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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 OSTI2025

Energetic Electron Transport in Magnetized Plasma with Magnetic Islands (Final Technical Report)

The main scientific goal of this project was to investigate the interactions between energetic electrons and magnetic islands in magnetized plasmas from lab to space. The proposed plan of addressed the following specific objectives: (1) Determine if energetic electrons are trapped by magnetic islands. Specifically, test the hypothesis that energetic electrons are trapped near island O-points due to stable orbits and de-confined near island X-points due to X-point tangles. (2) Determine how electron transport changes with island width and location. Specifically, test the hypothesis that electrons are accelerated by contracting magnetic islands through a Fermi acceleration process. (3) Assess how electron transport is affected by island dynamics, including island rotation, bifurcation, and/or island overlap. Specifically, test the hypothesis that electrons are deconfined and possibly accelerated during island rotations, bifurcations, and overlap due to stochastization of the magnetic field lines.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

The Ductility of 49Fe-49Co-2V Soft Magnetic Alloy Bar: Surface Effects and Test Methods

The tensile ductility of 49Fe-49Co-2V (Hiperco® 50A) bar was investigated in both as-received and heat-treated conditions. The as-received/machined specimens exhibit very low ductility compared to samples where heat treatment was the final step prior to testing. Microstructural characterization showed that internal residual strain from bar processing and, most importantly, surface machining damage, cause lower elongation in the as-received material. Because fracture of this intermetallic alloy initiates at the surface, it is particularly susceptible to surface machining damage, i.e., the near-surface region has already exhausted most of its ability to accumulate tensile strain. During heat treatment, the internal residual strain and near-surface machining damage are eliminated and ductility is improved, despite a higher degree of crystallographic ordering in the heat-treated condition (which typically lowers ductility). Furthermore, if machining is again performed after heat treatment, the material again exhibits brittle behavior, even with only light touch-up machining passes. Here, in this work, methods of tensile strain measurement were investigated, namely conventional knife-edge extensometry and noncontact digital image correlation (DIC) on heat-treated material. For clip-on knife-edge extensometry, the range of failure strain was 2.5-5.5% for heat-treated Hiperco. For noncontact methods, ductility up to 7% was observed. The results highlight the tendency for the alloy to fail at surface imperfections, even those produced by application of the extensometer itself. Noncontact laser extensometry is recommended for determining the intrinsic ductility of the alloy. A method of laser surface modification was developed which increased ductility by ~ 100% compared to unmodified samples. The high cooling rates achieved during laser surface processing can bypass the ordering reaction and produce a ductile disordered structure at the surface that exhibits ductile fracture characteristics.

EBSD↗
DOE OSTI2021

Can High Current Density HTS Magnets be Quench Protected Using Methods Used to Protect High Current Density LTS Magnets?

In the 1970s the Lawrence Berkeley Laboratory (LBL) was testing high current density magnets where the EJ 2 limit was up to two orders of magnitude higher than the quench protection methods of the period would permit at the time. LBL was designing a high current density (J) thin solenoid with a large volume and stored energy (E). The accepted EJ 2 limit at the time was ~10 23 J A 2 m -4 . In order to exceed the EJ 2 limit by two orders of magnitude, one had to greatly increase the quench protection voltages (V) and magnet current (I). In 1977, LBL tested four quench protection methods on a 2-meter diameter high current density solenoid with a stored energy of 2 MJ. Three of these quench protection methods worked well, but the fourth didn't appear to work. These methods will be discussed as to whether they can be applied to HTS or MgB 2 high current density magnets.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Development and Test of a Large Aperture $Nb_3Sn$ Cos-Theta Dipole Coil with Stress Management

An innovative stress-management (SM) concept for cos-theta (CT) coils (SMCT coil concept) has been proposed at Fermilab. A large-aperture two-layer Nb3Sn SMCT dipole coil was designed and manufactured to validate and test the SM concept including coil design, fabrication technology, and performance. The first large-aperture SMCT coil (SMCT1) was fabricated and assembled with a small-aperture Nb3Sn coil inside a dipole mirror magnet. SMCT1 coil tests in a dipole mirror structure was performed in two configurations - SMCTM1a with only powered two-layer SMCT1 coil and SMCTM1b with the SMCT coil connected in series with an inner two-layer dipole coil. The test goals are to prove the SMCT coil concept in two-layer and four-layer mirror configurations; demonstrate that the magnet can reach the targeted quench current at the established preload; study magnet training, training memory after thermal cycle, ramp rate and temperature dependences of the magnet quench current; and test the SMCT1 coil quench protection parameters. This paper summarizes the SMCT1 coil design and parameters, the coil main fabrication steps, its assembly in the dipole mirror structure. The results of the SMCTM1a/b mirror test are presented and discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Test samples and infrastructure for accelerator magnet developments

