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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 1,657 records · Page 92
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Advanced Rotordynamic Nonlinear Transient Simulation

Advanced rotordynamic nonlinear transient-simulation program, TRANSIM, developed to predict response of high-performance rotating machinery to variety of forcing functions. Works by modal superposition of rotor and casing subsystems. Transient response of system calculated by numerical integration of equations of motion, performed in modal coordinates. Resulting data transformed back into physical coordinates as required to determine user-requested loads and accelerations as function of time. Used to analyze Space Shuttle main engine high-pressure fuel turbopump. TRANSIM written in FORTRAN 77.

Becht, D. G.↗
NASA NTRS1987

Nonlinear, relativistic Langmuir waves in astrophysical magnetospheres

Large amplitude, electrostatic plasma waves are relevant to physical processes occurring in the astrophysical magnetospheres wherein charged particles are accelerated to relativistic energies by strong waves emitted by pulsars, quasars, or radio galaxies. The nonlinear, relativistic theory of traveling Langmuir waves in a cold plasma is reviewed. The cases of streaming electron plasma, electronic plasma, and two-streams are discussed.

Chian, Abraham C.-L.↗
NASA NTRS2004

High-Altitude Particle Acceleration and Radiation in Pulsar Slot Gaps

We explore the pulsar slot gap (SG) electrodynamics up to very high altitudes, where for most relatively rapidly rotating pulsars both the standard small-angle approximation and the assumption that the magnetic field lines are ideal stream lines break down. We address the importance of the electrodynamic conditions at the SG boundaries and the occurrence of a steady-state drift of charged particles across the SG field lines at very high altitudes. These boundary conditions and the cross-field particle motion determine the asymptotic behavior of the scalar potential at all radii from the polar cap (PC) to near the light cylinder. As a result, we demonstrate that the steady-state accelerating electric field, E(sub ll), must approach a small and constant value at high altitude above the PC. This E(sub ll) is capable of maintaining electrons moving with high Lorentz factors (approx. a few x 10(exp 7)) and emitting curvature gamma-ray photons up to nearly the light cylinder. By numerical simulations, we show that primary electrons accelerating from the PC surface to high altitude in the SG along the outer edge of the open field region will form caustic emission patterns on the trailing dipole field lines. Acceleration and emission in such an extended SG may form the physical basis of a model that can successfully reproduce some pulsar high-energy light curves.

Muslimov, Alex G.↗
NASA NTRS2011

Why Density Dependent Propulsion?

In 2004 Khoury and Weltman produced a density dependent cosmology theory they call the Chameleon, as at its nature, it is hidden within known physics. The Chameleon theory has implications to dark matter/energy with universe acceleration properties, which implies a new force mechanism with ties to the far and local density environment. In this paper, the Chameleon Density Model is discussed in terms of propulsion toward new propellant-less engineering methods.

Robertson, Glen A.↗
NASA NTRS2012

Fermi LAT Observations of the Crab Nebula During the Exceptional April 2011 Outburst

The Crab Nebula, formerly thought to be steady in gamma rays, shows unexpected and occasionally dramatic variability in high-energy gamma rays. The Large Area Telescope (LAT) on Fermi recorded several strong outbursts, including dedicated pointed observations of the brightest yet seen, a spectacular flare in April 2011. These observations provide a particularly detailed look at the temporal and spectral characteristics of the nebula during the flare. The LAT data show an additional component in the spectral energy distribution that peaks at a maximum of $375\pm26~\mathrm{MeV}$. In the probable scenario that this component is synchrotron emission, the electrons are accelerated to extreme energies that are difficult to reconcile with the very rapid change in flux and the expectation for acceleration processes and conditions occurring within the pulsar wind nebula. The physical location and mechanism driving the flares remains undetermined despite observations across the spectrum made by a variety of instruments including the Hubble Space Telescope, the Chandra X-ray Observatory, and the Very Large Array. I will present timing and spectral studies of the high-energy gamma-ray data, discuss implications for the origin of the flares, and highlight preparations for the next major flare.

