2017 Pacific Symposium on Pulsed Power and Applicationsp3e.ttu.edu/symp2017/tp2017.pdf · 2017-08-02 · Technical Program 2017 Pacific Symposium on Pulsed Power and Applications,

2017 Pacific Symposium on

Pulsed Power and Applications

Waikoloa Beach, Hawaii August 8 – 11, 2017

Hotel Map with Event Locations

2017 Pacific Symposium on Pulsed Power and

Applications Technical Program

August 8 - 11, 2017 Waikoloa Beach Marriott Resort and Spa

Waikoloa Beach, Hawaii, USA

Technical Topics

High-Power Microwave and RF Sources

Compact Pulsed Power Sources

Repetitive Pulsed Power

Pulsed Power Switches and Electromagnetic Launch

Industrial, Commercial, and Medical Applications

Advisory Committee Prof. Weihua Jiang Extreme Energy-Density Research Institute, Nagaoka University of Technology, Japan Prof. John Mankowski Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering, Texas Tech University, USA Prof. Jianjun Deng Institute of Fluid Physics, China Academy of Engineering Physics, China Prof. David Wetz Pulsed Power and Energy Lab, University of Texas Arlington, USA

[email protected] http://www.scandinovasystems.com/

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http://www.stangenes.com/

[email protected] http://pulsepowersolutions.com/

[email protected]

http://www.divtecs.com/

[email protected]

http://www.eagleharbortech.com

mailto:[email protected]

http://www.scandinovasystems.com/


http://www.stangenes.com/


http://pulsepowersolutions.com/


http://www.divtecs.com/


http://www.eagleharbortech.com/

Schedule

Tuesday, August 8th

Check-in / Registration 2:00 PM – 5:00 PM Welcome Reception 6:00 PM – 8:00 PM Paniolo Ocean Terrace

Wednesday, August 9th

Breakfast 7:00 AM – 8:45 AM Session 1: Compact Pulsed Power I 9:00 AM – 10:25 AM Coffee Break 10:25 AM –10:45 AM Session 2: Compact Pulsed Power II 10:45 AM – 11:45 AM Lunch Break 11:45 AM – 2:00 PM Session 3: Pulsed Power Switches and Railguns 2:00 PM – 4:20 PM Sunset Lu’au Dinner 5:30 PM – 8:30 PM The Waikoloa Beach Marriott

Thursday, August 10th

Breakfast 7:00 AM – 8:30 AM Session 4: High Power Microwave and RF Sources I 8:45 AM – 10:25 AM Coffee Break 10:25 AM – 10:45 AM Session 5: High Power Microwave and RF Sources II 10:45 AM – 12:45 PM Lunch Break 12:45 PM – 2:15 PM Catamaran Dinner Cruise 2:15 PM – 9:00 PM Bus Pick up 2:15 at Marriott

Friday, August 11th

Breakfast 7:00 AM – 8:30 AM Session 6: Industrial, Commercial, & Medical Applications 8:45 AM – 10:25 AM Coffee Break 10:25 AM – 10:45AM Session 7: Repetitive Pulsed Power 10:45 AM – 11:45 PM

NOTE: SCHEDULE IS SUBJECT TO CHANGE

Technical Program

2017 Pacific Symposium on Pulsed Power and Applications, Waikoloa, Hawaii, USA 1

Session 1: Compact Pulsed Power I

Wednesday, August 9th Naupaka IV 9:00 AM – 10:25 AM

Chair: Prof. David Wetz – Pulsed Power and Energy Lab, University of Texas at Arlington, Arlington, TX, USA

9:00 AM

INTRODUCTORY REMARKS

Prof. John Mankowski – Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, TX, USA

9:05 AM

TESTING RESULTS FOR A 35 KV INDUCTIVE ADDER AND NON-LINEAR TRANSMISSION LINE FOR HIGH POWER RF PRODUCTION* Timothy Ziemba, Kenneth Miller, James Prager, John Carscadden, Ilia Slobodov and Chris Bowman Eagle Harbor Technologies, Inc., Seattle, WA 98119 USA

Eagle Harbor Technologies, Inc. (EHT) has developed a 35 kV pulser for driving 50 Ω loads with nanosecond-scale rise times. This inductive adder uses EHT’s nanosecond pulser technology to drive nonlinear transmission lines (NLTL) to construct an all-solid-state RF plasma heating system for fusion science applications. The inductive adder configuration allows for independently adjustable control of the output voltage (35 kV), pulse width (20 – 200 ns), and pulse repetition frequency (up to 100 kHz). EHT will present results showing high voltage, fast rise time pulses into low impedance loads. In addition to RF generation, this inductive adder has applications to high voltage kickers for accelerations, plasma loads, high power modulators, and other tube-driving applications.

*Work supported under DOE SBIR, Contract DE-SC0013747

9:25 AM

SPACE PLASMA GENERATOR FOR CONTROLLED ENHANCEMENT OF THE IONOSPHERE* James Y.-B. Kim1, Dennis Papadopoulos2, Daniel Bentz1, Michael Barnard1, Eric Enig1 1Enig Associates, Inc., Bethesda, MD, USA 2University of Maryland, College Park, MD, USA

We are presenting an innovative space plasma generator, using explosive-driven flux compression generators to convert explosive chemical energy to electromagnetic energy. We will then use a Joule heating to heat up light metallic load in a sub millisecond time scale to transform the load from a solid metallic state to a first

Technical Program


ionization plasma state going through multi-phase transitions to generate an artificial man-made plasma cloud in the ionosphere. The target plasma cloud will be composed of 1025 ion-electron pairs of fully-ionized plasma with a few eV temperature propagating initially as a plasma disk jet depending on the choice of load geometry and launch scenario. This is the required amount of plasma to control enhancement of the ionosphere over the wide area of application zone. We also present analytical/computational studies of the generated plasma cloud interacting with the ionosphere and the geomagnetic field. We used the ALEGRA-MHD code with the multi-phase equation of state and conductivity models to study multi-phase transition, plasma formation, and initial plasma evolution. We studied the dispersal of the injected artificial plasma clouds, their interaction with the ambient particles and magnetic field as a function of the injection altitude, ambient ionospheric parameters and energy and mass of the injected artificial plasma over several hours. A sounding rocket can be utilized to demonstrate the device performance in ionospheric test environments.

*Work supported by US Air Force

9:45 AM

THE NEW SCHEME OF IGNITION DRIVEN BY COMPACT PULSED POWER SYSTEM* Xian-Jun Yang Institution of Applied Physics & Computational Mathematics 2 Feng Hao East Road, Beijing 100094 China

Six years ago, we initiated the feasibility research program of fusion ignition driven by the compact explosive pulsed power system for magnetized plasma. The primary goals we figured out include: (1) building the several tens MA’ s explosive pulsed power device; (2) building the "MC-1-like" device to conduct a serious of experiment research for ultrahigh magnetic fields; (3) building the so- call "Ying Guang 1" facility to create and investigate the high temperature density target of magnetized plasma of field reversed configuration (FRC); (4) developing a simulation tool to describe the process of formation and transportation of FRCs; (5) investigating the feasibility of ignition of the high temperature density target of magnetized plasma by means of first principle and MHD simulation. After six years now, the 10’s MA explosive pulsed power device and related two dimensional simulation code have been developed. On the other hand, the ultrahigh magnetic fields over 1400 Tesla has been achieved at the CAEP of China, which is believed to be important to suppress the heat conduction from charged particles and deposit the energy of alpha particle to promote the ignition process while the "YG 1 facility " has been built and it is believed that the centimeter's length and diameters of the formed FRC is formed, which has the average density is 1.3×1016 cm-3, and the average temperature is 137 eV. The two dimensional magneto hydrodynamic code, which is MPF-2D tools, has been developed to simulate and investigate the process of the formatting process of FRC. As the primary progress, the simulating results of this 2-D MHD code agree well with the experiment approximately. On the other hand,

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we are investigating the feasibility of achieving ignition of magnetized plasma by means of first physical principle and one dimensional Magneto-Hydrodynamic simulation. The ignition condition for plasma target with the embedded magnetic field has been investigated and the relationship of size of fusion facility with the embedded magnetic field has been derived at the first time. Due to the progress mentioned above, the new scheme of ignition of compressing the magnetized plasmoid with the solid liner merged by the colliding process of two FRCs has been proposed by us. We believe this scheme can make sense to achieve the ignition economically and quickly. Right now, five-year plan of nation may help us to get the chance of significant fund from Chinese Government to begin of this scheme.

