, and combustion and ignition over a period of $\approx 45$ years. Research was conducted primarily at the University of Southern California (USC), at Texas Tech University (TTU), and through collaborations with other laboratories and personnel. Pulsed power, applied on a nanosecond time scale, was found to enable a range of new applications; several examples are detailed below. The range of applications for research based in short-pulse, or nanosecond pulsed power, and applied plasma science, strongly encourage defining and supporting the extension of programmatic research goals to beyond the academic laboratories and into the commercial environment.

The Story of the LTD Development

In this article, the story of linear transformer driver (LTD) development is presented, which began in the 1980s when the inductive energy storage (IES) systems with plasma opening switches (POSs) were the focus of pulsed power research all over the world. The accompanying problems of this technology resulted in the development of microsecond LTDs by Boris Kovalchuk, which was the first crucial step toward the development of this new technology. Next came the fast (~100 ns) LTDs, eliminating completely the need for any pulse compression and power amplification. Most recently, the LTD technology was further developed to generate fast rising output pulses with a flat or trapezoidal (rising or falling) top. Such LTD cavities, called Square Pulse LTDs, are better suited for applications such as flash radiography, Z-pinch, high-power microwaves, etc. A number of recent new suggestions important for the viability of LTD technology are also presented.

ChemInform Abstract: Direct Observation of an Abrupt Insulator‐to‐Metal Transition in Dense Liquid Deuterium.

AbstractAbrupt insulator‐to‐metal transition is experimentally observed in dense liquid D2 by application of magnetic shock waves of several hundred GPa to a cryocell containing D2 (22 K, density of 0.167 g/cm3) at the Sandia Z machine (Albuquerque, New Mexico, USA) for pulsed power research.

Overview of Pulsed Power Research at CAEP

Pulsed power research for military and civil applications has been conducted at the China Academy of Engineering Physics (CAEP) for more than 50 years. The pulsed power research activities include development of pulsed power components, such as different kinds of high-voltage switches, series of pulsed power sources and pulsed X-ray machines, high-current accelerators for $Z$ -pinch and flash X-ray radiography, as well as medical application and electromagnetic launch. The most recent progress of pulsed power research at CAEP will be presented.

National Security Research in Plasma Physics and Pulsed Power: Past, Present, and Future

The Naval Research Laboratory (NRL) was established in 1923 to fulfill Thomas Edison's vision of a government research laboratory that could develop and translate scientific knowledge into effective military systems in times of war. The NRL Plasma Physics Division was established in 1966 to create X-ray simulators for testing the effects of nuclear weapons on materials and components of military hardware, to study the physics and effects of high-altitude nuclear explosions, and to perform nuclear fusion research. This paper traces the development of pulsed power and plasma physics from 1940 to the present day through a set of graphical timeframes that depict both the major geopolitical events and the major pulsed power facilities that were noteworthy in a series of 15–20 year epochs. Pulsed power research began at the U.K. Atomic Weapons Establishment, where it was first used for radiography. Subsequently, Sandia, Los Alamos, and Livermore performed pulsed power research for an expanding set of missions. The earliest facilities consisted mostly of single-module machines that had limited ability to synchronize and pulse shape. The 1983 Strategic Defense Initiative led to the development of technologies for directed energy weapons, railguns, and X-ray lasers. The cessation of nuclear testing in 1992 created an increased need for above ground testing including advanced radiography, nuclear weapons effects simulators, hydrotest facilities, and inertial confinement fusion devices. The Stockpile Stewardship Program, which began in the mid-1990s, saw the construction of several major facilities [e.g., National Ignition Facility, Z, Omega, and DAHRT], with increased power, as well as sophisticated synchronization and pulse shaping capabilities. In 2012, the Department of Defense (DoD) announced a strategic pivot to the joint force of 2020 and a rebalance toward the Asian-Pacific region. Looking to the future, a number of DoD documents describe the need to develop and deploy transformational technologies. For example, the 2012 Naval S&T Strategic Plan emphasizes hypervelocity railguns, DE, the detection and neutralization of weapons of mass destruction, and the ability to retain access in contested environments, especially in space. Future military systems will require pulsed power that is compact, repetitive, efficient, and is thermally managed. Low-temperature plasmas and nonequilibrium plasma chemistry are emerging research areas that could impact DoD missions. Atmospheric plasmas are creating new opportunities in plasma biology and plasma medicine. The research capabilities of the rest of the world, especially China, are rapidly growing, and new ideas and capabilities will increasingly come from outside of the U.S. This paper explores some of the future challenges and opportunities for plasma physics and pulsed power research.

Status of KERI's Pulsed Power Research and Development

This paper reviews the research and development results achieved in the Korea Electrotechnology Research Institute (KERI) in a decade. KERI develops pulsed power technology and its applications are mostly based on power electronics. KERI's research and development activity covers components, military systems, and industry applications. High-voltage switching means developed in KERI are a rotary arc gap (RAG) switch (11 kV and 400 kAp), a vacuum RAG (20 kV and 150 kAp), an inverse pinch switch (20 kV and 150 kAp), and 10-kV semiconductor switch stacks made of thyristors and Insulated Gate Bipolar Transistors (IGBTs). The IGBT and thyristor stacks consist of 10 or 12 1.2-kV discrete devices and are operated by only one active drive circuit installed in the groundside. Some ferromagnetic opening switch schemes are also researched on trial bases. Some of KERI's research and development works from devices to application systems will be described.

