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NASA NTRS1983

Apparatus and method for jet noise suppression

A method and apparatus for jet noise suppression through control of the static pressure of the jet and control of the rate of entrainment of ambient fluid into the jet downstream of the exhaust nozzle is disclosed. The momentum flux over an extended region of the jet is regulated, affecting Reynolds stresses in the jet and the spreading angle of the jet. Static pressure is controlled through a long hollow, porous nozzle plug centerbody which may be selectively vented to ambient conditions, connected to a vacuum source, or supplied with fluids of various densities for injection into the stream. Sound in the jet may be channeled along the nozzle plug centerbody by injecting coolant such as a cryogenic fluid throughout the center-body into the jet.

Maestrello, L.↗

NASA NTRS1986

Proton acceleration in gamma-ray bursts

Proton acceleration and subsequent secondary electron production are proposed as the process responsible for the radiation emission in gamma-ray bursts. In this mechanism electrons are naturally injected at energies much larger than m(e) x c-squared and emission above 10 MeV is expected to be one of their common features, in agreement with observations showing that most of the luminosity of these events is emitted in gamma-rays. This mode of injection guarantees copious e(+)-e(-) pair production at the source and implies a relationship between the luminosity and the spectra of the bursts, the soft bursts being, in general, the most (intrinsically) luminous and hence the most distant. This, in turn, implies that bursts with soft spectra should show a galactic distribution, a fact consistent with the limited available data. It is also argued that the observed red-shift of the e(+)-e(-) annihilation feature may not always be gravitational.

Kazanas, Demosthenes↗

NASA NTRS1994

High Altitude Plasma Instrument (HAPI) data analysis

The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

Burch, J. L.↗

NASA NTRS2014

Using the NASA GRC Sectored-One-Dimensional Combustor Simulation

The document is a user manual for the NASA GRC Sectored-One-Dimensional (S-1-D) Combustor Simulation. It consists of three sections. The first is a very brief outline of the mathematical and numerical background of the code along with a description of the non-dimensional variables on which it operates. The second section describes how to run the code and includes an explanation of the input file. The input file contains the parameters necessary to establish an operating point as well as the associated boundary conditions (i.e. how it is fed and terminated) of a geometrically configured combustor. It also describes the code output. The third section describes the configuration process and utilizes a specific example combustor to do so. Configuration consists of geometrically describing the combustor (section lengths, axial locations, and cross sectional areas) and locating the fuel injection point and flame region. Configuration requires modifying the source code and recompiling. As such, an executable utility is included with the code which will guide the requisite modifications and insure that they are done correctly.

Combustion Stability↗

NASA NTRS2016

High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link

We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.

optical navigation↗

DOE OSTI2022

Tropical Cirrus in Global Storm-Resolving Models: 1. Role of Deep Convection

Pervasive cirrus clouds in the upper troposphere and tropical tropopause layer (TTL) influence the climate by altering the top-of-atmosphere radiation balance and stratospheric water vapor budget. These cirrus are often associated with deep convection, which global climate models must parameterize and struggle to accurately simulate. By comparing high-resolution global storm-resolving models from the Dynamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) intercomparison that explicitly simulate deep convection to satellite observations, we assess how well these models simulate deep convection, convectively generated cirrus, and deep convective injection of water into the TTL over representative tropical land and ocean regions. The DYAMOND models simulate deep convective precipitation, organization, and cloud structure fairly well over land and ocean regions, but with clear intermodel differences. All models produce frequent overshooting convection whose strongest updrafts humidify the TTL and are its main source of frozen water. Intermodel differences in cloud properties and convective injection exceed differences between land and ocean regions in each model. We argue that, with further improvements, global storm-resolving models can better represent tropical cirrus and deep convection in present and future climates than coarser-resolution climate models. To realize this potential, they must use available observations to perfect their ice microphysics and dynamical flow solvers.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2012

Design and fabrication of a superconducting magnet for an 18 GHz electron cyclotron resonance ion/photon source NFRI-ECRIPS

