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

{"title":"Tribute to Dillon McDaniel","authors":"K. Struve, J. VanDevender","doi":"10.1109/MEGAGAUSS.2012.6781412","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781412","url":null,"abstract":"A dear friend and colleague, Dillon H. McDaniel, passed away unexpectantly at his home in Placitas, New Mexico on May 1, 2012. We give tribute to a lifetime of work and contribution to the field of high-energy density science, pulsed power, and megagauss physics.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"4 Suppl 1 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":"130310209","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":"Cascade explosive magnetic generator of rapidly increasing current pulses","authors":"A. V. Shurupov, V. Fortov, A. V. Koslov, A. Leont'ev, N. Shurupova, V. E. Zavalova, S. Dudin, V. Mintsev, A. E. Ushnurtsev","doi":"10.1109/MEGAGAUSS.2012.6781431","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781431","url":null,"abstract":"The results of experimental study of two-stage explosive magnetic generator with magnetic flux trapping (EMG MFT) and opening switch in the primary circuit are presented. It was shown that this type of generator demands less than 3 μs to achieve the maximum of current derivative (30 - 100 kA/μs) and maximum of the output voltage. The generators with such parameters are necessary for a number of loads, for example, for the plasma accelerator with growing inductance. At the same time the problem of emerging surge in the secondary circuit of the generator was solved through the introduction of a separate single-turn closing switch with high breakdown voltage. The comparison of the performance of two types of EMG MFT is described. The first type generator was with opening switch in the primary circuit, the second one was without breaking of the primary circuit. They had approximately the same initial input parameters (inductances of the primary and the secondary circuits and the coupling coefficients) and the same inductance of model load - 1.16 μH.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"1 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":"131191864","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":"Beyond Phelix: Compact transformer drive For other high current applications","authors":"P. Turchi","doi":"10.1109/MEGAGAUSS.2012.6781455","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781455","url":null,"abstract":"The approach called PHELIX, for Precision High Energy-density Liner Implosion eXperiment, provides a technique to allow research on high energy-density phenomena associated with liner implosions in a scaled-down system suitable for use with proton radiography. In the embodiment selected at Los Alamos National Laboratory, a static transformer arrangement is used to obtain currents in excess of 5MA from a compact, 486 kJ capacitor bank that provides 1.3 MA to the primary circuit. The cm-scale liner implosion on the secondary side successfully attains speeds in the km/s range. It has been noted that the ratio of load current to bank energy is almost an order of magnitude higher using this transformer technique than achievable with direct drive from high energy capacitor banks. This increase in current per stored-joule offers the opportunity for using similar transformer arrangements for other applications apart from imploding liners. These potential applications include rail-guns, and the dense plasma focus (DPF). In the latter case, the strong dependence of neutron yield on peak current (Y ~ J4, perhaps) places a premium on performing DPF research at higher currents. For systems comparable to the PHELIX apparatus at LANL, modest capacitor banks may thus allow progress on DPF studies without demanding large systems, such as Shiva Star or Atlas. Similar improvements in the current per joule may also apply to explosively-driven generator sources, thereby reducing the resources required for explosive operation. Larger devices to obtain operation at much higher currents (e.g., beyond Z) may also be possible. Results from the dimensionless analyses previously used successfully to design PHELIX will be described for these new applications and design limitations will be discussed. Such limitations may require a shift to dynamically-switched vs static transformer operation, which may be satisfactory for experiments that involve significant load and diagnostic refurbishment each shot.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"29 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":"121569015","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":"Verification and validation adventures in simulating megagauss-magnetic-field-induced plasma formation on thickwire metallic surfaces","authors":"I. Lindemuth, R. Siemon, B. Bauer, W. Atchison","doi":"10.1109/MEGAGAUSS.2012.6781440","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781440","url":null,"abstract":"We discuss various verification and validation issues in computational modeling of a series of aluminum “thick-wire,” i.e., rod, experiments that have been conducted on the University of Nevada, Reno (UNR) Zebra generator (2 TW, 1 MA, 100 ns). These conceptually simple experiments involve multi-megagauss surface magnetic fields and have proven to be exceptionally rich in physical phenomena. The experiments also present severe computational challenges. We show that with a proper choice of equation-of-state and resistivity models Eulerian simulations can reproduce many of the observations to a reasonable degree. We also show that Eulerian and Lagrangian computations agree only with serious caveats, leading to the question of whether or not the computations are satisfactorily verified.