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244 results on '"Oona, H."'

1. New Data From the Integration of the Los Alamos MK-X and R43S6 Flux Compression Generators

Author

Goforth, J. H., primary, Ahluwalia, V. Z., additional, Baca, E. V., additional, Barnes, A. T., additional, Brown, E. N., additional, Bullis, R. S., additional, Farnsworth, C. J., additional, Foley, T. J., additional, Gianakon, T. A., additional, Gielata, J. A., additional, Gunderson, J. A., additional, Glover, B., additional, Herrera, D. H., additional, Jakulewicz, M. S., additional, Jaramillo, D. C., additional, Lopez-Pulliam, I. D., additional, Madden, S. M., additional, Novak, A. M., additional, Oona, H., additional, Rae, P. J., additional, Rainey, K., additional, Rettinger, R. C., additional, Rousculp, C. L., additional, Seitz, D. N., additional, Shofner, W. S., additional, Watt, R. G., additional, Yoder, J. L., additional, Johnson, A. J., additional, and Young, A. J., additional

Published
2021
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3. Environmental spaces for palsas and peat plateaus are disappearing at a circumpolar scale.

Author

Könönen, Oona H., Karjalainen, Olli, Aalto, Juha, Luoto, Miska, and Hjort, Jan

Abstract

The anthropogenic climate change threatens northern permafrost environments. This compromises the existence of permafrost landforms, such as palsas and peat plateaus, which have been assessed to be critically endangered habitats. In this study, for the first time we integrated geospatial datasets and statistical methods, to model the distribution of palsas and 10 peat plateaus across the Northern Hemisphere permafrost region. The models were calibrated using data from years 1950- 2000. The effects of climate change on the future distribution of palsas were assessed by using moderate and high emission scenarios (Representative Concentration Pathways; RCP4.5 and RCP8.5, respectively) for two periods (2041-2060 and 2061-2080). Hotspots for palsas and peat plateaus occurred in Northern Europe, Western Siberia, and subarctic Canada. Climate change was predicted to cause an almost complete loss (-98.2 %) of suitable environmental spaces under a high 15 emissions scenario by 2061-2080, while under a moderate emissions scenario 89.3 % were predicted to disappear. The comparison with previously published thermokarst data supported our findings regarding the recent degradation of palsa and peat plateau environments. Our results fill the knowledge gaps in the distribution of the permafrost landforms in less studied areas such as Central and Eastern Siberia. In addition, the projections provide insights into the changing geoecological conditions of the circumpolar region with important implications for greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Published
2022
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5. High voltage pulses for high impedance loads using explosive formed fuses

Author

Degnan, James H., Kiuttu, Gerald F., Turchi, Peter J., Graham, Jack D., Goforth, James H., Lopez, Emmanuel A., Oona, H., and Tasker, Douglas G.

Subjects
Electric fuses -- Research, Electric power systems -- Load dispatching, Impedance (Electricity) -- Research, Magnetic induction (Electromagnetic induction) -- Research, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

Explosive formed fuses (EFF's) use conducting elements that are deformed by explosive pressure (typically, against dielectric dies). This causes the fuse geometry to change, so that the conducting element cross section decreases. This enables a higher ratio of current conduction to current interrupt time than for normal fuses, and it enables more control of when current interruption occurs. In combination with a suitable output closing switch, EFF's can be used to obtain several hundred kilovolt voltage pulses from inductive stores to drive several ohm loads. With proper choices of inductive store, EFF geometry and material, and output closing switch features, such a voltage pulse can be approximately flat topped for microsecond duration and have a small fraction of microsecond risetime. We present theoretical analysis and circuit simulations which illustrate this, using scaled empirical EFF parameters for inductive stores in the 1 weber flux, several hundred nanohenry range. The circuit simulations were done using MicroCap-IV, with user defined elements. These simulations were done with static inductive stores and with explosive magnetic flux compression generators driving inductive stores. Index Terms - Explosive formed fuses, explosive magnetic flux compression, high impedance loads, high voltage pulses, inductive stores.

Published
1998

6. The Selling of Supreme Court Nominees.

Author

Hathaway, Oona H.

