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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Assessment of Variability of the TEC in the Equatorial Anomaly Region with a Focus over Africa Using Rz and F10.7 as Input Drivers

This paper mainly intends to address the assessment of altitudinal variability of the vertical total electron content (VTEC) extracted from the Global Positioning System (GPS), the new versions of the International Reference Ionosphere Extended to the Plasmasphere (IRI-Plas 2017), and a quick-run ionospheric electron density (NeQuick 2) model in the equatorial anomaly region with a focus over Africa. This is manipulated employing the daily sunspot number (Rz) and 10.7 cm solar radio flux (F10.7) indices as the driver for the models during 2013–2016. The results show that the GPS-derived VTEC values are generally smaller than the modeled VTEC (IRI-Plas 2017 and NeQuick 2 VTEC) values, especially while utilizing the models with the Rz index. The modeled VTEC values are closer to the GPS VTEC values while using the models with the F10.7 index than Rz. The VTEC values obtained while using both models with the F10.7 index tend to increase while traversing from the high to the low solar activity years (especially in the March equinox and December solstice). The top-side ionospheric and plasmaspheric layers contribute the highest and lowest values to the total VTEC. Hence, the signal propagation through the ionosphere is largely affected when the signal crosses the top-side layer. Unlike other layers, due to the limited impact of the EUV on the ionization of neutral particles in the plasmasphere, the VTEC in the plasmaspheric layer (ECpl) shows smooth pattern with similar hourly values. Moreover, the IRI-Plas 2017 model does not effectively respond to the geomagnetic storm time variability of the VTEC with altitude.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1993

Design of a Particle Beam Satellite System for Lunar Prospecting

One potential use for neutral particle beam (NPB) technology is as an active orbital probe to investigate the composition of selected locations on the lunar surface. Because the beam is narrow and can be precisely directed, the NPB probe offers possibilities for high resolution experiments that cannot be accomplished using passive techniques. Rather, the combination of both passive and active techniques can be used to provide both full-coverage mapping (passively) at low resolution (tens of kilometers) and high-resolution information for discrete locations of special interest. A preliminary study of NPB applicability for this dual-use application was recently conducted. The study was completed in Feb. 1993. A novel feature was the consideration of the use of a Russian launch vehicle (e.g., the Proton). The use of other Russian space hardware and capabilities was also encouraged. This paper describes the lunar prospector system design. Other researchers discuss the issues and opportunities involving lunar scientific experimentation using an NPB. The NPB lunar prospector utilizes a modified design of the Far Field Optics Experiment (FOX). Like the Earth-orbiting FOX, the core capability of the NPB lunar prospector will be a pulsed RF LINAC that produces a 5-MeV proton beam that is projected to the target with a 30-micro-r beam divergence and a 10-micro-r beam-pointing accuracy. Upon striking the lunar surface, the proton beam will excite characteristic radiation (e.g., X-rays) that can be sensed by one or more detectors on the NPB platform or on a separate detector satellite.

Berwald, D. H.↗
DOE OSTI2021

Methods for Estimating Dose from Galactic Cosmic Rays and Jovian Radiation Belts on Reduced-Order Monte Carlo Geometries

This document outlines the methods and tools developed to estimate dose rates from galactic cosmic rays and the trapped radiation belts surrounding Jupiter using Monte Carlo particle transport software. Furthermore, the techniques described here are specific for translating high-resolution MAVRIC models to analogous but lower resolution Monte Carlo N-Particle Transport (MCNP) code models to estimate charged particle effects on models originally developed to study neutral particles only. This capability was initially developed to predict doses to various components of dynamic radioisotope power systems for spaceflight applications, but the tools and methods can be easily applied to other problem geometries and expanded to other space radiation environments.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1972

The upper atmosphere as a regulator of subauroral red arcs.

The mechanisms for producing a subauroral red arc (SARARC) are studied by solving a system of basic ionospheric and atmospheric equations. It is shown that many of the observed features of a SARARC can be explained within the framework of the two processes generally responsible for the ionospheric behavior during a magnetic storm: (1) energy conduction from the magnetosphere to the ionosphere and (2) the changes in neutral composition of the lower atmosphere caused by the increase in turbulent mixing. Both processes trigger a complex chain of events which ultimately results in the redistribution of both the charged and neutral particles, an increase in the electron, ion, and neutral temperatures, and a decrease in the electron density in the altitude region near the F2 peak. It is shown that both the occurrence and the emission intensity of a SARARC are regulated by the neutral atmosphere, even though conduction of the thermal energy from the magnetosphere to the ionosphere provides the excitation energy of the optical remission.