*Work supported by National Natural Science Foundation of China (Grant No. 11575029)

10:05 AM

THICK-CAST, THREE-PHASE NANOCOMPOSITES FOR PULSED POWER APPLICATIONS R. E. Beverly III and R. N. Campbell R. E. Beverly III and Associates, PO Box 198 Lewis Center, OH 43035 USA

Composites formed by the combination of high dielectric constant εr ceramic particles and polymer matrixes represent a new class of materials with unique properties such as high energy density Es (J/cm3).1 We investigate the dielectric properties and electrical breakdown characteristics of three phase nanocomposites consisting of metal nanoparticles such as Ag, Co, or Ni, calcium copper titanate (CaCu3Ti4O12 or CCTO) submicron particles, and polymers such as Bisphenol-A (epoxy) and polydimethylsiloxane. CCTO is a perovskite-derivative with a huge dielectric constant that is prepared either by solid-state or sol-gel processes. Synergism between the two fillers increases εr and Es, and reduces leakage current with a concomitant increase in breakdown voltage compared with a single, submicron-size filler. Nanometer-sized particles of the ceramic filler aggregate because of van der Waals forces, which must be overcome by homogeneous dispersion in an organic matrix prior to mixing with the polymer carrier. Organic modification of the nanoparticles in order to reduce the surface energy is a critical step during material preparation and the choice of modifier silane compound affects not only the degree of disaggregation during ultra-sonification but also the curing behavior, glass transition temperature Tg, and dielectric loss (tan δ).2 Other researchers report very promising properties with rather exotic nanocomposites (e.g., CCTO nanofibers 3,4), however synthesizing these materials in quantity and/or at an affordable price remains to be demonstrated. The emphasis in our work is the production of comparatively inexpensive nanocomposites in quantities sufficient for pulsed power applications such as compact PFL’s. These new

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materials possess mechanical and thermal properties sufficient for casting in thick sections.

1. P. Barber et al., “Polymer composite and nanocomposite dielectric materials for pulse power energy storage,” Mat., Vol. 2, pp. 1697-1733, 2009. 2. S. Ramesh et al., “Dielectric nanocomposites for integral thin film capacitors,” IEEE Trans. Adv. Packaging, Vol. 26, No. 1, pp. 17-24, 2003. 3. Yang Yang et al., “Polyimide/CaCu3Ti4O12 nanofiber functional hybrid films with improved dielectric properties,” APL Mat., Vol. 1, pp. 050701-13, 2013. 4. D. Qin, G. Liang, and A. Gu, “CaCu3Ti4O12 electrospun fiber,” J. Alloys Comp., Vol. 549, pp. 11-17, 2013.

10:25 AM – Coffee Break

Session 2: Compact Pulsed Power II

Wednesday, August 9th Naupaka IV 10:45 AM – 11:45 AM

Chair: Prof. Sunao Katsuki – Institute of Pulsed Power Science, Kumamoto University, Kumamoto, Japan

10:45 AM

RESEARCH ON A COMPACT PULSED POWER SOURCE BASED ON INDUCTIVE ENERGY STORAGE Shirong Hao, Lidong Geng, Wenfeng Dai, Weiping Xie, Youcheng Wu, Minhua Wang, Longbo Cao and Chuanjun Feng Key Laboratory of Pulsed Power Institute of Fluid Physics, CAEP P.O.Box 919-108, Mianyang 621900, China

By adopting inductive energy storage technology, a compact pulsed power source is developed which consists of a high voltage supply and an inductive storage/opening switch pulse modulator. By utilizing inverter boost-doubling rectifier circuits, we developed a high voltage supply which can transform 48 Vdc to 200 kVdc and charge the 1 μF capacitor to 200 kV. The pulsed power modulator consists of a 1 μF/200 kV capacitor, a 1 μH storage inductor, a miniaturized high-performance exploding opening switch, a triggered switch and an output switch. Current out of the capacitor flows through the storage inductor and metal wire array, which exploding at peak current, opening the circuit, creating overvoltage on the output switch that closes, driving the load with high power pulse. By integrating the high voltage supply with the pulse modulator, a compact pulsed power source is developed with maximum dimension of 0.42 m×0.4 m×1.4 m and with a weight of 200 kg. Using a 12 Ω resistor as the load, we obtained a pulse voltage of about 800 kV with more than 150 ns duration time and less than 50 ns rise time. The peak power and energy efficiency is more than 50 GW and 40% respectively.

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11:05 AM

DIELECTRIC BREAKDOWN OF VENTED ELECTROLYTES* Charles Nybeck1, David Wetz1, John Heinzel2 and David Dodson1 University of Texas at Arlington, Arlington, TX, USA Naval Surface Warfare Center Philadelphia Division, Philadelphia, PA, USA2

Lithium-ion batteries are being more widely utilized as the prime power source of rep-rate pulsed power systems. Battery open circuit potentials as high as 1 kV have been proposed for use in naval shipboard power architectures. While this potential may not seem that high to engineers within the pulsed power and/or high voltage power system communities, it is significant and must be designed with caution, especially when field enhancements are present that could significantly multiply the applied electric field. The amount of energy stored in a shipboard battery could exceed a few GJ in some instances making it critical that any potential electrical breakdown weaknesses be identified and studied in detail. Though it is likely easy to engineer the battery such that dielectric clearances well exceed any 1 kV potential in a normal operating conditions, it is unclear how failure of a cell, and the leakage of electrolyte gas from a sealed cell(s), may affect the surrounding environment and the dielectric strength between high voltage electrodes separated by air. Reduction in the dielectric strength could result in a cascading effect whereby more cells are allowed to fail. The dielectric strength of vented electrolyte gas has not been previously documented and it is the aim of this work to fill this knowledge gap.

*Work supported by the US Office of Naval Research (ONR) under grant number N00014-16-1-2453

11:25 AM

DEVELOPMENT OF A 15 KV, PWM CONTROLLED NEUTRAL BEAM INJECTOR POWER SYSTEM BASED ON A RESONANT CONVERTER TOPOLOGY James Prager, Timothy Ziemba, Kenneth Miller, John Carscadden, Ilia Slobodov, and Alex Henson Eagle Harbor Technologies, Inc., Seattle, WA 98119 USA

Next generation solid-state systems for high voltage grid driving for neutral beam injection (NBI) and other applications will require precision control for fast feedback schemes. Both the large and small NBI power systems are based on decades old technologies that cannot respond on the necessary timescales. As new demands for increased control and performance are realized, solid-state technologies can be utilized to meet these demands. The next generation of NBI/grid driving power systems should include the following characteristics lower overall cost, smaller, reduced complexity, higher degree of controllability, and fast fault (arc) detection.

11:45 AM – Lunch Break

Technical Program


Session 3: PULSED POWER SWITCHES AND ELECTROMAGNETIC LAUNCH I

Wednesday, August 9th Naupaka IV 2:00 PM – 4:20 PM

Chair: Dr. William Nunnally – Applied Physical Electronics, L.C., Austin, Texas, USA

2:00 PM

GENERATION OF MEGAHERTZ REPETITIVE PULSES BASED ON LASER DIODE DRIVEN PHOTOCONDUCTIVE SEMICONDUCTOR SWITCHES* Jianqiang Yuan, Weiping Xie, Yu Gu, Hongwei Liu, Lingyun Wang and Sheng Ding Key Laboratory of Pulsed Power Institute of Fluid Physics, CAEP Mianyang 621900, China

Photoconductive semiconductor switches (PCSSs) are considered a promising device for applications in compact pulsed power generator due to their advantages over conventional switches, such as fast rise time, negligible time jitter, optical electrical isolation, compact packaging and high repetition rate up to MHz level. In order to obtain trigger laser pulses with the repetition rate in MHz, driven module based on MOSFET has been developed for laser diode. Digital delay generator was used to generate pulsed signals with the repetition rate up to MHz as the trigger of MOSFET. For a lateral GaAs PCSS with a gap of 5 mm and a depth of 3 mm, the pulses with repetition rate in 9 MHz (limited by digital delay generator) and photocurrent less than 1 A has been obtained when the switch operated in linear mode. Numerical analysis shows that the observed trend of minimum on-state resistances of the switch is directly related to the carrier mobility, which changes with the electrical field strength. At bias voltages of 16 kV, the PCSS operated in nonlinear mode, and a photocurrent of 200 A, which is thousand times higher than that in linear mode, has been achieved. With the pulse delay of 13 μs set by digital delay generator, the pulses with repetition rate in 77 kHz has been obtained for now.

