Wire Array Research Articles

Progress on Single-Feed Quality Wideband Linear Wire Array

This paper presents the latest developments regarding the single-feed Quality Wideband Linear (QWL) wire array antenna, known for its broadband and high-gain electromagnetic characteristics and robust design. A systematic review of recent advances in relation to the QWL antenna is provided, covering its driven element, director, reflector, low common-mode current interference connector, and array series-feed configuration. For the first time, an analytical expression and a quick design formula for the input impedance of the QWL antenna’s driven element, the linear Wideband High-gain Electromagnetic Structure (WHEMS) antenna, are presented. Theoretical analysis demonstrates the potential for broadband performance using the WHEMS antenna. The rugged design of the QWL array antenna offers engineering advantages such as simple feeding, low wind resistance, a lightweight construction, low cost, and structural robustness. The QWL antenna has already found applications in various industrial sectors, with potential for broader use in the future, contributing to further advancements in antenna technology.

A novel method for investigating the underwater explosion loads and bubble evolution

This paper presents an innovative experimental method for studying the evolution and energy output characteristics of underwater explosion bubbles. We independently constructed an experimental testing system for underwater electrical wire explosions (UEWE), in which electrodes connected to a metal wire serve as the load, and underwater explosions are initiated through instantaneous high-voltage discharge. By varying the diameter of the metal wire and configuring parallel wire arrays, we analyzed and discussed the explosion characteristic parameters and the current–voltage (I–V) signals under different conditions. The maximum bubble radius of the underwater metal wire explosion was compared with the corresponding equivalent explosive simulation results, and a numerical model for underwater metal wire explosion equivalent to explosive detonation was established. Subsequently, we discussed the characteristics of bubble generation and evolution under various conditions, clarifying the similarities and differences between wire explosions and explosive detonations. On this basis, we explored the propagation laws of shock waves and secondary pulsation waves (SPW) under different conditions. We also calculated and analyzed energy output characteristic parameters, such as shock wave energy and bubble energy. The results indicate that there are significant differences between copper wire and aluminum wire loads in UEWE. For copper wires with a diameter greater than 0.4 mm, the shock wave overpressure peak value significantly decreases, while for aluminum wires with a diameter greater than 0.5 mm, it slightly decreases. Both metals exhibit similar trends in parallel wire arrays, with the shock wave overpressure peak value initially increasing and then decreasing as the number of wires increases. Unlike underwater explosive detonations, the SPW peak value in UEWE may exceed that of the shock wave. For single wires, the SPW peak value of copper wires is generally higher than that of aluminum wires, but in wire arrays, the trend is reversed. The multi-wire parallel connection can improve the energy conversion efficiency of the shock waves. However, for bubble energy, under all conditions, a single aluminum wire with a diameter of 0.5 mm produced the maximum bubble energy, reaching 1023.1 J. These findings provide new insights into the energy features of UEWE.

Generation of Superhard X-Ray Radiation at The Compressing of Aluminum Wire Arrays

At the S-300 generator (2 MA, 400 kV, 100 ns), the appearance of superhard X-ray radiation was observed during magnetic compression of cylindrical nested aluminum arrays with a linear mass of ~350 μg/cm, consisting of aluminum wires with a diameter of 15 μm. At the final compression phase of the arrays, a compact pinch is formed, consisting of a large number of hot spots located along the axis. This phase is accompanied by the emission of soft X-rays with a duration of ~10 ns. Simultaneously with the pulses of soft X-ray radiation, superhard X-ray radiation with an energy exceeding 450 keV was discovered. Superhard X-ray radiation was measured with shielded scintillation detectors with lead filters 20–70 mm thick. The main cause of overvoltage on the plasma column appears to be constriction instability.

Structure and dynamics of magneto-inertial, differentially rotating laboratory plasmas

We present a detailed characterization of the structure and evolution of differentially rotating plasmas driven on the MAGPIE pulsed-power generator (1.4 MA peak current, 240 ns rise time). The experiments were designed to simulate physics relevant to accretion discs and jets on laboratory scales. A cylindrical aluminium wire array Z pinch enclosed by return posts with an overall azimuthal off-set angle was driven to produce ablation plasma flows that propagate inwards in a slightly off-radial trajectory, injecting mass, angular momentum and confining ram pressure to a rotating plasma column on the axis. However, the plasma is free to expand axially, forming a collimated, differentially rotating axial jet that propagates at ${\approx }100\,{\rm km}\,{\rm s}^{-1}$ . The density profile of the jet corresponds to a dense shell surrounding a low-density core, which is consistent with the centrifugal barrier effect being sustained along the jet's propagation. We show analytically that, as the rotating plasma accretes mass, conservation of mass and momentum implies plasma radial growth scaling as $r \propto t^{1/3}$ . As the characteristic moment of inertia increases, the rotation velocity is predicted to decrease and settle on a characteristic value ${\approx }20\,{\rm km}\,{\rm s}^{-1}$ . We find that both predictions are in agreement with Thomson scattering and optical self-emission imaging measurements.