Hays, Elizabeth↗
NASA NTRS2018

The Fusion Driven Rocket: Nuclear Propulsion through Direct Conversion of Fusion Energy

The future of manned space exploration and development of space depends critically on the creation of a dramatically more efficient propulsion architecture for in-space transportation. A very persuasive reason for investigating the applicability of nuclear power in rockets is the vast energy density gain of nuclear fuel when compared to chemical combustion energy. The Fusion Driven rocket (FDR) represents a revolutionary approach to fusion propulsion where the power source releases its energy directly into the propellant, not requiring conversion to electricity. It employs a solid lithium propellant that requires no significant tankage mass. The propellant is rapidly heated and accelerated to high exhaust velocity (> 30 km/s), while having no substantial physical interaction with the spacecraft thereby avoiding damage to the rocket and limiting both the thermal heat load and radiator mass. The key to achieving this stems from research at MSNW and the UW on the magnetically driven implosion of metal foils onto a magnetized plasma target to obtain fusion conditions. A logical extension of this work leads to a method that utilizes these metal shells (or liners) to not only achieve fusion conditions, but to serve as the propellant as well. Several low-mass, magnetically driven metal liners are inductively driven to converge radially and axially and form a thick blanket surrounding the target plasmoid and compress the plasmoid to fusion conditions. Virtually all of the radiant, neutron and particle energy from the plasma is absorbed by the encapsulating, thick metal blanket thereby isolating the spacecraft from the fusion. This energy, in addition to the intense Ohmic heating at peak magnetic field compression, is adequate to vaporize and ionize the metal blanket. The expansion of this hot, ionized metal propellant through a magnetically insulated nozzle produces high thrust at the optimal Isp. The energy from the fusion process, along with the waste heat, is thus utilized at very high efficiency. The basic scheme for FDR is illustrated and described in the report (see Fig. 2) The two most critical issues in meeting challenges introduced employing magneto-inertial fusion as the power source is driver efficiency and “stand-off” – the ability to isolate and protect fusion and thruster from the resultant fusion energy. By employing metal shells for compression, it is possible to produce the desired convergent motion inductively by inserting the metal sheets along the inner surface of cylindrical or conically tapered coils. Both stand-off and energy efficiency issues are solved by this arrangement. 3 This two year effort focused on achieving three key criteria for the Fusion Driven Rocket to move forward for technological development: (1) the physics of the FDR must be fully understood and validated, (2) the design and technology development for the FDR required for its implementation in space must be fully characterized, and (3) an in-depth analysis of the rocket design and spacecraft integration as well as mission architectures enabled by the FDR need to be performed. A subscale, laboratory liner compression test facility was assembled at the University of Washington Plasma Dynamics Laboratory with sufficient liner kinetic energy (~ 0.5 MJ) to reach conditions required for fusion breakeven conditions. Detailed experimental studies of the dynamic behavior of the driven liners as well as liner convergence and magnetic compression were performed. The development of both the 1D liner dynamics code and the full 3D ANSYS® liner calculations was achieved. The characterization of both the FDR and spacecraft as well as a design architecture analysis was conducted that included an examination of a wide range of mission architectures and destinations for which this fusion propulsion system would be enabling or critical. In particular a rapid, single launch manned Mars mission was developed.

Energy↗
DOE OSTI2021

Alvin Tollestrup (1924-2020): A Life in Science

Alvin Tollestrup was a physicist and engineer of uncommon insight, intuition, and ingenuity who was revered in life for his essential leadership in the development of superconducting magnets for high-energy accelerators. He exhibited a matchless mastery of what he called freshman physics — though his mastery hardly ended there — and an uncanny gift for joining careful measurements with transparent calculations to reveal the essence of a subject. To watch Alvin at work was to learn how a true scientist formulates and solves a problem. He had other gifts: a nose for significant problems in both science and technology, the ability to draw talented people to an important cause, and a mentor's instinct for spotting gifted junior colleagues and helping them to mature as engineers and scientists. He was also good company! Alvin brought his keen vision about what constitutes important science, along with powerful ambition for the institution and for fundamental science, to considerat ions about Fermilab's future. His questions were uniformly probing, his opinions unfailingly interesting, and his appetite for work consistently inspiring. Among Alvin's many contributions to experimental particle physics — in a career that spanned seven decades — the rich achievements of the Collider Detector at Fermilab Collaboration, of which he was a founder and an enduring leader, stand out. The discovery of the top quark in 1995 earned worldwide acclaim. He reaped individual accolades as well, including election to the National Academy of Sciences. The National Medal of Technology, conferred in 1989, recognized Alvin’s leading role in developing superconducting magnets for Fermilab's Tevatron. Universities Research Association created the Tollestrup Award for Postdoctoral Research, commemorating Alvin's avuncular support for young scientists. This volume celebrates Alvin Tollestrup’s career and the rich, fulfilling life he led beyond the laboratory. Contributions from colleagues and family illuminate many facets of this remarka! ble figure. May old friends savor the memory of the Alvin they knew, while discovering less-familiar parts of his history; and may readers who did not have the opportunity to know Alvin firsthand find inspiration in his exemplary life in science.