2:20 PM

LIMITATION OF THERMIONIC EMISSION BY THE CATHODE SHEATH* Michael D. Campanell and Maxim V. Umansky Lawrence Livermore National Laboratory Livermore, California, USA

Thermionically emitting hot cathodes are used to generate many laboratory plasmas. Sometimes they are operated in pulsed mode, as in the Large Plasma Device at UCLA1. Hot cathodes also find use in pulsed power applications as thyratron switches2. For many decades it was assumed in the literature that when thermionic emission is limited a non-monotonic “space charge limited” (SCL) sheath3 is present. In a SCL regime the surface potential is below the plasma potential. Our recent analyses suggest that SCL sheaths are unstable and the surface potential should be above the plasma potential when the emission is limited4. A monotonic “inverse”

Technical Program


type sheath is present. Inverse sheaths fundamentally change how a plasma and surface interact. The erosion rate, energy flux, and loss rate of plasma to the surface are very different when the sheath is inverse compared to SCL. In recent studies, we demonstrated properties of the inverse regime under steady state floating conditions4. In ongoing work we are studying cases where current-carrying surfaces and temporal bias pulses are involved.

1. W. Gekelman et al., “The Upgraded Large Plasma Device, a Machine for Studying Frontier Basic Plasma Physics”, Rev. Sci. Instrum. 87, 025105 (2016). 2. A. Larsson, “Gas-Discharge Closing Switches and their Time Jitter”, IEEE Trans. Plasma. Sci. 40, 2431 (2012). 3. G. D. Hobbs and J. A. Wesson, “Heat Flow Through a Langmuir Sheath in the Presence of Electron Emission,” Plasma Phys. 9, 85 (1967). 4. M. D. Campanell and M. V. Umansky, “Strongly Emitting Surfaces Unable to Float Below Plasma Potential”, Phys. Rev. Lett. 116, 085003 (2016).

*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE- AC52-07NA27344.

2:40 PM

CORE-FREE ELECTRICAL EXPLOSION OF BARE TUNGSTEN WIRE IN VACUUM * Shi H T, Zou X B and Wang X X Department of Electrical Engineering Tsinghua University Beijing 100084, China

This paper presents an effective method to improve the specific energy into an exploding wire, which we called “method of heightening surface potential barrier”. For both negative and positive polarity explosions, a small insulator to provide a flashover surface was inserted between wire-end and cathode. It could greatly improve the radial-electric-field distribution along the exploding wire. Both laser shadowgrams and interferograms show a faster and more uniform explosion; dense wire core can no longer be observed from the interferograms, and the calculated specific energy into the wire increased by at least 200%. Based on our experiments and analysis, a new wire-array structure with inserted insulation surface for z-pinch experiments is suggested.

*Work supported by the National Natural Science Foundation of China under Contact Nos. 51177086, and 51237006.

3:00 PM

BATTERY-INDUCTOR POWER SUPPLY FOR A NAVAL RAILGUN Oliver Liebfried1, Stephan Hundertmark1 and Paul Frings2 French-German Research Institute of Saint-Louis, 68301 Saint-Louis, France1 Laboratoire National des Champs Magnétiques Intenses (LNCMI), 31400 Toulouse, France2

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Railguns allow to accelerate military payloads to large muzzle velocities and large muzzle energies. This enables the design of range enhanced artillery systems. These systems would allow to cover target distances of more than 100 km. As modern naval ships do have electrical power generation capabilities of the order of 10s of megawatts, it is reasonable to think of electrical, heavy naval deck guns. Some preliminary parameters of such a gun were developed in a recent study1. To further investigate the electrical behavior of the proposed 25 MJ muzzle energy railgun, simulations with two different pulsed power supply units (PSU) were performed. The more conventional approach uses a capacitor based PSU, the other investigated option is an inductive PSU. This paper deals with the design of a battery-inductor PSU based on the XRAM generator technology with opening switches based on the counter-current principle2. Parameters like size, weight, efficiency, maximum rep-rate and heating are estimated. The results are compared with the estimation of a capacitor based PSU, presented earlier by Hundertmark3. This study will give support for the selection of the most suited pulsed power supply for a naval based railgun artillery system.

1. S. Hundertmark, D. Lancelle, "A Scenario for a Future European Shipboard Railgun", IEEE Transactions on Plasma Science, Vol. 43, No. 5, May 2015, p.1194. 2. P. Dedie, V. Brommer, S. Scharnholz, ICCOS Countercurrent-Thyristor High-Power Opening Switch for Currents up to 28 kA, IEEE Transactions on Magnetics, Vol. 45, No. 1, Jan. 2009, pp. 536-539. 3. S. Hundertmark, O. Liebfried, “Power Supply Options for a Naval Railgun”, IEEE Pulsed Power Conference, Brighton, UK, June 18-22, 2017

3:20 PM

THE IMPACT OF CORROSION ON THE COPPER RAILS OF A SMALL RAILGUN* Clint Gnegy-Davidson and David Wetz University of Texas at Arlington, Arlington, TX, USA

As the U.S. Navy gets closer to fielding shipboard railguns; there is increasing concern with how surface corrosion of the rail claddings will affect launcher performance and lifetime. It is intuitive to hypothesize that corrosion on the rail surface will negatively affect both the performance and lifetime since significant surface oxide formation on the rail surface will increase the rail/armature contact resistance and surface pitting will reduce the rail/armature contact area. Negative effects from surface corrosion could include increase arcing contact between the armature and the rails, also known as transition, decreasing the launcher efficiency, muzzle velocity, and enhance the rate of rail erosion. In the experiments discussed here, the University of Texas at Arlington (UTA) has performed two unique sets of experiments. In the first, 6.35 mm diameter C18150 copper rods were pulsed with high current while immersed in a salt fog environment to study how pulsed currents affect surface corrosion. In the second set of experiments, a 1 m long railgun was used to evaluate the impact of rail corrosion on the launcher operation. A controlled corrosion process was used to induce damage on rail sections positioned at two locations within the gun, the startup

Technical Program


and peak current regions respectively. The launcher has a peak current of roughly 120 kA and a muzzle energy of 1.8 kJ when 14 g launch packages, fabricated from 6061-T6 aluminum, are used. The rail sections, which have dimensions of 1” x 4” x 1/8”, are fabricated of C18150 and were corroded using a using potentiostatic polarization to drive oxide formation and growth. Railgun performance was evaluated using the standard measurements of armature current, breech voltage, muzzle voltage, and velocity interpolated through b-dots. The rail sections were characterized at the material surface level prior to and after a shot series using scanning electron microscope (SEM) imagery and x-ray diffraction (XRD). Three different sets of samples were tested and include: baseline samples, i.e. no corrosion, samples corroded with a potentiostatic polarization of -0.1 V SCE for 20 ksec in 3.5% NaCl, and samples corroded with a potentiostatic polarization of -0.2 V SCE for 28.8 ksec in 3.5% NaCl. Each set of samples were subjected to a series of five railgun shots with a 10-minute rest between each shot. The aim of these experiments was to study the surface corrosion induced by the high ohmic heating and pulsed magnetic fields while immersed in a salt fog. The results of both respective types of experiments will be presented here.

1. C. G. Gnegy-Davidson, D. A. Wetz, D. Wong, and D.J. Horton, ‘The Effect of Saltwater Corrosion on Copper Alloy Rail Claddings in a Small Railgun,’ IEEE Transactions on Plasma Science, Accepted for Publication in May 2017, Publication Pending.

*Work supported by the US Office of Naval Research (ONR) under grant number N00014-13-1-0393

3:40 PM

OVERVIEW OF AN ELECTROMAGNETIC LAUNCHER TESTBED WITH PROGRAMMABLE ACCELERATION* Victor W. Sung and W. G. Odendaal Virginia Tech Blacksburg, VA 24060 USA

The paper gives an overview of a pulsed-power electromagnetic launcher testbed with programmable acceleration over 1 ms. The system features a modular pulse forming network, high power busbars, solid armatures, a loader for the armature, a projectile catch, instrumentation, advanced galvanically isolated controls, extensive fiber optic electrical isolation, and other safety systems all contained within a 5.5 meter by 3 meter footprint with a height of 3 meters. The overall design philosophy centered on ensuring safety and maximizing the energy conversion efficiency of the launcher while minimizing cost. The launcher fires solid aluminum armatures from rest to velocities on the order of 1000 m/s. The pulse forming network stores a total of 50 kJ of energy and is comprised of 32 identical pulsed-power modules for a maximum capacity of one million amperes peak. Each module is composed of a capacitor bank, solid-state

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pulsed-power switch, and custom litz wire inductor1. Custom designed high power busbars link each module in parallel, and coaxial cables connect the busbars to the launcher. All of the systems are controlled remotely using a user-friendly LabVIEW interface. The control software is responsible for monitoring the capacitor voltage on the modules, monitoring the status of and control of the capacitor charging power supply, controlling the safety relays that connect the modules to the power supply, controlling the linear actuator that loads the armature into the railgun breech, and firing the railgun. Programmable acceleration of the projectile is accomplished by sequentially firing each module at a specific time to achieve the desired acceleration profile2. Smart algorithms were developed to automatically calculate when each module should fire using a mathematical model of the launcher system.

