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

{"title":"International steering committee","authors":"V. Barger","doi":"10.1109/peds.2007.4487661","DOIUrl":"https://doi.org/10.1109/peds.2007.4487661","url":null,"abstract":"s for Plenary Talks Monday, August 8, 2016 9:25 am Eiichiro Komatsu, MPA, Garching. From initial conditions to structure formation, and back Precise measurements of temperature and polarisation anisotropies of the cosmic microwave background (CMB) taught us a remarkable story. We now think that all the structures in our observable universe, such as galaxies, stars, planets, and eventually ourselves, originated from tiny quantum fluctuations generated during cosmic inflation. This remarkable hypothesis has passed all the observational tests to date, and we have learned a great deal about the physics of inflation. The current model for the subsequent evolution of initial fluctuations due to gravity and baryonic physics on large scales also agrees with the observational data. Turning this around, we can learn more about inflation and the late-time evolution of the universe using the large-scale structure of the universe. In this presentation I review the recent progress in this area of cosmology, and present three new results from our group over the last few years: testing symmetry of space-time during inflation, state-of-the-art calculation of the thermal gas pressure distribution in the universe and comparison to observations, and a new way to look at the large-scale structure of the universe using the â position-dependent power spectrumâ . But, are we totally convinced that inflation did occur? Not yet, because extraordinary claims require extraordinary evidence. The CMB community agrees that the next big step is to find a signature of primordial gravitational waves (GW) from inflation in the so-called B-mode polarisation of the CMB. Unlike the GW detected by LIGO recently, which has a wavelength of thousands of kilometres, the wavelength of the primordial GW from inflation a ecting CMB is on the order of billions of light years. To this end, I will describe our proposal for the next-generation CMB polarisation mission called “LiteBIRD”, a proposed JAXA mission with a target launch date in mid 2020. 10:10 am Rachel Rosen, Columbia University. A Massive Gravity Status Report The predictions of General Relativity (GR) have been confirmed to a remarkable precision in a wide variety of tests. From the theoretical viewpoint, consistent and well-motivated modifications of GR have been notoriously di cult to obtain. However, in recent years a conceptually simple modification has been shown to be free of the traditional pathologies. This is the theory of massive gravity, in which the graviton has a small mass. In this talk I will give a general review of massive gravity, discuss potential observational signatures and present the current challenges facing this theory. 11:20 am Enrico Sessolo, Nat. Centre for Nuclear Res., Warsaw. Dark matter — What it is and how to determine its properties I will review the present status of particle dark matter, with some attention to the case of supersymmetry. I will focus on the interplay of collider, direct, and indir","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122616977","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":"Development of the vacuum power flow channel for the Mini-G","authors":"J. Javedani, D. Goerz, D. Reisman, T. Houck, M. Perkins, R. Richardson, G. Vogtlin","doi":"10.1109/MEGAGAUSS.2012.6781424","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781424","url":null,"abstract":"The Mini-G explosive pulsed power system is a two-stage helical-coaxial FCG that is geometrically a half-scale version of LLNL's FFT device. The generator is capable of delivering 60 MA currents and 10 MJ of energy to suitable inductive loads. The Mini-G is presently used in high-energy-density physics experiments that require efficient current delivery through a vacuum power flow region to the load. As with the FFT device, the Mini-G system requires a compact, high-voltage gas-to-vacuum insulator and low-inductance vacuum power flow channel to achieve high performance and maximum energy delivery. In designing the Mini-G system, we followed the successful approach used in developing the FFT device. This included shaping the electrodes and insulators to manage electric field enhancements, applying coatings to cathode surfaces to suppress electron field emission, introducing baffles to the power flow channel to block UV, and applying coatings to electrode surfaces to absorb UV. This paper describes the design of the Mini-G vacuum interface and power flow region, and results of modeling and simulations that were done to evaluate and optimize performance. Appropriate codes were used to examine electric field enhancements, magnetic insulation, flashover inhibition and UV ray tracing in the channel. In this paper, we also present results of laboratory testing on`and shapes, UV induced insulator flashover, along with measurements of HV thresholds for electron emission. We also report on UV reflectance data for some of the coatings considered. To date, there have been eight experiments performed using the Mini-G system. For the first two tests, the power flow channel had an extremely low vacuum inductance of 0.9 nH. On the second Mini-G test it appeared that a partial shorting occurred in the power flow channel, limiting full energy delivery to the load. The design was modified to reduce electrical stress, improve UV attenuation, and incorporate additional diagnostics. This increased the inductance of the power flow channel to 1.5 nH. On the third Mini-G test the partial shorting reoccurred and the new diagnostics (inner Bdot probe) helped to identify the location at the vacuum insulator surface - about 10% of total current of 41 MA was diverted into the short. Further design modifications were incorporated to decrease electrical stress across the insulator and reduce UV illumination of the insulator surface. This increased the inductance of the power flow channel to 1.9 nH. On subsequent Mini-G experiments full current delivery to the load has been achieved with no occurrence of