19 results on '"Michael Edward Cuneo"'
Search Results
2. Measurements of Z Electrode Temperatures Using Absolutely Calibrated Streaked Visible Spectroscopy Systems and Avalanche Photodiodes
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Ross Falcon, Daniel Scoglietti, Mark E. Savage, S. G. Patel, George Laity, Michael Edward Cuneo, Mark D. Johnston, Matthew R. Gomez, David E. Bliss, and Keven MacRunnels
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Materials science ,business.industry ,Streak ,Laser ,Avalanche photodiode ,law.invention ,Wavelength ,Optics ,Integrating sphere ,law ,Radiance ,Calibration ,business ,Spectroscopy - Abstract
Absolute calibration of streaked visible spectroscopy systems has been performed at Z-machine at Sandia National Labs in order to determine temperatures of electrode surfaces during the current pulse. The ability to calibrate the full system, including all fiber optic runs and probes is crucial to understanding errors in the calibration process. The calibration procedure involves imaging a blackbody light source, with a known spectral radiance which is coupled to an integrating sphere. This source is streaked slowly over a few ns using Sydor streak cameras. The slow sweep is converted to a $100-500ns$ sweep by imaging a bright light source on both sweep rates, and obtaining wavelength and time dependent correction curves. Any broadband light source or several laser lines of differing wavelengths can be used for this correction. This technique has yielded temperature estimates of several eV in the Z convolute.
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- 2018
3. Transmission-line-circuit model of an 85-TW, 25-MA pulsed-power accelerator
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M. H. Hess, Dale Welch, Christopher Jennings, George Laity, Derek C. Lamppa, B. A. Whitney, D.D. Hinshelwood, Brian Hutsel, Ryan D. McBride, J. K. Moore, Stephen A. Slutz, A. Myers, Matthew R. Gomez, David V. Rose, P.A. Corcoran, William A. Stygar, Michael Edward Cuneo, and Eduardo Waisman
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Nuclear and High Energy Physics ,Electron density ,Materials science ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,business.industry ,Particle accelerator ,Surfaces and Interfaces ,Pulsed power ,01 natural sciences ,Space charge ,Energy storage ,010305 fluids & plasmas ,law.invention ,Transmission line ,law ,0103 physical sciences ,lcsh:QC770-798 ,Optoelectronics ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,business ,Short circuit ,Diode - Abstract
We have developed a physics-based transmission-line-circuit model of the Z pulsed-power accelerator. The 33-m-diameter Z machine generates a peak electrical power as high as 85 TW, and delivers as much as 25 MA to a physics load. The circuit model is used to design and analyze experiments conducted on Z. The model consists of 36 networks of transmission-line-circuit elements and resistors that represent each of Zs 36 modules. The model of each module includes a Marx generator, intermediate-energy-storage capacitor, laser-triggered gas switch, pulse-forming line, self-break water switches, and tri-plate transmission lines. The circuit model also includes elements that represent Zs water convolute, vacuum insulator stack, four parallel outer magnetically insulated vacuum transmission lines (MITLs), double-post-hole vacuum convolute, inner vacuum MITL, and physics load. Within the vacuum-transmission-line system the model conducts analytic calculations of current loss. To calculate the loss, the model simulates the following processes: (i) electron emission from MITL cathode surfaces wherever an electric-field threshold has been exceeded; (ii) electron loss in the MITLs before magnetic insulation has been established; (iii) flow of electrons emitted by the outer-MITL cathodes after insulation has been established; (iv) closure of MITL anode-cathode (AK) gaps due to expansion of cathode plasma; (v) energy loss to MITL conductors operated at high lineal current densities; (vi) heating of MITL-anode surfaces due to conduction current and deposition of electron kinetic energy; (vii) negative-space-charge-enhanced ion emission from MITL anode surfaces wherever an anode-surface-temperature threshold has been exceeded; and (viii) closure of MITL AK gaps due to expansion of anode plasma. The circuit model is expected to be most accurate when the fractional current loss is small. We have performed circuit simulations of 52 Z experiments conducted with a variety of accelerator configurations and load-impedance time histories. For these experiments, the apparent fractional current loss varies from 0% to 20%. Results of the circuit simulations agree with data acquired on 52 shots to within 2%.