Subjects
The Selling of Supreme Court Nominees (Book), Books -- Book reviews
Abstract

I Ever since the brutal confirmation hearings of Robert Bork, President Ronald Reagan's failed nominee to the Supreme Court, scholars and commentators have bemoaned the current state of the judicial [...]

Published
1996

11. Evidence of hydrodynamic processes in multimegampere copper fuses.

Author

Lindemuth, I. R., Caird, R. S., Goforth, J. H., Oona, H., and Reinovsky, R. E.

Subjects
MAGNETIC flux, ELECTRIC currents, ELECTRIC fuses
Abstract

Presents a study which performed experiments in which an explosively formed fuse transferred a fraction of the 10 MA output current from an explosively powered magnetic flux compression generator to a conventional exploding metallic fuse load. Materials and methods used; Measurement of currents measured through the fuse load; Analysis of the hydrodynamic processes in the experiment.

Published
1990
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12. Grid-controlled extraction of pulsed ion beams.

Author

Humphries, S., Burkhart, C., Coffey, S., Cooper, G., Len, L. K., Savage, M., Woodall, D. M., Rutkowski, H., Oona, H., and Shurter, R.

Subjects
ION bombardment, PLASMA gases
Abstract

Presents a study which developed a method for extracting well-focused ion beams from plasma sources with time-varying properties. Principle of grid-controlled ion extraction; Experimental apparatus; Results.

Published
1986
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13. Improvements in Ranchero magnetic flux compression generators

Author

Goforth, J. H., primary, Baca, E. V., additional, Briggs, M. E., additional, Cochran, F. L., additional, Gianakon, T. A., additional, Glover, B. B., additional, Herrera, D. H., additional, Holmes, R. L., additional, Johnson, J. L., additional, Martinez, E. C., additional, Meyer, R. K., additional, Oona, H., additional, Peterson, D. L., additional, Rae, P. J., additional, Rousculp, C. L., additional, and Watt, R. G., additional

Published
2015
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16. The Ranchito Helical Magnetic Flux Compression Generator

Author

LOS ALAMOS NATIONAL LAB NM, Goforth, J H, Fowler, C M, Herrera, D H, Lopez, E A, Oona, H, Tasker, D G, Torres, D T, Anderson, R A, Baluyot, E V, Clancy, T J, LOS ALAMOS NATIONAL LAB NM, Goforth, J H, Fowler, C M, Herrera, D H, Lopez, E A, Oona, H, Tasker, D G, Torres, D T, Anderson, R A, Baluyot, E V, and Clancy, T J

Abstract

The Ranchito helical flux compression generator (HFCG) was designed at Los Alamos in the mid 1990s by Max Fowler. The intent was to supply a few megamperes as the initial current for a fast high current FCG in situations where large capacitor banks were not available. A complete characterization of Ranchito has never been published. However, a recent experiment was conducted that provides data suitable for publication. In the test a Ranchito generator was used to feed current into a simulated plate generator. In the test, we supplied 17.24 kA initial current to the 125 muH Ranchito from a capacitor bank, and a 2.75 MA current was subsequently delivered to a load of 287 nH. Full details of the generator design and experimental results are presented in the paper. Our analysis makes use of an inductance (L(t)) curve taken from paper copies in Max Fowler's original notes, and follows the approach used by Fowler and Caird1 to characterize the MK-IX HFCG. A complete working model of Ranchito results, although newer computer codes may now provide a better approach. The data presented are useful for comparing results from newer models., See also ADM002371. 2013 IEEE Pulsed Power Conference, Digest of Technical Papers 1976-2013, and Abstracts of the 2013 IEEE International Conference on Plasma Science. IEEE International Pulsed Power Conference (19th). Held in San Francisco, CA on 16-21 June 2013., The original document contains color images.