Chandra, S.↗
DOE OSTI2021

Two-photon absorption laser induced fluorescence measurements of absolute neutral deuterium density, temperature, and bulk flow in Proto-MPEX

Neutral particle control is critical for fusion fueling and confinement. Neutral diagnostics for fusion-relevant plasmas are commonly restricted to line-integrated or ex situ methods. A non-perturbative, two-photon absorption laser induced fluorescence (TALIF) diagnostic is implemented on the Prototype Material Plasma Exposure eXperiment (Proto-MPEX) to probe neutral atomic deuterium in a fusion-relevant plasma at 1 cm intervals along the radius of the vacuum vessel. The diagnostic is situated ~20 m from the vacuum vessel, and a signal is collected along the laser injection axis, requiring only one line-of-sight. TALIF measurements are absolutely calibrated using xenon and krypton. Absolute atomic densities derived from xenon calibration are compared to absolute atomic densities derived from krypton calibration. In this work, preliminary measurements of absolute atomic deuterium density, temperature, and local bulk flow dependence on radial location and input power in Proto-MPEX are presented. Neutral atomic deuterium velocity distribution functions are measured throughout a one-second plasma pulse with a time resolution of 250 ms.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2015

Calibration and Readiness of the ISS-RAD Charged Particle Detector

The International Space Station (ISS) Radiation Assessment Detector (RAD) is an intravehicular energetic particle detector designed to measure a broad spectrum of charged particle and neutron radiation unique to the ISS radiation environment. In this presentation, a summary of calibration and readiness of the RAD Sensor Head (RSH) - also referred to as the Charged Particle Detector (CPD) - for ISS will be presented. Calibration for the RSH consists of p, He, C, O, Si, and Fe ion data collected at the NASA Space Radiation Laboratory (NSRL) and Indiana University Cyclotron Facility (IUCF). The RSH consists of four detectors used in measuring the spectroscopy of charged particles - A, B, C, and D; high-energy neutral particles and charged particles are measured in E; and the last detector - F - is an anti-coincidence detector. A, B, and C are made from Si; D is made from BGO; E and F are made from EJ260XL plastic scintillator.

Rios, R.↗
NASA NTRS1998

300 GeV Observations of Unidentified EGRET Sources. A Search for TeV Counterparts to BATSE Gamma-ray Bursts

There are few things more intriguing in high energy astrophysics than the study of the highest energy particles in the universe. Where and how these particles achieve their extreme energies is of interest not only to the astrophysicist but also to the particle physicist. At GeV and TeV energies the problem is manageable since the physics is known and the acceleration processes feasible. But the energy spectrum extends to 10(exp 20)Ev and there the problem of their origin is both more difficult and interesting; in fact at these high energies we do not even know what the particles are. The study of the origin and distribution of relativistic particles in the universe has been a challenge for more than 80 years but it is only in recent years that the technology has become available to really address the question. Although something can be learned from studies of composition and energy spectrum, the origins (and thence the acceleration mechanisms) can only come from the direct study of the neutral particle component (in this respect the highest energy particles are effectively neutral since they are virtually undeflected). The feasible channels of investigation are therefore the study of the arrival directions of: (1) TeV photons (covered by the following U.S. experiments: STACEE, Whipple/VERITAS, MILAGRO and, to some extent, by EGRET/GLAST); (2) neutrinos of TeV energy and above (AMANDA/KM3); (3) the highest energy cosmic rays (HiRes, Auger). While these studies represent a form of astronomy they are the astronomy of the extraordinary universe, the universe populated by the most dynamic and physically exciting objects, the universe of the high energy astrophysicist whose cosmic laboratories represent conditions beyond anything that can be duplicated in a terrestrial laboratory. This extraordinary astronomy may say little about the normal evolution of stars and galaxies but it opens windows into cosmic particle acceleration where new and strange physical processes take place.

Weekes, Trevor C.↗
NASA NTRS1986

Neutron and antineutron production in accretion onto compact objects

Nuclear reactions in the hot accretion plasma surrounding a collapsed star are a source of neutrons, primarily through spallation and pion-producing reactions, and antineutrons, principally through the reaction p+p yields p+p+n+anti-n. We calculate spectra of neutrons and antineutrons produced by a variety of nonthermal energetic particle distributions in which the target particles are either at rest or in motion. If only neutral particles are free to escape the interaction site, a component of the proton and antiproton fluxes in the cosmic radiation results from the neutrons and antineutrons which leave the accretion plasma and subsequently decay in the interstellar medium. This additional antiproton component could account for the enhanced flux of antiprotons in the cosmic radiation, compared to values expected from the standard leaky-box model of cosmic-ray propagation and confinement. Moreover, the low-energy antiproton flux measured by Buffington et al. (1981) could result from target-particle motion in the accretion plasma. This model for the origin of antiprotons predicts a narrow 2.223 MeV line which could be observable.

