2007 IEEE 34th International Conference on Plasma Science (ICOPS)最新文献

{"title":"Operation of Free-Electron Maser Based on a Two-Dimensional Distributed Feedback","authors":"C. Whyte, A. Cross, I. Konoplev, W. He, P. Mclnnes, A. Phelps, K. Ronald, C. Robertson","doi":"10.1109/PPPS.2007.4346328","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4346328","url":null,"abstract":"Summary form only given. Intensive studies of operation of a coaxial high-power Free-Electron Maser (FEM) based on a two-dimensional distributed feedback are currently taking place at the University of Strathclyde. It has been demonstrated that highest output power and efficiency was achieved if the FEM two-mirror cavity was formed by a 2D Bragg (input mirror) and 1D Bragg structure (output mirror) (2D-1D cavity) in comparison with the case when 2D-2D two-mirror cavity was installed. The input mirror provides two-dimensional (2D) distributed feedback and ensures mode selection over the wave azimuthal index. The use of a 1D Bragg structure as an output mirror reduces the cavity Q-factor, improves the RF field profiles inside the cavity and decreases the power losses inside the output mirror as compared to a 2D Bragg output mirror. The FEM has been driven by an oversized high-current, mildly relativistic thin (0.2 cm wall thickness) annular (7 cm diameter) electron beam of 200 ns pulse duration. The electron beam was guided thorough a coaxial transmission line of length ~2m with the diameters of inner and outer conductors of 6 and 8 cm respectively. The directional mode pattern of the microwave radiation launched from the output horn was measured. The output power measured at the detector was integrated over the radiation pattern resulting in an FEM output power of ~60MW corresponding to an efficiency of ~10%. To study the frequency of the output radiation first the cut-off filters were used and it has been established that the 2D Bragg FEM operated within the 36 GHz and 39 GHz. The frequency was also measured using a heterodyne frequency diagnostic. Microwave radiation from the FEM was mixed in a non-linear waveguide balanced mixer and the resultant intermediate signal captured on a LeCroy digitizing oscilloscope. By taking the FFT of the recorded signal and knowing accurately the local oscillator frequency the radiation spectrum was measured and the main maximum coincided with 37.3 GHz which is in good agreement with theoretical predictions.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125480591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LTGS Performance and Down-Selection for the Hydrus IVA PFL","authors":"P. Corcoran, V. Bailey, B. Whitney, P. Sanders, K. Hanzel, R. Broff, I. Smith, H. Kishi, V. Carboni, J. Pearce, R. Stevens, J. Douglas, K. Thomas, M. Bockle, M. Myall, M. Świerkosz","doi":"10.1109/PPPS.2007.4345734","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345734","url":null,"abstract":"Summary form only given. Two switch designs were tested in the prototype PFL test bed at L-3 as part of the recently completed IVA design effort for flash radiographic sources in the new Hydrus hydrodynamics research facility at AWE. One design, called the slab switch, was scaled from the Phermex Laser Triggered Gas Switch (LTGS) and the other, called the diaphragm switch, was scaled from the Nike LTGS. Both switches have a single ~8 cm, laser triggered gap pressurized to 150 psig with SF6, are 42 inches in diameter, and designed to fit within the same 7-ohm PFL which is nominally charged to 2.5 MV, in 1.5 mus. The PFL and switch were tested up to 3 MV in the prototype facility. Test results for the LTGS performance based on >2730 shots are presented in this paper along with the switch type down-selection that was based on electrical, mechanical, and manufacturing criteria. The performance and reliability test results for the overall PFL are presented separately. The LTGS test results include measurements of jitter, rate of prefire, and the throughput risetime (due to inductance and resistive phase combined). The PFL design was based on a relatively low inductance prediction of between 220 to 240 nH. The effect of laser focal position in the switch gap, flow rate of the continuously flowing SF6, gas density, laser power, the mechanical deformation of the switch, and laser optic alignment on the switch jitter, risetime, and arc formation were investigated and are presented. Two dimensional EM simulations of the switch were also performed to estimate the contribution of two dimensional effects on the risetime. Circuit models that match the measured performance are presented.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125483268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Piezoelectric Resonance in a Ferroelectric Plasma Source","authors":"M. Kemp, S. Kovaleski","doi":"10.1109/PPPS.2007.4345464","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345464","url":null,"abstract":"Ferroelectric plasma sources have been studied extensively for the past few decades. Potential applications include cathodes for traveling wave tubes or high-energy electron beams, triggers for pulsed power gas switches, and microspacecraft propulsion. In addition to liberation of ions and electrons from the ferroelectric itself, one hypothesized source of particles is from plasma generated on the ferroelectric surface. Factors identified influencing the plasma formation include triple point enhancement due to microgaps and surface charges generated by polarization switching. In this paper, we detail the utilization of piezoelectric resonance to generate plasma with reduced applied voltages. To study this effect, an rf bipolar voltage is applied across the ferroelectric. A non-linear device impedance is observed around the radial resonant frequency of the disk. The plasma breakdown voltage is shown to correlate with the impedance of the device. This effect is similar to what occurs in Rosen-type piezoelectric transformers manufactured with the secondary in a dielectric barrier discharge geometry. In our experiments, the plasma is generated in backgrounds of both vacuum and atmospheric pressure air. In addition, both lead zirconate titanate and lithium niobate ferroelectrics are utilized.