L. Pecastaing

Université de Pau et des Pays de l'Adour | UPPA · Laboratory of Engineering Sciences Applied Mechanics and Electrical engineering

Ultra‐wideband (UWB) microwave sources driven by specialised pulsed power generators have experienced a considerable development in the last decade due to their wide domain of new applications such as defence or counter‐terrorism activity. The authors present the main findings of a research dedicated to the development of a pulsed power‐driven elec...

This article demonstrates the impact-ionization switching of standard thyristors in a series-parallel configuration. The series–parallel triggering of thyristors holds a substantial promise for enhancing both voltage blocking and current capacity of the switch simultaneously. Nevertheless, the key obstacle in this context revolves around acquiring...

This article investigates the use of off-the-shelf (OTS) diodes as opening switches in a 500-kV nanosecond pulsed power generator. A 40-J test bench based on a saturable pulse transformer and a primary thyratron switch is designed to evaluate the performance of the OTS diodes in comparison with standard semiconductor opening switch (SOS) diodes A d...

This article investigates the impact-ionization switching mechanism in parallel-connected high-voltage thyristors, aiming to bridge the gap between experimental observations and numerical simulations. A novel experimental setup is designed to study four parallel thyristors triggered in impact-ionization wave mode, marking the first instance of such...

Semiconductor opening switch (SOS) diodes are capable to switch currents with a density of more than 1 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and withstand nanosecond pulses with an amplitude of up to 1 MV. SOS diodes, however, require a specific pumping circuit that must simulta...

Thyristors triggered in the impact-ionization wave mode is a promising switching method in pulsed power technology. This triggering approach enhances the current capability of standard thyristors, allowing switching a current pulse with an amplitude of 200 kA and a current rise time rate-of-change (dI/dt) of 58 kA/ $\mu$ s. Thyristor wafer area ca...

This article is devoted to saturable pulse transformers (SPTs), combining the functions of a pulse transformer and a magnetic switch. Two nanocrystalline magnetic cores are investigated in the SPT of an inductive energy storage (IES) pulsed power system based on a semiconductor opening switch (SOS). The first magnetic core has a square hysteresis l...

For many years, modern defense and security applications have driven the development of compact pulsed power generators to produce high-power electromagnetic waves. Usually, such generators fill a volume of at least a few tens of liters. This article aims to present the development and tests of an ultra-compact ultra-wideband (UWB) radiating electr...

The electromagnetic pulse (EMP) generators in use at the CEA Gramat, France, deliver up to 2 MV with a 1-ns rise time. This high performance relies on sulfur hexafluoride (SF $_{6})$ as the main insulator vector to withstand high-voltage stresses. To foresee further restrictions on greenhouse gases, CEA Gramat has started to look for a solution to...

Gelidium corneum (syn. sesquipedale) is an industrially and ecologically important species of red alga used for the production of high-quality agar. However, the species is also of growing interest for the production of other valuable compounds, such as mycosporine-like amino acids (MAAs), with potential cosmeceutical and biomedical applications. N...

This article presents an advanced 3-D electromagnetic co-simulation approach developed using the CST software to evaluate the characteristics of a bipolar subnanosecond pulse forming system for application in the biomedical and defense domains. To the best of the authors’ knowledge, the simulation technique presented in this article, which integrat...

Impact-ionization wave triggering of a thyristor enables it to switch significantly higher currents with much faster rise times ( $\text{d}I / \text{d}t$ ) than through conventional triggering; indeed tests on commercial components demonstrate that both current and $\text{d}I / \text{d}t$ can be increased an order of magnitude over their specifi...

Microsecond-range high-current pulses (hundreds of kA) with high $dI/dt$ (100 $\textrm {kA/$\mu $s}$ ) are used to generate megagauss-range magnetic fields. Industrial applications of such technology require high average power, repeatability, and a reliable high-current pulse generator with a long lifespan. Hence, the development of a fast soli...

This article presents the electrical and mechanical design of a compact 13-stage 0.5-MV Marx generator operating at a pulse repetition frequency (PRF) of 100 Hz. The fast-switching process of the generator is based on spark gaps, operated under pressurized air and leading to the generation of an output pulsed voltage with a peak of 0.5 MV and a ris...

A semiconductor opening switch (SOS) (also known as SOS diode) is a solid-state nanosecond switch of gigawatt power level. Due to its high pulse repetition rate, long lifetime, and maintenance-free capability, the SOS diodes are becoming increasingly attractive for use in solid-state pulsed power generators. However, the lack of SOS diode manufactu...