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- 2018
4. Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes
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Mark L. Kiefer, Ross Falcon, Mark D. Johnston, S. G. Patel, Keith L. Cartwright, Michael Edward Cuneo, and Yitzhak Maron
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Materials science ,Plasma formation ,business.industry ,Optoelectronics ,Field strength ,Current (fluid) ,Pulsed power ,business ,Diode - Published
- 2017
5. Investigating Radial Wire Array <tex-math notation='LaTeX'>$Z$ </tex-math>-Pinches as a Compact X-Ray Source on the Saturn Generator
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S. N. Bland, Brent Manley Jones, Sergey Lebedev, Jason D. Serrano, Michael Edward Cuneo, D. J. Ampleford, Gareth Hall, Jeremy Chittenden, Ryan D. McBride, Francisco Suzuki-Vidal, Christopher Jennings, and S. C. Bott-Suzuki
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Physics ,Nuclear and High Energy Physics ,business.industry ,Concentric ,Condensed Matter Physics ,Cathode ,Anode ,law.invention ,Generator (circuit theory) ,Optics ,Hohlraum ,law ,Saturn ,Pinch ,Atomic physics ,business ,Inertial confinement fusion - Abstract
Radial wire array $Z$ -pinches, where wires are positioned radially outward from a central cathode to a concentric anode, can act as a compact bright X-ray source that could potentially be used to drive a hohlraum. Experiments were performed on the 7-MA Saturn generator using radial wire arrays. These experiments studied a number of potential risks in scaling radial wire arrays up from the 1-MA level, where they have been shown to be a promising compact X-ray source. Data indicate that at 7 MA, radial wire arrays can radiate $\sim 9$ TW with 10-ns full-width at half-maximum from a compact pinch.
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- 2015
6. 2-D RMHD Modeling Assessment of Current Flow, Plasma Conditions, and Doppler Effects in Recent Z Argon Experiments
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Drew Johnson, Derek C. Lamppa, Brent Manley Jones, Gregory Rochau, Y. K. Chong, Nathan W. Moore, Mahadevan Krishnan, P.L. Coleman, Stephanie Hansen, Michael Jones, D. J. Ampleford, A. J. Harvey-Thompson, Eduardo Waisman, Christopher Jennings, Arati Dasgupta, J. Ward Thornhill, John P. Apruzese, Christine Anne Coverdale, John Giuliani, and Michael Edward Cuneo
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Physics ,Nuclear and High Energy Physics ,Argon ,chemistry.chemical_element ,Implosion ,Plasma ,Condensed Matter Physics ,Spectral line ,symbols.namesake ,Radiative equilibrium ,chemistry ,Radiative transfer ,symbols ,Electron temperature ,Atomic physics ,Doppler effect - Abstract
By varying current-loss circuit parameters, the Mach2-tabular collisional radiative equilibrium 2-D radiation magnetohydrodynamic model was tuned to reproduce the radiative and electrical properties of three recent argon gas-puff experiments (same initial conditions) performed on the Z machine at Sandia National Laboratories. The model indicates that there were current losses occurring near or within the diode region of the Z machine during the stagnation phase of the implosion. The “good” simulation reproduces the experimental K-shell powers, K-shell yields, total powers, percentage of emission radiated in $\alpha $ lines, size of the K-shell emission region, and the average electron temperature near the time-of-peak K-shell power. The calculated atomic populations, ion temperatures, and radial velocities are used as input to a detailed multifrequency ray-trace radiation transport model that includes the Doppler effect. This model is employed to construct time-, space-, and energy-resolved synthetic spectra. The role the Doppler effect likely plays in the experiments is demonstrated by comparing synthetic spectra generated with and without this effect.
