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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Giant halos in medium nuclei within modified relativistic mean field (MRMF) model

The large number of neutrons in a region beyond a closed shell core indicates the presence of giant halos in nuclei. In this work, by using the Rotival method within a modified relativistic mean field (MRMF) model, we predict theoretically the formation of giant halos in Cr and Zr isotopes. The MRMF model is a modification of standard RMF model augmented with isoscalar and isovector tensor terms, isovector-isoscalar vector cross coupling term and electromagnetic exchange term for Coulomb interaction in local density approximation (LDA).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Nonlinear susceptibilities for weakly turbulent magnetized plasma: Electrostatic approximation

The plasma weak turbulence theory is a perturbative nonlinear theory, which has been proven to be quite valid in a number of applications. However, the standard weak turbulence theory found in the literature is fully developed for highly idealized unmagnetized plasmas. As many plasmas found in nature and laboratory are immersed in a background static magnetic field, it is necessary to extend the existing discussions to include the effects of ambient magnetic field. Such a task is quite formidable, however, which has prevented fundamental and significant progresses in the subject matter. The central difficulty lies in the formulation of the complete nonlinear response functions for magnetized plasmas. The present paper derives the nonlinear susceptibilities for weakly turbulent magnetized plasmas up to the third order nonlinearity, but in doing so, a substantial reduction in mathematical complexity is achieved by the use of Bessel function addition theorem (or sum rule). The present paper also constructs the weak turbulence wave kinetic equation in a formal sense. For the sake of simplicity, however, the present paper assumes the electrostatic interaction among plasma particles. Fully electromagnetic generalization is a subject of a subsequent paper.

Physics↗
DOE OSTI2026

Improving ICARUS track reconstruction algorithms

The ICARUS experiment is part of the Short-Baseline Neutrino program at Fermilab. Its primary objective is to explore the possible existence of sterile neutrinos in the O(1 eV) mass range and to clarify the anomalies observed in the Liquid Scintillator Neutrino Detector and MiniBooNE experiments. The ICARUS-T600 detector is a Liquid Argon Time Projection Chamber, capable of producing high-resolution 3D images and precise calorimetric measurements of ionizing particles. This technology allows for a detailed study of neutrino interactions across a broad energy range, from a few keV to several hundred GeV. The track reconstruction is achieved through a software framework that applies a series of pattern recognition algorithms, transforming raw detector signals into fully reconstructed event topologies. This process involves identifying interaction vertices, particle tracks, and electromagnetic showers within the TPC. However, in certain cases, these algorithms may mistakenly break a single particle track into several shorter segments, interpreting each as a distinct particle. Since track length is used to estimate the particle's energy, such fragmentation can result in an energy underestimation of several hundred MeV. Furthermore, when a track is split into multiple segments, the particle identification (which relies on analyzing the energy loss as a function of the residual range) may fail, potentially leading to the loss of the entire event. To mitigate this problem, we have developed a dedicated algorithm designed to identify and reconnect (“stitch”) the tracks that were erroneously divided into multiple segments.

Ricci, Alessandro Maria [Pisa U.; INFN, Pisa] (ORC↗
DOE OSTI2024

Achieving a near-ideal silicon crystal neutron interferometer using submicrometer fabrication techniques

Perfect-crystal neutron interferometry, which is analogous to Mach-Zehnder interferometry, uses Bragg diffraction to form interfering neutron paths. The measured phase shifts can be used to probe many types of interactions whether it be nuclear, electromagnetic, gravitational, or topological in nature. For a perfect-crystal interferometer to preserve coherence, the crystal must possess a high degree of dimensional tolerance as well as being relatively defect-free with minimal internal stresses. In the past, perfect-crystal neutron interferometers have been produced by a two-step process. First, a resin diamond wheel would be used to remove excess material and shape the interferometer. Afterword, the crystal would be etched to remove surface defects and elevate strains. This process has had limitations in terms of repeatability and in maximizing the final contrast, or fringe visibility, of the interferometer. We have tested various fabrication and post-fabrication techniques on a single perfect-crystal neutron interferometer and measured the interferometer's performance at each step. Here we report a robust, nonetching fabrication process with high final contrast. For the interferometer used in this work, we achieved contrasts of greater than 90% several times and ultimately finished with an interferometer that has 92% contrast and a uniform phase distribution. Published by the American Physical Society 2024

