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3. On the emergence of macroscopic transport barriers from staircase structures

Author

Diamond, P. [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093, USA, Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA, Center for Astrophysics and Space Sciences (CASS) and Department of Physics, University of California San Diego, La Jolla, California 92093, USA]

Published
2017
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39. Numerical study of jets produced by conical wire arrays on the Magpie pulsed power generator

Author

Francisco Suzuki-Vidal, Jeremy Chittenden, Sergey Lebedev, M. Bocchi, P. de Grouchy, Simon C. Bott, Gareth Hall, Andrea Ciardi, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Center for Energy Research, University of California, San Diego

Subjects
Work (thermodynamics), FOS: Physical sciences, Methods laboratory, ASTROPHYSICAL JETS, Pulsed power, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Generator (circuit theory), Optics, Shield, Jets, 0103 physical sciences, Low density, Numerical simulations, ASTRONOMY & ASTROPHYSICS, 010306 general physics, 010303 astronomy & astrophysics, Laboratory astrophysics, Physics, Jet (fluid), Science & Technology, business.industry, Astronomy and Astrophysics, Plasma, Conical surface, SIMULATIONS, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Space and Planetary Science, Physical Sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business
Abstract

The aim of this work is to model the jets produced by conical wire arrays on the MAGPIE generator, and to design and test new setups to strengthen the link between laboratory and astrophysical jets. We performed the modelling with direct three-dimensional magneto-hydro-dynamic numerical simulations using the code GORGON. We applied our code to the typical MAGPIE setup and we successfully reproduced the experiments. We found that a minimum resolution of approximately 100 is required to retrieve the unstable character of the jet. We investigated the effect of changing the number of wires and found that arrays with less wires produce more unstable jets, and that this effect has magnetic origin. Finally, we studied the behaviour of the conical array together with a conical shield on top of it to reduce the presence of unwanted low density plasma flows. The resulting jet is shorter and less dense., Accepted for publication in Astrophysics & Space Science. HEDLA 2010 conference procedings. Final pubblication will be available on Springer

Published
2011

40. Generation of episodic magnetically driven plasma jets in a radial foil Z-pinch

Author

Sergey Lebedev, Gareth Hall, Francisco Suzuki-Vidal, Simon C. Bott, Andrea Ciardi, Jeremy Chittenden, Alberto Marocchino, Simon Bland, Eric G. Blackman, Adam Frank, George Swadling, Adam Harvey-Thompson, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Department of Physics and Astronomy, University of Rochester, and Center for Energy Research, University of California, San Diego

Subjects
Physics, MECHANISM, Jet (fluid), Astrophysics::High Energy Astrophysical Phenomena, Magnetic Reynolds number, Plasma, LASER-PRODUCED PLASMAS, ALUMINUM, Condensed Matter Physics, YOUNG STELLAR OBJECTS, Instability, SIMULATIONS, HYDRODYNAMICS, ARRAY Z-PINCH, Physics::Plasma Physics, OUTFLOWS, Z-pinch, LABORATORY ASTROPHYSICS, Magnetic pressure, Astrophysical plasma, Atomic physics, ACCRETION, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], FOIL method
Abstract

International audience; We present experimental results of the formation of magnetically driven plasma jets, showing for the first time a way of producing episodic jet/ouflows in the laboratory. The jets are produced using a 6.5 mum thick aluminum disk (a radial foil), which is subjected to the 1 MA, 250 ns current pulse from the MAGPIE generator [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)]. The early time motion of the foil is characterized by the bulk motion of the mass due to the magnetic pressure, together with the formation of a surface plasma following the direction of the J×B force. A low density plasma fills the region above the foil preceding the formation of subsequent magnetically driven jets on the axis of expanding magnetic bubbles. The outflows emerge in timescales of ~30-40 ns and their episodic nature is the result of current reconnection in the foil, aided by the formation of current-driven instabilities in the jet and the distribution of mass available from the foil. The additional inductance due to the new current path inside the cavities was measured using an inductive probe, allowing to estimate the energy balance associated with the episodes. The measured temperature of the compressed jet resulted in Te~300 eV and a magnetic Reynolds number of ReM~200-1000, allowing the experiments to be in the regime relevant for scaled representations of astrophysical outflows.

