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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Involving the new generations in particle physics endeavours

Since 1984 INFN and University of Pisa scientists performing experiments at Fermilab have been running a two-month summer training program for Italian students at the lab. In 1984 the program involved only a few physics students from the University of Pisa, but it was later extended to other INFN groups and to engineering students. Since 2004 the program has been supported in part by the US Department of Energy (DOE) in the frame of an exchange agreement with INFN and has been run by the Cultural Association of Italians at Fermilab (CAIF). In 2007 the Sant’Anna School of Advanced Studies (Pisa) established an agreement with Fermilab to share the cost of four engineering students each year. In the almost 40 years of its history, the program has hosted at Fermilab approximately 550 Italian students from more than 20 Italian universities and from some non-Italian universities. In addition, in the years 2010-2019, with the support of the Italian National Institute of Astrophyics (INAF), the Italian Space Agency (ASI), and CAIF, 30 students were hosted in other US laboratories and universities. The Fermilab training programs spanned from data analysis to design and construction of particle detectors and accelerator components, R/D on superconductive elements, theory of accelerators, and analysis of astrophysical data. At the other US laboratories the offered training was on Space Science. In 2015 the University of Pisa endorsed the program as one of its own Summer Schools. The interns are enrolled as Pisa students for the duration of the internship. They are required to write summary reports published in the Fermilab and University of Pisa web pages. Upon positive evaluation by a University board, students are acknowledged 6 ECTS credits. The entire program is expected to expand further under CAIF management. An agreement has been signed between ASI and CAIF, for ASI to support yearly three two-months fellowships in US space science. In the following we inform on student recruiting, training programs, and final evaluation

Barzi, E.↗
NASA NTRS2010

279 - Xanes Studies on UV-Irradiated Interstellar Ice Analogs: A Comparison to STARDUST Samples

We present C-, N-, and O-XANES (X-ray Absorption Near-Edge Spectroscopy) results of organic residues produced in the laboratory from the UV irradiation of astrophysical ice analogs containing H20, CO, CH30H, NH31 in order to mimic processes that may occur in cold icy bodies of the outer Solar System, particularly in comets, Such analyses showed that laboratory-formed organic residues mainly consist of a solid phase and an oily phase. C-XANES analysis of the solid phase suggests a rich distribution of organic functionalities, among which carbonyl groups, C=C bonds, and alcohols are present. Results from N-XANES indicate the possible presence of amide, amine, and nitrile groups, The O-XANES spectra confirmed the a-bearing groups, These results are compared with the XANES spectra obtained from STARDUST cometary samples,

Milam, Stefanie N.↗
DOE OSTI2026

RTN-108: Impact of CCD Non-Flatness In Rubin LSSTCam PSF Measurements and Modeling

Modeling the point-spread function (PSF) precisely is essential for achieving optimal science with the NSF-DOE Vera C. Rubin Observatory. In this work, we inspect a PSF residual pattern present in both Rubin's LSSTComCam and LSSTCam observations. We show that it is likely due to effects from CCD non-flatness and explain the physical mechanism by which height offsets could influence the PSF. Finally, we demonstrate that incorporating height information into PSF modeling greatly reduces the observed residual.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1996

Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas

Charge transfer at electron-volt energies between multiply charged atomic ions and neutral atoms and molecules is of considerable importance in astrophysics, plasma physics, and in particular, fusion plasmas. In the year covered by this report, several major tasks were completed. These include: (1) the re-calibration of the ion gauge to measure the absolute particle densities of H2, He, N2, and CO for our current measurements; (2) the analysis of data for charge transfer reactions of N(exp 2 plus) ion and He, H2, N2, and CO; (3) measurement and data analysis of the charge transfer reaction of (Fe(exp 2 plus) ion and H2; (4) charge transfer measurement of Fe(exp 2 plus) ion and H2; and (5) redesign and modification of the ion detection and data acquisition system for the low energy beam facility (reflection time of flight mass spectrometer) dedicated to the study of state select charge transfer.