Huber, M. G. (ORCID:0000000237958445)↗
DOE OSTI2015

Plasma system of the GOL-3T facility

The plasma system and diagnostics of the new facility GOL-3T are described. This facility is the final result of the first stage in the deep upgrade of the GOL-3 multiple-mirror system, which has operated at the Budker Institute of Nuclear Physics since 1988. The upgrade project supposes creation of two new independent facilities at the site of GOL-3. The GOL-3T facility is intended to study the physics of beam—plasma interaction and generation of subterahertz electromagnetic radiation during the collective relaxation of a high-power relativistic electron beam with a duration of 5–10 μs. Studies on the physics of multiple-mirror plasma confinement in axisymmetric magnetic systems will be continued in a new range of experiment parameters at the second facility, named GOL-NB.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Long-Lived Magnetoexcitons and Two-Dimensional Magnetofermionic Condensate in GaAs/AlGaAs Heterostructure

Excitation of long-lived triplet magnetoexcitons in a Hall insulator (filling factor ν = 2) with a high mobility of electrons, at low temperatures, Т < 1 K, enabled to discover a new collective state − magnetofermionic condensate, that interacts coherently with an external electromagnetic field, exhibits superradiant properties and, owing to its low viscosity, spreads over the surface of the two-dimensional structure for macroscopically large distances.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Ponderomotive Forces On Waves In Modulated Media

Nonlinear interactions of waves via instantaneous cross-phase modulation can be cast in the same way as ponderomotive wave-particle interactions in high-frequency electromagnetic fi eld. The ponderomotive effect arises when rays of a probe wave scatter off perturbations of the underlying medium produced by a second, modulation wave, much like charged particles scatter off a quasiperiodic field. Parallels with the point-particle dynamics, which itself is generalized by this theory, lead to new methods of wave manipulation, including asymmetric barriers for light.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Impacts of electromagnetic fields associated with marine and hydrokinetic surrogate technologies on fish movements and behaviors.

Marine and hydrokinetic energy (MHK) and offshore wind devices are being developed and deployed in U.S. and international waters. Electric current flowing through subsea transmission cables associated with these devices will generate electromagnetic fields (EMF), which may interact with, and potentially impact, marine fishes. Some marine fishes can detect electric and/or magnetic fields and use them to navigate, orientate, and sense prey, mates and predators. Over the past five years there have been multiple comprehensive reviews and studies evaluating the potential vulnerability of marine fishes to EMF produced by MHK devices. Most documented effects involve sub-lethal behavioral responses of individual fish when in close proximity to EMF (e.g., fish being repelled by or attracted to fields). These reviews reach conclusions that the current state of research on this topic is still in its infancy and evaluations of potential impacts are associated with great uncertainty. A variety of MHK technologies are likely to be considered for deployment offshore of the Hawaiian Islands, and there is a need to be able to better predict and assess potential associated environmental impacts. The goal of this study was to provide a complementary piece to these previous reviews (e.g., Normandeau et al. 2011) by focusing on marine fish species in the Hawaii region. We compiled the relevant available information, then prioritized fish species as candidates for various paths of future research. To address this, we first developed a list of Hawaii Region Focal Species, which included fishes that are more likely to be sensitive to EMF. We then compiled species-specific information available in the literature on their sensitivity to EMF, as well as life history, movement and habitat use information that could inform an analysis of their likelihood of encountering EMF from subsea cables associated with MHK devices. Studies have only documented EMF sensitivity in 11 of the marine fish species in this region. There was also relatively little detailed information on fish movement and habitat use patterns for most of the focal species. Our last objective was to develop recommendations for research needs to close the important knowledge gaps. We describe species-independent baseline research that primarily consists of in situ quantification of EMF generated by MHK devices and undersea cables that can occur as pilot and commercial scale MHK devices are deployed in Hawaii. Then we propose a simple approach for prioritizing Hawaii Region Focal Species (ranked relative to each other) as candidates in multiple related research paths. The prioritization approach incorporates EMF sensitivity information with the likelihood of interacting with EMF generated undersea transmission cables associated with MHK devices. Finally, we discuss the types of research needed to help fill gaps in the scientific knowledge base for this region. These involve studies to better define species-specific EMF sensitivity thresholds under various environmental conditions, studies of life history, movement and habitat use patterns to improve our understanding of the likelihood and frequency fishes may be in the vicinity of EMF generated by subsea transmission cables, and studies of the potential for related population, community or ecosystem impacts. Many of these studies can and should occur opportunistically as pilot and commercial scale MHK devices are deployed in Hawaii.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

A Panoramic View of Temperature and Field Distributions of the Structured Catalyst Under Microwave Irradiation Using Experimental and Modeling Approaches

This is a presentation covers NETL's recent research outcome in numerical modeling of microwave-assisted catalytic reaction. In this presentation, the intrinsic microwave-material interaction was demonstrated in this study through numerical modeling and experimental measurement. Different material combinations and reactor setups were investigated and compared. By combining numerical modeling with advanced measurement techniques, the microwave-material interaction and the relationship between electromagnetic field and heating can be better understood, which further benefits the development of microwave-assisted reactors and their application in process intensification.