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- 2015
7. Wire-Array Z-Pinch Length Variations for K-Shell X-Ray Generation on Z
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John P. Apruzese, Brent Manley Jones, Arati Dasgupta, Christopher Jennings, Stephanie Hansen, Christine Anne Coverdale, Michael Edward Cuneo, Eduardo Waisman, John Giuliani, J. Ward Thornhill, Jack Davis, Robert W. Clark, and D. J. Ampleford
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Physics ,Nuclear and High Energy Physics ,Yield (engineering) ,business.industry ,Electrical engineering ,Electron shell ,chemistry.chemical_element ,Plasma ,Condensed Matter Physics ,Copper ,Computational physics ,chemistry ,Z-pinch ,Pinch ,Pinhole (optics) ,Spectroscopy ,business - Abstract
In developing stainless-steel (SS) and copper wire-array X-ray sources on the Z machine, we consider the optimization of K-shell yield as a function of load height. Theory, numerical modeling, and experimental data suggest that an optimum exists corresponding to a tradeoff between the increase in radiating mass and the decrease in coupled current with increasing pinch height. A typical load height of 20 mm used on many previous Z wire-array X-ray sources is found to be near optimal for K-shell yield production in SS and copper implosions. Electrical data, pinhole imaging, and spectroscopy are used to study plasma conditions in wire-array z pinches corresponding to the variation in K-shell power and yield per unit length as the pinch height is changed from 12 to 24 mm.
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- 2015
8. New Capabilities for Hostile Environments on Z Grand Challenge LDRD - Final Status
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Derek C. Lamppa, Mark E. Savage, V. Harper Slaboszewicz, Roger Alan Vesey, H. C. Peebles, Michael Edward Cuneo, Timothy McGuire Flanagan, J. A. Bierner, D. K. Balch, Dean C. Rovang, William Joseph Martin, Kate Bell, Christine Anne Coverdale, Brent Manley Jones, R. Tang, John Lee McKenney, Patrick J. Griffin, Nathan W. Moore, Stephanie Hansen, and Edward J. Parma
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Engineering ,Surprise ,Order (business) ,business.industry ,media_common.quotation_subject ,Stockpile ,Nuclear force ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,business ,Computer security ,computer.software_genre ,computer ,media_common - Abstract
The purpose of this project was to develop new physical simulation capabilities in order to support the science-based qualification of nonnuclear weapon components in hostile radiation environments. The project contributes directly to the goals of maintaining a safe, secure, and effective US nuclear stockpile, maintaining strategic deterrence at lower nuclear force levels, extending the life of the nuclear deterrent capability, and to be ready for technological surprise.
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- 2016
9. Optimization of Isentropic Compression Loads on Current-Adder Pulsed Power Accelerator Architectures
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Michael Edward Cuneo, Eduardo Waisman, William A. Stygar, Brian Stoltzfus, Christopher T Seagle, Jean-Paul Davis, Thomas A. Haill, R. B. Spielman, Justin Brown, and David Reisman
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Adder ,Materials science ,Isentropic process ,business.industry ,Electrical engineering ,Current (fluid) ,Pulsed power ,business - Published
- 2016
10. Contribution of the backstreaming ions to the Self-Magnetic pinch (SMP) diode current
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Michael G. Mazarakis, Joshua J. Leckbee, Nichelle Bennett, Mark D. Johnston, Dale Welch, Sean Simpson, Timothy J. Renk, Raymond E. Cignac, Derek Ziska, Robert J. Obregon, Timothy J. Webb, F. Wilkins, Mark L. Kiefer, Darryl W. Droemer, Michael Edward Cuneo, Bryan V. Oliver, D. S. Nielsen, Sean Donovan Fournier, and Chase C. Smith
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Adder ,Materials science ,Switched-mode power supply ,business.industry ,Transmission line ,Pinch ,Optoelectronics ,High voltage ,business ,Anode ,Diode ,Voltage - Abstract
The results presented here were obtained with an SMP diode mounted at the front high voltage end of the RITS accelerator. RITS is a Self-Magnetically Insulated Transmission Line (MITL) voltage adder that adds the voltage pulses of six 1.3 MV inductively insulated cavities.