Published
2007

17. High Accuracy Isentropic Compression Studies with High Explosive Pulsed Power

Author

LOS ALAMOS NATIONAL LAB NM, Tasker, D G, Goforth, J H, Oona, H, LOS ALAMOS NATIONAL LAB NM, Tasker, D G, Goforth, J H, and Oona, H

Abstract

An study of the one-dimensional isentropic compression experiment (ICE), performed with High Explosive Pulsed Power (HEPP), has demonstrated that accurate, high stress, isentropic Equations of State (EOS) data may be obtained with this technique. The physics and accuracy of electromagnetic loading in the ICE technique is presented. It is shown that the HEPP-ICE load configuration is capable of producing magnetic stresses that are uniform to 1 part in 1000 over the central 87% of the sample faces, and that HEPP-ICE provides exact matching of the stresses between opposing samples. This magnetic uniformity, the exact matching, and the large sample samples possible with HEPP-ICE, are necessary for the highest accuracy isentropic EOS data. Isentropic EOS data have been obtained with a prototype HEPP-ICE system, and the results for tungsten and copper demonstrate the inaccuracy of the technique, which may be as low as 0.2% in stress. It is shown that a large-scale HEPP-ICE system is capable of producing shock-free loading up to 2.2 TPa in 10-mm thick tungsten samples., See also ADM002371. 2013 IEEE Pulsed Power Conference, Digest of Technical Papers 1976-2013, and Abstracts of the 2013 IEEE International Conference on Plasma Science. IEEE International Pulsed Power Conference (19th). Held in San Francisco, CA on 16-21 June 2013.

Published
2007

19. High current performance of the 43 cm long Ranchero generator

Author

Goforth, J. H., primary, Alme, M. L., additional, Atchison, W. L., additional, Glover, B. B., additional, Herrera, D. H., additional, Holtkamp, D. B., additional, Nelson, E. M., additional, Meyer, R. K., additional, Oona, H., additional, Rae, P. J., additional, Sheppard, M. G., additional, Sgro, A. G., additional, Tabaka, L. J., additional, Torres, D. T., additional, Watt, R. G., additional, and Reisman, D. B., additional

Published
2012
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20. Ranchero overview and expectations for performance at currents over 50 MA (LA-UR 11-04345)

Author

Goforth, J. H., primary, Alme, M. L., additional, Atchison, W. L., additional, Glover, B. B., additional, Herrera, D. H., additional, Herrera, T. J., additional, Holtkamp, D. B., additional, Meyer, R. K., additional, Kaul, A., additional, Molvig, K., additional, Nelson, E. M., additional, Oona, H., additional, Rae, P., additional, Reynolds, J. M., additional, Rousculp, C. L., additional, Salazar, P. J., additional, Sgro, A. G., additional, Sheppard, M. G., additional, Tabaka, L. J., additional, Torres, D. T., additional, and Watt, R. G., additional

Published
2011
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21. A new 40 MA Ranchero explosive pulsed power system

Author

Goforth, J. H., primary, Atchison, W.L., additional, Colgate, S. A., additional, Griego, J. R., additional, Guzik, J., additional, Herrera, D. H., additional, Holtkamp, D. B., additional, Kaul, G. Idzorek A., additional, Kirkpatrick, R. C., additional, Menikoff, R., additional, Meyer, R. K., additional, Oona, H., additional, Reardon, P. T., additional, Reinovsky, C. R. E., additional, Rousculp, L., additional, Sgro, A. G., additional, Tabaka, L.J., additional, Tierney, T. E., additional, Torres, D. T., additional, and Watt, R. G., additional

Published
2009
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22. Argon charge states due to impact of H+ and He+ ions

Author

Oona, H

Subjects
Physics, Atomic, Molecular, And Nuclear
Abstract

Charge states of argon produced by bombardment with 100-keV to 1-MeV H+ and He+ projectiles were studied by examining high-resolution L-shell X-ray satellite spectra. Large differences appear in charge-state populations determined from X-ray data and Auger-electron data.