LHC still does not operate at full energy due to training features in magnets. Higher field practical superconductors (Nb 3 Sn) show much worse training behavior than NbTi. Most magnet performance issues relate to quenching, and it is this phenomenon and its dependencies that need to be understood for us to succeed addressing them in magnets. For pragmatic and scientific reasons underlying mechanisms are hard to investigate in real magnets. Available data suggest that emulating local conditions at quench location may be enough to arrive at a good understanding of what drives observed behavior. "Local" conditions imply emulation by small samples of cables/"stacks" powered within a facility with controllable conditions, including external magnetic and force fields. This paper argues about the necessity of this approach, while reminding current understanding and directions of quench studies, and pointing out inadequacy of available techniques. Improved facilities and change of perspective are required for consistent and affordable development.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Superconducting Magnet Qualification Methodology for the Material Plasma Exposure Experiment

The Material Plasma Exposure eXperiment (MPEX), currently under design, is a new linear plasma device to advance the understanding of plasma-material interactions through the generation and delivery of plasmas as they are expected in future fusion reactor divertors. MPEX will be a steady-state device to study high-fluence exposures of plasma-facing materials and components. The requirements for the magnetic field at the target and the heating stages make the application of superconducting coils necessary. Conceptual designs for the superconducting magnets have been developed, and multiple cryostats with warm bore diameters of either 65 cm or 156 cm are envisioned to facilitate their integrated and timely assembly with other systems such as vacuum, water cooling, and RF power. Although design, fabrication, and testing for the magnets as stand-alone units are straightforward, challenges will arise during the integration of the system. Two different field profiles will be used during operation. The magnetic field where the electron cyclotron heating occurs needs to operate at both 1.25 and 2.5 T. It is critical that the magnets all share the same magnetic axis and alignment. The mutual inductance between cryostats will affect the quench behavior of the system. Also, cryostat-to-cryostat forces can be as large as 700 kN, and the magnitude and direction will change depending on which coils are energized. The design of the system must take those characteristics into account along with the quench scenarios. This paper describes the qualification approach that will be used to determine whether stand-alone tests can be used to ensure the success of the integrated system. Fiducials will be used to define the location of the magnetic axis for each cryostat to ensure proper alignment. Quench tests of a single magnet will be performed at a current above the normal operating current to account for additional stored energy from the mutual inductance to adjacent cryostats. Also, a 1018 steel plate will be mounted on either end of a cryostat to simulate the cryostat-to-cryostat forces. Requirements for the size and location of the steel plates are described.

Burkhardt, Earle↗
DOE OSTI2024

R&D Needs for a US Fusion Magnet Base Program

Significant technology maturation efforts are underway by privately funded fusion startups with the goal to demonstrate mature HTS magnet technology. To support the private sector development effort and the DOE milestone based program, a U.S. Fusion Magnet Community Workshop was held on March 14-15, 2023 in Princeton, NJ. This was the first U.S. community workshop focused on fusion magnet technologies aimed at determining the structure and technical direction for a public program designed to complement the private fusion industry landscape. Based on the wide range of different contributions, a set of general themes and fusion magnet R&D needs were identified and discussed. Feedback received to the workshop charge questions highlighted critical magnet R&D gaps such as availability of existing large cable and coil test facilities, a magnet education program that can generate a trained and essential workforce by leveraging R&D capabilities of universities, U.S. national labs, and fusion industry. Other opportunities synergistic and complementary with high energy physics, high field magnets that are open for a broad range of science drivers. The defined R&D gaps underpin the need for a mid-term and long-term public program in fusion magnet development, which reflects the purpose of the workshop in developing the rationale and consent for such a base program. A self-consistent, fusion specific U.S. fusion magnet program will complement and de-risk fusion pilot plants (FPPs) of promising magnetic configurations developed by private companies on a timeline consistent with the NASEM report on bringing fusion to the U.S. grid. We describe the magnet challenges presented and R&D needs discussed in the workshop. In conclusion, these challenges and R&D needs provide focus for the development of U.S. mid-term and long term roadmaps on enabling HTS for high field fusion.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Critical current and stability tests of Nb 3 Sn for LBNL CCT magnet project

