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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Excluded-volume model for quarkyonic matter: Three-flavor baryon-quark mixture

The single-flavor excluded-volume model based on the effective size of baryons reproduces the hard-soft density evolution of the equation of state (EoS) required by the recent studies of GW170817. This phenomenological model basically realizes the concept of quarkyonic matter which is introduced from large-$N_c$ gauge theory for dense matter. Further, enhanced nucleon interactions and dynamically generated quark degrees of freedom can reproduce the hard-soft evolution of the EoS. In this paper, we extend the excluded-volume model to a three-flavor system by considering electromagnetic charge and possible weak equilibrium in order to obtain a proper description for the hard-soft behavior of the EoS inferred from the gravitational waves observations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Laser-plasma ion beam booster based on hollow-channel magnetic vortex acceleration

Laser-driven ion acceleration provides ultrashort, high-charge, low-emittance beams, which are desirable for a wide range of high-impact applications. Yet after decades of research, a significant increase in maximum ion energy is still needed. This paper introduces a quality-preserving staging concept for ultraintense ion bunches that is seamlessly applicable from the nonrelativistic plasma source to the relativistic regime. Full three-dimensional particle-in-cell simulations prove robustness and capture of a high-charge proton bunch, suitable for readily available and near-term laser facilities.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Role of {sup 8}Be {yields} 2 {alpha} intermediate nuclei in the fragmentation of {sup 16}O relativistic nuclei in nuclear track emulsions

In searches along a track in the chamber irradiated at the Laboratory of High Energies at the Joint Institute for Nuclear Research (JINR, Dubna) with oxygen ions accelerated to a momentum of 4.5 GeV/c per nucleon, 215 events containing two or more doubly charged fragments of the primary nucleus were found. Emission angles in the track-emulsion plane were measured in these events. Their distribution is consistent with that which alpha particles are expected to have in an oxygen nucleus prior to its interaction with a track-emulsion nucleus. Events of the {sup 16}O {yields} 2{sup 8}Be {yields} 4{alpha} type were discovered for the first time. They are treated as events of the coherent electromagnetic dissociation of an oxygen nucleus. Among all events, about 14% of the {sup 8}Be {yields} 2{alpha} decays proceed through the ground state of spin-parity 0{sup +}; an approximately the same fraction of such decays proceed through the first excited state of spin-parity 2{sup +}.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Evaluation of the Inclusive Electron Scattering Observables in the Resonance Region from the Experimental Data

The method for evaluation of inclusive electron scattering observables in the resonance region from the experimental data is presented. The computer codes in the web page allow user to evaluate inclusive electron scattering, virtual photon-proton cross sections and the F{sub 1} and F{sub 2} structure functions at the invariant masses of the final hadrons 1.0 < W < 4.0 GeV and at photon virtualities 0.5 < Q {sup 2} < 7.0 GeV{sup 2}. The developed approach is of interest for analyses of the experimental data on exploration of the hadron structure in the experiments with electromagnetic probes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

The NOvA Test Beam Experiment

aThe motivation for the NOvA test beam project is to understand a number of limiting factors that impinges the NOvA's analyses. These factors include the detector’s hadronic and electromagnetic shower response, light yield and optical transportation, as well as discrepancies between data and MC modeling of the detector. In addition, the test beam setup will collect data to build a large libraries of particle interactions at well-known energies, which would later become a useful input in the development of better data driven PID algorithms for NOvA's analyses. The main component of the experiment - two 2$\times$2$\times$32 blocks, filled with NOvA liquid scintillator - is placed along the MC7 beamline to study the interaction with beam particles. The tertiary beam composes primarily of protons and pions as well as a discernible contribution from electrons, muons and kaons, all within a momentum range from 0.3 to 2 GeV$/c$. The PID and kinematics of beam particles will be determined by the auxiliary detectors including four MWPCs, two TOFs and a CO$_2$ gas Cherenkov counter. In this poster, recent status on beamline instrumentation, data acquisition, simulation, momentum reconstruction and PID will be presented. Also, implications for the neutrino oscillation measurements will be discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Imaging Photonic Resonances within an All‐Dielectric Metasurface via Photoelectron Emission Microscopy