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"10 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":"129455123","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":"Adventures in the experimental development of an ultrahigh speed plasma flow","authors":"M. Domonkos, J. Degnan, P. Adamson, D. Amdahl, B. Blasy, R. Cooksey, T. Grabowski, F. Lehr, P. R. Robinson, W. White, M. Frese, S. Frese, S. Coffey, J. F. Camacho, V. Makhin, N. Roderick, J. Parker, A. Lerma, D. Gale, M. Kostora, J. McCullough, D. Ralph, C. Roth, W. Sommars, T. Montoya, A. Lynn, P. Turchi, D. Schroen","doi":"10.1109/MEGAGAUSS.2012.6781456","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781456","url":null,"abstract":"In 1991, Turchi et al. [1] reported evidence for a 2,000 km/s aluminum plasma that originated from the upstream boundary of a wire array armature in a plasma flow switch (PFS) [2]. The 2008 article by Turchi et al. [3] posits that if such high Z plasma could instead be composed of deuterium or a deuterium-tritium mixture then the resultant multi-keV plasma would make an effective target for magnetized plasma compression to fusion conditions. This report documents several exploratory tests executed in an effort to achieve significant energy transfer from a plasma flow switch to a deuterium plasma. The first phase of this research concentrated on extension of the earlier work [1, 2] to a lower current system that would emulate the PFS used in series with an imploding liner load. The apparatus was also modified to permit pulsed injection of deuterium gas along the insulated coaxial electrodes between the PFS armature and the vacuum power feed. In analyzing the armature behavior, the initial conditions used in 2-D axisymmetric MHD simulations to approximate the wire-array/polymer film composite armature resulted in significant uncertainty in the validity of the calculations. This uncertainty confounded efforts to improve the opening switch behavior of the armature. Low density foams, commonly used in other high energy density plasma experiments, were seen as a candidate material for the armature that would facilitate greater fidelity between simulations and the experiment. Two subsequent tests were conducted using foam armatures. In both cases, current prematurely shunted upstream in the vacuum feed. Several possible causes were explored for the shunting of the current. Among the modifications implemented, the gas injection system was altered to increase both the quantity of gas adjacent to the armature while facilitating an increased pressure gradient between the armature and the current feed. A series of low energy shots were conducted to examine the impact of several proposed design modifications on current delivery to the armature. One conclusion of these experiments was that it has been very difficult to forestall breakdown in the injected gas as required by Turchi et al. [3]. Nevertheless, two experiments were conducted to evaluate performance with foam armatures. Both experiments exhibited good current delivery to the armature, behaving initially like the low energy experiments. The magnetic flux convected downstream was greater than in any of the prior experiments, though significant work remains to demonstrate the ultra-high-speed plasma flow concept.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"124 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":"131921629","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":"Experiments with explosive flux compression Generators Confirming the CAGEN-CALE threshold predictions for internal electric breakdown","authors":"S. Ault, R. Kuklo, J. Chase","doi":"10.1109/MEGAGAUSS.2012.6781430","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781430","url":null,"abstract":"A total of seven shots were fired at the HyperSpectral Sciences, Inc. firing site in Cinebar, WA, in support of the program to elucidate the internal electric breakdown phenomena. Three experiments were full-up HFCG shots. All of the HFCG shots broke down, while the last one exhibited the clearest example of “classical” breakdown. The correlation of the computer model threshold calculation with the last shot is quite good. The use of framing and streak cameras as a diagnostic has proved viable; the contact point as well as the breakdown are very visible. It was found that the electrical arcs that result from the breakdowns do not move. They are overrun by the contact point. The compressed gas in the interior of the HFCG must be taken into account. While it seems quite evident that the breaks are from the stator to the armature, our evidence cannot prove the point. Details of the firing arrangements, the data recovery methods, and the results with comparisons to theory [1], [2], and [3] are presented.