Kwong, Victor H. S.↗
NASA NTRS1997

Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas

The laser ablation/ion storage facility at the UNLV Physics Department is dedicated to the study of atomic processes in low temperature plasmas. Our current program is directed to the study of charge transfer of multiply charged ions and neutrals that are of importance to astrophysics at energies less than 1 eV (about 10(exp 4) K). Specifically, we measure the charge transfer rate coefficient of ions such as N(2+), Si(3+), Si(3+), with helium and Fe(2+) with molecular and atomic hydrogen. All these ions are found in a variety of astrophysical plasmas. Their electron transfer reactions with neutral atoms can affect the ionization equilibrium of the plasma.

Kwong, Victor H. S.↗
DOE OSTI2026

RTN-124: Photometric Redshifts for the Vera C. Rubin Observatory Data Preview

We present the photometric redshifts (photo-z) inferred using algorithms implemented in the Redshift Assessment Infrastructure Layers (RAIL) for the NSF-DOE Vera C. Rubin Observatory Data Preview 2 (DP2). We produce a compilation of reference redshift catalog using spectroscopic, grism and many band photometric redshift dataset hosted on the LIneA Photo-z Server. We curate training and testing set for assessing the scientific and technical performance of Rubin photo-z. The algorithm applied to the object catalog are FlexZBoost, BPZ, kNN, GPz, DNF and TPz; with a combination of 6-band and 4-band photo-z depending on availability of u and y photometry. The redshift point estimates and uncertainty estimation in tabular format through the Large Survey DataBase (LSDB).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Indirect Measurement of the 23 Na(p, γ) 24 Mg Direct Capture Reaction Rate via ( 3 He,d) Spectroscopy

The cross section of the $^{23}\text{Na}(p,γ)^{24}\text{Mg}$ reaction is dominated by direct capture at low energies relevant for stellar burning. Such cross sections can be constrained using spectroscopic factors($C^2S$) or asymptotic normalization coefficients(ANCs) from transfer reactions. In this work, the $^{23}\text{Na}(^3\text{He},d)^{24}\text{Mg}$ reaction was measured at $E_{lab}=21$ MeV to extract spectroscopic factors for $^{24}\text{Mg}$ states with excitation energies in $E_x=7 - 12$ MeV using the Enge split-pole spectrograph at the Triangle Universities Nuclear Laboratory. A new non-resonant astrophysical S factor and the direct capture reaction rate for the $^{23}\text{Na}(p,γ)$ reaction are calculated and presented based on this measurement. The new rate at $T<0.04$ GK is 43$\%$ smaller than in previous studies. Rigorous treatments of uncertainties are presented using a Bayesian Markov Chain Monte Carlo (MCMC) method. Finally, sources of uncertainties for computing the direct capture cross section are also discussed in detail.

electromagnetic moments↗
DOE OSTI2021

Time-resolved turbulent dynamo in a laser plasma

Understanding magnetic-field generation and amplification in turbulent plasma is essential to account for observations of magnetic fields in the universe. A theoretical framework attributing the origin and sustainment of these fields to the so-called fluctuation dynamo was recently validated by experiments on laser facilities in low-magnetic-Prandtl-number plasmas (Pm < 1). However, the same framework proposes that the fluctuation dynamo should operate differently when Pm ≳ 1, the regime relevant to many astrophysical environments such as the intracluster medium of galaxy clusters. This paper reports an experiment that creates a laboratory Pm ≳ 1 plasma dynamo. We provide a time-resolved characterization of the plasma’s evolution, measuring temperatures, densities, flow velocities, and magnetic fields, which allows us to explore various stages of the fluctuation dynamo’s operation on seed magnetic fields generated by the action of the Biermann-battery mechanism during the initial drive-laser target interaction. The magnetic energy in structures with characteristic scales close to the driving scale of the stochastic motions is found to increase by almost three orders of magnitude and saturate dynamically. It is shown that the initial growth of these fields occurs at a much greater rate than the turnover rate of the driving-scale stochastic motions. Here, our results point to the possibility that plasma turbulence produced by strong shear can generate fields more efficiently at the driving scale than anticipated by idealized magnetohydrodynamics (MHD) simulations of the nonhelical fluctuation dynamo; this finding could help explain the large-scale fields inferred from observations of astrophysical systems.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1987