1. V. Sung and W. G. Odendaal, “Litz wire pulsed power air core coupled inductor,” IEEE Transactions on Industry Applications, vol. 51, pp. 3385– 3393, July 2015. 2. T. G. Engel and W. C. Nunnally, “Design and operation of a sequentially fired pulse forming network for non-linear loads,” IEEE Transactions on Plasma Science, vol. 33, pp. 2060–2065, Dec 2005.

4:00 PM

SOPHISTICATED DIGITAL CONTROL SYSTEM OF AN OPERATIONAL EML TESTBED Robin S. Yang and Dr. Willem G. Odendaal Virginia Tech Blacksburg, VA 24061 USA

This paper describes a sophisticated, custom designed, and fully operational pulsed power electromagnetic launch testbed. This system employs design decisions and algorithms that maximizes safety and lifetime of an electromagnetic launcher. It also incorporates an algorithm that automatically generates the capacitor-discharge-based pulsed power current profile firing angles necessary for electromagnetic launchers in a timely manner. This pulse finding algorithm is deterministic, allows variable system parameter input, and generates firing angles at the set desired accuracy within seconds. This system employs a pulse forming network (PFN) composed of capacitor banks as PFN modules. The controls system software employs a state machine to allow the user to safely advance through the launch procedures. This paper discusses why the controls schemes are used and how it maximizes safety of the system during high energy operations. Automation is used along with a complex relay system to return to safe energy levels when faults are detected along with selective PFN module charging. This controls system also employs a self-developed algorithm to balance the wear of the PFN modules experienced by the thyristors by prioritizing selecting the least worn modules to be used for launch first.1

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1. T. Wolfe, P. Riedy, J. Drake, F. MacDougall, and J. Bernardes, “Preliminary design of a 200 mj pulsed power system for a naval railgun proof of concept facility,” 2005 IEEE Pulsed Power Conference, June 13 – June 15. 2005, pp. 70-74.

5:30 PM – Sunset Lu’au Dinner

Waikoloa Beach Resort Marriott

Technical Program


Session 4: High Power Microwaves and RF Sources I

Thursday, August 10th Naupaka IV 8:45 AM – 10:25 AM

Chair: Dr. Zhang Jun – College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, China

8:45 AM

THE STUDY OF COMPACT MICROWAVE PULSE COMPRESSION SYSTEMS* Segey N. Artemenko1, Vladislav S. Igumnov1 and Robert E. Beverly III2 1National Research Tomsk Polytechnic University Tomsk, 634050, Russia 2R.E.Beverly III and Associates Lewis Center, Ohio 43035, USA

The article describes new results of the study of microwave pulse compression systems with a planar or spatial compact storage cavity. The planar resonant cavity was made as a flat meander from a set of single-mode or moderately multimode sections of round waveguide connected through H-tees or their analogues. Spatial resonant cavities are three-dimensional forms of arbitrary configuration, composed of sections of moderately-multimode, round waveguide connected through analogues of tees. The resonant cavity is deemed compact due to its small dimensions in comparison with the length of the wave emitted from the resonant cavity during its double transit time. A detailed theoretical analysis of such compression systems was performed by the scattering matrix method. Conditions for waves traveling along storage cavities with few reflections were established. The energy distribution during resonance is determined, as well as the effect of the energy distribution on the shape of the output pulses. We demonstrate that compact microwave compression systems can be used to form rectangular pulses with discretely varying duration from several to hundreds of nanoseconds, and from tens to hundreds of megawatts. The authors present new experimental data of microwave pulse compression systems in the X- and S- bands, thus confirming the results of the theoretical analysis.

*The work was founded by the program for improving the competitiveness of Tomsk Polytechnic University.

9:05 AM

RECIRCULATING PLANAR MAGNETRON GENERATORS OF HIGH POWER MICROWAVES* Ronald M. Gilgenbach, Geoffrey Greening, Steven Exelby, Nicholas Jordan, Drew Packard and Yue Ying Lau Nuclear Engineering & Radiological Sciences Dept., University of Michigan Ann Arbor, MI 48109-2104

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The Recirculating Planar Magnetron (RPM) is being explored as a generator of 100’s MW microwaves at single and multiple frequencies.1-3 The RPM has the advantages of a large cathode area, power scalability with the number of cavities/length, and smaller magnetic field volume compared to cylindrical magnetrons. The pulsed power driver for the UM RPM is the MELBA-C Marx/Abramyan generator operating at -300 kV, 1-10 kA and pulse-lengths from 300-1000 ns. Two RPM oscillators and an amplifier are being investigated. The RPM-12A utilizes two linear arrays consisting of 6-cavities with a central cathode to generate 150 MW microwave power at a frequency of 1 GHz.1,2 A multi-frequency RPM employing two, separate, linear arrays of L-band and S-band cavities has been demonstrated to operate in frequency-locked state, generating in excess of 30 MW at 1 GHz and 10 MW at 2 GHz.3 High power Recirculating Planar Crossed Field Amplifier (RPCFA) experiments employ a rectangular-cross-section slow wave structure driven by MELBA. The RPCFA is designed to amplify 1 MW signals to 10 MW at a frequency of 3 GHz. Simulations and initial experiments are testing the RPCFA amplifier’s zero-drive stability versus electron current.

1. R.M. Gilgenbach, Y.Y. Lau, B.W. Hoff, D. French, J. Luginsland, and M. Franzi, “Crossed Field Device” US Patent # 8,841,867 B2 (issued Sept. 23, 2014) 2. M. Franzi, G. Greening, N. Jordan, R. Gilgenbach, D. Simon, Y. Y. Lau, B. Hoff, and J. Luginsland, “Microwave power and phase measurements on a recirculating planar magnetron,” IEEE Trans. Plasma Sci., vol. 43, no. 5, pp. 1675–1682, May 2015. 3. G. B. Greening, N. M. Jordan, S. C. Exelby, D. H. Simon, Y. Y. Lau, and R. M. Gilgenbach, “Multi-frequency recirculating planar magnetrons,” Appl. Phys. Lett., vol. 109, no. 7, pp. 074101, Aug. 2016.

* Research supported by Air Force Office of Scientific Research under award number FA9550-15-1-0097, Office of Naval Research under grant numbers N00014-13-1-0566 and N00014-16-1-2353, AFRL and L-3 Communications Electron Devices.

9:25 AM

AN EFFICIENT X-BAND CHERENKOV TYPE HIGH-POWER-MICROWAVE OSCILLATOR WITHOUT GUIDING MAGNETIC FIELD T. Shu, Li M. Guo, Zhi Q. Li, Jin C. Ju College of Optoelectronic Science and Engineering National University of Defense Technology, Changsha 410073, People’s Republic of China

The compactness and miniaturization of high-power-microwave (HPM) systems are drawing more and more attention 1, 2. Based on this demand, HPM generators without guiding magnetic field are developed. However, relatively low efficiency (about 10%) bothers the two types of existing relatively mature devices, Vircator and MILO. Referring to the traditional efficient Cherenkov HPM oscillators, researchers are trying to apply this type oscillator to developing moderately efficient HPM generators without guiding magnetic field 3-5. This paper presents an X-band Cherenkov type HPM oscillator without guiding magnetic field. By particle-in-cell codes6, this oscillator achieves an efficiency of 40% in simulation. When diode voltage

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and current are 620kV and 9.0kA respectively, a TEM mode microwave is generated with a power of 2.2GW, and a frequency of 9.1GHz. In this oscillator, electrons interact with microwave in longitudinal and radial directions, unlike the traditional magnetized Cherenkov type oscillator of only longitudinal interaction. As discussed in this paper, this two dimensional beam-wave interaction mechanism is significant to the power conversion efficiency of the oscillator.

1. R. J. Barker and E. Schamiloglu, High Power Microwave Sources and Technologies (Wiley, New York, 2001). 2. J. Benford, J. Swegle, and E. Schamiloglu, High Power Microwaves, 2nd edn (CRC, New York, 2007). 3. E. M. Totmeninov S. A. Kitsanov, and P. V. Vykhodtsev, “Repetitively Pulsed Relativistic Cherenkov Microwave Oscillator Without a Guiding Magnetic Field”, IEEE Trans. Plasma Sci. 39(4), 2011, 1150. 4. E. M Totmeninov, A. I Klimov, “On reduction of transient process duration in a relativistic Cherenkov microwave oscillator without a guiding magnetic field”, Tech. Phys. 61(6), 2016, 950–952. 5. L. M. Guo, T. Shu, Z. Q Li, H. Zhang, and J. C. Ju, “An efficient gigawatt level X-band Cerenkov type oscillator without guiding magnetic field”, Phys. Plasmas. 21(07), 2014, 073106. 6. V. P. Tarakanov, User’s Manual for Code KARAT Berkeley Research Associate, Springfield, 1998.