Palmer, Mark↗
DOE OSTI2022

Search For Excited Cascade Hypersons (¿*-) Using the CLAS12 Spectrometer at Jefferson Laboratory

The number of experimentally observed doubly strange Cascade states to date is far fewer than has been predicted theoretically. The CLAS12 Very Strange physics program (E12- 11-005A) at the Thomas Jefferson National Accelerator Facility aims to study the electroproduction of these states using the newly upgraded CEBAF Large Acceptance Spectrometer for 12 GeV (CLAS12) in experimental Hall B. In this project, the reaction ep ! e0K+K+??? ! e0K+K+K?(?=?0) is studied using CLAS12 Run Group A (RG-A) data sets taken by impinging electron beams of 10:2 and 10:6 GeV energies on an LH2 target. Scattered electrons are detected with either the Forward Detector (FD), covering a polar angle range of 5? to 35? to study electroproduction, or with the Forward Tagger (FT), covering a polar angle range of 2:5? to 4:5?, to study quasi-real photoproduction. The CLAS12 detector with nearly a 4? solid angle coverage is used to detect scattered electrons and charged kaons in the ?final state. ?=?0 hyperons are reconstructed using the missing mass technique to explore intermediate doubly-strange hyperons (???) that decay to K? and ?=?0. No statistically significant ??? states other than the ???(1530) were found in the missing mass spectra based on the currently available statistics in the CLAS12-FD acceptance only. A maximum log-likelihood method is implemented to determine the statistical significance and the upper limits on the ???(1820) electroproduction cross section by constructing 95% confidence level boundaries on the ???(1820) yields. Additional research was conducted to investigate the upper limit electroproduction cross section of the reaction ep ! e0K+K+??? ! e0K+K+K?(?=?0) as a function of the electroproduced ??? mass and the differential cross section ( d?dMM(e0K+K+) ) as a function of missing mass MM(e0K+K+) for electroproduction and quasi-real photoproduction processes.

Khanal, Achyut↗
DOE OSTI2024

Status of the Ce+BAF project

Jefferson Lab is proposing to add positron beams to the 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF). A team of accelerator and nuclear scientists was formed in 2018 to develop the physics case as well as a concept for the generation, production and delivery of Continuous (CW) polarized positron beams to the experimental halls, up to the full 12 GeV. A layout of the proposed concept will be shown. We will report on the ongoing efforts in the positron generation and capture, target design, beam transport and expected properties of the e+ beam on the experimental targets at 12GeV. This project is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177

Roblin, Yves↗
DOE OSTI2025

PID-Regulated Heating System for PIP-II Reference Line

The Proton Improvement Project-2 centers on building a new superconducting linear particle accelerator (Linac) at Fermilab. At the heart of the accelerator is the reference line, a critical system that defines the ideal path for the particle beam as it passes through magnets, RF cavities, and other beamline elements. Temperature stability is crucial for the reliable operation of RF components, such as mixers and filters. Fluctuations affect key performance parameters like conversion loss, isolation, and linearity. To mitigate any drift caused by ambient temperature changes, a heating plate assembly is utilized to maintain key components at a controlled temperature of 40°C. The system utilizes an aluminum 36”x36”x0.5” heat plate powered by a MOSFET-based control circuit, delivering approximately 460 W of thermal energy through a resistor array. Real-time temperature feedback is provided by a PT100 Resistance Temperature Detector (RTD), which interfaces with a Proportional–Integral–Derivative (PID) control algorithm to maintain closed-loop temperature regulation. The control signal actively modulates the gate voltage of an N channel MOSFET, dynamically adjusting power delivery in response to deviations from the temperature setpoint. Simulations and LTspice models validate the functionality and responsiveness of the circuit under varying conditions. The prototype has successfully demonstrated stable thermal control, paving the way for integration into the PIP-II infrastructure. The final design will feature an expanded resistor array, as well as communication with a PLC for continuous data acquisition and diagnostics. This work directly supports Fermilab’s broader mission by contributing to the stability and reliability of core accelerator systems, enhancing the precision of particle beam delivery for future physics experiments.