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- 2016
11. Implementing and diagnosing magnetic flux compression on the Z pulsed power accelerator
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Daniel Sinars, Marc Ronald Lee Jobe, Matthew R. Gomez, R. R. Paguio, Stephanie Hansen, Derek C. Lamppa, K. Tomlinson, Dean C. Rovang, Lu Fang, Andrew Maurer, Daniel H. Dolan, Patrick Knapp, Michael Edward Cuneo, Thomas Weber, Thomas James Awe, Kelly Hahn, Gordon A. Chandler, Carlos L. Ruiz, Raymond W. Lemke, Christopher Jennings, Ryan D. McBride, Matthew Martin, Paul Schmit, Stephen A. Slutz, M. H. Hess, John Greenly, G. E. Smith, Gary Wayne Cooper, David E. Bliss, G. K. Robertson, and Tom Intrator
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Engineering ,Helmholtz coil ,business.industry ,Electrical engineering ,Magnetized Liner Inertial Fusion ,Plasma ,Pulsed power ,Magnetic flux ,symbols.namesake ,Optics ,Faraday effect ,symbols ,Neutron ,Coaxial ,business - Abstract
We report on the progress made to date for a Laboratory Directed Research and Development (LDRD) project aimed at diagnosing magnetic flux compression on the Z pulsed-power accelerator (0-20 MA in 100 ns). Each experiment consisted of an initially solid Be or Al liner (cylindrical tube), which was imploded using the Z accelerator's drive current (0-20 MA in 100 ns). The imploding liner compresses a 10-T axial seed field, B z ( 0 ) , supplied by an independently driven Helmholtz coil pair. Assuming perfect flux conservation, the axial field amplification should be well described by B z ( t ) = B z ( 0 ) x [ R ( 0 ) / R ( t )] 2 , where R is the liner's inner surface radius. With perfect flux conservation, B z ( t ) and dB z / dt values exceeding 10 4 T and 10 12 T/s, respectively, are expected. These large values, the diminishing liner volume, and the harsh environment on Z, make it particularly challenging to measure these fields. We report on our latest efforts to do so using three primary techniques: (1) micro B-dot probes to measure the fringe fields associated with fluxmore » compression, (2) streaked visible Zeeman absorption spectroscopy, and (3) fiber-based Faraday rotation. We also mention two new techniques that make use of the neutron diagnostics suite on Z. These techniques were not developed under this LDRD, but they could influence how we prioritize our efforts to diagnose magnetic flux compression on Z in the future. The first technique is based on the yield ratio of secondary DT to primary DD reactions. The second technique makes use of the secondary DT neutron time-of-flight energy spectra. Both of these techniques have been used successfully to infer the degree of magnetization at stagnation in fully integrated Magnetized Liner Inertial Fusion (MagLIF) experiments on Z [P. F. Schmit et al. , Phys. Rev. Lett. 113 , 155004 (2014); P. F. Knapp et al. , Phys. Plasmas, 22 , 056312 (2015)]. Finally, we present some recent developments for designing and fabricating novel micro B-dot probes to measure B z ( t ) inside of an imploding liner. In one approach, the micro B-dot loops were fabricated on a printed circuit board (PCB). The PCB was then soldered to off-the-shelf 0.020- inch-diameter semi-rigid coaxial cables, which were terminated with standard SMA connectors. These probes were recently tested using the COBRA pulsed power generator (0-1 MA in 100 ns) at Cornell University. In another approach, we are planning to use new multi-material 3D printing capabilities to fabricate novel micro B-dot packages. In the near future, we plan to 3D print these probes and then test them on the COBRA generator. With successful operation demonstrated at 1-MA, we will then make plans to use these probes on a 20-MA Z experiment.« less
- Published
- 2015
12. Water desorption from rapidly-heated metal oxide surfaces—first principles, molecular dynamics, and the Temkin isotherm
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Kevin Leung, J. Matthew D. Lane, Aidan P. Thompson, and Michael Edward Cuneo
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Oxide minerals ,Materials science ,Binding energy ,Oxide ,Thermodynamics ,Sorption ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Molecular dynamics ,chemistry ,Desorption ,General Materials Science ,0210 nano-technology ,Water binding ,Electronic density - Abstract
Quantitative understanding and control of water and impurity desorption from steel surfaces are crucial for high-voltage, pulsed power, vacuum technology, catalysis, and environmental applications. We apply a suite of modeling techniques, ranging from electronic density functional theory, to classical molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) methods to study the thermodynamics and kinetics of fast water desorption from different surfaces of hematite Fe2O3 and Cr2O3. Water binding energies on chromium oxide are found to be higher than iron oxide at zero temperature. MD simulations are conducted on Fe2O3 surfaces using thermodynamically consistent initial water inventory deduced with GCMC. The resulting time- and temperature-dependent desorption profiles on the Fe2O3 [Formula: see text] surfaces show multi-water cooperative behavior which cannot be deduced from zero temperature predictions, but which are in reasonable agreement with simple Temkin isotherm model estimates if finite temperature effects are incorporated into the Temkin binding energy parameter. Qualitatively different desorption behaviors associated with the [Formula: see text] and [Formula: see text] facets are discussed.