European Laboratories for Pulsed Power Research

In this paper, the newly founded European Pulsed Power Laboratories (EPPL) will be introduced. The objective of this initiative is to bundle the resources of the involved institutions and to bring together research and expertise of Europe’s principal pulsed power laboratories with the goals to minimize the overlap of research, to achieve a critical mass and to establish a European network. The pulsed power topics of EPPL cover a broad range. Besides pulsed power components, complete pulsed power systems are studied as well. In the area of pulsed power applications, both military and civilian (commercial) ones are envisaged.

Transient electrical field across cellular membranes: pulsed electric field treatment of microbial cells

The pulsed electric field (PEF) treatment of liquid and pumpable products contaminated with microorganisms has attracted significant interest from the pulsed power and bioscience research communities particularly because the inactivation mechanism is non-thermal, thereby allowing retention of the original nutritional and flavour characteristics of the product. Although the biological effects of PEF have been studied for several decades, the physical mechanisms of the interaction of the fields with microorganisms is still not fully understood. The present work is a study of the dynamics of the electrical field both in a PEF treatment chamber with dielectric barriers and in the plasma (cell) membrane of a microbial cell. It is shown that the transient process can be divided into three physical phases, and models for these phases are proposed and briefly discussed. The complete dynamics of the time development of the electric field in a spherical dielectric shell representing the cellular membrane is then obtained using an analytical solution of the Ohmic conduction problem. It was found that the field in the membrane reaches a maximum value that could be two orders of magnitude higher than the original Laplacian electrical field in the chamber, and this value was attained in a time comparable to the field relaxation time in the chamber. Thus, the optimal duration of the field during PEF treatment should be equal to such a time.

The Light Ion Beam Approach to ICF Energy Production

Light ion beam fusion is an approach to electrical power production in which intense beams of low atomic number ions would be used to drive inertial confinement fusion (ICF) targets to ignition and gain. The authors anticipate that an Engineering Test Facility (ETF) designed to demonstrate moderate yield with a repetition rate would be a major step along the route to an ICF demonstration power plant. In the present paper, they describe their vision of how ongoing light ion beam and pulsed power research at Sandia National Laboratories (SNL) might be utilized for ETF and eventual inertial fusion energy (IFE) applications.

SDIO pulsed power R&D requirements

The Strategic Defense Initiative Organization (SDIO) performs pulse power research and technology base development to satisfy the requirements of six major systems. These systems-neutral particle beams (NPBs), space-based free electron lasers (SBFELs), ground-based lasers (GBLs), electromagnetic launchers (EMLs), laser radars (LRs), and high-power microwaves (HPMs)-are described. The research is focused on component development with mass, volume, and efficiency being the key technology drivers. Order-of-magnitude improvements are in many cases required. These development efforts include those power conditioning devices and components needed to match the electrical characteristics of the power source with those required by the load. Technology areas include energy storage, switching, and power conversion. The specific component requirements and two space experiments integrating developmental components are described. >

The Pulse Physics Research Program of the Netherlands Organization for Applied Scientific Research TNO

The pulse physics program is directed toward pulsed power, electromagnetic-launch, and materials research. An overview of specific research efforts being pursued in these areas is given. Details concerning the Pulse Physics Laboratory at Delft and its equipment are described. An in-house-developed fast discharge megawatt bipolar battery and a 6.7 MJ pulsed homopolar-generator-driven repetitive electromagnetic launcher are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Basic plasma physics research in pulsed-power technology at Ecole Polytechnique

Various aspects of the pulsed power research program at Ecole Polytechnique are reviewed. Topics include a surface and a flashboard switch, the development of plasma guns for both switching and z-pinch diodes, and studies of beam control and synchronization.

The Design of a 2 TW Pulsed Power Research Facility

Physics International (PI) has designed a modular pulse generator for research in high-power switching, pulse compression, power flow, magnetic insulation, and dielectric breakdown. The generator is one wedge-shaped 1/20th "slice" of PI's conceptual design for a 40-50 TW, radial, tri-disk accelerator designed to drive imploded plasma or particle beam loads. The nominal design goal of the "slice" (or module) is to produce a 100 ns, 2 TW, 2 MV, 1 MA pulse into a resistive load, or a 150 to 200 ns pulse at lower power. The module consists of an 0.8 MJ Marx generator and four water-dielectric triplates with adjustable impedances. The first is a gas-switched transfer capacitor. Next are two water-switched pulse-compression stages, and last, an output line converging to a racetrack insulator. This article describes the design and planned experiments.

A Low Jitter Triggered Gas Switch to Synchronize Modular Accelerators

Physics International (PI) has developed a high voltage, low jitter, command triggered gas switch to serve as an output switch for the slow-charging transfer capacitor in EAGLE, a 2 TW pulsed power research facility presently under construction. EAGLE is a prototype module of PI's conceptual design for a 40-50 TW, 4-5 MJ pulsed accelerator called ROULETTE (see Figure 1). The use of our triggered gas switch in ROULETTE provides distinct advantages over conventional water switches: considerably lower intermodule jitter, less ohmic dissipation, reduced mechanical shock loading of structures, and better control of the current distribution.