Published
1974
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24. The Ranchito Helical Magnetic Flux Compression Generator

Author

Goforth, J. H., primary, Fowler, C. M., additional, Herrera, D. H., additional, Oona, H., additional, Tasker, D. G., additional, Torres, D. T., additional, Anderson, R. A., additional, Baluyot, E. V, additional, Clancy, T. J., additional, Milhous, D. P., additional, Reisman, D. B., additional, and White, A. D., additional

Published
2007
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26. Mean lives of excited levels in O I-O VI

Author

Berry, H. G, Bickel, W. S, Martinson, I, and Oona, H

Subjects
Biosciences
Abstract

Ion beam-foil produced oxygen spectra in wavelength range between 450 and 2200 A, determining mean radiative lives of O I - O VI excitation levels

Published
1971

29. CHARACTERIZATION OF A TARGET PLASMA FOR MTF

Author

WYSOCKI, F. J., primary, TACCETTI, J. M., additional, IDZOREK, G., additional, OONA, H., additional, KIRKPATRICK, R. C., additional, LINDEMUTH, I. R., additional, SHEEHEY, P. T., additional, and THIO, Y. C. F., additional

Published
2004
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30. ISENTROPIC COMPRESSION OF ARGON AND KRYPTON USING AN MC-1 FLUX COMPRESSION GENERATOR

Author

VEESER, L., primary, EKDAHL, C., additional, OONA, H., additional, RODRIGUEZ, P., additional, SCHMITT, G., additional, SOLEM, J., additional, YOUNGER, S., additional, BAKER, S., additional, HUDSON, C., additional, LEWIS, W., additional, MARSHALL, B., additional, TURLEY, W., additional, BYKOV, A., additional, BORISKOV, G., additional, DOLOTENKO, M., additional, EGOROV, N., additional, KOLOKOL’CHIKOV, N., additional, KOZLOV, M., additional, KUROPATKIN, Y., additional, and VOLKOV, A., additional

Published
2004
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31. HIGH VOLTAGE APPLICATIONS OF EXPLOSIVELY FORMED FUSES

Author

TASKER, D. G., primary, GOFORTH, J. H., additional, FOWLER, C. M., additional, HERRERA, D. H., additional, KING, J. C., additional, LOPEZ, E. A., additional, MARTINEZ, E. C., additional, OONA, H., additional, MARSH, S. P., additional, REINOVSKY, R. E., additional, STOKES, J., additional, TABAKA, L. J., additional, TORRES, D. T., additional, SENA, F. C., additional, KIUTTU, G., additional, and DEGNAN, J., additional

Published
2004
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32. HYDRODYNAMIC LINER EXPERIMENTS USING THE RANCHERO FLUX COMPRESSION GENERATOR SYSTEM

Author

GOFORTH, J. H., primary, ATCHISON, W. L., additional, FOWLER, C. M., additional, HERRERA, D. H., additional, KING, J. C., additional, LOPEZ, E. A., additional, OONA, H., additional, REINOVSKY, R. E., additional, STOKES, J. L., additional, TABAKA, L. J., additional, TASKER, D. G., additional, TORRES, D. T., additional, SENA, F. C., additional, MCGUIRE, J. A., additional, LINDEMUTH, I. R., additional, FAEHL, R. J., additional, KEINIGS, R. K., additional, GARCIA, O. F., additional, and BROSTE, B., additional

Published
2004
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33. OPTIMIZING THE RANCHERO COAXIAL FLUX COMPRESSION GENERATOR

Author

TASKER, D. G., primary, GOFORTH, J. H., additional, ATCHISON, W. L., additional, FOWLER, C. M., additional, HERRERA, D. H., additional, KING, J. C., additional, LINDEMUTH, I. R., additional, LOPEZ, E. A., additional, MARTINEZ, E. C., additional, OONA, H., additional, REINOVSKY, R. E., additional, STOKES, J., additional, TABAKA, L. J., additional, TORRES, D.T., additional, and MILLER, P. J., additional

Published
2004
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34. INSTABILITY GROWTH OF MAGNETICALLY IMPLODED CYLINDRICAL ALUMINUM AND HIGH-STRENGTH ALUMINUM ALLOY LINERS