At present, underwater electric pulsed discharges are used in a wide range of modern applications. During the development of a system for generating underwater acoustic pressure pulses, a numerical model is an essential tool for guiding the design and interpreting the data. Developing a complex one-dimensional numerical code, like those presented i...

This paper investigates the electric breakdown along the surface of a cylindrical dielectric, part of a coaxial transmission line. The particular geometry of the insulator is very common, as it is used at the input or output of most high-power, high voltage generators. The streamer propagation criterion is used to calculate the flashover voltage. S...

Depending on practical applications in the field of electrical discharges in liquids, the controlling of the propagation mode of the electrical discharge is key. It is now well know that the breakdown voltage in tap water under atmospheric conditions is affected by the duration of the applied voltage. In one hand, pulses shorter than a microsecond...

Depending on practical applications in the field of electrical discharges in liquids, the controlling of the propagation mode of the electrical discharge is key. It is now well know that the breakdown voltage in tap water under atmospheric conditions is affected by the duration and electric field. In one hand, configurations with high electric fiel...

The toroidal electromagnetic coupler has many advantages over the classical transformer. It is widely used in low-power applications. However, there are some limits that hamper its use in modern and high-power applications, such as the cost, the difficulty of winding and, especially, the limited number of studies carried out on the thermal aspect....

Power thyristors triggered in impact-ionization wave mode are capable to replace spark gap switches, bringing major advantages into repetitive pulsed power industrial applications. Low power thyristors remained for the moment out of the research focus, most likely because of the challenging driver, which must provide a sufficiently fast and powerfu...

Depending on practical applications in the field of electrical discharges in liquids, the controlling of the propagation mode of the electrical discharge is key. It is now well known that the breakdown voltage in tap water under atmospheric conditions is affected by the duration of the applied voltage. On one hand, pulses shorter than a microsecond...

Depending on practical applications in the field of electrical discharges in liquids, the controlling of the propagation mode of the electrical discharge is key. It is now well know that the breakdown voltage in tap water under atmospheric conditions is affected by the duration of the applied voltage. In one hand, pulses shorter than a microsecond...

This work shows the possibility of replacing a conventional and bulky transformer by an air-core toroidal electromagnetic coupler galvanically isolated that will address the main challenges of smart grid technology using High Resonant Power Transmission (HRPT) method. The design of the lightweight structure and high-efficient system are the key e...

Wireless power transmission (WPT) has seen rapid growth during the last decades. It is a promising technology which has gained worldwide attentions in several applications. WPT has proved its capability to be convenient, safe and autonomous. Nevertheless, WPT for specific application such as charging electrical vehicle requires a high power and lar...

This article presents an experimental arrangement which, using 3-D numerical modeling, aims to study biomedical effects using subnanosecond pulsed electric fields (PEFs). As part of a major effort into developing contactless technology, the final aim of this study is to determine conditions of the applied PEFs (number of pulses, strength, pulse rep...

This is a Special Issue containing selected papers presented at the 7th Euro-Asian Pulsed Power Conference (EAPPC 2018) and the 22nd International Conference on High-Power Particle Beams (BEAMS 2018) in Changsha, China, held on September 16–20, 2018. The objective of this Special Issue was to provide the widest possible distribution of archival qua...

De nos jours, pour accroître le potentiel applicatif des machines de hautes puissances pulsées, il est nécessaire de développer des modulateurs compacts capables de délivrer des impulsions de l’ordre de plusieurs Mégawatts de durée pouvant atteindre plusieurs centaines de microsecondes. Cette amélioration requiert le développement de structures inn...

This paper introduces the work undertaken to reliably use off-the-shelf differentiating voltage probes attached to coaxial transmission lines. The results obtained prove that indeed such probes are a valid and simple instrument for measuring nanosecond and subnanosecond voltage impulses. As a bonus, this paper also highlighted an important challeng...

A prolate spheroidal reflector was designed, manufactured, and attached to a bipolar former at the output of a 10-GW-Tesla-driven Blumlein pulsed power generator. The reflector, operated in water, is capable of producing intense pulsed electric fields of the order of 50 kV/cm. Constructional details are provided, together with experimental results,...