shorting.","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":"2012-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116881128","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 current performance of the 43 cm long Ranchero generator","authors":"J. Goforth, M. Alme, W. Atchison, B. Glover, D. Herrera, D. Holtkamp, E. Nelson, R. Meyer, H. Oona, P. Rae, M. Sheppard, A. Sgro, L. Tabaka, D. Torres, R. Watt, D. Reisman","doi":"10.1109/MEGAGAUSS.2012.6781420","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781420","url":null,"abstract":"A Ranchero flux compression generator (FCG) was recently tested at the 76 MA level. Ranchero generators were designed to be cost effective high current devices, and a variety of configurations have been tested. The Ranchero armature is a 152 mm diameter aluminum cylinder with a 6 mm thick wall. The high explosive (HE) is detonated simultaneously on axis, and the armature is expanded by a factor of two. At the final 300 mm diameter, the circumference is over 950 mm, which has been anticipated to accommodate currents approaching 100 MA. The test was performed with a 43 cm long module having an initial inductance of 56 nH, and a load inductance of 0.55 nH, consisting of a short load feed slot and probe grooves. A 12 mF capacitor bank at ~16.5 kV provided the initial 3.75 MA seed current. The performance of the generator with this load was calculated using a 2D MHD ALE code, and agreement was excellent. Generator design, test data, and details of the MHD calculations are given. The most important aspect of the results is verification of codes at the 76 MA level. The same codes do not show excessive losses up to the 100 MA level, and it is a much smaller extrapolation to that level at this time.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131803462","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":"A consistent approach to modeling MHD-driven cylindrical damage experiments","authors":"A. Kaul","doi":"10.1109/MEGAGAUSS.2012.6781441","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781441","url":null,"abstract":"Well-characterized experimental data is essential for development of models describing complex material processes such as damage and failure. There is currently a dearth of experimental data capturing material behavior for the processes of non-uniaxial loading to failure and void closure after damage. LANL and VNIIEF recently completed a series of ten helical-generator-driven cylindrical damage experiments using high-precision diagnostics to measure the drive conditions and the material response. These experiments produced a well-characterized damage data set ranging from void initiation to complete failure and recollection for a well-studied material, aluminum. Combining magneto-hydrodynamics (MHD) and material modeling capabilities in a Lagrangian hydrocode allows for self-consistent end-to-end simulations of MHD-driven material property experiments. Simulation results for the damage experiments compared to experimental data will be presented.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126694392","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":"Explosive pulsed power experimental capability at LLNL","authors":"A. D. White, D. P. Milhous, D. Goerz, R. Anderson, T. Ferriera, R. Speer, R. Kuklo, A. Young, D. Lahowe, G. Mease, M. Suda, A. Wiltse, D. Reisman, E. Daykin","doi":"10.1109/MEGAGAUSS.2012.6781442","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781442","url":null,"abstract":"LLNL has developed a family of advanced magnetic flux compression generators (FCGs) used to perform high energy density physics experiments and material science studies. In recent years we have performed these experiments at explosive test sites in New Mexico and Nevada. In 2011, we re-established an explosive pulsed power test facility closer to Livermore. LLNL's Site 300 is a U.S. DOE-NNSA experimental test site situated on 7000 acres in rural foothills approximately 15 miles southeast of Livermore. It was established in 1955 as a non-nuclear explosives test facility to support LLNL's national security mission. On this site there are numerous facilities for fabricating, storing, assembling, and testing explosive devices. Site 300 is also home to some of DOE's premier facilities for hydrodynamic testing, with sophisticated diagnostics such as high-speed imaging, flash X-ray radiography, and other advanced diagnostics for performing unique experiments such as shock physics experiments, which examine how materials behave under high pressure and temperature. We have converted and upgraded one particular firing bunker at Site 300 (known as Bunker 851) to provide the necessary infrastructure to support high explosive pulsed power (HEPP) experiments. In doing so, we were able to incorporate our established practices for handling grounding, shielding, and isolation of auxiliary systems and diagnostics, in order to effectively manage the large voltages produced by FCGs, and minimize unwanted coupling to diagnostic data. This paper will discuss some of the key attributes of the Bunker 851 facility, including the specialized firesets and isolated initiation systems for multistage explosive systems, a detonator-switched seed bank that operates while isolated from earth and building ground, a fiber-optic based timing, triggering and control system, an EMI Faraday cage that completely encloses diagnostic sensors, cabling and high-resolution digitizers, optical fiber-based velocimetry and current sensor systems, and a flash X-ray radiography system. The photos and experimental results from recent FCG experiments will also be shown and discussed.","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":"2012-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125031846","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":"Explosive flux compression generators at LLNL","authors":"D. Reisman, J. Javedani, G. F. Ellsworth, J. T. Paladichuk, R. Kuklo, D. Goerz, A. D. White, G. Earley, L. Tallerico, M. Murphy, J. Chase","doi":"10.1109/MEGAGAUSS.2012.6781423","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781423","url":null,"abstract":"At Lawrence Livermore National Laboratory we have developed a coupled helical-coaxial FCG device called the Full Function Test (FFT). This device was used to deliver 98 MA of current and 66 MJ of energy to an inductive load. The successful testing of the FFT represented the culmination of an effort to establish a high-energy pulsed power program that would greatly exceed the performance of capacitor bank facilities. Using the modeling, design, and experimental capabilities developed for the FFT, we have developed a new generator, the Mini-G. Based upon a half-scaling of the FFT device, the Mini-G is a coupled helical-coaxial FCG capable of delivering up to 60 MA of current and 8 MJ of energy. We will describe the design of this generator which involved the use of simulation codes as well as innovative pulsed power techniques to obtain a compact, optimized device.