Mosher, Alexander [Fermilab]↗
DOE OSTI2026

Scalings of laser-driven MeV electron sources with relativistic multi-picosecond laser pulses

We investigate the generation of MeV electrons in relativistic multi-picosecond laser–solid interactions, using two-dimensional particle-in-cell simulations. Scanning a parameter space of intensities from 10 18 to 10 20 W/cm 2 and pulse durations between 100 fs and 10 ps, we discuss scalings of the effective hot electron temperature and MeV electron dose relevant to applications, as well as the direct laser acceleration mechanism that drives electrons to energies much higher than the ponderomotive potential of the laser pulse.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Accelerating the discovery of low-energy structure configurations: A computational approach that integrates first-principles calculations, Monte Carlo sampling, and Machine Learning

Finding Minimum Energy Configurations (MECs) is essential in fields such as physics, chemistry, and materials science, as they represent the most stable states of the systems. In particular, identifying such MECs in multi-component alloys considered candidate PFMs is key because it determines the most stable arrangement of atoms within the alloy, directly influencing its phase stability, structural integrity, and thermo-mechanical properties. However, since the search space grows exponentially with the number of atoms considered, obtaining such MECs using computationally expensive first-principles DFT calculations often results in a cumbersome task. To escape the above compromise between physical fidelity and computational efficiency, we have developed a novel physics-based data-driven approach that combines Monte Carlo sampling, first-principles DFT calculations, and Machine Learning to accelerate the discovery of MECs in multi-component alloys. More specifically, we have leveraged well-established Cluster Expansion (CE) techniques with Local Outlier Factor models to establish strategies that enhance the reliability of the CE method. In this work, we demonstrated the capabilities of the proposed approach for the particular case of a tungsten-based quaternary high-entropy alloy. However, the method is applicable to other types of alloys and enables a wide range of applications.

36 MATERIALS SCIENCE↗
NASA NTRS1978

Ultrahigh-energy neutrino astronomy

High-energy cosmic-ray interactions can produce neutrinos. The neutrino fluxes are calculated over a range of energies. The sources considered (and their ranges of importance) are cosmic-ray interactions in earth's atmosphere (neutrino energies less than 10,000 GeV), cosmic-ray interactions with ambient hydrogen in galaxies (neutrino energies between 10,000 and 1 million GeV), regions of cosmic-ray acceleration - e.g., pulsars - and cosmic-ray interactions with the microwave background radiation (neutrino energies greater than 100 million GeV). In addition, estimates of the flux from compact sources, such as active galaxies, are made. These flux levels, calculated conservatively, may be high enough for practical detection with a 1-cu km seawater detector; i.e., count rates greater than 1 per day. Such observations would provide information mainly about high-energy physics, but also (over long times) about cosmic-ray spectra, composition, and acceleration, as well as supernova and galactic-nucleus explosions.

Margolis, S. H.↗
DOE OSTI2021

Electro-optic sampling beam position monitor for relativistic electron beams

Here, an electro-optic sampling beam position monitor for installation at the SLAC National Accelerator Laboratory FACET-II facility is described. Simulations of the detector signal were performed using realistic electron beam current profiles, demonstrating that this single-shot, non-destructive, compact detector is capable of resolving the relative transverse offset and longitudinal separation of an ultra-relativistic, two-bunch electron beam to order 1 μm and 10 fs, respectively. A design study was performed to optimize the detector’s response to the ultra-relativistic two-bunch electron beam utilized in plasma wakefield accelerator experiments. In addition, the expected sensitivity to beam tilt is studied for typical electron beams used in free electron lasers.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1978