Published
2010

41. Experimental Studies of Magnetically Driven Plasma Jets

Author

G. C. Burdiak, Francisco Suzuki-Vidal, Jerry Chittenden, Gareth Hall, Simon C. Bott, S. N. Bland, Alejandro Frank, Andrea Ciardi, M. Bocchi, P. de Grouchy, Alberto Marocchino, Sergey Lebedev, George Swadling, Adam Harvey-Thompson, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Department of Physics and Astronomy, University of Rochester, and Center for Energy Research, University of California, San Diego

Subjects
jets, criteria, laboratory astrophysics, magnetic bubble, magnetic cavity, toroidal magnetic field, z-pinch, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Astrophysical jet, 0103 physical sciences, ASTRONOMY & ASTROPHYSICS, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Jet (fluid), Toroid, Science & Technology, Astronomy and Astrophysics, Plasma, Physics - Plasma Physics, Computational physics, Magnetic field, Plasma Physics (physics.plasm-ph), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Z-pinch, Beta (plasma physics), Poynting vector, Physical Sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present experimental results on the formation of supersonic, radiatively cooled jets driven by pressure due to the toroidal magnetic field generated by the 1.5 MA, 250 ns current from the MAGPIE generator. The morphology of the jet produced in the experiments is relevant to astrophysical jet scenarios in which a jet on the axis of a magnetic cavity is collimated by a toroidal magnetic field as it expands into the ambient medium. The jets in the experiments have similar Mach number, plasma beta and cooling parameter to those in protostellar jets. Additionally the Reynolds, magnetic Reynolds and Peclet numbers are much larger than unity, allowing the experiments to be scaled to astrophysical flows. The experimental configuration allows for the generation of episodic magnetic cavities, suggesting that periodic fluctuations near the source may be responsible for some of the variability observed in astrophysical jets. Preliminary measurements of kinetic, magnetic and Poynting energy of the jets in our experiments are presented and discussed, together with estimates of their temperature and trapped toroidal magnetic field., Comment: 7 pages, 6 figures, accepted for publication in Astrophysics & Space Science

Published
2010
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42. Bow shocks in ablated plasma streams for nested wire array z-pinches: A laboratory astrophysics testbed for radiatively cooled shocks

Author

Eric G. Blackman, Christopher Jennings, Simon C. Bott, Gareth Hall, Andrea Ciardi, D. J. Ampleford, Adam Frank, Sergey Lebedev, S. N. Bland, F.A. Suzuki-Vidal, J. B. A. Palmer, M. E. Cuneo, Jerry Chittenden, Sandia National Laboratories, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Center for Energy Research, University of California, San Diego, Department of Physics and Astronomy, University of Rochester, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Physics, Shock wave, Shock (fluid dynamics), Radiative cooling, Astrophysics::High Energy Astrophysical Phenomena, Implosion, Plasma, Astrophysics, Condensed Matter Physics, Z-pinch, Astrophysical plasma, Supersonic speed, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

International audience; Astrophysical observations have demonstrated many examples of bow shocks, for example, the head of protostellar jets or supernova remnants passing through the interstellar medium or between discrete clumps in jets. For such systems where supersonic and super-Alfvénic flows and radiative cooling are all important, carefully scaled laboratory experiments can add insight into the physical processes involved. The early stage of a wire array z-pinch implosion consists of the steady ablation of material from fine metallic wires. Ablated material is accelerated toward the array axis by the J×B force. This flow is highly supersonic (M>5) and becomes super-Alfvénic (MA>2). Radiative cooling is significant in this flow and can be controlled by varying the material in the ablated plasma. The introduction of wires as obstructions in this steady flow leads to the formation of bow shocks, which can be used as a laboratory testbed for astrophysical bow shocks. The magnetic field associated with this obstruction wire can be controlled by varying the current through it. Differences in the shock for different cooling rates and different magnetic fields associated with the obstruction will be discussed, along with comparisons of dimensionless parameters in the experiments to astrophysical systems.