9:45 AM

ANGLE DEPENDENCE ON TRIPLE JUNCTION OF DIELECTRIC DISCHARGE COLD CATHODE TO USE FOR BACKWARD-WAVE OSCILLATOR Takeru Otsuki1, Akira Sugawara1, Masamiti Sakagami1 Kiyoyuki Yambe1, Kazuo Ogura1, and Wonsop Kim2

1Graduate School of Science and Technology, Niigata University, Niigata, Japan 2Department of New & Renewable Energy Electrical Engineering Jeonnam Provincial College, Korea

In recent years, microwaves are used in wide ranges of fields such as radar, communication system, and fusion. Development of high power microwave sources with a small size and variable frequency is desired. For microwave sources like backward-wave oscillators (BWOs)1, it is essential to use reliable cathode producing a high current electron beam with uniform cross sectional shape. In this research, angle dependence on the triple junction of dielectric discharge cold cathodes (DDCCs) is measured. The DDCC equips with a ceramic cylinder around a disk copper electrode. Electron beam emission characteristics (current-voltage characteristics and burn patterns by electron beam) using three DDCCs with different angles of the triple junction of 45, 90 and 135 degrees were measured. We also apply them to the BWO and measure microwave oscillation characteristics. An axial magnetic field of 0.819 T is applied in these experiments.

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As a result, the most uniform circular shape of the burn pattern was observed at 90 degrees of the triple junction. At this time, a peak current of 66.7 A was observed at the applied voltage of 26.0 kV. However, in the case of 135 degrees at 25.48 kV, the largest current of 500 A was observed in the first phase. In the case of 45 degrees at 26.0 kV, the largest current of 583 A by a pseudospark2 was observed in the second phase3. From this, it can be expected that π point operation of BWO increases microwave power at the second phase of the DDCC with 45 degrees.

1. S. Gong, K. Ogura, S. Nomizu, A. Shirai, K. Yamazaki, K. Yambe. S. Kubo, T. Shimozuma, S. Kobayashi, and K. Okada, IEEE Transactions on Plasma Science, vol. 43, no. 10, Oct. 2015. 2. H. Yin, A. W. Cross, W. He, A. D. R. Phelps, K. Ronald, D. Bowes, and C. W. Robertson, Physics of Plasmas, vol. 16, 063105, 2009. 3. K. Yambe, K. Ogura, S. Hasegawa, T. Shinada, T. Iwasaki, and T. Furuichi, IEEE Trans. Plasma Science, vol. 41, pp. 2781-2785, Oct. 2013.

10:05 AM

RESEARCH ON RADIAL-LINE RELATIVISTIC KLYSTRON OSCILLATOR AND AMPLIFIER Fangchao Dang, Xiaoping Zhang, Huihuang Zhong, Jinchuan Ju, and Baiyun Bao College of Optoelectronic Science and Engineering National University of Defense Technology, Changsha, People’s Republic of China

High power microwave (HPM) generators essentially suffer from the radio-frequency breakdown problem induced by ultrahigh electric field strength, and this issue becomes more challenging when the frequency-band, as well as the power conversion efficiency and pulse duration, is enhanced. The radial-line structure devices provide an inspiring solution for this issue owing to its intrinsic merit of high power capacity. In this paper, we report on the recent progress of radial-line relativistic klystron in National University of Defense Technology (NUDT), including an oscillator and an amplifier. In radial-line HPM devices, the electron beam is emitted from a disk-shape cathode and transports along the radial direction, appearing a radial-radiated shape. We firstly design a magnetic-excited system to guide the radial-radiated beam transporting steadily with two groups of magnetic solenoids, which possess the same dimension but opposite-direction currents. Then, a radial-line relativistic klystron oscillator (RL-RKO) is proposed and designed in our lab. We have demonstrated its feasibility in an initial experiment, in which a microwave with frequency of 14.86 GHz, power of 1.5 GW and efficiency of 24% is generated. The guiding magnetic field strength is only 0.4 T, which benefits the prominent magnet (PM) packaged. Recently, have we realized this idea in our design, and the PM packaged RL-RKA is currently being tested experimentally in NUDT. In addition to that, a radial-line relativistic klystron amplifier (RL-RKA) is proposed and investigated by means of theoretic calculation and simulation design. In particle-in-cell (PIC) simulation, the amplifier is capable of generating Ku-band microwave with power of 3 GW and efficiency of 50%. The corresponding electromagnetic structure is illustrated and physically explained in this paper.

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1. F. Dang, X. Zhang, H. Zhong, Y. Li, and Z. Qi, “Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field”, Phys. Plasmas 21, 063307 (2014) 2. F. Dang, X. Zhang, H. Zhong, and Y. Li, “Preliminary experimental investigation of a Ku-band radial line oscillator based on transition radiation effect”, Phys. Plasmas 22, 093301 (2015). 3. F. Dang, X. Zhang, H. Zhong, J. Zhang and J. Ju, “A high efficiency radial-line relativistic klystron amplifier”, Phys. Plasmas 23, 073113 (2016).


Session 5: High Power Microwaves and RF Sources II

Thursday, August 10th Naupaka IV 10:45 AM – 12:45 PM

Chair: Dr. James Dickens – Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, TX, USA

10:45 AM

PERFORMANCE OF A CATHODE-LESS RELATIVISTIC MAGNETRON WITH DIFFRACTION OUTPUT Wilkin Tang, C. Leach and P. Cravens Air Force Research Laboratory/Directed Energy Directorate, 3550 Aberdeen Ave SE, Kirtland AFB, Albuquerque NM 87117

Relativistic magnetrons with diffraction output (MDO) that use solid cathodes operate with efficiencies as high as 70%. 1-5 However, a solid cathode submerged inside the MDO’s interaction region often produces undesirable effects such as ion-back bombardment, cathode plasma formation etc., which often leads to pulse shortening, frequency shifting and decrease in efficiency. Researchers at University of New Mexico (UNM) have proposed a beam injection technique which moves the cathode out of the interaction region, which mitigates many issues.6 In this work, we followed the technique utilized by researchers at UNM, and performed particle-in-cell simulations to investigate the effects and performance of the cathode-less MDO, in which the cathode exists outside the interaction region, and an electron beam with high enough current and energy to form a virtual cathode is injected into the MDO’s interaction space. Cathode priming of the injected electron beam was also investigated to determine its effects on the MDO’s performance.

1. M. Daimon and W. Jiang, “Modified configuration of relativistic magnetron with diffraction output for efficiency improvement,” Appl. Phys. Letts 91, 191503 (2007). 2. M. Daimon, K.Itoh, G. Imada, and W. Jiang, “Experimental demonstration of relativistic magnetron with modified output configuration,” Appl. Phys. Letts. 92, 191504 (2008).

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3. M.I. Fuks, and E. Schamiloglu, “70% efficient relativistic magnetron with axial extraction of radiation through a horn antenna,” IEEE Trans. Plasma Sci., vol. 38, no. 6, pp. 1302-1312, Jun. 2010. 4. C.J. Leach, “High efficiency axial diffraction output schemes for the A6 relativistic magnetron,” Ph.D. dissertation, Dept. Elect. Eng., Univ. New Mexico, Albuquerque, NM, USA 2014. 5. C. Leach, S. Prasad, M. Fuks, J. Buchenauer, J. McConaha, and E. Schamiloglu, “Test of a high efficiency relativistic magnetron with diffraction output (MDO) and spherical cathode endcap,” in Proc. IEEE Int. Conf. Plasma Sci., Antalya, Turkey, May 2015, p.1. 6. M.I. Fuks and E. Schamiloglu, “Efficient magnetron with a virtual cathode,” IEEE Trans. Plasma Sci. Vol. 44 (8) Aug. 2016, pp.1298-1302.