Dielectric metasurfaces, through volume‐type photonic resonances, enable precise control of light‐matter interactions for applications including imaging, holography, and sensing. The application space of dielectric metasurfaces has extended from infrared to visible wavelengths by incorporating high refractive index materials, such as titanium dioxide (TiO 2 ). Understanding the fundamental and fabrication limits for these applications requires metrology with nanoscale resolution, sensitivity to electromagnetic fields within the meta‐atom volume, and far‐field excitation. In this work, photoelectron emission microscopy (PEEM) is used to image field distributions of photonic resonances in a TiO 2 metasurface excited with far‐field, visible‐wavelength illumination. The local volumetric field variations within the meta‐atoms are analyzed as a function of illumination angle and polarization by comparing photoelectron images to finite‐difference time‐domain simulations. This study determines the inelastic mean free path of very low‐energy (<1 eV) photoelectrons to be 35 ± 10 nm, which is comparable to the meta‐atom height thereby highlighting PEEM sensitivity to resonances within the volume. Additionally, the simulations reveal high sensitivity of PEEM images to an in‐plane component of the illumination k ‐vector. These results demonstrate that photoelectron imaging with subwavelength resolution offers unique advantages for examining light‐matter interactions in volume‐type (as opposed to surface) photonic modes within dielectric nanophotonic structures.

electron inelastic mean free path↗
DOE OSTI2014

Sub-wavelength waveguide loaded by a complementary electric metamaterial for vacuum electron devices

We report the electromagnetic properties of a waveguide loaded by complementary electric split ring resonators (CeSRRs) and the application of the waveguide in vacuum electronics. The S-parameters of the CeSRRs in free space are calculated using the HFSS code and are used to retrieve the effective permittivity and permeability in an effective medium theory. The dispersion relation of a waveguide loaded with the CeSRRs is calculated by two approaches: by direct calculation with HFSS and by calculation with the effective medium theory; the results are in good agreement. An improved agreement is obtained using a fitting procedure for the permittivity tensor in the effective medium theory. The gain of a backward wave mode of the CeSRR-loaded waveguide interacting with an electron beam is calculated by two methods: by using the HFSS model and traveling wave tube theory; and by using a dispersion relation derived in the effective medium model. Results of the two methods are in very good agreement. The proposed all-metal structure may be useful in miniaturized vacuum electron devices.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

t matrix of metallic wire structures

To study the electromagnetic resonance and scattering properties of complex structures of which metallic wire structures are constituents within multiple scattering theory, the t matrix of individual structures is needed. We have recently developed a rigorous and numerically efficient equivalent circuit theory in which retardation effects are taken into account for metallic wire structures. Here, we show how the t matrix can be calculated analytically within this theory. We illustrate our method with the example of split ring resonators. The density of states and cross sections for scattering and absorption are calculated, which are shown to be remarkably enhanced at resonant frequencies. The t matrix serves as the basic building block to evaluate the interaction of wire structures within the framework of multiple scattering theory. This will open the door to efficient design and optimization of assembly of wire structures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Sowing the seeds of massive black holes in small galaxies: Young clusters as the building blocks of ultracompact dwarf galaxies

Interacting galaxies often have complexes of hundreds of young stellar clusters of individual masses ∼10{sup 4}-10{sup 6} M {sub ☉} in regions that are a few hundred parsecs across. These cluster complexes interact dynamically, and their coalescence is a candidate for the origin of some ultracompact dwarf galaxies. Individual clusters with short relaxation times are candidates for the production of intermediate-mass black holes of a few hundred solar masses, via runaway stellar collisions prior to the first supernovae in a cluster. It is therefore possible that a cluster complex hosts multiple intermediate-mass black holes that may be ejected from their individual clusters due to mergers or binary processes, but bound to the complex as a whole. Here we explore the dynamical interaction between initially free-flying massive black holes and clusters in an evolving cluster complex. We find that, after hitting some clusters, it is plausible that the massive black hole will be captured in an ultracompact dwarf forming near the center of the complex. In the process, the hole typically triggers electromagnetic flares via stellar disruptions, and is also likely to be a prominent source of gravitational radiation for the advanced ground-based detectors LIGO and VIRGO. We also discuss other implications of this scenario, notably that the central black hole could be considerably larger than expected in other formation scenarios for ultracompact dwarfs.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Optical N-plasmon: topological hydrodynamic excitations in graphene from repulsive Hall viscosity