Published
2010

43. Formation of Episodic Magnetically Driven Radiatively Cooled Plasma Jets in the Laboratory

Author

Gareth Hall, Simon C. Bott, Eric G. Blackman, Adam Harvey-Thompson, Thomas P. Ray, Andrea Ciardi, Francisco Suzuki-Vidal, Sergey Lebedev, S. N. Bland, C. Ning, Alberto Marocchino, Alejandro Frank, Chantal Stehlé, J. P. Chittenden, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, University of Rochester, Center for Energy Research, University of California, San Diego, and Dublin Institute for Advanced Studies (DIAS)

Subjects
Young stellar object, Bubble, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Pulsed power, Astronomy & Astrophysics, Jets, Radial foil, Hydrodynamic jet, Jet-ambient interaction, Magnetic field, Magnetic tower, Protostars, YSO jet, Z-pinch, Astronomy and Astrophysics, Space and Planetary Science, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Jet (fluid), Toroid, Science & Technology, Plasma, Physics - Plasma Physics, Computational physics, Plasma Physics (physics.plasm-ph), TOWER, Astrophysics - Solar and Stellar Astrophysics, OUTFLOWS, Physical Sciences, DISCS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], STARS
Abstract

We report on experiments in which magnetically driven radiatively cooled plasma jets were produced by a 1 MA, 250 ns current pulse on the MAGPIE pulsed power facility. The jets were driven by the pressure of a toroidal magnetic field in a ''magnetic tower'' jet configuration. This scenario is characterized by the formation of a magnetically collimated plasma jet on the axis of a magnetic ''bubble'', confined by the ambient medium. The use of a radial metallic foil instead of the radial wire arrays employed in our previous work allows for the generation of episodic magnetic tower outflows which emerge periodically on timescales of ~30 ns. The subsequent magnetic bubbles propagate with velocities reaching ~300 km/s and interact with previous eruptions leading to the formation of shocks., 6 pages, 5 figures. Accepted for publication in Astrophysics & Space Science

Published
2009

44. Laboratory Astrophysics Experiments with Magnetically Driven Plasma Jets

Author

Simon Bland, J. P. Chittenden, Geoffrey Hall, George Swadling, Francisco Suzuki-Vidal, Adam Frank, M. Bocchi, Simon C. Bott, Adam Harvey-Thompson, Andrea Ciardi, Guy Burdiak, P. de Grouchy, Sergey Lebedev, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), Imperial College London, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Center for Energy Research, University of California, San Diego, and University of Rochester

Subjects
Physics, History, Jet (fluid), Toroid, Astrophysics::High Energy Astrophysical Phenomena, Plasma, Astrophysics, Computer Science Applications, Education, Magnetic field, Astrophysical jet, Beta (plasma physics), Poynting vector, High Energy Physics::Experiment, Supersonic speed, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We present experimental results on the formation of supersonic, radiatively cooled jets driven by the toroidal magnetic field generated by the 1.5 MA, 250 ns current from the MAGPIE generator. The morphology of the jet produced in the experiments is relevant to astrophysical jet scenarios in which the jet on the axis of a magnetic cavity expanding into an ambient medium is collimated by a toroidal magnetic field. The jets in our experiments have similar Mach number, plasma beta and cooling parameter to those in protostellar jets and additionally the Reynolds, magnetic Reynolds and Peclet numbers are much larger than unity, allowing the experiments to be scaled to astrophysical flows. The experimental configuration generates episodic magnetic cavities, suggesting that periodic formation of jets in astrophysical situations could be responsible for some of the variability observed in astrophysical jets. The dynamics of the formation of laboratory jets are presented, together with new results including preliminary measurements of magnetic, kinetic and Poynting energy of the outflows. In addition first estimates of jet temperature and trapped toroidal magnetic field are presented and discussed.