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- 2018
13. Contribution of the backstreaming ions to the self-magnetic pinch (SMP) diode current
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Dale Welch, Michael Edward Cuneo, Bryan V. Oliver, Nichelle Bennett, Carlos L. Ruiz, F. Wilkins, Mark L. Kiefer, Sean Simpson, Derek Ziska, Robert J. Obregon, Timothy J. Renk, Raymond E. Gignac, Timothy J. Webb, Michael G. Mazarakis, M. E. Sceiford, Darryl W. Droemer, Sean Donovan Fournier, D. S. Nielsen, Mark D. Johnston, and Joshua J. Leckbee
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Physics ,010308 nuclear & particles physics ,business.industry ,High voltage ,Condensed Matter Physics ,01 natural sciences ,Acceleration voltage ,Cathode ,010305 fluids & plasmas ,Anode ,law.invention ,Optics ,Transmission line ,law ,0103 physical sciences ,Pinch ,business ,Voltage ,Diode - Abstract
The results presented here were obtained with a self-magnetic pinch (SMP) diode mounted at the front high voltage end of the RITS accelerator. RITS is a Self-Magnetically Insulated Transmission Line (MITL) voltage adder that adds the voltage pulse of six 1.3 MV inductively insulated cavities. The RITS driver together with the SMP diode has produced x-ray spots of the order of 1 mm in diameter and doses adequate for the radiographic imaging of high area density objects. Although, through the years, a number of different types of radiographic electron diodes have been utilized with SABER, HERMES III and RITS accelerators, the SMP diode appears to be the most successful and simplest diode for the radiographic investigation of various objects. Our experiments had two objectives: first to measure the contribution of the back-streaming ion currents emitted from the anode target and second to try to evaluate the energy of those ions and hence the Anode-Cathode (A-K) gap actual voltage. In any very high voltage inductive voltage adder utilizing MITLs to transmit the power to the diode load, the precise knowledge of the accelerating voltage applied on the A-K gap is problematic. This is even more difficult in an SMP diode where the A-K gap is very small (∼1 cm) and the diode region very hostile. The accelerating voltage quoted in the literature is from estimates based on the measurements of the anode and cathode currents of the MITL far upstream from the diode and utilizing the para-potential flow theories and inductive corrections. Thus, it would be interesting to have another independent measurement to evaluate the A-K voltage. The diode's anode is made of a number of high-Z metals in order to produce copious and energetic flash x-rays. It was established experimentally that the back-streaming ion currents are a strong function of the anode materials and their stage of cleanness. We have measured the back-streaming ion currents emitted from the anode and propagating through a hollow cathode tip for various diode configurations and different techniques of target cleaning treatment: namely, heating at very high temperatures with DC and pulsed current, with RF plasma cleaning, and with both plasma cleaning and heating. We have also evaluated the A-K gap voltage by energy filtering technique. Experimental results in comparison with LSP simulations are presented.The results presented here were obtained with a self-magnetic pinch (SMP) diode mounted at the front high voltage end of the RITS accelerator. RITS is a Self-Magnetically Insulated Transmission Line (MITL) voltage adder that adds the voltage pulse of six 1.3 MV inductively insulated cavities. The RITS driver together with the SMP diode has produced x-ray spots of the order of 1 mm in diameter and doses adequate for the radiographic imaging of high area density objects. Although, through the years, a number of different types of radiographic electron diodes have been utilized with SABER, HERMES III and RITS accelerators, the SMP diode appears to be the most successful and simplest diode for the radiographic investigation of various objects. Our experiments had two objectives: first to measure the contribution of the back-streaming ion currents emitted from the anode target and second to try to evaluate the energy of those ions and hence the Anode-Cathode (A-K) gap actual voltage. In any very high voltage i...