A superconducting magnet was designed and fabricated for an 18 GHz ECR ion/photon source, which will be installed at National Fusion Research Institute (NFRI) in South Korea. The magnetic system consists of a set of four superconducting coils for axial mirror field and 36 pieces of permanent magnets for hexapolar field. The superconducting coils with a cryocooler (1.5 W - 4.2 K) allow one to reach peak mirror fields of 2.2 T in the injection and those of 1.5 T in the extraction regions on the source axis, and the resultant hexapolar field gives 1.35 T on the plasma chamber wall. The unbalanced magnetic force between the coils and surrounding yoke has been minimized to 16 ton by a coil arrangement and their electrical connection, and then was successfully suspended by 12 strong thermal insulating supports made of large numbers of carbon fibers. In order to block radiative thermal losses, multilayer thermal insulations are covered on the coil windings as well as 40-K aluminum thermal shield. Also new schemes of quench detection and safety system (coil divisions, quench detection coils, and heaters) were employed. For impregnation of the windings a special epoxy has been selected and treated to have a higher breaking strength and a higher thermal conductivity, which enables the superconductors to be uniformly and rapidly cooled down or heated during a quench.

43 PARTICLE ACCELERATORS↗

NASA NTRS2006

Jupiter Icy Moons Orbiter interplanetary injection period analysis

This paper investigates the sensitivity of the planned Jupiter Icy Moons Orbiter mission to variations in interplanetary injection date, magnitude, and direction, starting in a low-Earth assembly orbit. These results are used to determine the frequency and number of injection opportunities from a processing assembly obit. It is shown that the use of a low-thrust propulsion system with a nuclear-electric power source would allow the interplanetary trajectory performance to be relatively insensitive to variations in injection conditions. This result yields many injection opportunities due to the long injection period and consecutive orbits with favorable geometry.

trajectory↗

DOE OSTI2017

Process-based approach for the detection of CO2 injectate leakage

The present invention includes a method for distinguishing between a natural source of deep gas and gas leaking from a CO.sub.2 storage reservoir at a near surface formation comprising: obtaining one or more surface or near surface geological samples; measuring a CO.sub.2, an O.sub.2, a CH.sub.4, and an N.sub.2 level from the surface or near surface geological sample; determining the water vapor content at or above the surface or near surface geological samples; normalizing the gas mixture of the CO.sub.2, the O.sub.2, the CH.sub.4, the N.sub.2 and the water vapor content to 100% by volume or 1 atmospheric total pressure; determining: a ratio of CO.sub.2 versus N.sub.2; and a ratio of CO.sub.2 to N.sub.2, wherein if the ratio is greater than that produced by a natural source of deep gas CO.sub.2 or deep gas methane oxidizing to CO.sub.2, the ratio is indicative of gas leaking from a CO.sub.2 storage reservoir.

58 GEOSCIENCES↗

DOE OSTI2013

The ReA electron-beam ion trap charge breeder for reacceleration of rare isotopes

ReA is a post-accelerator at the National Superconducting Cyclotron Laboratory at Michigan State University. ReA is designed to reaccelerate rare isotopes to energies of a few MeV/u following production by projectile fragmentation and thermalization in a gas cell. The facility consists of four main components: an electron-beam ion trap (EBIT) charge breeder, an achromatic charge-over-mass (Q/A) separator, a radio-frequency quadrupole accelerator, and a superconducting radio-frequency linear accelerator. The EBIT charge breeder was specifically designed to efficiently capture continuous beams of singly charged ions injected at low energy (<60 keV), charge breed in less than 50 ms, and extract highly charged ions to the Q/A separator for charge-state selection and reacceleration through the accelerator structures. The use of highly charged ions to reach high beam energies is a key aspect that makes ReA a compact and cost-efficient post-accelerator. The EBIT is characterized by a high-current electron gun, a long multi-electrode trap structure and a dual magnet to provide both the high electron-beam current density necessary for fast charge breeding of short-lived isotopes as well as the high capture probability of injected beams. This paper presents an overview and the status of the ReA EBIT, which has extracted for reacceleration tests stable {sup 20}Ne{sup 8+} ion beams produced from injected gas and more recently {sup 39}K{sup 16+} beams by injecting stable {sup 39,41}K{sup +} ions from an external ion source.