Abstract Edge states occurring in Chern and quantum spin-Hall phases are signatures of the topological electronic band structure in two-dimensional (2D) materials. Recently, a new topological electromagnetic phase of graphene characterized by the optical N-invariant was proposed. Optical N-invariant arises from repulsive Hall viscosity in hydrodynamic many-body electron systems, distinct from the Chern and Z 2 invariants. In this paper, we introduce the topologically protected edge excitation—optical N-plasmon of interacting many-body electron systems in the topological optical N-phase. These optical N-plasmons are signatures of the topological plasmonic band structure in 2D materials. We demonstrate that optical N-plasmons exhibit unique dispersion relations, stability against various boundary conditions, and edge profiles when compared with the topologically trivial edge magneto plasmons. Based on the optical N-plasmon, we design an ultra sub-wavelength broadband topological hydrodynamic circulator, which is a chiral quantum radio-frequency circuit component crucial for information routing and interfacing quantum–classical computing systems. Furthermore, we reveal that optical N-plasmons can be effectively tuned by the neighboring dielectric environment without breaking the topological properties. Our work provides a smoking gun signature of topological electromagnetic phases occurring in 2D materials arising from repulsive Hall viscosity.

Physics↗
DOE OSTI2024

Design of B1pF-A Large Aperture Dipole Magnet for EIC

The design of interaction region (IR) magnets for the Electron Ion Collider (EIC), demands tight boundary conditions on the magnet design given by the high field requirements and the proximity of electron and hadron beams within a common yoke and resultant crosstalk. Here, this article discusses the electromagnetic design of the superconducting collared magnet B1pF. The magnet will be built as the prototype for several collared magnets (dipoles and quadrupoles) for the hadron beam in the forward direction of the IR. The magnet design is based on a single layer coil with an inner diameter of 300 mm over a slot length of 3 m. The magnet produces an integral field of 10.34 T.m at a current of 11.9 kA to produce a nominal field of about 3.96 T at its center. Given by the common Rutherford cable parameters, the magnet will be used as a baseline for optimization of all the collared magnets. The article further discusses yoke optimizations, quench analysis, coil end design and efforts on fine tuning of field quality.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Two-photon excited deep-red and near-infrared emissive organic co-crystals

Abstract Two-photon excited near-infrared fluorescence materials have garnered considerable attention because of their superior optical penetration, higher spatial resolution, and lower optical scattering compared with other optical materials. Herein, a convenient and efficient supramolecular approach is used to synthesize a two-photon excited near-infrared emissive co-crystalline material. A naphthalenediimide-based triangular macrocycle and coronene form selectively two co-crystals. The triangle-shaped co-crystal emits deep-red fluorescence, while the quadrangle-shaped co-crystal displays deep-red and near-infrared emission centered on 668 nm, which represents a 162 nm red-shift compared with its precursors. Benefiting from intermolecular charge transfer interactions, the two co-crystals possess higher calculated two-photon absorption cross-sections than those of their individual constituents. Their two-photon absorption bands reach into the NIR-II region of the electromagnetic spectrum. The quadrangle-shaped co-crystal constitutes a unique material that exhibits two-photon absorption and near-infrared emission simultaneously. This co-crystallization strategy holds considerable promise for the future design and synthesis of more advanced optical materials.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Elastic electron-deuteron scattering in the light-front Hamiltonian dynamics

Within the Light-Front Hamiltonian Dynamics, we are extending our investigation of the deuteron electromagnetic properties by adding new, dynamical two-body terms to the one-body current operator, introduced in previous works. These two-body contributions are generated in a four-dimensional Yukawa model (two fermions interacting through a pion) from an analysis of the Light-Front-projected current that acts on the three-dimensional valence component and fulfills the Ward-Takahashi identity. Preliminary results for the magnetic moment and the non valence probability are shown.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Photon-dark photon conversions in extreme background electromagnetic fields

