2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)最新文献

{"title":"About quantization of strong magnetic fields in laser-produced plasmas","authors":"V. Skvortsov, N. Vogel","doi":"10.1109/MEGAGAUSS.2012.6781457","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781457","url":null,"abstract":"The effect of quantization of strong magnetic fields in laser-produced plasmas has been investigated experimentally by means of Faraday's rotation and theoretically by computer RMHD modeling for the first time. It is not surprisingly, because of the Maxwell equations in matter have the same closed symmetry as Dirac equation in quantum mechanics. The observed “plasma droplets” have anomalous high lifetime and fine structure. Their typical diameters range from 10 to 200 μm. In the vicinity of such droplets a 1-5 miniature magnetic dipoles has been detected. The measured magnetic fields by means of Faraday rotation method are as great as 4 - 120 MG at distance of r ≈10 -14 μm.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126326959","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":"Numerical simulations of the electromagnetic flux compression experiments at the Megagauss Science Laboratory at ISSP","authors":"S. F. Garanin, G. G. Ivanova, S. Kuznetsov","doi":"10.1109/MEGAGAUSS.2012.6781436","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781436","url":null,"abstract":"The International MegaGauss Science Laboratory at the Institute for Solid State Physics, (ISSP) Japan, conducts experiments on magnetic flux compression by liners [1]. Magnetic fields produced in these experiments currently reach 700 T and break laboratory-scale records. We have conducted 1D numerical simulations of magnetic flux compression under these experimental conditions to determine distributions of parameters across the liner and correlations between resulting magnetic fields and parameters of the liner (thickness and velocity) and seed magnetic field, and to calculate characteristics of plasma, which is predicted [2, 3] to form in such megagauss fields. Our simulation results verify generation of 6-7 MG range magnetic fields in the experiments by Takeyama [1]. In the 1D simulations, as distinct from the experiments, the resulting magnetic fields grow with decrease in the seed magnetic field, which in the simulations is attributed to the fact that the level of magnetic energy produced is controlled by the kinetic energy of the liner and is a weak function of the seed field. Consequently, with decrease in the seed magnetic field, the minimum radius of the liner decreases, and the maximum magnetic field increases. In addition, increase in the liner velocity in the simulations (even for a thinner liner with the same kinetic energy) also leads to higher magnetic fields, which is not observed in the experiments, either. One can suppose that these contradictions between simulation and experiment are related to the development of magnetohydrodynamic instabilities, which produce a compression picture different from 1D. The simulations have also demonstrated that plasma, the temperature of which turns out to be on the order of 20 eV at maximum compression, forms on the inside liner surface (magnetic field/matter interface) starting from a ~360 T magnetic field.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126345294","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":"Fiber-optical probes to measure megampere currents and megagauss magnetic fields in conditions of high-power radiation effect","authors":"I. V. Victorov, V. V. Grushko, I. M. Markevtsev, A. N. Moiseenko, V. Platonov, P. B. Repin, O. Tatsenko, A. V. Filippov","doi":"10.1109/MEGAGAUSS.2012.6781452","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781452","url":null,"abstract":"The paper presents optical probes to measure currents of tens megamperes and megagauss magnetic fields of ~10 MGs. Operating principle of the probes is based on the Faraday effect. Investigation results on determination of optical losses appearing at fibers alloyed with different dopants in a core under influence of an ionizing radiation at its rise time up to 1013 Rs are described in the paper. The least optical losses have been observed in the fibers of POD type. The core of this fiber is made of pure quartz, and the shell is alloyed with fluorine. Optical spectrum range of the least optical losses is ~(1.0...1.3) μm. We did not observe light depolarization at radiation effect on the POD type fiber with small LB (low-birefringence), i.e. general light intensity attenuation without disturbance of its linear polarization takes place. Such fiber could be used as the optical probes to record the currents of tens megamperes at rise time of ≤ 100 ns in the conditions of radiation influence on the fiber with exposition dose increase rate up to 1013 R/s.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129912144","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":"Numerical simulations of foil electrical explosion under helical EMG current drive for Warm Dense Matter generation","authors":"A. Buyko, S. F. Garanin, S. Kuznetsov, R. Reinovsky","doi":"10.1109/MEGAGAUSS.2012.6781450","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781450","url":null,"abstract":"Warm Dense Matter (WDM), i. e. substance at densities of the order of that of solids and temperatures of the order of 1-10 eV, can be produced using a helical explosive magnetic flux compression generator (EMG) with an opening switch. A diameter 200 mm EMG with an explosive opening switch can deliver a current of ~5 MA with a characteristic rise time of 0.3 μs to drive thick wires (posts) and study WDM in larger volumes than on stationary facilities. An improved WDM generation system was investigated, in which WDM is produced in cylindrical geometry as a result of an electrical explosion of a thin metal foil, surrounded by an insulator. It is shown that in such a system driven by an EMG with an opening switch one can obtain a large volume of matter with density on the order of (0.01-1) of solid density and temperature about 2-3 eV with better accessibility for electric measurements.