- Published
- 2018
14. Experimental Demonstration of Fusion-Relevant Conditions in Magnetized Liner Inertial Fusion
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G. K. Robertson, Matthew Martin, Patrick Knapp, Daniel Sinars, Dean C. Rovang, John L. Porter, Mark Herrmann, Michael Edward Cuneo, Stephen A. Slutz, O. Johns, Adam B Sefkow, M. H. Hess, M. Geissel, Kelly Hahn, Gordon A. Chandler, Paul Schmit, Gary Wayne Cooper, Ian C. Smith, Christopher Jennings, Derek C. Lamppa, Carlos L. Ruiz, Roger Alan Vesey, Ryan D. McBride, Gregory Rochau, Matthew R. Gomez, Stephanie Hansen, William A. Stygar, A. J. Harvey-Thompson, Thomas James Awe, Kyle Peterson, Eric Harding, and Mark E. Savage
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Physics ,Nuclear physics ,Full width at half maximum ,Stagnation temperature ,Thermonuclear fusion ,Deuterium ,General Physics and Astronomy ,Implosion ,Magnetized Liner Inertial Fusion ,Plasma ,Magneto-inertial fusion ,Atomic physics - Abstract
This Letter presents results from the first fully integrated experiments testing the magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)], in which a cylinder of deuterium gas with a preimposed 10 Taxial magnetic field is heated by Z beamlet, a 2.5 kJ, 1 TW laser, and magnetically imploded by a 19 MA, 100 ns rise time current on the Z facility. Despite a predicted peak implosion velocity of only 70 km = s, the fuel reaches a stagnation temperature of approximately 3 keV, with T(e) ≈ T(i), and produces up to 2 x 10(12) thermonuclear deuterium-deuterium neutrons. X-ray emission indicates a hot fuel region with full width at half maximum ranging from 60 to 120 μm over a 6 mm height and lasting approximately 2 ns. Greater than 10(10) secondary deuterium-tritium neutrons were observed, indicating significant fuel magnetization given that the estimated radial areal density of the plasma is only 2 mg = cm(2).
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- 2014
15. Exploring magnetized liner inertial fusion with a semi-analytic model
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John L. Porter, Mark Herrmann, Michael Edward Cuneo, Paul Schmit, Patrick Knapp, Eric Harding, Daniel Sinars, Roger Alan Vesey, Kelly Hahn, Charles Nakhleh, Gregory Rochau, E. M. Campbell, William A. Stygar, Ryan D. McBride, Dean C. Rovang, Matthew Martin, Kyle Peterson, Matthew R. Gomez, Adam Harvey-Thompson, Adam B Sefkow, Stephen A. Slutz, Christopher Jennings, Matthias Geissel, Kyle Robert Cochrane, Stephanie Hansen, and Thomas James Awe
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Physics ,Analytic model ,FOS: Physical sciences ,Magnetized Liner Inertial Fusion ,Plasma ,Parameter space ,Condensed Matter Physics ,01 natural sciences ,Physics - Plasma Physics ,010305 fluids & plasmas ,Magnetic field ,Computational physics ,Plasma Physics (physics.plasm-ph) ,0103 physical sciences ,Radiative transfer ,010306 general physics - Abstract
In this paper, we explore magnetized liner inertial fusion (MagLIF) [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] using a semi-analytic model [R. D. McBride and S. A. Slutz, Phys. Plasmas 22, 052708 (2015)]. Specifically, we present simulation results from this model that: (a) illustrate the parameter space, energetics, and overall system efficiencies of MagLIF; (b) demonstrate the dependence of radiative loss rates on the radial fraction of the fuel that is preheated; (c) explore some of the recent experimental results of the MagLIF program at Sandia National Laboratories [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)]; (d) highlight the experimental challenges presently facing the MagLIF program; and (e) demonstrate how increases to the preheat energy, fuel density, axial magnetic field, and drive current could affect future MagLIF performance., Comment: Published in Physics of Plasmas [http://dx.doi.org/10.1063/1.4939479]