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125524353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study on 0.5THz Superradiant Smith-Purcell Radiation","authors":"J. So, Y. Shin, K. Jang, J. Won, A. Srivastava, M. Sattorov, G. Park","doi":"10.1109/PPPS.2007.4346179","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4346179","url":null,"abstract":"Summary form only given. Since it was first discovered, Smith-Purcell radiation (SPR) from electrons moving over a grating has been noted for its simple radiation mechanism and adopted for the generation of radiation which covers wide range of electromagnetic spectrum. These days' growing interest in Terahertz frequency regime, 0.3-3 THz, and the lack of compact tunable sources in this spectral range are attracting more attention to SPR and various attempts have been made to improve the weak intensity of spontaneous Smith-Purcell radiation. Adopting quasi-optical Fabry-Perot cavity, backward wave interaction, pre-bunched electron beam, and photonic crystals are such examples. Recently, we've introduced another way of enhancing the Smith-Purcell radiation intensity by the use of counter-streaming electron beams and 1D slit array.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126822351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Voltage Multi-Pulse Generator Based on Series-PFL","authors":"Li Yuan, Zhang Wenvvei, L. Xiaoping, Li Jing","doi":"10.1109/PPPS.2007.4346100","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4346100","url":null,"abstract":"Summary form only given. This paper describes the details of design and construction of the device that is able to produce three high-voltage pulses of 200 kV sequentially. The device consists of four pulse-forming lines connected in series by three switches, and three Marx generators to charge the PFLs. The interval between pulses, determined by triggering pulses, ranges from 0 to 1mus. Two kinds of switches, V/N switch and coaxial switch, have been tested on the device. Although pulses obtained at the matched resistance load remain stable, due to changing of the state of the switches, the quality of second and third pulses are worse than the first one.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126472268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetically Insulated Pulse Transformers","authors":"M. Istenič, B. Novac, J. Luo, R. Kumar, I. Smith","doi":"10.1109/PPPS.2007.4345577","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345577","url":null,"abstract":"Summary form only given. This paper records the most recent developments in the research programme on the magnetic insulation of pulsed transformers that began at Loughborough University (LU) some six years ago, with the successful proof-of-concept demonstration of a small 100 kV prototype. Most recently, LU has designed and constructed two much larger-scale units for the study of alternative approaches to magnetic insulation, that are capable of producing voltages up to 1 MV. One alternative uses an externally injected magnetic field to achieve magnetic insulation while the other uses the field generated by its own winding currents, thereby forming a magnetically self-insulated system. Various novel features invoked in the two units will be described, with experimental results being presented and compared with theoretical predictions. The potential impact of this innovative technology on the design and development of future multi-MV lightweight and autonomous compact pulsed-power radiation generators will be highlighted.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"491 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123035207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Generation of High - Power Semiconductor Closing Switches for Pulsed Power Applications","authors":"S. Belyaev, V. G. Bezuglov, I. Galakhov, S. G. Garanin, S. Grigorovich, M.I. Kinzibaev, S. L. Logutenko, V. M. Murugov, V. Osin, I. N. Pegoev, V. Zolotovski, E. Kopelovich, F. A. Flat, V. V. Chibirkin, G. D. Chumakov, A. A. Khapugin, V.A. Martyinenko","doi":"10.1109/PPPS.2007.4345496","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345496","url":null,"abstract":"Summary form only given. A new generation of semiconductor closing switches based on reverse switched dynistors (RSD) has been developed to switch high-power current pulses with microsecond duration. In this report the results of theoretical and experimental investigations of RSD at peak current more than 500 kA and pulse duration up to 500 mus (at 0.1 Imax) are observed. The criteria of extreme peak current for switch taking into consideration the longtime performance under pulse-periodical mode are gave. The design and test results for switch under single pulse mode at operating voltage up to 25 kV and peak current up to 300 kA are described. The possibility of using such a switch in the ISKRA-6 capacitor bank is estimated.