Author

BUYKO, A. M., primary, BURENKOV, O. M., additional, GARANIN, S. F., additional, GORBACHEV, YU. N., additional, GRINEVICH, B. E., additional, ZMUSHKO, V. V., additional, IVANOVA, G. G., additional, KUZYAYEV, A. I., additional, MOKHOV, V. N., additional, NIZOVTSEV, P. N., additional, PETRUKHIN, A. A., additional, PISHCHUROV, A. I., additional, SOLOVYEV, V. P., additional, SOFRONOV, V. N., additional, CHERNYSHEV, V. K., additional, YAKUBOV, V. B., additional, ANDERSON, B. G., additional, ANDERSON, W. E., additional, ATCHISON, W. L., additional, BARTSCH, R. R., additional, BROSTIE, W., additional, COCHRANE, J., additional, EKDAHL, C. A., additional, FAEHL, R., additional, LINDEMUTH, I. R., additional, MORGAN, D. V., additional, OONA, H., additional, REINOVSKY, R. E., additional, STOKES, J., additional, TABAKA, L. C., additional, and YOUNGER, S. M., additional

Published
2004
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35. ISENTROPIC COMPRESSION STUDIES WITH HIGH EXPLOSIVE PULSED POWER.

Author

Tasker, D. G., Goforth, J. H., and Oona, H.

Subjects
EXPLOSIONS, SHOCK waves, CONDENSED matter, MECHANICAL shock, ELECTROMAGNETIC pulses
Abstract

A study of the one-dimensional isentropic compression experiment (ICE), performed with High Explosive Pulsed Power (HEPP), has demonstrated that accurate, high stress, isentropic Equations of State (EOS) data may be obtained with this technique. The physics and accuracy of electromagnetic loading in the ICE technique are presented. It is shown that the HEPP-ICE load configuration is capable of producing magnetic stresses that are uniform to 1 part in 1000 over the central 87% of the sample faces, and that HEPP-ICE provides exact matching of the stresses between opposing samples. This magnetic uniformity, the exact matching, and the large sample sizes possible with HEPP-ICE, are necessary for the highest accuracy isentropic EOS data. The results for tungsten and copper demonstrate the inaccuracy of the technique, which may be as low as 0.2% in stress. [ABSTRACT FROM AUTHOR]

Published
2007
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37. Results from Isentropic Compression Experiments (ICE).

Author

Tasker, D. G., Goforth, J. H., Oona, H., Rigg, P. A., Dennis-Koller, D., King, J., Torres, D., Herrera, D., Sena, F., Abeyta, F., and Tabaka, L.

Subjects
MATERIALS compression testing, MAGNETIC fields, PRESSURE, STRAINS & stresses (Mechanics), SURFACES (Physics)
Abstract

We have developed high explosive pulsed power (HEPP) methods to obtain accurate isentropic EOS data with the isentropic compression experiment (ICE). In the HEPP-ICE experiment, fast rising current pulses (with risetimes from 400 to 600 ns) at current densities of many MA/cm, create continuous magnetic compression of materials to Mbar pressures. The response of materials to this isentropic loading, as determined with VISAR measurements of free surfaces, provides the required isentropic EOS. Experiments on copper will be presented here. The data are analyzed using conventional Lagrangian and Backward techniques. In the present arrangement four samples can be studied at one time, but accurate EOS data can only be obtained from opposing sample pairs, because it is only these pairs that share the same magnetic fields. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
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43. Advances in Isentropic Compression Experiments (ICE) Using High Explosive Pulsed Power.

Author

Tasker, D. G., Goforth, J. H., Oona, H., Fowler, C. M., King, J. C., Herrera, D., and Torres, D.

Subjects
PULSED power systems, MAGNETIC flux, ELECTROMAGNETIC induction, PROTOTYPES, ELECTRIC inductance, ELECTRIC inductors, COPPER, TUNGSTEN
Abstract

We are developing a prototype high explosive pulsed power (HEPP) system to obtain isentropic Equation of State (EOS) data with the Asay technique. Our prototype system comprises a flat-plate explosive driven magnetic flux compression generator (FCG), an explosively formed fuse (EFF) opening switch, and a series of explosively-actuated closing switches. The FCG is capable of producing ∼10 MA into suitable loads, and, at a length of 216 mm, the EFF will sustain voltages in excess of 200 kV. The load has an inductance of ∼3 to 10 nH, allowing up to ∼7 MA to be delivered in times of ∼0.5 μs. This prototype will produce isentropic compression profiles in excess of 2 Mbar in a material such as tungsten. We will obtain isentropic EOS data for copper at pressures up to ∼1.5 Mbar with the prototype system, immediately after this conference; eventually we plan to reach several tens of Mbar with larger, more advanced systems. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2004
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45. A Pegasus dynamic liner friction experiment.