11:05 AM

RECENT PROGRESS OF HIGH EFFICIENCY HPM AMPLIFIERS AND OSCILLATORS Jun Zhang, Jinchuan Ju, Wei Zhang, Xiaoping Zhang, Fangchao Dang, Wei Li, Difu Shi, and Huihuang Zhong College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, People’s Republic of China

In this paper, recent progresses about high-power microwave (HPM) amplifiers and compact high efficient oscillators researches carried out at the National University of Defense Technology (NUDT) in China are presented. In experiments of an X-band triaxial klystron amplifier, we successfully demonstrated a phase-locked HPMs output with power of 1.1 GW, pulse duration in excess of 100 ns, and typical phase shift deviation of around 10 degrees1. Based on the experimental results, an improved design with a higher efficiency of 44%, a higher gain of 50 dB and a higher output power 2.5GW was achieved in simulation. In terms of radial-line HPM devices, a Ku-band radial-line relativistic klystron oscillator (RL-RKO) is proposed and examined. We have demonstrated its feasibility in a preliminary experiment, in which a HPM with a frequency of 14.86 GHz, a power of 1.5 GW and an efficiency of 24% was generated. The guiding magnetic field strength was only 0.4 T. In addition, a radial-line relativistic klystron amplifier (RL-RKA) is proposed and investigated by simulation with significant high efficiency of 50%, gain of 50 dB, and power of 3 GW2. As for relativistic magnetron, an S-band magnetron with permanent magnet package has been developed, which can produce 1 GW HPM at a frequency of 2.4 GHz with efficiency of 25% and the total weight of about 50 kg. More recently, we successfully designed an improved S-band magnetron which can generate circularly polarized HPM with TE11 mode3 with the efficiency as high as 50%.

1. J. Ju, J. Zhang, Z. Qi, J. Yang, T. Shu, J. Zhang, and H. Zhong, “Towards coherent combining of X-band high power microwaves: phase-locked long pulse radiations by a relativistic triaxial klystron amplifier”, Sci. Rep. 6, 30657 (2016).

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2. F. Dang, X. Zhang, J. Zhang, J. Ju, and H. Zhong, “experimental demonstration of a Ku band radial-line relativistic klystron oscillator based on transition radiation”, Journal Applied Physics 121,12305 (2017). 3. F. Dang, X. Zhang, H. Zhong, J. Zhang and J. Ju, “A high efficiency radial-line relativistic klystron amplifier ”, Phys. Plasmas 23, 073113 (2016). 4. W. Li, J. Zhang, Z. Li, and J. Yang, “A portable high power microwave source with permanent magnets”. Physics of Plasmas 23, 063109 (2016) 5. D. Shi, B. Qian, H. Wang, W. Li, and G. Du, “A novel relativistic magnetron with circularly polarized TE11coaxialwaveguide mode”, J. Phys. D: Appl. Phys. 49, 465104 (2016).

11:25 AM

ANALYSIS OF EFFECTS OF CATHODE OUT-GASSING IONIZATION ON THE PERFORMANCE OF A MILO Zhi-Wei Dong1, Hui-Fang Sun1, Fang Zhang1, Wen-Yuan Yang1, Ye Dong1, Xiao-Hui Meng2

Institute of Applied Physics and Computational Mathematics, Beijing 100094, China Graduate School of Chinese Academy of Engineering Physics, Beijing 100088, China

The plasma phenomena produced by cathode out-gassing ionization is a possible factor to limit Magnetic Insulation Line Oscillator’s work performance, and also is the main obstacle to limit its repeat frequency. In this paper, physical modeling technology of high-power microwave device MILO cathode out-gassing ionization phenomena and particle simulation techniques to achieve the desired three-dimensional self-consistent simulation are analyzed. According to the preliminary simulation, the performance of an L band 100ns long MILO will be affected by the ionized plasma depending on the out-gassing rates: if the out-gassing rate is under controlled within a certain threshold, the output microwave power will have a little increase because of the ambipolar effects; when the out-gassing rate exceeds a certain threshold, the plasma caused by the ionization will rapidly decline microwave output power because of the resonant condition’s break, or directly unload the voltage pulse. The fundamental rules of effect of cathode out-gassing ionization on the performance of an MILO are summarized primarily.

11:45 AM

COMPACT REFLEX TRIODE RADIATION PATTERN AND POWER D.H. Barnett, J. C. Dickens, A. A. Neuber and J.J. Mankowski Center for Pulsed Power and Power Electronics, Dept. of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, USA

This study focuses on the radiation pattern and power of a compact reflex triode virtual cathode oscillator (vircator). The cathode is bimodal carbon fiber (CF) material paired with a pyrolytic graphite anode. These materials display ideal operating characteristics which including but not limited to, long lifetime > 106 shots, high operating temperatures > 1000 K, and large current densities ~200 A/cm2. A 12 stage,

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158 J pulse forming network (PFN) based Marx generator serves to drive the Vircator at 350 kV, 4 kA with ~100 ns pulsewidth. The operating frequency varies in the range of 1-6 GHz. The tunability is achieved by varying 3 main points in the system, the length of the anode-cathode (A-K) gap, the length from the back wall to the A-K gap, or/and the distance from the bottom of the cavity to the anode. The primary focus in this experiment is to determine the radiation pattern and power at the dominating frequencies.

12:05 PM

RESEARCH ON MAGNETICALLY INSULATED TRANSMISSION LINE OSCILLATOR WITH IMPROVED PERFORMANCE* Yu-wei Fan, Xiao-yu Wang, An-kun Li, Jin-chuan Ju, Zhi-qiang Li, Xiao-ping Zhang and Tao Jiang National University of Defense Technology, Changsha, Hunan 410073, People’s Republic of China

This paper reviews the recent progress in the National University of Defense Technology magnetically insulated transmission line oscillator (MILO). To improve the power efficiency, a double-band high-power microwave (HPM) source and a complex MILO are presented. Compared with the conventional load-limited MILO, the power efficiency of the complex MILO has an increase of above 50%. Moreover, the complex MILO can generate two microwave frequencies, and so a beat wave can be generated. To obtain a tunable HPM source, a tunable MILO is presented. In simulation, when the tunable MILO is driven by a 430 kV, 40.6 kA electron beam, HPM is generated with a peak output power of 3.0 GW and frequency of 1.51 GHz, and the relevant power efficiency is 17.2%. The 3-dB tunable frequency range is 2.25–0.825 GHz, and the 3-dB tuning bandwidth is 92%. A prototype is manufactured and the relative experiments are performed. In experiments, the microwave frequency can be changed arbitrarily in the range of 1.337–1.760 GHz, and the tuning bandwidth is 27%. To improve power efficiency and solve the problem of the vacuum recovery, a high-efficiency repetitively pulsed MILO (HERP-MILO) is presented. In a 5 Hz, 5pulses experiment, when the diode voltage and the current are 368-421kV and 36.8-40.1kA respectively, the minimum microwave power is 2.1 GW and the corresponding power efficiency is 15.5%. Moreover, the vacuum condition is improved. To increase the lifetime of the cathode, a carbon fiber array cathode is presented. When the diode voltage and current are 480 kV and 44 kA, respectively, HPMs with a peak power of about 3GW and a pulse duration of about 60 ns are obtained in a MILO device with the carbon fiber array cathode. The maintain-free lifetime of the carbon fiber array cathode can be more than 700 shots at voltage of about 480 kV, and there is no obvious damage observed on the carbon fiber surface. To expand the microwave frequency, an X-band MILO and a Ku-band MILO are presented. In the experiments of the X-band MILO, severe pulse shortening and electrode erosion are observed. The theoretical analyses show that anode plasma formation in the load region is the essential reason. In order to eliminate the anode

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plasma formation in the load region, an improved beam dump is presented. In the experiments of the Ku-band MILO, the measured microwave power is 1.2GW, the frequency is 12.36GHz, and the pulse duration is 35ns. On the whole, the development trends of MILO are high efficiency, tunable, intelligent, repetitive rate operation, and higher frequency.

*Work supported by the National Natural Science Foundation of China under Grant No. 61671457.

12:25 PM

PULSE LENGTHENING OF AN S-BAND REPETITIVE LONG-PULSE RELATIVISTIC BACKWARD-WAVE OSCILLATOR (RBWO)* Zhenxing Jin, Jun Zhang, Baoliang Qian, Jianhua Yan and Xingjun Ge College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, People’s Republic of China

In this paper, the recently simulated and experimental results of an S-band repetitive long-pulse RBWO in National University of Defense Technology (NUDT) of China are presented. The work of pulse lengthening is carried out by both RF structure optimization and Slow-wave structure (SWS) inner-surface treatment. By making the particle simulation optimization, compared to the former device1-3, the surface maximal RF electric field in the modified S-band repetitive long-pulse RBWO decrease from 1 MV/cm to about 800 kV/cm, and the efficiency increase from 20% to about 25%. Besides, the time of generating microwave precedes about 20 ns, and the microwave pulse duration prolong from 130 ns to almost 150 ns when the duration of diode voltage is 160 ns in simulation. In the 20 Hz repetitively operating experiment, the pulse width reached to about 120 ns with 2 GW output microwave power. There is still having some pulse-shortening problem. By adopting the useful surface treatment method of Low-Energy High-Current Electron Beam (LEHCEB)4, the output pulse width is lengthened to about 140 ns with 2 GW output microwave, and there is no obvious pulse-shortening phenomenon by carefully comparing the details of both the microwave and the diode voltage waveforms. The energy of the single pulse of the output microwave reaches to nearly 300 J.