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134534930","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":"Edge effect for transverse electromagnetic field penetration into a conductor","authors":"G. Shneerson, I. A. Belozerov","doi":"10.1109/MEGAGAUSS.2012.6781414","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781414","url":null,"abstract":"The magnetic field absolute value |H| calculated within the ideal conductivity approximation is known to behave near the conductor edge according to the law |H| = C S^α Here s is the shortest distance between a given point and the conductor edge, which is a dihedral angle θ <; π. The factor C is determined by the magnetic system configuration and by currents in the conductors. The coefficient α = (θ - π)/(2π - θ), therefore |H| grows unrestrictedly at S→0. For a medium with a finite conductivity, a formula derived in the linear approximation, which gives a possibility to calculate the magnetic field near the dihedral angle edge (in the point S = 0), when the skin depth is small. This formula reads H(0) = γC Δ^α for the sinusoidal current. Here Δ is the skin depth, γ is the frequency-independent dimensionless factor. Factor γ(π/2) is calculated. Formulae for the current density in the angle θ apex, for the Joule heating and for the volume energy density in this point are derived.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116419596","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":"Magneto-hydrodynamic simulation of explosive current opening switch operation","authors":"V. A. Demidov, V. N. Barabanov, Y. Vlasov","doi":"10.1109/MEGAGAUSS.2012.6781451","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781451","url":null,"abstract":"Explosive and electro-exploded opening switches are used for current sharpening of magneto-cumulative generators (MCG). The electro-exploded opening switches (EEOS) are well studied both in calculations and experimentally; the explosive opening switches (EOS) have been studied mostly experimentally. Calculation and theoretical studies of the explosive current opening switches has been carried out by means of phenomenological model building or in two-dimensional gas-dynamic approximation. The mentioned approaches have some limits, and they do not allow completely revealing the complicated pattern of physical phenomena taking place during the opening switch operation. Whereas it is necessary to optimize the explosive opening switches, it is almost impossible to solve this problem completely at expensive full-scale explosive experiments. Two-dimensional numerical magneto-hydrodynamic simulation of the processes is very close to the reality. The paper describes the statement of problem, compares calculation and experimental data on the circuit breaking of the magneto-cumulative generator using the explosive current opening switch with the ribbed barrier. Investigation results of the electric circuit parameters, opening switch construction, and linear density of the breaking current dependence on the load current pulse characteristics are presented. Possible reasons of differences in calculation and experimental results are shown; ways of improvement of the calculation model and opening switch optimization are outlined.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122371801","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":"Ferroelectric Generators","authors":"L. Altgilbers, A. Stults, S. Shkuratov, J. Baird, E. Alberta","doi":"10.1142/9781848163232_0012","DOIUrl":"https://doi.org/10.1142/9781848163232_0012","url":null,"abstract":"Ferroelectric Generators (FEGs) are compact single shot high voltage generators. They consist of a small explosive charge, ferroelectric ceramic, and an output circuit. There has been and continues to be active Small Business Innovative Research (SBIR), University, and Government programs to develop FEGs as very compact power supplies for a variety of loads including antennas, microwave sources, and detonator arrays. In this paper, we will report on some of our recent efforts to improve the performance of FEGs and to use them to drive various loads.