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"1 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":"130610832","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":"Predicting the threshold for onset of internal electric breakdown in helical flux compression generators using CAGEN and CALE","authors":"J. Chase, G. Kiuttu, G. Peterson, D. Chato","doi":"10.1109/MEGAGAUSS.2012.6781419","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781419","url":null,"abstract":"The objective of this work is to provide predictability for the threshold of the onset of internal electrical breakdown for helical magnetic flux compression generators (HFCG) to enable higher performance and higher voltage designs and reduce the cost of relying on empirical design methods. The Care'n LLC has used the code CAGEN [1] in conjunction with CALE [2] to investigate the phenomenon of internal electrical breakdown in these devices. The CAGEN was modified to compute the peak electric field strength between the armature and the stator as well as between adjacent wires of the stator. Shock compressed gas within the HFCG plays an essential role so the 2-D hydro-code CALE was necessary in order to get a full prediction of the thresholds. An overview of the modeling and the comparison of experiment are presented. An issue is the role bifurcations play in the electric field breakdown. A new code BSBIF [3] models some of the effects. In order to confirm the modeling, a set of very special HFCGs were fabricated and then fired by Hyperspectral Sciences, Inc. The fabrication details [4], the experimental set-up, and the measurements [5] were entirely the work of HSI.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"18 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":"132075075","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":"The precision fabrication of non-split-turn, bare wire, constant pitch high explosive flux compression generators for use in internal electric breakdown experiments","authors":"R. Kuklo, S. Ault, J. Chase","doi":"10.1109/MEGAGAUSS.2012.6781429","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781429","url":null,"abstract":"In order to have sufficient precision to make experimental studies of the internal electric breakdown in flux compression generators, units were constructed using CNC techniques. The requirements were to have bare copper wires for the stator, aluminum armatures and transparent support materials. Reproducibility was critical. The details will be discussed along with metrology of the resulting devices.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"280 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":"116438846","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":"The PHELIX pulsed power project: Bringing portable magnetic drive to proton radiography","authors":"C. Rousculp, W. Reass, D. Oró, P. Turchi, B. Hollander, J. Griego, R. Reinovsky","doi":"10.1109/MEGAGAUSS.2012.6781454","DOIUrl":"https://doi.org/10.1109/MEGAGAUSS.2012.6781454","url":null,"abstract":"The PHELIX pulsed power project will introduce magnetically driven hydrodynamics experiments to the Los Alamos National Laboratory's proton radiography facility (pRad). The Precision High Energy-density Liner Implosion eXperiment (PHELIX) has been commissioned at Los Alamos. A small footprint capacitor bank consisting of four parallel, air-insulated, single-stage, marx units (U ~ 300 kJ) is cable coupled to a toroidal, current step-up transformer to deliver multi-megampere current pulses (tpulse ~10 μs) to cm size cylindrical loads. In a sequence of tests the performance of each component (capacitor bank and transformer) was evaluated and compared to a computer model. The transformer coupling was observed to be k ~ 0.93. A series of liner implosion experiments has been performed in which an aluminum liner (R ~3 cm, r = 0.8 mm, L = 3 cm) was accelerated to a velocity of ~ 1 km/s. The suite of machine diagnostics included linear Rogowski coils and Faraday rotation for current measurements. The experimental diagnostics include B-dot probes, multi-channel photon Doppler velocimetry (PDV), and single-frame, flash X-radiography to evaluate the performance of the high precision liner implosion. Currently, work is focused on integrating PHELIX into normal operations with the 800 MeV proton radiography facility at the Los Alamos Neutron Science Center (LANSCE), to enable high-resolution, high-frame-rate imaging of hydrodynamic experiments.","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134448687","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":"Copyright page","authors":"","doi":"10.1109/edcc.2018.00003","DOIUrl":"https://doi.org/10.1109/edcc.2018.00003","url":null,"abstract":"","PeriodicalId":299352,"journal":{"name":"2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1970-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122981289","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}