The US/USSR Biological Satellite Program: COSMOS 936 Mission Overview

On August 3, 1977, the Soviet Union launched Cosmos 936, an unmanned spacecraft carrying biology and physics experiments from 9 countries, including both the Soviet Union and U.S. The launch marked the second time the Soviet Union has flown U.S. experiments aboard one of its spacecraft, the first being Cosmos 782 launched Nov. 25, 1975, which remained in orbit 19.5 days. Aboard Cosmos 936 were: 30 young male Wistar SPF rats, 20 of which was exposed to hypogravity during flight while the remainder were subjected to a l x g acceleration by continuous configuration; 2) experiments with plants and fruit flies; 3) radiation physics experiments; and 4) a heat convection experiment. After 18.5 days in orbit, the spacecraft landed in central Asia where a Soviet recovery team began experiment operations, including animal autopsies, within 4.5 hr of landing. Half of the animals were autopsied at the recovery site and the remainder returned to Moscow and allowed to readapt to terrestrial gravity for 25 days after which they, too, were autopsied. Specimens for U.S. were initially prepared at the recovery site or Soviet laboratories and transferred to U.S. laboratories for complete analyses. An overview of the mission focusing on preflight, on-orbit, and postflight activities pertinent to the seven U.S. experiments aboard Cosmos 936 will be presented.

Souza, K. A.↗
DOE OSTI2022

Flux Creep in a Bi-2212 Rutherford Cable for Particle Accelerator Applications

Bi-2212 superconducting cables are being considered for use in the high field magnets needed for the next generation of particle accelerators. Magnetization in these cables and the decay of that magnetization lead to field error and field-error drift, respectively, which need to be compensated. To study this, a segment of the winding pack was extracted from a racetrack coil made from Bi-2212 Rutherford cable. Using a Hall probe measurement technique, we measured the response of the cable's magnetization and its magnetization decay to changes in the applied magnetic field. The effect of adjustments to the cycling of the magnetic field was studied, intended to simulate the preinjection cycles of an accelerator magnet. Three M vs. H loops were constructed by sweeping the magnetic field applied to the sample from 0 to 2.5 T, then to a preinjection field 'x' (where x = 0, 0.25, 0.75 T), and finally up to 1 T. The applied field was then held at 1 T for 1500 s, and the magnetization decay was measured. Finally, the decay was found to vary from 8% to 14% after 1500 s, depending on the preinjection field cycle.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Emergency vacuum repairs in an aging accelerator: Case studies and lessons learned

Jefferson Lab operates the CEBAF electron accelerator at energies to 12 GeV for the Department of Energy Nuclear Physics program. The CEBAF injector beamline was designed and built in the early 1990s. Although we’ve upgraded and replaced many of the vacuum systems, we still have unique original components installed which operate daily. Over the past 3 years, we have had several vacuum leaks in ageing components leading to emergency repairs on a tight timeline. I’ll discuss the nature of these vacuum component failures, the difficulties in repair due to their ages, the lessons we’ve learned, and how we hope to minimize similar failures going forward.

Stutzman, Marcy [Thomas Jefferson National Acceler↗
DOE OSTI2022

Optimization of Superconducting Linac for Proton Improvement Plan-II (PIP-II)

PIP-II is an essential upgrade of the Fermilab complex that will enable the worlds most intense high-energy beam of neutrinos for the international Deep Underground Neutrino Experiment at LBNF and support a broad physics program at Fermilab. Ultimately, the PIP-II superconducting linac will be capable of accelerating the $H-$ CW beam to 800 MeV with an average power of 1.6 MW. To operate the linac with such high power, beam losses and beam emittance growth must be tightly controlled. In this paper, we present the results of global optimization of the Linac options towards a robust and efficient physics design for the superconducting section of the PIP-II linac. We also investigate the impact of the nonlinear field of the dipole correctors on the beam quality and derive the requirement on the field quality using statistical analysis. Finally, we assess the need to correct the quadrupole focusing produced by Half Wave, and Single Spoke accelerating cavities. We assess the feasibility of controlling the beam coupling in the machine by changing the polarity of the field of linac focusing solenoids

43 PARTICLE ACCELERATORS↗