- Published
- 2016
16. Demonstration of thermonuclear conditions in magnetized liner inertial fusion experimentsa)
- Author
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Roger Alan Vesey, William A. Stygar, Daniel Sinars, Mark Herrmann, Derek C. Lamppa, Stephen A. Slutz, Michael Edward Cuneo, Gary Wayne Cooper, A. J. Harvey-Thompson, M. H. Hess, Kelly Hahn, Gordon A. Chandler, Ryan D. McBride, Ian C. Smith, John L. Porter, Eric Harding, Diana Grace Schroen, Christopher Jennings, Gregory Rochau, Mark E. Savage, Carlos L. Ruiz, Matthias Geissel, Patrick Knapp, Kyle Peterson, Adam B Sefkow, Thomas James Awe, Matthew R. Gomez, Matthew Martin, Paul Schmit, Stephanie Hansen, and Dean C. Rovang
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Nuclear physics ,Physics ,Thermonuclear fusion ,Neutron source ,Electron temperature ,Implosion ,Neutron ,Magnetized Liner Inertial Fusion ,Plasma ,Atomic physics ,Condensed Matter Physics ,Inertial confinement fusion - Abstract
The magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of inertial confinement fusion. The first experiments to test the concept [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] were conducted utilizing the 19 MA, 100 ns Z machine, the 2.5 kJ, 1 TW Z Beamlet laser, and the 10 T Applied B-field on Z system. Despite an estimated implosion velocity of only 70 km/s in these experiments, electron and ion temperatures at stagnation were as high as 3 keV, and thermonuclear deuterium-deuterium neutron yields up to 2 × 1012 have been produced. X-ray emission from the fuel at stagnation had widths ranging from 50 to 110 μm over a roughly 80% of the axial extent of the target (6–8 mm) and lasted approximately 2 ns. X-ray yields from these experiments are consistent with a stagnation density of the hot fuel equal to 0.2–0.4 g/cm3. In these experiments, up to 5 × 1010 secondary deuterium-...
- Published
- 2015
17. Diagnosing magnetized liner inertial fusion experiments on Za)
- Author
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G. K. Robertson, M. H. Hess, William A. Stygar, Paul Schmit, Michael Edward Cuneo, Stephen A. Slutz, Matthew R. Gomez, A. J. Harvey-Thompson, Roger Alan Vesey, Christopher Jennings, Kyle Peterson, Kelly Hahn, Gordon A. Chandler, Thomas James Awe, Gary Wayne Cooper, D. D. Ryutov, Matthias Geissel, K. Tomlinson, Gregory Rochau, Chimpén Ruiz, Derek C. Lamppa, Matthew Martin, Ian C. Smith, Patrick Knapp, Daniel Sinars, Adam B Sefkow, Mark Herrmann, Diana Grace Schroen, Ryan D. McBride, Eric Harding, John L. Porter, O. Johns, Dean C. Rovang, B. E. Blue, Stephanie Hansen, and Mark E. Savage
- Subjects
Physics ,Thermonuclear fusion ,Astrophysics::High Energy Astrophysical Phenomena ,Magnetic confinement fusion ,Magnetized Liner Inertial Fusion ,Plasma ,Condensed Matter Physics ,Nuclear physics ,Deuterium ,Physics::Plasma Physics ,Neutron ,Plasma diagnostics ,Atomic physics ,Inertial confinement fusion - Abstract
Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (∼1012 DD neutrons) from multi-keV deuterium plasmas inertially confined by slow (∼10 cm/μs), stable, cylindrical implosions. Effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 1010. Analysis of extensive power, imaging, and spectroscopic x-ray measurements provides a detailed picture of ∼3 keV temperatures, 0.3 g/cm3 densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.