Enhancing and sustaining arsenic removal in a zerovalent iron-based magnetic flow-through water treatment system

In areas affected by arsenicosis, zerovalent iron (ZVI)/sand filters are extensively used by households to treat groundwater, but ZVI surface passivation and filter clogging limit their arsenic (As) removal performance. Here we present a magnetic confinement-enabled column reactor coupled with periodic ultrasonic depassivation (MCCR-PUD), which efficiently and sustainably removes As by reaction with continuously generated iron (oxyhydr)oxides from ZVI oxidative corrosion. In the MCCR, ZVI microparticles self-assemble into stable millimeter-scale wires in forest-like arrays in a parallel magnetic field (0.42−0.48 T, produced by two parallel permanent magnets), forming a highly porous structure (87 % porosity) with twice the accessible reactive surface area of a ZVI/sand mixture. For a feed concentration of 100 μg/L As(III), the MCCR-PUD, with a short empty bed contact time (1.6 min), treated ca. 7340 empty bed volume (EBV) of water at breakthrough (10 μg/L), 9.4 folds higher than that of a ZVI/sand filter. Due to the large interspace between ZVI wires, the MCCR-PUD effectively prevented column clogging that occurred in the ZVI/sand filter. The high water treatment capacity was attributed to the much enhanced ZVI reactivity in the magnetic field, sustained through rejuvenation by PUD. Furthermore, most of As was structurally incorporated into the produced iron (oxyhydr)oxides (mostly ferrihydrite) in the MCCR-PUD, as revealed by Mössbauer spectroscopy, X-ray absorption spectroscopy, and sequential extraction experiments. This finding evinced a different mechanism from the surface adsorption in the ZVI/sand filter. The structural incorporation of As also resulted in much less As remobilization from the produced corrosion products during aging in water, in total ∼1 % in 28 days. Furthermore, the MCCR-PUD exihibted robust performance when treating complex synthetic groundwater containing natural organic matter and common ions (∼3700 EBV at breakthrough). Taken together, our study demonstrates the potential of the magnetic confinement-enabled ZVI reactor as a promising decentralized As treatment platform.

Effect of Droplet-Removal Processes on Fog-Harvesting Performance on Wettability-Controlled Wire Array with Staggered Arrangement.

Development of freshwater resources is vital to overcoming severe worldwide water scarcity. Fog harvesting has attracted attention as a candidate technology that can be used to obtain fresh water from a stream of foggy air without energy input. Drainage of captured droplets from fog harvesters is necessary to maintain the permeability of harp-shaped harvesters. In the present study, we investigated the effect of the droplet-removal process on the amount of water harvested using a harvester constructed by wettability-controlled wires with an alternating and staggered arrangement. Droplet transfer from hydrophobic to hydrophilic wires, located upstream and downstream of the fog flow, respectively, was observed with a fog velocity greater than 1.5 m/s. The proportion of harvesting resulting from droplet transfer exceeded 30% of the total, and it reflected more than 20% increase of the harvesting performance compared with that of a harvester with wires of the same wettability: this value varied with the adhesive property of the wires and fog velocity. Scaled-up and multilayered harvesters were developed to enhance harvesting performance. We demonstrated certain enhancements under multilayered conditions and obtained 15.99 g/30 min as the maximum harvested amount, which corresponds to 13.3% of the liquid contained in the fog stream and is enhanced by 10% compared with that without droplet transfer.

Axial confinement of wire array Z-pinch precursor plasmas by a pulsed magnetic mirror field

A novel wire-array Z-pinch platform has been developed to study the effect of a pulsed magnetic mirror field on a collisional high energy density plasma. The mirror is driven in series with the Z-pinch target and, therefore, scales with driver current. Axial confinement is observed based on visible imaging and axial flow velocity measurements. The presence of axial compressing J ×B force is determined indirectly based on Thomson scattering and interferometry measurements and corroborated by three-dimensional extended-MHD simulations. Compared to non-magnetized wire array Z-pinch, a modified pulsed mirror configuration is observed to increase precursor plasma thermal energy density by about 30%. If optimized, such a configuration could potentially improve magnetized liner inertial fusion performance by reducing axial plasma end loss.