Author

Hammerberg, J. E., Kyrala, G. A., Oro, D. M., Fulton, R. D., Anderson, W. E., Obst, A. W., Oona, H., Stokes, J., and Wilke, M. D.

Subjects
FRICTION, INTERFACES (Physical sciences), METALLIC surfaces, ALUMINUM
Abstract

We report on a pulsed power experiment performed at the Los Alamos National Laboratory Pegasus facility which was designed to measure material flow at metal interfaces driven to high relative velocities. Material motion at and near four flat Ta/Al(6061) interfaces was measured using flash radiographic techniques. A series of fine Pb wires (407 micron diameter) was implanted in the Al normal to the interfaces. The motion of these markers under shock loading provided a picture of material motion in the Al interfacial region. The surface roughness of the interfaces was varied between 32 and 125 micro-inches. We discuss the implications of these measurements for constitutive models of high speed friction and interfacial morphological change. [ABSTRACT FROM AUTHOR]

Published
2000

46. Material failure and pattern growth in shock-driven aluminum cylinders at the Pegasus facility.

Author

Stokes, John, Fulton, R. D., Morgan, D. V., Obst, A. W., Oro, D. M., Oona, H., Anderson, W., Chandler, E. A., and Egan, P.

Subjects
METAL fractures, ALUMINUM, FRACTURE mechanics, MECHANICAL shock
Abstract

Experiments on the Pegasus pulsed power facility have investigated material failure and the growth of sinusoidal perturbations machined on the free inner surface of both A1 1100 and A1 6061-T6 samples undergoing shocked acceleration. The material behind the free surface exhibits massive microspall resulting in a volume of low-density material. Rapid pattern growth in the failed material and subsequent pattern growth on the surface, including jetting in some cases, were seen. Shock pressures were 15 GPa and 50 GPa. [ABSTRACT FROM AUTHOR]

Published
2000

47. Application of 2-D simulations to hollow Z-pinch implosions

Author

Peterson, D. L., primary, Bowers, R. L., additional, Brownell, J. H., additional, Lund, C., additional, Matuska, W., additional, McLenithan, K., additional, Oona, H., additional, Deeney, C., additional, Derzon, M., additional, Spielman, R. B., additional, Nash, T. J., additional, Chandler, G., additional, Mock, R. C., additional, Sanford, T. W. L., additional, Matzen, M. K., additional, and Roderick, N. F., additional

Published
1997
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50. Target Plasma Formation for Magnetic Compression/Magnetized Target Fusion

Author

Lindemuth, I. R., primary, Reinovsky, R. E., additional, Chrien, R. E., additional, Christian, J. M., additional, Ekdahl, C. A., additional, Goforth, J. H., additional, Haight, R. C., additional, Idzorek, G., additional, King, N. S., additional, Kirkpatrick, R. C., additional, Larson, R. E., additional, Morgan, G. L., additional, Olinger, B. W., additional, Oona, H., additional, Sheehey, P. T., additional, Shlachter, J. S., additional, Smith, R. C., additional, Veeser, L. R., additional, Warthen, B. J., additional, Younger, S. M., additional, Chernyshev, V. K., additional, Mokhov, V. N., additional, Demin, A. N., additional, Dolin, Y. N., additional, Garanin, S. F., additional, Ivanov, V. A., additional, Korchagin, V. P., additional, Mikhailov, O. D., additional, Morozov, I. V., additional, Pak, S. V., additional, Pavlovskii, E. S., additional, Seleznev, N. Y., additional, Skobelev, A. N., additional, Volkov, G. I., additional, and Yakubov, V. A., additional

Published
1995
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