Bai, Xinwei↗
NASA NTRS1974

Auroral effects in the D region of the ionosphere

Physical phenomena associated with the interaction between auroral particles and electromagnetic fields, auroral energy flow, and the propagation of auroral effects to low altitudes are discussed in detail. It is concluded that energy deposition of soft auroral X-rays would be negligible at stratospheric altitudes. New data from incoherent backscatter measurements of neutral winds in the auroral region indicate a lack of correlation between stratospheric winds and winds in the auroral ionosphere. Magnetograms are used to show that sector boundary crossings with a time scale of approximately one hour (as opposed to the sector structure itself with a time scale of several days) do not couple effectively with the magnetosphere and are not significant energy inputs to it.

Akasofu, S. I.↗
NASA NTRS1975

Harmonic generation at high field strengths - Frequency shifts and saturation phenomena

Optical harmonic generation and mixing in the gas phase has been proposed as a technique for the generation of coherent radiation in the vacuum ultraviolet and soft X-ray spectral region. At the high field strengths required by these processes the interaction between atoms and the electromagnetic field shows intensity-dependent resonances. In this paper we modify harmonic generation theory to include the effect of these frequency shifts. Closed-form expressions for generated dipole moment, absorption probability, and coherence length are presented. The most important consequences of frequency shifts on resonantly enhanced processes are that the pump laser must be tuned away from the small-field resonance frequency, that the conversion efficiency may saturate, and that the dispersion of the medium may change sign. As an example, the generation of 198-A radiation by a five-photon mixing process in Li(+) is considered.

Stappaerts, E. A.↗
NASA NTRS1985

Recoverable Plasma Diagnostics Package (RPDP)

The recoverable plasma diagnostics package (RPDP) is an ejectable and recoverable satellite with flight and ground support systems so that it can be utilized in three modes: attached to an remote manipulator system; tethered; or as a subsatellite. The satellite is well instrumented with particle and field diagnostic as well as optical sensors to: investigate the dynamics of the natural environment or ejected perturbations from particle beams; measure the characteristics and propagation of electrostatic and electromagnetic waves; study wave particle interactions; and study natural properties of the magnetosphere, ionosphere, and upper atmosphere.

Roberts, W. T.↗
NASA NTRS1986

Recoverable Plasma Diagnostics Package (RPDP)

The recoverable plasma diagnostics package (RPDP) is an ejectable and recoverable satellite with flight and ground support systems so that it can be utilized in three modes: attached to an remote manipulator system; tethered; or as a subsatellite. The satellite is well instrumented with particle and field diagnostic as well as optical sensors to: investigate the dynamics of the natural environment or ejected perturbations from particle beams; measure the characteristics and propagation of electrostatic and electromagnetic waves; study wave particle interactions; and study natural properties of the magnetosphere, ionosphere, and upper atmosphere.

Roberts, B.↗
NASA NTRS1986

Comparison of abrasion model differences in heavy ion fragmentation - Optical versus geometric models

Two different abrasion formalisms, one based on an energy-independent geometric model and the other based on a quantum-mechanical optical model, are shown to yield comparable fragmentation cross section predictions when used as input to an abrasion-ablation frictional-spectator interaction fragmentation calculation which includes electromagnetic dissociation contributions. The results suggest that any dependence upon the incident ion's kinetic energy above 200 MeV/nucleon is weak. It is also noted that the larger surface diffusiveness of the optical model densities only affects nuclear cross sections for near-projectile-mass fragments, while for heavier nuclei, the sizable cross-section contributions from electromagnetic dissociation negate these differences.

Townsend, L. W.↗
NASA NTRS1988

An exact solution to the relativistic equation of motion of a charged particle driven by a linearly polarized electromagnetic wave

An exact analytic solution is found for a basic electromagnetic wave-charged particle interaction by solving the nonlinear equations of motion. The particle position, velocity, and corresponding time are found to be explicit functions of the total phase of the wave. Particle position and velocity are thus implicit functions of time. Applications include describing the motion of a free electron driven by an intense laser beam..

Shebalin, John V.↗