- Published
- 2015
18. Effects of magnetization on fusion product trapping and secondary neutron spectraa)
- Author
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Patrick Knapp, Daniel Sinars, Michael P. Desjarlais, A. J. Harvey-Thompson, Matthew R. Gomez, Thomas James Awe, Carlos L. Ruiz, Christopher Jennings, Mark Herrmann, Kelly Hahn, Gordon A. Chandler, Gregory Rochau, Matthias Geissel, Kyle Peterson, Ian C. Smith, Adam B Sefkow, Stephen A. Slutz, Paul Schmit, William A. Stygar, Gary Wayne Cooper, John L. Porter, Dean C. Rovang, Stephanie Hansen, Mark E. Savage, Eric Harding, and Michael Edward Cuneo
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Physics ,Magnetization ,Physics::Plasma Physics ,Magnetic confinement fusion ,Nuclear fusion ,Magnetized Liner Inertial Fusion ,Plasma ,Atomic physics ,Condensed Matter Physics ,Stagnation pressure ,Inertial confinement fusion ,Magnetic field - Abstract
By magnetizing the fusion fuel in inertial confinement fusion (ICF) systems, the required stagnation pressure and density can be relaxed dramatically. This happens because the magnetic field insulates the hot fuel from the cold pusher and traps the charged fusion burn products. This trapping allows the burn products to deposit their energy in the fuel, facilitating plasma self-heating. Here, we report on a comprehensive theory of this trapping in a cylindrical DD plasma magnetized with a purely axial magnetic field. Using this theory, we are able to show that the secondary fusion reactions can be used to infer the magnetic field-radius product, BR, during fusion burn. This parameter, not ρR, is the primary confinement parameter in magnetized ICF. Using this method, we analyze data from recent Magnetized Liner Inertial Fusion experiments conducted on the Z machine at Sandia National Laboratories. We show that in these experiments BR ≈ 0.34(+0.14/−0.06) MG · cm, a ∼ 14× increase in BR from the initial value, and confirming that the DD-fusion tritons are magnetized at stagnation. This is the first experimental verification of charged burn product magnetization facilitated by compression of an initial seed magnetic flux.
- Published
- 2015
19. The effect of gradients at stagnation on K-shell x-ray line emission in high-current Ar gas-puff implosions
- Author
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Nathan W. Moore, Eduardo Waisman, J.W. Thornhill, N. D. Ouart, Derek C. Lamppa, A. L. Velikovich, Brent Manley Jones, Mahadevan Krishnan, Y. K. Chong, P.L. Coleman, John Giuliani, D. J. Ampleford, A. J. Harvey-Thompson, Michael Edward Cuneo, J. P. Apruzese, Christine Anne Coverdale, Drew Johnson, Michael Jones, Stephanie Hansen, Arati Dasgupta, Christopher Jennings, and Gregory Rochau
- Subjects
Physics ,Argon ,Astrophysics::High Energy Astrophysical Phenomena ,Electron shell ,chemistry.chemical_element ,Plasma ,Photon energy ,Condensed Matter Physics ,Spectral line ,chemistry ,Physics::Plasma Physics ,Z-pinch ,Emission spectrum ,Atomic physics ,Line (formation) - Abstract
Argon gas puffs have produced 330 kJ ± 9% of x-ray radiation above 3 keV photon energy in fast z-pinch implosions, with remarkably reproducible K-shell spectra and power pulses. This reproducibility in x-ray production is particularly significant in light of the variations in instability evolution observed between experiments. Soft x-ray power measurements and K-shell line ratios from a time-resolved spectrum at peak x-ray power suggest that plasma gradients in these high-mass pinches may limit the K-shell radiating mass, K-shell power, and K-shell yield from high-current gas puffs.
- Published
- 2015
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