Dermer, C. D.↗
NASA NTRS1986

Neutron and antineutron production in accretion onto compact objects

Nuclear reactions in the hot accretion plasma surrounding a collapsed star are a source of neutrons, primarily through spallation and pion-producing reactions, and antineutrons, principally through the reaction p+p yields p+p+n+anti-n. We calculate spectra of neutrons and antineutrons produced by a variety of nonthermal energetic particle distributions in which the target particles are either at rest or in motion. If only neutral particles are free to escape the interaction site, a component of the proton and antiproton fluxes in the cosmic radiation results from the neutrons and antineutrons which leave the accretion plasma and subsequently decay in the interstellar medium. This additional antiproton component could account for the enhanced flux of antiprotons in the cosmic radiation, compared to values expected from the standard leaky-box model of cosmic-ray propagation and confinement. Moreover, the low-energy antiproton flux measured by Buffington et al. (1981) could result from target-particle motion in the accretion plasma. This model for the origin of antiprotons predicts a narrow 2.223 MeV line which could be observable.

Dermer, Charles D.↗
DOE OSTI2024

Verification of a Monte Carlo binary collision model for simulating elastic and inelastic collisions in particle-in-cell simulations

We present the development and verification of a Monte Carlo binary collision model for simulating elastic and inelastic collisions in particle-in-cell simulations. We apply the corrected binary collision model originally developed for charged-particles collisions to all considered scattering channels, including Coulomb collisions, elastic neutral–neutral and charged–neutral collisions, ionization, excitation, and fusion. The model's implementation is described and verified through a series of simulations, including charged- and neutral-particle thermal equilibration, slowing of electrons in warm solid-density aluminum, collisional damping of a Langmuir wave, helium gas breakdown in an applied electric field, and thermonuclear and beam–target fusion. Then, we demonstrate the model within simulations of hydrogen plasma formation in the Princeton Field-Reversed Configuration as well as of the burning of aneutronic fusion fuel p-11B. The latter includes measurement of the fusion power density in a low-density plasma and fusion production due to the stopping of a proton ignitor beam in a compressed boron target.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Optimization of the BDX experiment for Light Dark Matter searches at JLab

The Light Dark Matter (LDM) hypothesis postulates the existence of a new class of sub GeV particles, neutral under Standard Model (SM) interactions. In its simplest form, LDM consists of particles ¿ with masses below 1 GeV/c2, interacting with SM particles via a new force mediated by a light, spin-1 boson A0, commonly referred to as “Dark Photon”. This framework envisions a distinct “Dark Sector” with its own particles and interactions, offering a theoretically well motivated explanation for Dark Matter, consistent with astrophysical observations and a thermal production mechanism. The Beam Dump eXperiment (BDX) is an approved experiment at Jefferson Lab designed to search for Light Dark Matter. BDX will utilize an 11 GeV electron beam impinging on a thick target to produce a forward-boosted secondary beam of Light Dark Matter particles, which will then be detected by a dedicated downstream detector. Approved in 2018, BDX is expected to be commissioned in 2026 and run in 2027-2029. My thesis focuses on the preparatory work to deploy the BDX experiment. The detector design has been optimized to balance practicality with enhanced Light Dark Matter detection capabilities. Extensive characterization of detector components has been performed to ensure a precise understanding of detector response. A custom Monte Carlo framework has been developed to simulate Light Dark Matter signal and explore various theoretical models of interest. Additionally, a comprehensive data analysis framework has been developed to maximize the experiment sensitivity to Light Dark Matter, with optimizations based on expected detector performance. The ultimate goal of this thesis is to optimize BDX as a flagship experiment in Light Dark Matter searches, enabling it to probe different Dark Matter models.