The mixing of photons with light pseudoscalars in the presence of external electromagnetic fields has been used extensively to search for axion-like-particles. A similar effect for dark photon propagating states is usually not considered due to the Landau-Yang theorem. We point out that mixing between photon and dark photon propagating states in background electromagnetic fields can indeed occur, in non-linear QED, through a four-photon vertex by integrating out the electron box diagram. Starting from the Schwinger Lagrangian, we derive the equations of motion for dark photons interacting with the Standard Model photon through gauge kinetic terms. We provide expressions for the perpendicular and parallel refractive indices in series expansions in the critical field strength, valid both in the strong and weak background field limits. We then consider mixing between the photon-dark photon propagating system in the presence of pure electric and magnetic background fields, and work out the probability of conversion when the background fields are homogeneous. We indicate outlines of the calculation in the inhomogeneous case, and finally express our results in the active-sterile basis, where we find that the mixing induced by background fields can lead to corrections to the tree-level mixing in the zero field limit that is usually considered to probe such systems. Our results may find applications for probing photon-dark photon conversions in the vicinity of neutron stars and in table-top petawatt laser experiments.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Procedure for measuring photon and vector meson circular polarization variation with respect to the reaction plane in relativistic heavy-ion collisions

The electromagnetic (EM) eld pattern created by spectators in relativistic heavy-ion collisions plants a seed of positive (negative) magnetic helicity in the hemisphere above (below) the reaction plane. Owing to the chiral anomaly, the magnetic helicity interacts with the fermionic helicity of the collision system, and causes photons emitted in upper- and lower-hemispheres to have different preferences in the circular polarization. Similar helicity separation for massive particles, due to the global vorticity, is also possible. In this paper, we lay down a procedure to measure the variation of the circular polarization w.r.t the reaction plane in relativistic heavy-ion collisions for massless photons, as well as similar polarization patterns for vector mesons decaying into two daughters. We propose to study the yield differentially and compare the yield between upper- and lower-hemispheres in order to identify and quantify such effects.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

COSMIC DAWN: Distributed Analysis of Wireless at Nextscale

Distributed Analysis of Wireless at Nextscale (DAWN) is a novel simulation framework for large-scale design-space exploration (DSE) of unmodified software-defined radio (SDR) applications interacting in a scalable, high-fidelity, virtual physics environment. The software-defined nature of the coupled software-physics simulation leverages hardware emulation to permit in-depth examination and modification of not only the electromagnetic environment, including each signal in flight, but also the precise state of system software and components. DAWN supports modular, customizable physics environments allowing realistic propagation effects so that computationally efficient empirical models, reduced order/surrogate models, or large-scale, high-fidelity, site-specific simulations can be used as a propagation medium based on scenario requirements. This paper introduces DAWN’s design and initial implementation, detailing key architectural components, including the Physics Realization Engine (PhyRE), Runtime Infrastructure for Simulation Environments (RISE), and the design space exploration (DSE) suite. It concludes with demonstrations using unmodified 4G/LTE software available from srsRAN on computing resources ranging from a small cluster to ORNL’s Frontier Exascale system.

Wise, Mike [ORNL] (ORCID:0000000266120641)↗
DOE OSTI2011

The {gamma}-ray production in neutral-current neutrino-oxygen interaction in the energy range above 100 MeV

We calculate the cross section of the {gamma}-ray production from neutral-current neutrino-oxygen quasi-elastic interaction, {nu}+{sup 16}O{yields}{nu}+p+{sup 15}N*, or {nu}+{sup 16}O{yields}{nu}+n+{sup 15}O*, in which the residual nuclei ({sup 15}N* or {sup 15}O*) lead to the {gamma}-ray emission with E{sub {gamma}>}6 MeV at the branching ratio of 41%. Above 200 MeV, this cross section dominates over that of {gamma}-ray production from the inelastic reaction, {nu}+{sup 16}O{yields}+{sup 16}O*. In the present calculation, spectral function and the spectroscopic factors of 1p{sub 1/2}, 1p{sub 3/2} and 1s{sub 1/2} states are essential. The {gamma}-ray production is dominated by the deexcitation of 1p{sub 3/2} state of the residual nucleus.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