Approximate penetration factors for nuclear reactions of astrophysical interest

The ranges of validity of approximations of P(l), the penetration factor which appears in the parameterization of nuclear-reaction cross sections at low energies and is employed in the extrapolation of laboratory data to even lower energies of astrophysical interest, are investigated analytically. Consideration is given to the WKB approximation, P(l) at the energy of the total barrier, approximations derived from the asymptotic expansion of G(l) for large eta, approximations for small values of the parameter x, applications of P(l) to nuclear reactions, and the dependence of P(l) on channel radius. Numerical results are presented in tables and graphs, and parameter ranges where the danger of serious errors is high are identified.

Humblet, J.↗
DOE OSTI2026

Plasma flow generation and particle acceleration from expanding magnetic bubbles

Impulsive plasma dynamics in the laboratory are often driven by rising electric currents, yet their quantitative plasma response has not been well established. By means of fully kinetic particle-in-cell simulations and laser-driven capacitor-coil experiments, we show that a rising current expels plasma, forming an expanding magnetic bubble and accelerating particles. The expansion front velocity scales with the Alfvén speed determined by the magnetic field at its inner edge and the plasma density at its outer edge. This mechanism establishes impulsive current drive as a fundamental way that generates plasma flows and accelerates particles in laboratory plasmas, with potential relevance to astrophysics.

Zhang, Yang [Princeton University, NJ (United Stat↗
DOE OSTI2026

Production of Heavy α -Elements and 44 Ti in Cas A: Comparison to Abundances from 1D Core-collapse Supernova Models and Evidence for Carbon–Oxygen Shell Mergers

The merger between the carbon (C) and oxygen (O) shells hours to days before the collapse of a massive star significantly changes its nucleosynthesis, which is reflected in the elemental ratios observed in supernova remnants (SNRs). We present a nucleosynthesis study of 44 Ti production in core-collapse supernovae (CCSNe), highlighting large silicon (Si), sulfur (S), calcium (Ca), and, most importantly, argon (Ar) to neon (Ne) ratios as diagnostics for carbon–oxygen (C–O) shell mergers. We compare yields from eight different sets of CCSNe models to observations of Cassiopeia A (Cas A), and show that C–O shell mergers are consistently the models that best match X-ray and infrared observations. These models produce high Ar/Ne ratios (≳0.1), due to 20 Ne depletion and production of 36 Ar and 38 Ar, while lower ratios are obtained from nonmerger cases. Based on the Ar/Ne diagnostic, we compare the range of expected 44 Ti produced by C–O shell mergers, which is up to ∼20%–30% of the overall 44 Ti, but expected to be located outside the reverse shock. Based on the sets of models considered, the photon flux expected from the 44 Ti synthesized in the C–O shell merger in Cas A is below the NuSTAR and COSI detection limits, compatible with current limits locating most of the 44 Ti interior to the reverse shock, but might be detectable from proposed missions like ASCENT. Finally, for the SNR of 1987A, a dominant C–O merger origin of the observed 44 Ti is unlikely based on the observed redshift in its 44 Ti line.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1999