Spreafico, M. [Univ. of Genova (Italy)]↗
DOE OSTI2025

Software For Advanced Large-scale Analysis Of Magnetic Confinement For Numerical Design, Engineering & Research (salamander)

As magnetic confinement fusion energy gains traction internationally to enable abundant energy production, designing components for fusion systems is a pressing challenge. During the planned lifetime of a fusion device, components evolve in extreme environments and must withstand large, repeated thermal loads and bombardment by 14 MeV neutrons, plasma ions, and neutral particles (deuterium, tritium, and helium), corrosive conditions, etc. All these physical processes take place simultaneously, interact in intricate ways, and impose important constraints that can affect performance. Experimental data is rare and costly to obtain, making design particularly challenging. Predictive computational frameworks must be an integral part of an accelerated and cost-effective design process by modeling fusion system performance in simulated environments. To better understand component degradation and operational impacts on their performance, the Software for Advanced Large-scale Analysis of MAgnetic confinement for Numerical Design, Engineering & Research (SALAMANDER) is designed as an open-source, fully integrated, multiphysics, multiscale, NQA-1 compliant framework facilitating 3D, high-fidelity fusion system modeling. To that end, SALAMANDER is a MOOSE-based framework, and therefore leverages MOOSE upstream libraries such as PETSc and libMesh to deliver sophisticated finite element, finite volume, and nonlinear solver technology for fusion energy simulations. SALAMANDER couples MOOSE physics module capabilities—such as thermal hydraulics, heat conduction, Navier-Stokes, and thermomechanics—with tritium transport via TMAP8, neutronics via Cardinal, and nascent particle-in-cell capabilities. Direct simulation Monte Carlo methods will be used to address neutral transport near the walls. By coupling all these physics in an integrated application, SALAMANDER will enable high-fidelity modeling of irradiation levels and plasma exposure conditions of plasma facing components and their impact on heat and tritium distributions, as well as the resulting mechanical constraints experienced by the plasma facing components and performance of blanket systems. Furthermore, SALAMANDER will be particularly suited for engineering studies thanks to the stochastic tool module readily available in MOOSE, allowing for extended uncertainty quantification and risk analysis studies. It is also able to use computer-aided design (CAD) meshes to model complex geometries, which is indispensable for fusion systems. SALAMANDER therefore supports design, safety, engineering, and research projects for magnetic confinement fusion systems

Simon, Pierre-Clement [Idaho National Laboratory (↗
DOE OSTI2025

Conceptual Design Report for the MATHUSLA Long-Lived Particle Detector near CMS

We present the Conceptual Design Report (CDR) for the MATHUSLA (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) long-lived particle detector at the HL-LHC, covering the design, fabrication and installation at CERN Point 5. MATHUSLA is a 40 m-scale detector with an air-filled decay volume that is instrumented with scintillator tracking detectors, to be located near CMS. Its large size, close proximity to the CMS interaction point and about 100 m of rock shielding from HL-LHC backgrounds allows it to detect LLP production rates and lifetimes that are one to two orders of magnitude beyond the ultimate sensitivity of the HL-LHC main detectors for many highly motivated LLP signals. Data taking is projected to commence with the start of HL-LHC operations. We present a new 40m design for the detector: its individual scintillator bars and wavelength-shifting fibers, their organization into tracking layers, tracking modules, tower modules and the veto detector; define a high-level design for the supporting electronics, DAQ and trigger system, including supplying a hardware trigger signal to CMS to record the LLP production event; outline computing systems, civil engineering and safety considerations; and present preliminary cost estimates and timelines for the project. We also conduct detailed simulation studies of the important cosmic ray and HL-LHC muon backgrounds, implementing full track/vertex reconstruction and background rejection, to ultimately demonstrate high signal efficiency and $\ll 1$ background event in realistic LLP searches for the main physics targets at MATHUSLA. This sensitivity is robust with respect to detector design or background simulation details. Appendices provide various supplemental information.

Aitken, Branden [Victoria U.]↗
NASA NTRS1986

Measurements of n-p correlations in the reaction of relativistic neon with uranium

We report a preliminary measurement of coincident neutron-proton pairs emitted at 45 degrees in the interaction of 400, 530, and 650 MeV/A neon beams incident on uranium. Charged particles were identified by time of flight and momentum, as determined in a magnetic spectrometer. Neutral particles were detected using a thick plastic scintillator, and their time of flight was measured between an entrance scintillator, triggered by a charged particle, and the neutron detector. The scatter plots and contour plots of neutron momentum vs. proton momentum appear to show a slight correlation ridge above an uncorrelated background. The projections of this plane on the n-p momentum difference axis are essentially flat, showing a one standard deviation enhancement for each of the three beams energies. At each beam energy, the calculated momentum correlation function for the neutron-proton pairs is enhanced near zero neutron-proton momentum difference by approximately one standard deviation over the expected value for no correlation. This enhancement is expected to occur as a consequence of the attractive final state interaction between the neutron and proton (i.e., virtual or "singlet" deuterons). The implications of these measurements are discussed.