Full-color fiber light-emitting diodes based on perovskite quantum wires.

Fiber light-emitting diodes (Fi-LEDs), which can be used for wearable lighting and display devices, are one of the key components for fiber/textile electronics. However, there exist a number of impediments to overcome on device fabrication with fiber-like substrates, as well as on device encapsulations. Here, we uniformly grew all-inorganic perovskite quantum wire arrays by filling high-density alumina nanopores on the surface of Al fibers with a dip-coating process. With a two-step evaporation method to coat a surrounding transporting layer and semitransparent electrode, we successfully fabricated full-color Fi-LEDs with emission peaks at 625 nanometers (red), 512 nanometers (green), and 490 nanometers (sky-blue), respectively. Intriguingly, additional polydimethylsiloxane packaging helps instill the mechanical bendability, stretchability, and waterproof feature of Fi-LEDs. The plasticity of Al fiber also allows the one-dimensional architecture Fi-LED to be shaped and constructed for two-dimensional or even three-dimensional architectures, opening up a new vista for advanced lighting with unconventional formfactors.

Radiatively cooled magnetic reconnection experiments driven by pulsed power

We present evidence for strong radiative cooling in a pulsed-power-driven magnetic reconnection experiment. Two aluminum exploding wire arrays, driven by a 20 MA peak current, 300 ns rise time pulse from the Z machine (Sandia National Laboratories), generate strongly driven plasma flows (MA≈7) with anti-parallel magnetic fields, which form a reconnection layer (SL≈120) at the mid-plane. The net cooling rate far exceeds the Alfvénic transit rate (τcool−1/τA−1≫1), leading to strong cooling of the reconnection layer. We determine the advected magnetic field and flow velocity using inductive probes positioned in the inflow to the layer, and inflow ion density and temperature from analysis of visible emission spectroscopy. A sharp decrease in x-ray emission from the reconnection layer, measured using filtered diodes and time-gated x-ray imaging, provides evidence for strong cooling of the reconnection layer after its initial formation. X-ray images also show localized hotspots, regions of strong x-ray emission, with velocities comparable to the expected outflow velocity from the reconnection layer. These hotspots are consistent with plasmoids observed in 3D radiative resistive magnetohydrodynamic simulations of the experiment. X-ray spectroscopy further indicates that the hotspots have a temperature (170 eV) much higher than the bulk layer (≤75 eV) and inflow temperatures (about 2 eV) and that these hotspots generate the majority of the high-energy (>1 keV) emission.

Increase in Power of Radiation and Specific Concentration of Energy of Plasma of the High-Current Z-Pinches due to Compression of the Cascade Wire Arrays Interacting via Magnetic Field

Increase in Power of Radiation and Specific Concentration of Energy of Plasma of the High-Current Z-Pinches due to Compression of the Cascade Wire Arrays Interacting via Magnetic Field

Electrochemical Deposition and Etching of Quasi-Two-Dimensional Periodic Membrane Structure.

In this paper, two experimental procedures are reported, namely electro-deposition in the ultrathin liquid layer and chemical micro-etching. Firstly, a large area quasi-two-dimensional periodic membrane with adjustable density is deposited on a Si substrate driven by half-sinusoidal voltage, which is composed of raised ridges and a membrane between the ridges. The smaller the voltage frequency is, the larger the ridge distance is. The height of a raised ridge changes synchronously with the amplitude. The grain density distribution of membrane and raised ridge is uneven; the two structures change alternately, which is closely related to the change of growth voltage and copper ion concentration during deposition. The structural characteristics of membrane provide favorable conditions for micro-etching; stable etching speed and microscope real-time monitoring are the keys to achieve accurate etching. In the chemical micro-etching process, the membrane between ridges is removed, retaining the raised ridges, thus a large scale ordered micro-nano wires array with lateral growth was obtained. This method is simple and controllable, can be applied to a variety of substrates, and is the best choice for designing and preparing new functional materials. This experiment provides a basis for the extension of this method.

Plasmoid Formation and Strong Radiative Cooling in a Driven Magnetic Reconnection Experiment.