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"5 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":"132999606","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":"Using the Boundary Element Method to calculate 3-D magnetic fields and potentials","authors":"G. Kiuttu, J. Ingber, M. Ingber, Brian T. Smith","doi":"10.1109/MEGAGAUSS.2012.6781438","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781438","url":null,"abstract":"The Boundary Element Method (BEM) is a well-known technique for solving the integral form of potential and flux/field problems. In this method, the solution to a partial differential equation is found on a closed surface, from which the full 3-D solution can be directly calculated anywhere in the interior. Its advantages over directly solving the basic partial differential equation include reducing the dimensionality of the problem from three dimensions to two, the ability to solve so-called external problems - where the variables extend to infinity - without artificial boundaries and boundary conditions, and good scalability of parallel computations because the associated matrices are dense. While scalar potential problems have been solved extensively using the BEM, vector potential problems have not. We have derived a fully 3-D BEM technique to solve the vector Laplace equation for the magnetic vector potential and the vector Laplace equation for the magnetic flux density or field. While the solutions we obtain are strictly valid only for non-conducting media, the technique can be generalized to include magnetic diffusion. In this paper, we describe the 3-D technique, and show how it can be used to calculate magnetic fields on the surfaces of pulsed power system conductors.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"12 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":"133499962","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":"Welcome to Megagauss XIV","authors":"J. Degnan","doi":"10.1109/MEGAGAUSS.2012.6781401","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781401","url":null,"abstract":"The 2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS XIV) was held on 14–19 October 2012 at the Wailea Beach Marriott Resort and Spa on the beautiful island of Maui, Hawaii, USA.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"214 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":"133706744","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":"Helical EMG application for aluminum rheology studies","authors":"A. Balandina, P. Duday, V. Dudin, A. M. Glybin, V. A. Ivanov, A. V. Ivanovsky, A. I. Kraev, S. S. Nadezhin, A. Podurets, A. N. Skobelev, A. V. Tsibikov, O. A. Tyupanova, A. A. Zimenkov, W. Atchison, J. Griego, D. Holtkamp, A. Kaul, R. Reinovsky, L. Tabaka, C. Rousculp, J. B. Stone, D. Oró, J. Payton","doi":"10.1109/MEGAGAUSS.2012.6781422","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781422","url":null,"abstract":"To study the peculiarities of initiation, evolution and recollection of spall-type damage under axis-symmetric convergence using the impact method, the test bench with an explosive magnetic pulsed power source (EPPS) on the basis of a helical generator with an explosive opening switch and a current interrupter has been created. The EPPS allows shaping the trapezoidal current pulses with the amplitude from 4 MA to 12 MA, full base duration from 10 to 250 μs and front rise duration ~ 2 μs in the load (liner). The magnetic field produced by the EMG current ensures the isentropic drive of a cylindrical liner used to create a shock wave of the required characteristics in the targets. In experiments “R-Damage-8,9” representing the completion stage of the experimental series “R-Damage-0-9” realized jointly by the VNIIEF and LANL teams we used the isentropically driven liners to realize a set of processes of shock-wave compression, evolution of damage and recollection of a damaged matter under axis-symmetric convergence in the extruded aluminum. The features of these processes were recorded with the use of PDV technique due to the time dependencies of the hollow targets' inner surface velocity. The presented method allowed apparently for the first time realizing the full and incomplete recollection of the main crack as the results of metallographic analysis have showed. This result made it possible to verify the numerical models of the damaged medium recollection being developed at the present time.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"115 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":"117121267","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 configuration of experiments for MAGO program","authors":"O. Burenkov, Yuriy N. Dolin, P. Duday, V. Dudin, V. A. Ivanov, A. V. Ivanovsky, G. Karpov, A. I. Kraev, V. B. Kudelkin, V. Mamyshev, I. V. Morozov, S. V. Pak, S. M. Polyushko, A. N. Skobelev, V. A. Tokarev","doi":"10.1109/MEGAGAUSS.2012.6781427","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781427","url":null,"abstract":"The paper presents the current status of MAGO research and the basic results of the latest explosive experiments. The program of activities aimed at preparation and conduct of experiments on finish compression of high-temperature plasma generated in the thermonuclear compartment of the electric-discharge chamber will be described.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"5 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":"124637223","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}