NASA Program Space Medicine↗
NASA NTRS1978

The collisional interaction of a beam of charged particles with a hydrogen target of arbitrary ionization level

The classical theory of scattering under the Coulomb potential of both charged and neutral particles is used to derive formulae for the energy deposition rate and mean scattering of a beam of charged particles interacting with a cold hydrogen target of arbitrary ionization level as a function of the column density traversed by the beam. These general results hold for any form of stable injection energy spectrum, and their relevance to the existing literature on chromospheric heating during solar flares is discussed.

Emslie, A. G.↗
DOE OSTI2026

Characterization of core neutrals using passive measurements of the D α spectrum near the X -point in the DIII-D tokamak

New spectroscopic measurements of deuterium Balmer-α emission are used to infer the spatial distribution of neutral particles near the X-point in a diverted high confinement mode plasma. The charge exchange neutral spectroscopy (CENS) diagnostic—recently installed on the DIII-D tokamak—uses 15 lines of sight extending from the edge of the confined region (ρ ≈ 0.7) to the X-point in lower single-null plasmas. Each CENS line of sight is spectrally resolved around the deuterium Balmer-α wavelength (6561 Å) to measure the Doppler shift, line broadening, and intensity of Dα emission. Thermal line broadening is used to identify emission from neutrals undergoing charge-exchange (CX) with high temperature ions in the confined plasma. This spectral information allows a more accurate determination of the neutral density deeper inside the confined plasma compared to traditional filter-based diagnostics. We present two methods of analyzing CENS measurements: (1) fitting the spectrum from each view-chord separately, and (2) a tomographic method for inverting the neutral density over a 2D region of space using all CENS views collectively. The neutral density profile is found to decay exponentially in the radial direction with two scale-lengths. In the pedestal region the neutral density decays at a rate approximately equal to the local mean-free-path for CX collisions, $L_{n_\mathrm{D0}}\approx \lambda_\text{CX}$. Further inside the plasma the neutral density decays at a rate equal to the mean-free-path for ionization, $L_{n_\mathrm{D0}}\approx \lambda_\text{inz.}$. The separatrix $n_\mathrm{D0}$ value is found to be approximately $2\times10^{15}$ m−3. Based on results from the 2D inversion, the density of neutrals is found to increase along the separatrix approaching the X-point by a factor of $\approx 5\times$ over the region covered by the CENS diagnostic.

X-point neutrals↗
DOE OSTI2023

Time-Dependent Boundary Modeling to Inform Design of SPARC Diagnostic and Actuators

The purpose of this work was to inform the design of diagnostic and actuator systems for a new experimental facility for Commonwealth Fusion Systems (CFS), called SPARC [Creely2020], using time-dependent plasma boundary simulations with the Scrape Off Layer Plasma Simulator (SOLPS) code [Wiesen2015]. The SPARC tokamak is a device that aims to demonstrate fusion energy production and high-field plasma operating scenarios. The developed technologies will be incorporated into a net-electricity pilot that will demonstrate approximately 200MW of electric power. A major difference from other private industry fusion companies is the use of a standard aspect ratio, but at a high magnetic field strength, which provides a well-established physics basis and a modest extrapolation to reactor operation. Time-dependent simulations were used to inform the design of main-chamber plasma facing components, which are protected by feedback control of the heat and particle loads during high power operation. The simulations provide the timescales and magnitudes of plasma and neutral particle response useful for determining the position and operation of diagnostics and actuators that will enable control. The plasma response and phase-space diagrams also provide input into advanced model-based control schemes, which are envisioned for later SPARC operation. Model-based control can reduce the risk of component failure, which would require expensive in-situ repairs and the associated delays, by predicting the system response to actuators over a short time-horizon.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1979

The midnight temperature maximum in the earth's equatorial thermosphere

The paper reports in situ direct measurements of regularly observed thermosphere neutral particle (i.e., N2) temperature maxima that occur predominantly after midnight. The measurements were made using the Neutral Atmosphere Temperature Instrument aboard Atmosphere Explorer-E in circular orbit (inclination 19 deg) at about 275 km. Hundreds of midnight temperature maxima were observed, some having values exceeding the well-known afternoon maximum. Simultaneous in situ direct measurements of the wind component normal to the orbit plane have also been obtained and observed to correlate in a systematic way with the temperature maxima.

Spencer, N. W.↗