43 PARTICLE ACCELERATORS↗

DOE OSTI2019

Integration of Real-Time Geophysical Monitoring with In Situ Uranium Remedy Implementation

An in situ injection of polyphosphate amendment was conducted to address a uranium source zone for a plume near the Columbia River at the U.S. Department of Energy Hanford Site. This treatment was applied as an enhanced attenuation approach, targeting uranium in a periodically wetted zone where groundwater inundates as the water table rises in response to the seasonal high river stage. Uranium within this zone is mobilized into the groundwater at the high river stage, resulting in a persistent groundwater plume. The polyphosphate amendment creates precipitates that decrease uranium mobility so that the amount of uranium flushed into groundwater when the zone is periodically wetted is significantly decreased. With a reduced flux of uranium into the plume, the plume concentrations are expected to decrease over time. During injection, real-time geophysical monitoring was applied to provide hourly images of injected-fluid distribution. The real-time autonomous data collection, processing, and reporting enabled the electrical resistivity tomography images to provide operational feedback during injection. These data were used in conjunction with operational information (e.g., flow rate, pressures) and subsurface data from 24 monitoring wells placed within and downgradient of the treatment area (e.g., water level and specific conductance probes, uranium concentration, phosphate concentration) to assess overall performance of the treatment.

Johnson, Timothy C.↗

DOE OSTI2019

Integration of Real-Time Geophysical Monitoring with In Situ Uranium Remedy Implementation - 19094

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2023

Multiwell Fiber Optic Sensing Reveals Effects of CO2 Flow on Triggered Seismicity

Induced seismicity is one of the main risks for gigaton-scale geological storage of carbon dioxide (⁠CO 2 ⁠). Thus, passive seismic monitoring is often recommended as a necessary component of the monitoring systems for CO 2 storage projects, with a particular forcus on risk mitigation. We present the first field study, CO2CRC Otway Project Stage 3 (Victoria, Australia), where distributed acoustic sensing (DAS) enabled high-precision tracking of the induced seismicity triggered by a small CO 2 injection and also informed the reservoir models. In 610 days of passive seismic monitoring of the Stage 3 injection, we detected 17 microseismic events (maximum moment magnitude Mw 0.1) using five deep boreholes equipped with enhanced-sensitivity optical fiber. The DAS array has sensitivity sufficient for detection and location of induced events with M w ~ ₋2 in a monitoring borehole located up to 1500 m away. Thanks to the dense spatial sampling by the DAS, we were able to estimate the focal mechanisms for events with M w > ₋1.5; although the monitoring boreholes provided very limited angular coverage. The main cluster of the events has the same location and source mechanism as the one triggered by the previous CO 2 injection at the Otway Project site, Stage 2C. Surprizingly, the Stage 2C and Stage 3 events closely followed the actual movement of the CO 2 saturation plume front (not the pressure front), as observed using controlled-source reflection seismic images. The nature of the plume-fault interaction remains unclear, but some alteration of the fault gouge by CO 2 might be responsible for the faults’ reactivation by the pressure perturbation. Importantly, the seismogenic fault could not be identified in the seismic images and was only revealed by DAS observations, which also demonstrated the signature of fluid–rock interaction, that may control the CO 2 flow.