The generation of high-power electromagnetic waves is one of the major applications in the field of high-intensity pulsed power. The conventional structure of a pulsed power generator contains a primary energy source and a load separated by a power-amplification system. The latter performs time compression of the slow input energy pulse and deliver...

The development and construction of self-scanning capability short-range ultra wideband (UWB) radar is forthcoming for the French Military for Defense. This paper is devoted to the presentation of the self-scanning radar principle and of the development, construction and tests of the different blocks needed to implement the elementary part of the f...

A bipolar Blumlein former has been designed and successfully implemented as an extension to an existing 10-GW-Tesla-driven Blumlein pulsed power generator. The new system is capable of generating a voltage impulse with a peak-to-peak value reaching 650 kV and having a high-frequency limit of the bandwidth well in excess of 1 GHz. Constructional det...

The temperature dependence of the Kerr constant for water has been determined over the range 19 °C-45 °C at a wavelength of 658 nm. This paper presents the experimental arrangement used for this purpose and the data obtained, for which a polynomial fit is provided. A formula is also suggested to help estimate the variation of the Kerr constant for...

This paper presents an innovative design of an Ultra Wide-Band (UWB) impulse radiation source. The transmitting system is composed of an UWB antenna with an integrated optoelectronic generator, which is able to feed the system with appropriate waveforms, a pulsed high voltage source, and an optical command system. The radiation source is the elemen...

A Tesla-Blumlein PFL-Bipolar pulsed power generator, has been successfully designed, manufactured and demonstrated. The compact Tesla transformer that it employs has successfully charged capacitive loads to peak voltages up to 0.6 MV with an overall energy efficiency in excess of 90%. The Tesla–driven Blumlein PFL generator is capable of producing...

The paper [1] reports on comparative experiments on a triggered-gap electrode used as an early streamer emission air terminal, with some equivalent circuit analysis of the triggering circuit and simplified electric field calculations.

The study presented in this article belongs within the context of a design of a new kind of short-range Ultra Wide-Band (UWB) Radar with an autonomous scanning capability. The generation of short pulses is performed with an optoelectronic device triggered by a laser flash and operating in linear switching mode. By adding as many optical systems as...

The present work is directly related to a repetitive 0.6 MV, 10 GW Tesla-driven Blumlein pulsed power generator, successfully developed at Loughborough University. In the second phase of the project, aiming at further compressing and modulating the output pulse using a bipolar pulse forming line system, multi-GHz diagnostic equipment is required to...

In the class of emerging high power electromagnetic sources, a complete pulsed power source, named MOUNA (French acronym of “Module Oscillant Utilisant une Nouvelle Architecture”) has been developed. This device must transmit waveforms with a wide frequency band and a high figure-of-merit. To improve the overall performance of the MOUNA system whil...

The originality of the radiation source presented here is localized in its ultrafast speed and its autonomy of scanning a large spatial area. That behavior is obtained by means of a trigger mode of radiation perfectly controlled by a single optical source. The transmitter consists of a powerful picoseconds laser, an optical power divider and n opto...

Optoelectronic devices triggered by a laser flash and operating in linear switching regime, allow the generation of short pulses with small time jitters (2ps typically). An Ultra Wide Band antenna array combining as many of this photoswitches as antennas has the advantage to increase the radiation power on one hand and to offer the agility of the r...

This paper is devoted to a detailed presentation of all aspects involved in a novel experimental technique to prove the effectiveness of an early streamer emission air terminal (ESEAT) versus a traditional Franklin rod. An experimental test using a novel method and associated with electrostatic simulation demonstrates the effectiveness of an ESEAT...

Abstract|Optoelectronic devices triggered by a laser °ash and operating in linear switching regime allow the generation of short pulses with small time jitters (2 ps typically). An Ultra Wide Band antenna array combining as many of this photoswitches as antennas has the advantage to increase the radiation power on one hand and to o®er the agility o...

This paper is devoted to a detailed presentation of all aspects involved in a demonstration of a novel pulsed electric field technique that does not generate conduction currents or Joule effects. Details are given of both the experimental arrangement and the electro-optic Kerr-effect based diagnostic used in the measurement of the intense puls...

SPHINX is a microsecond linear transformer driver (LTD), used essentially for implosion of Z-pinch loads in direct drive mode. It can deliver a 6MA current pulse within 800 ns into a Z-pinch load. The Dynamic Load Current Multiplier (DLCM) concept enables the current pulse to be modified by increasing its amplitude while reducing its rise time befo...