1. Z.X. Jin, J. Zhang, J.H. Yang, H.H. Zhong, B.L. Qian et al. “A repetitive S-band long-pulse relativistic backward-wave oscillator”. Review of Scientific Instrument, 2011, 82: 084704. 2. J. Zhang, Z.X. Jin, J.H. Yang, H.H. Zhong, et al. “Recent Advance in long-pulse HPM sources with repetitive operation in S, C and X-band. IEEE Transactions on Plasma Science”, 2011, 39(6) pp.1438-1445. 3. J. Zhang, Z.X. Jin, J.H. Yang, D. Zhang, et al. Successful “Suppression of Pulse Shortening in an X-Band Overmoded Relativistic Backward-Wave Oscillator With Pure TM01 Mode Output”. IEEE Transactions on Plasma Science, 2015, 43(2) pp. 528-531. 4. A. V. Batrakov, K. V. Karlik, S. A. Kitsanov, et al. “Relativistic Gigawatt BWT Microwave Pulse Duration Increased upon Treating the Slow-Wave Structure Surface

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with a Low-Energy High-Current Electron Beam”. Technical Physics Letters, 2001, 27(4) pp. 150-152.

*This work was supported by the National High Technology Research and Development Program of China

12:45 PM – Lunch Break

2:15 PM – Catamaran Dinner Cruise

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Session 6: Industrial, Commercial and Medical Applications

Friday, August 11th Naupaka IV 8:45 AM – 10:25 AM

Chair: Dr. David Hemmert – HEM Technologies, Lubbock, TX

8:45 AM

PULSED ELECTRIC FIELD PROCESSING OF ALGAE: PREDATOR CONTROL AND PRODUCT EXTRACTION* Michael Kempkes and Rebecca Simpson Diversified Technologies, Inc., 35 Wiggins Ave, Bedford, MA 01730 USA

Diversified Technologies, Inc. (DTI) recently completed a grant focused on the application of Pulsed Electric Field (PEF) processing on the extraction of microalgae products. PEF processing uses short, high voltage electrical pulses to break cellular membranes. DTI worked closely with the Arizona Center for Microalgae Technology and Innovation (AzCATI) at Arizona State University (ASU) on this effort. In general, microalgae products are commodities that compete with alternative sources and processes. The cost of the final product is critical in achieving commercial viability. Many steps are required to produce economically valuable products from microalgae, with the most expensive being growing the algae in large quantity. The second most expensive step is extracting the desired products from the microalgae. Most microalgae products rely on drying and solvent extraction processes (e.g., hexane, butane, or supercritical CO2) to reach a commercial end product. These extraction processes are inherently slow, energy intensive, and expensive, limiting the market for microalgae products significantly due to their costs. Since PEF works on the cell membrane’s inherent structure, it is the lowest energy approach to lysing algal cells, requiring much less energy than alternative solutions such as ultrasound, heating, or freezing. In this effort, we successfully demonstrated PEF performance across 18 microalgae species, making their intra-cellular contents available for less expensive extraction methods than used today. Our results show that PEF is 30 - 98% less expensive than drying. Based on our Phase I results, we can draw several key conclusions: •PEF treatment is a valuable pre-treatment for extraction of algal components, with varying levels of efficacy against different species. The cost of PEF is much lower than drying for freshwater extraction. •Treating pre-concentrated algae requires no more energy than treating typical growth cultures, significantly reducing the energy required on a dry-weight basis. •There appears to be a sub-lethal stress effect on some algal strains, making them less permeable to Sytox® staining and potentially enhancing algal growth. The implications of this finding remain to be assessed.

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*Work supported by a Government Agency NIFA Award No.: 2016-33610-25460.

9:05 AM

EFFECTS OF INTENSE ELECTRICAL PULSES ON PROTEINS* Sunao Katsuki1, Soowon Lim1 Nobuaki Onishi2, Takuma Terahira2, and Toshiaki Katagiri2 1Institute of Pulsed Power Science, Kumamoto University Kumamoto, 860-8555 JAPAN 2GSST, Kumamoto University, Kumamoto, 860-8555 JAPAN

Non-thermal highly intense electrical pulses give unique physical impact to biological cells. One of the primary impacts of the pulses is an increase in the membrane permeability, which leads to the unregulated transmembrane ion mobilization and eventually results in specific responses associated to cell death or cell cycling. There are a number of reports on the field induced membrane permeabilization and subsequent secondary responses. However, the effect on proteins has not been discussed so far because they seem to be insignificant compared to the destructive membrane permeabilization. Since proteins, which are basically dielectrics and partially charged in cytoplasm, receive an electrostatic stress more or less from the external field, the possibility of structural or functional change of proteins due to the exposure to the pulse is of our great interest. This paper presents the structural change of proteins exposed to 5 ns-long intense electrical pulse up to 350 kV/cm. Aqueous solutions of several kinds of proteins including lysozyme, albumin and urease were exposed to the pulses and analyzed by means of sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE) and liquid chromatograph/mass spectrograph (LC/MS). Lysozyme and albumin, both of which are monomers and have disulfide bonds (S-S bonds) in their tertiary structure, seem to remain intact after exposing to the 300 kV/cm. On the other hand, urease, which is a hexamer and does not have S-S bonds in the tertiary and quarternary structures, was clearly deformed in the quarternary structure by exposing to the pulsed electric field more than 200 kV/cm. Our experiment demonstrates that some kinds of proteins are physically affected by intense electric fields in the level of 200 kV/cm, which implies that intense electrical pulses are capable of stimulating membrane and intracellular proteins without the significant membrane permeabilization.

*This work was supported by Grants-in-Aid for Scientific Research 17H03220 and 16F16370.

9:25 AM

PULSED ELECTRIC FIELD APPLICATIONS TO FRUITS AND VEGETABLES Michael Kempkes and Rebecca Simpson Diversified Technologies, Inc., 35 Wiggins Ave, Bedford, MA 01730 USA

Diversified Technologies, Inc. has introduced a new PEF (Pulsed Electric Field) system for processing fruits and vegetables by softening their tissue at the cellular

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level which makes slicing, dicing, peeling, drying, and juicing easier. Diversified Technologies' PEF System for the tissue modification of fruits and vegetables lowers their processing cost by actually making more of the cell contents accessible. Utilizing microsecond 1-5 kV/cm high voltage pulses to perforate cell membranes, this system can prepare tons-per-hour of whole fruits and vegetables for downstream processing. Capable of up to 85% higher juicing yields, Diversified Technologies' PEF System is instantaneous and requires very low energy. Non-thermal and non-chemical, it reduces energy requirements for cutting and peeling by 20-50% with less waste and breakage, claims the firm. Systems start at 100 kW, packaged in a CE Marked NEMA 4 stainless steel enclosure.

9:45 AM

EFFECT OF HIGH-POWER MICROWAVE IRRADIATION GENERATED BY REFLEX-TRIODE VIRCATOR ON HELA CELLS* Soowon Lim1, Sunao Katsuki1, Koki Nobutsuka2 and Kentarou Kishimoto2 1Institute of Pulsed Power Science, Kumamoto University Kumamoto, 860-8555 JAPAN 2GSST, Kumamoto University, Kumamoto, 860-8555 JAPAN

High-power microwave (HPM) is widely used in communications, defense, underground exploration and a host of other applications. Especially, applications to biological and medical area are receiving great interest. High peak, low average power radiation may cause biological reactions that are qualitatively different from known microwave effects and cannot be explained by ordinary heating. These biophysically different reactions will have a possibility of novel application area. Therefore, understanding of the biological effects of HPM irradiation is very important for extending use of HPM. Accumulation of experimental data including HPM conditions and theoretical analyzation of the data are also required. Current knowledge of HPM biological effects is very limited because of specialty of the HPM sources. In this research, a reflex-triode vircator (RTV) is used to generate the HPM pulse. An inductive energy discharge generator was used to generate high-voltage pulse. 20 kV is charged to a capacitor of 14.9 μF. Once we trigger a gas gap switch, the energy stored in the capacitor is transferred to a 1.8 μH inductor. 6 copper wires were used as opening switch to transfer the inductive energy to a reflex-triode vircator. The HPM pulse generated by the vircator was guided by a waveguide and irradiated to the target HeLa cells through a quartz window. A 90-degree bent waveguide and lead plates were used to block X-rays. We examined the cell responses and cell death ratio of the target cells. The cell proliferation, apoptosis and membrane intactness were investigated.