Interstellar Polycyclic Aromatic Compounds and Astrophysics

Polycyclic aromatic compounds (PACs), a class of organic molecules whose structures are characterized by the presence of two or more fused aromatic rings, have been the subject of astrophysical interest for nearly two decades. Large by interstellar standards (from as few as 20 to perhaps as many as several hundred atoms), it has been suggested that these species are among the most abundant interstellar molecules impacting a wide range of astrophysical phenomena including: the ubiquitous family of infrared emission bands observed in an ever-increasing assortment of astronomical objects; the subtle but rich array of discrete visible/near-infrared interstellar molecular absorption features known as the diffuse interstellar bands (DIBs); the broad near-infrared quasi-continuum observed in a number of nebulae known as excess red emission (ERE); the interstellar ultraviolet extinction curve and broad '2200 Angstrom bump'; the heating/cooling mechanisms of interstellar clouds. Nevertheless, until recently a lack of good-quality laboratory spectroscopic data on PACs under astrophysically relevant conditions (i.e. isolated, ionized molecules; ionized molecular clusters, etc.) has hindered critical evaluation and extension of this model

Hodgins, Douglas M.↗
DOE OSTI2023

Perspectives on relativistic electron–positron pair plasma experiments of astrophysical relevance using high-power lasers

The study of relativistic electron–positron pair plasmas is both of fundamental physics interest and important to understand the processes that shape the magnetic field dynamics, particle acceleration, and radiation emission in high-energy astrophysical environments. Although it is highly desirable to study relativistic pair plasmas in the laboratory, their generation and control constitutes a critical challenge. Significant experimental and theoretical progress has been made over recent years to explore the use of intense lasers to produce dense relativistic pair plasma in the laboratory and study the basic collective plasma processes associated with these systems. Important challenges remain in terms of improving the number of pairs, system size, and control over the charge neutrality required to establish laboratory platforms that can expand our understanding of relativistic pair plasma and help validate underlying models in conditions relevant to high-energy astrophysical phenomena. Furthermore, we highlight recent progress in this field, discuss the main challenges, and the exciting prospects for studying relativistic pair plasmas and astrophysics relevant instabilities in the laboratory in the near future.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

CMB-S4: Foreground-cleaning Pipeline Comparison for Measuring Primordial Gravitational Waves

We compare multiple foreground-cleaning pipelines for estimating the tensor-to-scalar ratio, r, using simulated maps of the planned CMB-S4 experiment within the context of the South Pole Deep Patch. To evaluate robustness, we analyze bias and uncertainty on r across various foreground suites using map-based simulations. The foreground-cleaning methods include: a parametric maximum likelihood approach applied to auto- and cross-power spectra between frequency maps; a map-based parametric maximum-likelihood method; and a harmonic-space internal linear combination using frequency maps. We summarize the conceptual basis of each method to highlight their similarities and differences. To better probe the impact of foreground residuals, we implement an iterative internal delensing step, leveraging a map-based pipeline to generate a lensing B-mode template from the large aperture telescope frequency maps. Our results show that the performance of the three approaches is comparable for simple and intermediate-complexity foregrounds, with σ(r) ranging from 3–5 ×10 −4 . However, biases at the 1σ–2σ level appear when analyzing more complex forms of foreground emission. By extending the baseline pipelines to marginalize over foreground residuals, we demonstrate that contamination can be reduced to within statistical uncertainties, albeit with a pipeline-dependent impact on σ(r), which translates to a detection significance between 2σ and 4σ for an input value of r = 0.003. These findings suggest varying levels of maturity among the tested pipelines, with the auto- and cross-spectra-based approach demonstrating the best stability and overall performance. Moreover, given the extremely low noise levels, mutual validation of independent foreground-cleaning pipelines is essential to ensure the robustness of any potential detection.

astronomy data analysis↗
DOE OSTI2025

DMTN-101: Verifying LSST Calibration Data Products

A description of plans for verifying LSST's Calibration Data Products. This document covers our approach to verification element LVV-57, addressing requirement DMS-REQ-0130.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