Published
2014

45. The value of long-duration energy storage under various grid conditions in a zero-emissions future.

Author

Staadecker M, Szinai J, Sánchez-Pérez PA, Kurtz S, and Hidalgo-Gonzalez P

Abstract

Long-duration energy storage (LDES) is a key resource in enabling zero-emissions electricity grids but its role within different types of grids is not well understood. Using the Switch capacity expansion model, we model a zero-emissions Western Interconnect with high geographical resolution to understand the value of LDES under 39 scenarios with different generation mixes, transmission expansion, storage costs, and storage mandates. We find that a) LDES is particularly valuable in majority wind-powered regions and regions with diminishing hydropower generation, b) seasonal operation of storage becomes cost-effective if storage capital costs fall below US$5 kWh -1 , and c) mandating the installation of enough LDES to enable year-long storage cycles would reduce electricity prices during times of high demand by over 70%. Given the asset and resource diversity of the Western Interconnect, our results can provide grid planners in many regions with guidance on how LDES impacts and is impacted by energy storage mandates, investments in LDES research and development, and generation mix and transmission expansion decisions., (© 2024. The Author(s).)

Published
2024
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46. Offshore wind and wave energy can reduce total installed capacity required in zero-emissions grids.

Author

Gonzalez N, Serna-Torre P, Sánchez-Pérez PA, Davidson R, Murray B, Staadecker M, Szinai J, Wei R, Kammen DM, Sunter DA, and Hidalgo-Gonzalez P

Abstract

As the world races to decarbonize power systems to mitigate climate change, the body of research analyzing paths to zero emissions electricity grids has substantially grown. Although studies typically include commercially available technologies, few of them consider offshore wind and wave energy as contenders in future zero-emissions grids. Here, we model with high geographic resolution both offshore wind and wave energy as independent technologies with the possibility of collocation in a power system capacity expansion model of the Western Interconnection with zero emissions by 2050. In this work, we identify cost targets for offshore wind and wave energy to become cost effective, calculate a 17% reduction in total installed capacity by 2050 when offshore wind and wave energy are fully deployed, and show how curtailment, generation, and transmission change as offshore wind and wave energy deployment increase., (© 2024. The Author(s).)

Published
2024
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47. Reduced-order model to approximate response matrices for filter stack spectrometers.

Author

Wong CS, Luedtke SV, Broughton DP, Strehlow J, Alvarado Alvarez M, Bogale A, Huang CK, Wolfe B, Schmidt TR, Reinovsky RE, Albright BJ, Batha SH, and Palaniyappan S

Abstract

We present a reduced-order model to calculate response matrices rapidly for filter stack spectrometers (FSSs). The reduced-order model allows response matrices to be built modularly from a set of pre-computed photon and electron transport and scattering calculations through various filter and detector materials. While these modular response matrices are not appropriate for high-fidelity analysis of experimental data, they encode sufficient physics to be used as a forward model in design optimization studies of FSSs, particularly for machine learning approaches that require sampling and testing a large number of FSS designs., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/).)

Published
2024
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48. Improved Reversibility of Thin-Film Solid Oxide Cells at 500 °C by Tailoring Sputtering Processes for Depositing Yttria-Stabilized Zirconia Electrolyte.