*Work supported by Japan Society for the Promotion of Science

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10:05 AM

400 kV 400 mA POWER SUPPLY Dr. Marcel Gaudreau, Gerry DelPriore, Neal Butler, Julian Merrick, Michael Kempkes and Rebecca Simpson Diversified Technologies, Inc., 35 Wiggins Ave, Bedford, MA 01730 USA

Diversified Technologies, Inc. (DTI) recently completed and delivered a 400 kVDC, 400 mA power supply for a commercial client. The 160 kW average power supply is comprised of 16 25 kV modules arranged in a vertical, air-insulated stack. Electrically, the system is a Cockcroft-Walton cascade multiplier fed by a standard DTI high power, high voltage inverter.


Session 7: Repetitive Pulsed Power

Friday, August 11th Naupaka IV 10:45 AM – 11:45 AM

Chair: Prof. John Mankowski – Center for Pulsed Power and Power Electronics, Texas Tech University, Lubbock, TX, USA

10:45 AM

INVESTIGATION OF A HIGH REPETITIVE FREQUENCY GENERATOR BASED ON INDUCTIVE VOLTAGE ADDER* Liu Hongwei, Yuan Jianqiang, Xie Weiping, Ma Xun, Wang Lingyun and Jiang Ping Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAEP, Mianyang 621900, China

In this paper, a repetitive frequency generator based on inductive voltage adder (IVA) has been investigated numerically and experimentally. The IVA has four inductive voltage adder cavities and each cavity has six input ports. High voltage fast recovery diodes were setting on the ports for isolating different input pulse. Then an output pulse with different burst frequency can be achieved through the control of the input time of pulses. A full circuit model was developed using PSPICE software to analyze key factors that influence output characteristics of the generator. Different modules including Blumlein pulse forming network with gas switch and pulse forming network with magnetic switches were used to generate input pulses. Preliminary results achieved with a dummy load of 100 show that the output pulse voltage is about 60kV and the smallest time interval is 1.2 μs which means an 800kHz repetitive frequency.

* Work supported by the Development Foundation of IFP Grant Nos. SFZ20140204

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11:05 AM

SYSTEM ASPECTS OF MULTI-PULSE DIODEISOLATED BLUMLEINS* C R Rose, J Barraza, M T Crawford, G Dale, K Dighe, J B Johnson, B T Mccuistian, and J M Taccetti Los Alamos National Laboratory, PO Box 1663 Los Alamos, NM 87545 USA

The Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory (LANL) uses two linear-induction accelerators (LIAs) for flash x-ray radiography of hydrodynamic tests. The Axis-I LIA uses a single beam pulse of 60 ns, 20 MeV, and 2 kA. The Axis-II LIA uses a long beam pulse, and a kicker to generate four radiation pulses. The National Nuclear Security Agency (NNSA) is planning a new, multi-pulse, single-axis, electron LIA for hydrodynamic experiments. One method for generating multiple beam pulses on a single axis, without a kicker, is to multi pulse the injector and each accelerator cell. Diode-isolated Blumleins are being considered as the pulsed-power drivers for the accelerator cells. This paper describes the diode-isolated Blumlein concept, performance requirements, trade space between critical component requirements, and proof-of-concept circuit simulation results.

*Work supported by the US National Nuclear Security Agency and the US Department of Energy under contract DEAC52-06NA25396

11:25 AM

RESEARCH ON A NOVEL REP-RATE LTD Wang Meng, Zhang Le, Zhou Liangji, Chen Lin, Zhao Yue, Tian Qing, Wei Bing, Qing Yanling, Jiang Jihao, Xie Weiping, and Deng Jianjun Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAEP Mianyang, Sichuan 621999, P. R. China

A novel rep-rate LTD module was developed in Institute of Fluid Physics. The LTD module consists of 50 individual four-stage Marx generators with an induction cavity, which integrated the technique advantages of traditional Marx generator and LTD. New designed 20 kA gas switches and 100nF capacitors were adopted. The lifetime of switch and capacitor can reach over 170 thousands shots with reasonably controlling of working parameters. The coaxial Marx generator overpassed 20 thousands continuously test in like manner. The module can output 900 kA current with rise time about 120ns on matched load about 0.14 Ω, with about 0.06 Hz rep-rate continuous working mode. This novel LTD can be an attractive candidate as prime-power sources for future rep-rate and long-life pulsed power accelerators.

Author Index


A

Artemenko, Segey N. 7

B

Bao, Baiyun 8 Barnard, Michael 1 Barnett, D.H. 10 Barraza, J 14 Bentz, Daniel 1 Beverly III, R. E. 2, 7 Bowman, Chris 1 Butler, Neal 13

C

Campanell, Michael D. 4 Campbell, R. N. 2 Cao, Longbo 3 Carscadden, John 1, 3 Chen, Lin 14 Cravens, P. 9 Crawford, M T 14

D

Dai, Wenfeng 3 Dale, G 14 Dang, Fangchao 8, 9 DelPriore, Gerry 13 Deng, Jianjun 14 Dickens, J. C. 10 Dighe, K 14 Ding, Sheng 4 Dodson, David 3 Dong, Ye 10 Dong, Zhi-Wei 10

E

Enig, Eric 1 Exelby, Steven 7

F

Fan, Yu-wei 11

Feng, Chuanjun 3 Frings, Paul 5

G

Gaudreau, Marcel 13 Ge, Xingjun 11 Geng, Lidong 3 Gilgenbach, Ronald M. 7 Gnegy-Davidson, Clint 5 Greening, Geoffrey 7 Gu, Yu 4 Guo, Li M. 7

H

Hao, Shirong 3 Heinzel, John 3 Henson, Alex 3 Hongwei, Liu 14 Hundertmark, Stephan 5

I

Igumnov, Vladislav S. 7

J

Jiang, Jihao 14 Jiang, Tao 11 Jianqiang, Yuan 14 Jin, Zhenxing 11 Johnson, J B 14 Jordan, Nicholas 7 Ju, Jin C. 7 Ju, Jinchuan 8, 9 Ju, Jin-chuan 11

K

Katagiri, Toshiaki 12 Katsuki, Sunao 12, 13 Kempkes, Michael 12, 13 Kim, James Y.-B. 1 Kim, Wonsop 8 Kishimoto, Kentarou 13

Author Index


L

Lau, Yue Ying 7 Leach, C. 9 Li, An-kun 11 Li, Wei 9 Li, Zhi Q. 7 Li, Zhi-qiang 11 Liebfried, Oliver 5 Lim, Soowon 12, 13 Lingyun, Wang 14 Liu, Hongwei 4

M

Mankowski, J.J. 10 Mccuistian, B T 14 Meng, Xiao-Hui 10 Merrick, Julian 13 Miller, Kenneth 1, 3

N

Neuber, A. A. 10 Nobutsuka, Koki 13 Nybeck, Charles 3

O

Odendaal, W. G. 6 Ogura, Kazuo 8 Onishi, Nobuaki 12 Otsuki, Takeru 8

P

Packard, Drew 7 Papadopoulos, Dennis 1 Ping, Jiang 14 Prager, James 1, 3

Q

Qian, Baoliang 11 Qing, Yanling 14

R

Rose, C R 14

S

Sakagami, Masamiti 8 Shi, Difu 9 Shi, H T 4 Shu, T. 7 Simpson, Rebecca 12, 13 Slobodov, Ilia 1, 3 Sugawara, Akira 8 Sun, Hui-Fang 10 Sung, Victor W. 6

T

Taccetti, J M 14 Tang, Wilkin 9 Terahira, Takuma 12 Tian, Qing 14

U

Umansky, Maxim V. 4

W

Wang, Lingyun 4 Wang, Meng 14 Wang, Minhua 3 Wang, X X 4 Wang, Xiao-yu 11 Wei, Bing 14 Weiping, Xie 14 Wetz, David 3, 5 Wu, Shaopeng 1 Wu, Songlin 1 Wu, Youcheng 3

X

Xie, Weiping 3, 4, 14 Xun, Ma 14

Y

Yambe, Kiyoyuki 8 Yan, Jianhua 11 Yang, Robin S. 6 Yang, Wen-Yuan 10 Yang, Xian-Jun 2

Author Index


Yuan, Jianqiang 4

Z

Zhang, Fang 10 Zhang, Jun 9, 11 Zhang, Le 14 Zhang, Wei 9 Zhang, Xiaoping 8, 9 Zhang, Xiao-ping 11 Zhao, Yue 14 Zhong, Huihuang 8, 9 Zhou, Liangji 14 Ziemba, Timothy 1, 3 Zou, X B 4

Author Index


Author Index


Documents

2017 Pacific Symposium on Pulsed Power and Applicationsp3e.ttu.edu/symp2017/tp2017.pdf · 2017-08-02 · Technical Program 2017 Pacific Symposium on Pulsed Power and Applications,