We present the first experimental study of plasmoid formation in a magnetic reconnection layer undergoing rapid radiative cooling, a regime relevant to extreme astrophysical plasmas. Two exploding aluminum wire arrays, driven by the Z machine, generate a reconnection layer (S_{L}≈120) in which the cooling rate far exceeds the hydrodynamic transit rate (τ_{hydro}/τ_{cool}>100). The reconnection layer generates a transient burst of >1 keV x-ray emission, consistent with the formation and subsequent rapid cooling of the layer. Time-gated x-ray images show fast-moving (up to 50 km s^{-1}) hotspots in the layer, consistent with the presence of plasmoids in 3D resistive magnetohydrodynamic simulations. X-ray spectroscopy shows that these hotspots generate the majority of Al K-shell emission (around 1.6keV) prior to the onset of cooling, and exhibit temperatures (170eV) much greater than that of the plasma inflows and the rest of the reconnection layer, thus providing insight into the generation of high-energy radiation in radiatively cooled reconnection events.

Structural and optical properties of position-controlled n-ZnO nanowire arrays: Potential applications in optoelectronics

Highly position-controlled ZnO nanowire (NW) arrays and nanowire-cluster (NW–C) arrays are grown on mask-patterned gallium nitride (GaN) substrates by hydrothermal method. Electroluminescence (EL) emissions with blue-violet light at forward-bias(fb) voltage, EL emissions with yellow light at reverse-bias(rb) voltage, and EL emission at both rb voltages and rb voltages were achieved by the adjustment of the size of the heterojunction interface between wire arrays and film. The high rb current is attributed to electron tunneling transport edge effect via a narrow tunnel barrier. The obtained results highlight that the EL characteristics of ZnO NWs can be tuned and controlled through the size of the heterojunction interface between wire arrays and film. Besides, the nonplanar heterogeneous structure of ZnO NW arrays/GaN film also shown a great spectral response characteristic in the ultraviolet(UV) band, which proves that the structure of is worthy of being studied to achieve high performance UV photodetectors.

Simulations of radiatively cooled magnetic reconnection driven by pulsed power

Magnetic reconnection is an important process in astrophysical environments, as it reconfigures magnetic field topology and converts magnetic energy into thermal and kinetic energy. In extreme astrophysical systems, such as black hole coronae and pulsar magnetospheres, radiative cooling modifies the energy partition by radiating away internal energy, which can lead to the radiative collapse of the reconnection layer. In this paper, we perform two- and three-dimensional simulations to model the MARZ (Magnetic Reconnection on Z) experiments, which are designed to access cooling rates in the laboratory necessary to investigate reconnection in a previously unexplored radiatively cooled regime. These simulations are performed in GORGON, an Eulerian two-temperature resistive magnetohydrodynamic code, which models the experimental geometry comprising two exploding wire arrays driven by 20 MA of current on the Z machine (Sandia National Laboratories). Radiative losses are implemented using non-local thermodynamic equilibrium tables computed using the atomic code Spk, and we probe the effects of radiation transport by implementing both a local radiation loss model and $P_{1/3}$ multi-group radiation transport. The load produces highly collisional, super-Alfvénic (Alfvén Mach number $M_A \approx 1.5$ ), supersonic (Sonic Mach number $M_S \approx 4-5$ ) strongly driven plasma flows which generate an elongated reconnection layer (Aspect Ratio $L/\delta \approx 100$ , Lundquist number $S_L \approx 400$ ). The reconnection layer undergoes radiative collapse when the radiative losses exceed the rates of ohmic and compressional heating (cooling rate/hydrodynamic transit rate = $\tau _{\text {cool}}^{-1}/\tau _{H}^{-1}\approx 100$ ); this generates a cold strongly compressed current sheet, leading to an accelerated reconnection rate, consistent with theoretical predictions. Finally, the current sheet is also unstable to the plasmoid instability, but the magnetic islands are extinguished by strong radiative cooling before ejection from the layer.

Abelian combinatorial gauge symmetry

Combinatorial gauge symmetry is a principle that allows us to construct lattice gauge theories with two key and distinguishing properties: a) only one- and two-body interactions are needed; and b) the symmetry is exact rather than emergent in an effective or perturbative limit. The ground state exhibits topological order for a range of parameters. This paper is a generalization of the construction to any finite Abelian group. In addition to the general mathematical construction, we present a physical implementation in superconducting wire arrays, which offers a route to the experimental realization of lattice gauge theories with static Hamiltonians.

Thermally Driven Field Emission from Zinc Oxide Wires on a Nanomembrane Used as a Detector for Time-of-Flight Mass Spectrometry.