This paper is devoted to a detailed presentation of all aspects involved in a novel experimental technique to prove the effectiveness of an early streamer emission air terminal (ESEAT) versus a traditional Franklin rod in a laboratory. Firstly, a theoretical basis for the equivalent-circuit analysis of an ESEAT model is presented. It is shown that...

A high-power, high-energy pulsed-power generator, based on a 415 kJ/22 kV capacitor bank, has recently been developed at Loughborough University [1]. The generator can drive a high-impedance system, generating a total electrical power of many GW, while depositing a Joule energy of many tens of kJ in the load. To remove the unwanted negative-polarit...

form only given. Ultra Wide Band (UWB) antenna arrays offer the possibility to generate a wide band signal in a sharp direction, which can drastically improve the detection sensitivity. With a configuration including as many antennas as generators, an UWB array presents the advantage of increasing the radiation power on one hand and offering the ag...

Two essential milestones have recently been achieved in an on-going research programme between Loughborough University (UK) and Pau University (France), aimed at developing a novel non-invasive PEF technology for use in industrial food processing. Firstly, a reliable measurement of the intense fast electric fields generated in water, essential for...

A complete pulsed power source, named MOUNA, is composed of a set of batteries, a DC/DC converter to charge four capacitors, four synchronized spark gap switches, a resonant transformer generating 600kV/265ns pulses, an oil peaking switch and a dipole antenna. This device must transmit waveforms with a wide frequency band and a high figure-of-merit...

SPHINX is a microsecond linear transformer driver LTD, used essentially for implosion of Z-pinch loads in direct drive mode. It can deliver a 6-MA current pulse within 800 ns into a Z-pinch load. The dynamic load current multiplier concept enables the current pulse to be modified by increasing its amplitude while reducing its rise time before being...

This work aims at producing high dynamic shock waves by high voltage electrical discharges (HVED) in a water suspension in order to increase polyphenols extraction from grape pomace. Experiments at the laboratory (1 L) and pilot (35 L) scales were compared. The total specific energy input was varied up to 800 kJ/kg. The intensification of the extra...

This paper is devoted to a detailed presentation of all aspects involved in the development and demonstration of a compact electric field measuring system using the Kerr effect in water. During the experimental program, the Kerr constant of water was determined as 2.45 ·10-14 m/V2 ±10% at a wavelength of 658 nm, standard pressure and temperature, a...

Two essential requirements arise before any proposed and novel non-invasive pulsed electric field (PEF) food processing technique can be implemented in industrially meaningful systems. These are the reliable measurement of the intense fast transient electric fields generated in water close to metallic electrodes and a convincing proof-of-principle...

Modern pulsed power applications of high power microwave technology require compact power-amplifier. In each case, the high pulsed power generator is made up of a primary energy source and a load, separated by the power-amplification system that forwards the energy from this source to the load. Usually a Marx generator or a Tesla transformer is use...

Nowadays, a broad range of modern defense applications requires compact pulsed power generators to produce high-power electromagnetic waves. In a conventional design, such generators consist of a primary energy source and an antenna, separated by a power-amplification system, such as a Marx generator or a Tesla transformer, which forwards the energ...

The paper describes a simple and compact 0.5 MV high-voltage capacitive probe developed in common by Université de Pau (France) and Loughborough University (UK). Design details are provided, together with a simple and straightforward methodology developed to assess the characteristics of high-voltage probes. The technique uses a 4 kV pulsed arrange...

SPHINX is a microsecond linear transformer driver located at Atomic Energy Comission (CEA) Gramat (France), which can deliver a current pulse of 6 MA within 800 ns in a Z -pinch load. Using the concept of the dynamic load current multiplier (DLCM), which was proposed by Chuvatin, we expect to increase the load current above 6 MA, while decreasing i...

This paper describes a simple and compact 0.5 MV high-voltage capacitive probe developed in common by Université de Pau (France) and Loughborough University (UK). Design details are provided, together with a simple and straightforward methodology developed to assess the characteristics of high-voltage probes. Finally, a practical example of high-vo...

The paper describes the successful development of a spark-gap which can be used as a very high-voltage diode. Operated in air at atmospheric pressure, the unit is capable of removing negative unwanted polarity voltage impulse precursors up to -300 kV while capable of closing at +180 kV and reducing the rise time of the main positive polarity voltag...