58 GEOSCIENCES↗

DOE OSTI2019

The nature and source of solar magnetic phenomena

The heliosphere appears to be powered by coaxial helicity injection from a negative helicity injector in the northern hemisphere and a positive one in the southern hemisphere. The injector magnetic flux for both is the measured solar polar magnetic flux, and the injector voltage is generated by a simple dynamo effect due to the differential rotation of the solar surface with the polar magnetic flux. The dynamo current is estimated from the solar motion that it causes. This current also appears to sustain a thin, shallow global magnetic structure over most of the solar surface that has the form of a 1D minimum energy state. The current channel appears to be destroyed and reformed every 11 years. The currents and magnetic fields reverse in this solar cycle. A brief discussion of surface phenomena observed during this cycle is given. Plasma self-organization is briefly discussed and used in this analysis of solar data. The magnetic phenomena discussed include torsional oscillations, the heat source for the chromosphere and the corona, filaments, meridional flow, the solar cycle, sunspots, CMEs, and flares.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2020

Observation of persistent species temperature separation in inertial confinement fusion mixtures

The injection and mixing of contaminant mass into the fuel in inertial confinement fusion (ICF) implosions is a primary factor preventing ignition. ICF experiments have recently achieved an alpha-heating regime, in which fusion self-heating is the dominant source of yield, by reducing the susceptibility of implosions to instabilities that inject this mass. We report the results of unique separated reactants implosion experiments studying pre-mixed contaminant as well as detailed high-resolution three-dimensional simulations that are in good agreement with experiments. At conditions relevant to mixing regions in high-yield implosions, we observe persistent chunks of contaminant that do not achieve thermal equilibrium with the fuel throughout the burn phase. The assumption of thermal equilibrium is made in nearly all computational ICF modeling and methods used to infer levels of contaminant from experiments. We estimate that these methods may underestimate the amount of contaminant by a factor of two or more.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRS2025

Efficient GPU-Accelerated MultiSource Global Fit Pipeline for LISA Data Analysis

The large-scale analysis task of deciphering gravitational-wave signals in the LISA data stream will be difficult, requiring a large amount of computational resources and extensive development of computational methods. Its high dimensionality, multiple model types, and complicated noise profile require a global fit to all parameters and input models simultaneously. In this work, we detail our global fit algorithm, called “Erebor,” designed to accomplish this challenging task. It is capable of analyzing current state-of-the-art datasets and then growing into the future as more pieces of the pipeline are completed and added. We describe our pipeline strategy, the algorithmic setup, and the results from our analysis of the LDC2A Sangria dataset, which contains massive black hole binaries, compact galactic binaries, and a parametrized noise spectrum whose parameters are unknown to the user. The Erebor algorithm includes three unique and very useful contributions: GPU acceleration for enhanced computational efficiency; ensemble Markov Chain Monte Carlo (MCMC) sampling with multiple MCMC walkers per temperature for better mixing and parallelized sample creation; and special online updates to reversible-jump (or transdimensional) sampling distributions to ensure sampler mixing and accurate initial estimates for detectable sources in the data.We recover posterior distributions for all 15 (6) of the injected massive black hole binaries (MBHB) in the LDC2A training (hidden) dataset. We catalog ∼12000 galactic binaries (∼8000 as high confidence detections) for both the training and hidden datasets. All of the sources and their posterior distributions are provided in publicly available catalogs.

LISA↗

DOE OSTI2015

Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this study, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz.

43 PARTICLE ACCELERATORS↗

DOE OSTI2021

On the Phase Grouping Mechanism for a Magnetron Coherent Oscillation

CW magnetrons, developed for industrial heaters, but driven by an injection-locking signal were suggested to power Superconducting RF (SRF) cavities due to higher efficiency and lower cost of generated RF power per Watt than traditionally used RF sources (klystrons, IOTs, solid-state amplifiers). When the magnetrons are intended to feed Room Temperature (RT) cavities, the injected phase or frequency locking signal may provide required phase or frequency stability of the accelerating field. However, when the magnetron RF sources are intended to feed high Q-factor SRF cavities, the sources must be controlled in phase and power in a wide bandwidth to compensate parasitic phase and amplitude modulations caused by microphonics. In dependence on parameters of magnetron and the injection-locking signal one can choose regime most suitable for feeding SRF cavities, enabling magnetron almost coherent oscillation at the wide bandwidth of control. A novel approach considering magnetrons as quasi-coherent or coherent RF generators enables choosing the tube parameters and operation most suitable for various SRF accelerators.

43 PARTICLE ACCELERATORS↗