Mass spectrometry is a crucial technology in numerous applications, but it places stringent requirements on the detector to achieve high resolution across a broad spectrum of ion masses. Low-dimensional nanostructures offer opportunities to tailor properties and achieve performance not reachable in bulk materials. Here, an array of sharp zinc oxide wires was directly grown on a 30 nm thin, free-standing silicon nitride nanomembrane to enhance its field emission (FE). The nanomembrane was subsequently used as a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry detector. When ionized biomolecules impinge on the backside of the surface-modified nanomembrane, the current-emitted from the wires on the membrane's front side-is amplified by the supplied thermal energy, which allows for the detection of the ions. An extensive simulation framework was developed based on a combination of lateral heat diffusion in the nanomembrane, heat diffusion along the wires, and FE, including Schottky barrier lowering, to investigate the impact of wire length and diameter on the FE. Our theoretical model suggests a significant improvement in the overall FE response of the nanomembrane by growing wires on top. Specifically, long thin wires are ideal to enhance the magnitude of the FE signal and to shorten its duration for the fastest response simultaneously, which could facilitate the future application of detectors in mass spectrometry with properties improved by low-dimensional nanostructures.

Snapshot compressive imaging at 855 million frames per second for aluminium planar wire array Z-pinch.

This paper present a novel, integrated compressed ultrafast photography system for comprehensive measurement of the aluminium planar wire array Z-Pinch evolution process. The system incorporates a large array streak camera and embedded encoding to improve the signal-to-noise ratio. Based on the "QiangGuang-I" pulsed power facility, we recorded the complete continuous 2D implosion process of planar wire array Z-Pinch for the first time. Our results contribute valuable understanding of imploding plasma instabilities and offer direction for the optimization of Z-Pinch facilities.

Modelling the Impact of Array Wiring on Electrical Output of Vertical Bifacial Agrivoltaic Installations

We present a model and study investigating the potential power output of vertical bifacial solar panels on New Jersey farms. The simulation calculates instantaneous brightness and shading based on the position of the sun and adjacent rows of panels, and uses that to calculate current and voltage values. We explore different strategies to improve the power output further. Double-high modules, which use two panels stacked together, offer significant gains per acre with only a modest increase of inter-row shading. When bypass diodes and improved inverter wiring are also used, much of the losses due to shading are avoided, and the total power output per acre is nearly doubled. In a double high configuration it is advantageous to have the top and bottom modules on separate inverter strings.

Multi frame radiography of supersonic water jets interacting with a foil target

Pulsed-power-driven underwater electrical explosion of cylindrical or conical wire arrays produces supersonic water jets that emerge from a bath, propagating through the air above it. Interaction of these jets with solid targets may represent a new platform for attaining materials at high pressure (>1010 Pa) conditions in a university-scale laboratory. However, measurements of the internal structure of such jets and how they interact with targets are difficult optically due to large densities and density contrasts involved. We utilized multi-frame x-ray radiographic imaging capabilities of the ID19 beamline at the European Synchrotron Radiation Facility to explore the water jet and its interaction with a 50 μm thick copper foil placed a few mm from the surface of water. The jet was generated with a ∼130 kA-amplitude current pulse of ∼450 ns rise time applied to a conical wire array. X-ray imaging revealed a droplet-type structure of the jet with an average density of <400 kg/m3 propagating with a velocity of ∼1400 m/s. Measurements of deformation and subsequent perforation of the target by the jet suggested pressures at the jet–target interface of ∼5 × 109 Pa. The results were compared to hydrodynamic simulations for better understanding of the jet parameters and their interaction with the foil target. These results can be used in future research to optimize the platform, and extend it to larger jet velocities in the case of higher driving currents supplied to the wire array.

Shallow conductance decay along the heme array of a single tetraheme protein wire.

Multiheme cytochromes (MHCs) are the building blocks of highly conductive micrometre-long supramolecular wires found in so-called electrical bacteria. Recent studies have revealed that these proteins possess a long supramolecular array of closely packed heme cofactors along the main molecular axis alternating between perpendicular and stacking configurations (TST = T-shaped, stacked, T-shaped). While TST arrays have been identified as the likely electron conduit, the mechanisms of outstanding long-range charge transport observed in these structures remain unknown. Here we study charge transport on individual small tetraheme cytochromes (STCs) containing a single TST heme array. Individual STCs are trapped in a controllable nanoscale tunnelling gap. By modulating the tunnelling gap separation, we are able to selectively probe four different electron pathways involving 1, 2, 3 and 4 heme cofactors, respectively, leading to the determination of the electron tunnelling decay constant along the TST heme motif. Conductance calculations of selected single-STC junctions are in excellent agreement with experiments and suggest a mechanism of electron tunnelling with shallow length decay constant through an individual STC. These results demonstrate that an individual TST motif supporting electron tunnelling might contribute to a tunnelling-assisted charge transport diffusion mechanism in larger TST associations.