White Paper On Nuclear Structure Reactions and Astrophysics

In preparation for the 2023 NSAC Long Range Plan (LRP), the DNP Town Meeting on Nuclear Structure, Reactions, and Astrophysics was held at Argonne National Laboratory (ANL) on Nov 14-16, 2022. The town meeting brought together 578 members of the low-energy nuclear science community, including 216 in-person attendees and 362 remote participants coming from US national laboratories, a wide range of US universities and other research institutions and universities abroad. Participants met in five topic-oriented and seven cross-cutting and intersecting working groups to discuss progress since the 2015 LRP and identify compelling science opportunities and the resources needed to realize them. These considerations were used during the Town Meeting to determine a set of resolutions outlining the highest priorities for our subfield. The full text of the resolutions endorsed by unanimous consent by the low-energy nuclear science community at the Town Meeting is presented at the end of this executive summary. The reports from all working groups that met during the Town Meeting are included as Secs. 1 to 11 of this Whitepaper. The intellectual challenges for nuclear structure, reactions and astrophysics can be captured in the following questions: What is the nature of the nuclear force that binds protons and neutrons into stable nuclei and rare isotopes, and how do the rich phenomena of nuclear structure and reactions emerge? How do single-nucleon, cluster, and collective degrees of freedom coexist and evolve with increasing proton-neutron imbalance and excitation energies? What are the limits of nuclear existence, and what features arise near and beyond these limits? What are the astrophysical origins of the elements and how did the associated chemical evolution proceed? How do stars evolve, and what nuclear signatures do they leave behind? What is the nature of neutron stars and dense matter? How can the knowledge and technological progress provided by nuclear science best be used to benefit society?

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Memoirs of Mass Accretion: Probing the Edges of Intracluster Light in Simulated Galaxy Clusters

The diffuse starlight extending throughout massive galaxy clusters, known as intracluster light (ICL), has the potential to be read as a memoir of mass accretion: informative, individual, and yet imperfect. Here, we combine dark-matter-only zoom-in simulations from the Symphony suite with the Nimbus “star-tagging” model of the stellar halo to assess how much information about the mass assembly of an individual galaxy cluster can be gleaned from idealized measurements of ICL outskirts. We show that the edges of a cluster’s stellar profile—the primary (R sp⋆,1 ) and secondary (R sp⋆,2 ) stellar “splashback” radii—are sensitive to both continuous mass accretion histories (MAHs) and discrete merger events, making them potentially powerful probes of a cluster’s past. We find that R sp⋆,1 strongly correlates with the cluster’s mass ∼1 dynamical time ago, while R sp⋆,2 traces more recent MAH to a slightly lesser degree. In combination, these features can further distinguish between clusters that have and have not undergone a major merger within the past dynamical time. We use both to predict realistic cluster MAHs with the MultiCAM framework. These outer ICL features are significantly more sensitive to mass accretion and merger histories than the stellar mass gap and halo concentration, and perform comparably to the commonly used X-ray-based tracer of relaxedness, x off . While our analysis is idealized, the relevant ICL features are potentially detectable in next-generation deep imaging of nearby clusters. This work highlights the promise of ICL measurements and lays the groundwork for more detailed forecasts of their power.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Astrophysical neutrino self-interactions in the high-statistics era

Do neutrinos have sizable self-interactions? They might. Laboratory constraints are weak, so strong effects are possible in astrophysical environments and the early universe. Observations with neutrino telescopes can provide an independent probe of neutrino self (“secret”) interactions, as the sources are distant and the cosmic neutrino background intervenes. We define a roadmap for making decisive progress on testing these interactions. This progress will be enabled by IceCube-Gen2 observations of high-energy astrophysical neutrinos. Critical to this is our comprehensive treatment of the theory, taking into account previously neglected or overly approximated effects, as well as including realistic detection physics. We show that IceCube-Gen2 can realize the full potential of neutrino astronomy for testing neutrino self-interactions, being sensitive to cosmologically relevant interaction models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