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"519 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123115356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Empirical Determination of Radiation Energetics of Inertial Confinement Fusion Relevant Wire-Array Z-Pinches","authors":"D. Sinars, M. Cuneo, R. Lemke, E. Waisman, B. Jones, M. Jones, J. Porter, S. Lebedev","doi":"10.1109/PPPS.2007.4345585","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345585","url":null,"abstract":"Summary form only given. The radiation power and energy produced by 20 mm diameter, 300-wire tungsten arrays of various masses was studied on the 20 MA, 100 ns Z pulsed power facility. On some tests, 1-mm diameter Al rods were inserted on the axis of the array both to limit the convergence and to reduce possible sources of magnetic kinetic energy. Empirical estimates of the kinetic energy of the implosion were made using x-ray pinhole camera and streak images, transmission-grating- spectrometers, and 6151 eV radiography. These were compared to the energy radiated before and during the main power pulse, which is the portion relevant for inertial confinement fusion applications, as well as the total energy radiated from the Z-pinch. It is clear that the total energy radiated by these wire arrays requires energy input above and beyond the kinetic energy of the implosion, as noted elsewhere for Al arrays, The energy radiated during the main power pulse (generally about half of the total radiated energy) is close to the estimated implosion kinetic energy for the heavy arrays studied here, but for the lightest arrays there may be some discrepancies. Specifically, the size of the X-ray emitting regions measured with three independent diagnostic methods appears too large to be consistent with the high convergence ratios required to explain the main pulse radiation energy. Supporting analyses of a mass-density profile obtained via radiography and circuit model energetics are ongoing at the time of this abstract, as well as an error analysis to understand whether we can conclusively support the statement that a non-kinetic source of energy is required to explain the main radiation pulse.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"220 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122190788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-Field Focusing of a Fast Electromagnetic Pulse","authors":"S. Xiao, T. Camp, J. Kolb, K. Schoenbach","doi":"10.1109/PPPS.2007.4345820","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345820","url":null,"abstract":"A new domain of pulsed electric field interactions with cell structures has been opened by using subnanosecond pulses, which are much less than the membrane charging time, allowing a direct electrical field-inner cell molecule interaction. This ultrashort pulse (rising 100 or so ps) also provides a possibility of guiding the energy into the deeper layers of biological targets nonintrusively. We are developing a wideband pulse system for focusing in the near field. This system has a spheroidal reflector with two focal points. A spherical TEM wave is launched in a rotationally symmetric structure towards the reflector from the first focal point by using a biconical radiator. Design issues like optimization of the reflector, biconical structure, feeding impedance and possible measurements will be presented.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114097523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical Diagnostics of the ZR Gas Switch","authors":"J. Woodworth, D. Bliss, M. Savage, K. LeChien, J. Maenchen, J. Lehr, J. Corley, K. Hodge, D. Guthrie, Z. Wallace, V. Anaya, G. Feltz, P. Wakeland, T. Thompson, J. Blickem, M. Hardin","doi":"10.1109/PPPS.2007.4345560","DOIUrl":"https://doi.org/10.1109/PPPS.2007.4345560","url":null,"abstract":"Summary form only given. The ZR gas switch is a multistage gas switch designed to hold off a voltage of ~6 MV and then transmit a 600-kA current pulse to the water section of ZR. The first stage of the switch, which holds off approximately 900 kV, is laser triggered by the focused beam from a frequency-quadrupled ND:YAG laser operating at 266 nm. The breakdown of the laser-triggered section causes a wave of breakdowns in the remaining 22 gaps in the switch, starting near the laser-triggered section and cascading to the other end of the switch. The gaps in this \"cascade\" section normally break down in multiple arc channels, which lowers the overall inductance of the switch. We are observing the details of normal and abnormal switch operation with fast framing and streak cameras, observing the time-history of the light emitted by the switch with fast photo-detectors and taking time-integrated photographs of the switch. The diagnostics indicate that the laser-triggered gap normally begins conducting current 10-to-15 ns after the laser arrives in the gap, with the entire switch breaking down 45-to 55-ns after the laser beam arrives in the switch. Details of the experiments and the operation of different switches are presented.","PeriodicalId":446230,"journal":{"name":"2007 IEEE 34th International Conference on Plasma Science (ICOPS)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114182188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}