Author

Lee S, Yu W, Jang Y, Ryu S, Hwang J, Cho GY, Ahn DG, and Cha SW

Abstract

The present study investigates the impact of sputtering configurations on the microstructure and crystallinity of thin-film yttria-stabilized zirconia electrolytes for anodized aluminum oxide-supported all-sputtered thin-film reversible solid oxide cells. Employing various sputtering parameters, such as target-substrate distance and substrate rotation speed, the present study reveals distinct surface characteristics and crystalline structures of thin-film yttria-stabilized zirconia. The microstructure analysis includes scanning electron microscopy and atomic force microscopy examinations, uncovering the influence of the process parameters on the surface morphology, roughness, and grain size. X-ray diffraction data illustrate the texture preferences and crystallite characteristics. The electrochemical characterization of the reversible solid oxide cells demonstrates that the optimized sputtering configuration significantly outperforms the others in both SOFC and SOEC modes, showing exceptional current densities of 964 mA/cm 2 at 1.3 V in electrolysis mode at 500 °C. Electrochemical impedance spectroscopy further reveals improved charge transfer reactions at the interface of the electrolyte. The enhanced electrochemical performance is attributed to the unique microstructure and crystallinity of the thin film of yttria-stabilized zirconia. The record-breaking electrolysis performance of this work at 500 °C underscores the potential of tailored sputtering parameters in optimizing the reversible solid oxide cell performance.

Published
2024
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49. Surface Composites Synthesized through the Incorporation of Atomic Layer Deposited AlO x into Nanoporous Fuzzy Tungsten.

Author

Cheng L, Patino M, Baldwin MJ, and Bandaru PR

Abstract

The incorporation of energetic helium gaseous species into materials such as tungsten (W) imparts intrinsic surface fragility, yielding fuzzy tungsten. To enhance the robustness of the surface layers, aluminum oxide (AlO x ) was deposited by atomic layer deposition into the fuzzy W. The conformally deposited ceramic yields a new class of surface composites. Structural characterization of the fuzzy W-AlO x composites through nanoindentation testing indicated enhanced indentation modulus ( E ind ) and was modeled through various rules of mixtures approaches. The distribution of AlO H ind W was explored and a systematic study of the extent of incorporation of the AlO x in fuzzy W was carried out. The synthesized composites may be utilized for improved structural characteristics, e.g., in reducing crack initiation and fracture. x into the fuzzy W was carried out. The synthesized composites may be utilized for improved structural characteristics, e.g., in reducing crack initiation and fracture.

Published
2024
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50. Robust unfolding of MeV x-ray spectra from filter stack spectrometer data.

Author

Wong CS, Strehlow J, Broughton DP, Luedtke SV, Huang CK, Bogale A, Fitzgarrald R, Nedbailo R, Schmidt JL, Schmidt TR, Twardowski J, Van Pelt A, Alvarez MA, Junghans A, Mix LT, Reinovsky RE, Rusby DR, Wang Z, Wolfe B, Albright BJ, Batha SH, and Palaniyappan S

Abstract

We present an inversion method capable of robustly unfolding MeV x-ray spectra from filter stack spectrometer (FSS) data without requiring an a priori specification of a spectral shape or arbitrary termination of the algorithm. Our inversion method is based upon the perturbative minimization (PM) algorithm, which has previously been shown to be capable of unfolding x-ray transmission data, albeit for a limited regime in which the x-ray mass attenuation coefficient of the filter material increases monotonically with x-ray energy. Our inversion method improves upon the PM algorithm through regular smoothing of the candidate spectrum and by adding stochasticity to the search. With these additions, the inversion method does not require a physics model for an initial guess, fitting, or user-selected termination of the search. Instead, the only assumption made by the inversion method is that the x-ray spectrum should be near a smooth curve. Testing with synthetic data shows that the inversion method can successfully recover the primary large-scale features of MeV x-ray spectra, including the number of x-rays in energy bins of several-MeV widths to within 10%. Fine-scale features, however, are more difficult to recover accurately. Examples of unfolding experimental FSS data obtained at the Texas Petawatt Laser Facility and the OMEGA EP laser facility are also presented., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Published
2024
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