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"os-24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127691180","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":"Flux and magnetized plasma compression driven by Shiva Star","authors":"J. Degnan, D. Amdahl, M. Domonkos, C. Grabowski, E. Ruden, W. White, G. Wurden, T. Intrator, J. Sears, T. Weber, W. Waganaar, M. Frese, S. Frese, J. F. Camacho, S. Coffey, V. Makhin, N. Roderick, D. Gale, M. Kostora, A. Lerma, C. Roth, W. Sommars, G. Kiuttu, B. Bauer, S. Fuelling, A. Lynn, P. Turchi","doi":"10.1109/MEGAGAUSS.2012.6781433","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781433","url":null,"abstract":"The AFRL Shiva Star capacitor bank (1300 microfarads, up to 120 kilovolts) operated typically with 4 to 5 megajoules of electrically stored energy, with axial discharge currents of 10 to 15 megamps, and current rise times of approximately 10 microseconds, has been used to drive metal shell (solid liner) implosions in several geometries, including long cylindrical designs, which are suitable for compression of axial magnetic fields to multi-megagauss levels. Such imploding liners are also suitable for compressing magnetized plasmas to magneto-inertial fusion conditions. Magneto-Inertial Fusion (MIF) approaches take advantage of embedded magnetic field to improve plasma energy confinement by reducing thermal conduction relative to conventional inertial confinement fusion (ICF). MIF reduces required implosion speed and convergence ratio relative to ICF. AFRL, its contractors and collaborating institutions LANL, UNM, and UNR have developed one version of magnetized plasmas at pre-compression densities, temperatures, and magnetic fields that may be suitable for such compression. These are Field Reversed Configurations (FRCs). This effort reliably formed, translated, and captured FRCs in magnetic mirrors inside10 cm diameter, 30 cm long, mm thick metal shells or liners in preparation for subsequent compression by liner implosion; imploded a liner with an interior magnetic mirror field, obtaining evidence for compression of 1.36 T field to approximately 500 T; performed a full system experiment of FRC formation, translation, capture, and imploding liner compression operation; identified by comparison of 2D-MHD simulation and FRC capture experiments factors limiting the closed- field lifetime of FRCs to about half that required for good liner compression of FRCs to multi-keV, 1019 ion/cm3, high energy density plasma (HEDP) conditions; and designed and prepared hardware to increase that closed field FRC lifetime to the required amount. Those lifetime extension experiments have obtained imaging evidence of FRC rotation (which is a phenomenon that limits such closed field lifetimes), and of initial rotation control measures slowing and stopping such rotation. These and the results of subsequent closed field plasma lifetime and compression experiments and related simulations will be discussed.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128008667","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":"MHD modeling of the performance of an explosive opening switch","authors":"P. Duday, A. V. Ivanovsky, V. A. Ivanov, A. A. Zimenkov, N. Kudryavtseva, I. Kutsyk, A. I. Panov, A. N. Skobelev, S. Sokolov","doi":"10.1109/MEGAGAUSS.2012.6781439","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781439","url":null,"abstract":"A computational model of explosive opening switches, in which the conductor is broken by a ribbed barrier or by dielectric jets, is presented. The setup and results of TIM-2D hydrodynamic simulations with elastoplasticity, magnetic diffusion and electric circuit effects are discussed. The numerical simulations were done in Lagrange variables on unstructured grids. The results of the MHD opening switch simulations are compared with experiment.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"222 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120885650","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":"Early history of Explosive Pulsed Power: 1943–1970","authors":"L. Altgilbers","doi":"10.1109/MEGAGAUSS.2012.6781413","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781413","url":null,"abstract":"Explosive driven magnetic compression was first proposed by J.L. Fowler and Woodward in late 1943 at the Los Alamos National Laboratory (LANL) during the Manhattan project. Implosion of a liner immersed in an external magnetic field would generate a signal that could be detected with a pickup coil. The objective was to measure the rate of implosion of the liner. The first flux compression experiment was conducted by J.L. Fowler on January 4, 1944. An analysis of the data from these experiments showed that the fields were compressed from a few gauss to a few hundred gauss. By June 1944, J.L. Fowler and his team were getting reproducible scope traces for imploding cylinders and spheres that were in good agreement with other diagnostic methods. This was the genesis for the work later carried out by C.M. Fowler at Los Alamos. In addition to LANL, there were several other Flux Compression Generator (FCG) programs conducted at various universities and organizations in the 1960s including Davidson Laboratory of the Stevens Institute of Technology for Picatinny Arsenal, Poulter Laboratories of the Stanford Research Institute for the Air Force Systems Command, Illinois Institute of Technology (ITT) for the Army Research Office, and Aerojet Corporation. Other countries including Russia, China, France, Italy, and England had established FCG programs in the 1950s and 1960s. In 1957, F.W. Neilson designed, built, and tested both Ferroelectric Generators (FEGs) and Ferromagnetic Generators (FMGs) at Sandia National Laboratory (SNL). This led to programs at Sandia in the 1960s to develop compact single shot power supplies. In addition, explosive driven FEGs were investigated by other others such as M.F. Rose, W.L. Gilbertson, and others at the Naval Surface Weapons Center, P.E. Houser at Picatinny Arsenal, and W.L. Baker at the Air Force Weapons Laboratory. In this paper, we will review FCG and FEG programs that occurred in the U.S. and other countries during the period ranging from 1943 - 1970.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114779671","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}