The Nb 3 Sn wires received from LBNL include the original round wires as well as the extracted wires from Rutherford cables. Total of 12 samples were prepared and heat treated. Five of them were tested for electric field versus current (E-I), among them 4 samples were further tested for electric field versus magnetic field (E-H). E-I traces were measured in magnetic field between 5 T and 8 T at 4.2 K. The critical currents of these sample are between 924 A and 993 A at 5 T. E-H measurements were performed at currents between 900 and 1500 A at 4.2 K. The stability currents, which is defined as the maximum current without quench during the E-H test, are determined to be between 1100 A and 1400 A. A separate Excel file presenting all the critical current and E-H curves is attached.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Fermilab Cryogenic Test Facilities

Fermi National Accelerator Laboratory (Fermilab) has multiple cryogenic test facilities, undertaking testing of superconducting magnets, Superconducting Radio Frequency (SRF) cavities, SRF cryomodules and other helium cryogenic components. The test areas within Fermilab include: Meson Cryogenic Test facility (Meson), Industrial Building 1 (IB-1), Heavy Assembly Building/Illinois Accelerator Research Center (HAB/IARC), New Muon Lab, (NML) and the Cryomodule Test Facility (CMTF). Meson and HAB/IARC utilize repurposed Tevatron era reciprocating engine based cryogenic refrigerator systems, whereas CMTF and IB-1 utilize gas bearing turbine based coldboxes. Each of these test areas support the various Fermilab projects and collaborations including the Linear Coherent Light Source II (LCLS-II), Proton Improvement Plan II (PIP-II), High Luminosity Large Hadron Collider (HL-LHC), and Mu2e. This paper outlines the diverse and extensive cryogenic test capabilities within Fermilab.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Double Aperture HTS Dipole Magnet Model for the Persistent Current Operation

Particle accelerators use many different types of magnets. There is an interest in replacing rather low-field conventional resistive magnets with high-temperature superconducting (HTS) magnets. The main goal is to reduce operational expenses, which is critical during the continuously increasing cost of electricity. At Fermilab, several HTS accelerator magnets were built and successfully tested. The paper described a variant of the double-aperture dipole magnet that could be suitable for future Lepton Colliders. A single short-circuited HTS coil of 3.8 kA generates a homogeneous magnetic field of 57 mT in both magnet gaps of 84 mm. The short model magnet was designed, built, and successfully tested at liquid nitrogen temperature. This magnet works in a persistent current mode, which provides additional cost savings when used in particle storage rings operated at a stable magnetic field. The results of design, fabrication, and tests are presented and discussed. The magnet demonstrated a high magnetic field stability in both apertures, efficiency of correction coils, and primary powering circuit.

Kashikhin, Vladimir [Fermilab] (ORCID:000000017249↗
DOE OSTI2021

A custom high-stability pulse generator for the test of a novel in-situ magnetic sensor developed to detect radiation damage in undulators

High-performance analog-to-digital converters (ADC) have been widely applied in many areas of science. For instance, magnetic field measurements based on the Faraday’s induction law require high-precision voltmeters to measure induced voltages. In this study in the context of free-electron lasers technology, the Magnetic Measurements Team at SLAC National Accelerator Laboratory proposed a novel in-situ radiation damage detection system (RDDS) for detecting small field variations in undulators. The system measures the flux change in a flexible printed-circuit coil attached to the magnet array during the undulator gap movement. The gap movement changes the magnetic field, which induces a voltage signal in the coil that is measured and integrated with an ADC. Although the system is capable of detecting relative flux changes better than 100 ppm, drift in the ADC’s gain or offset can cause apparent changes in the relative flux. This paper describes the first attempt to developed a high-precision verification circuit to perform ADC testing in the framework of the novel RDDS. The circuit generates a reference voltage pulse with a voltage–time integral relative precision better than 50 ppm for a few hundreds of mVs — the typical order of magnitude measured with the RDDS. The circuit’s design combines a fast and precise switch with a low-noise voltage reference. Long-term measurements allowed statistical analysis and showed that averaging the voltage–time integral of ten pulses gives the required 50 ppm stability. Moreover, reproducibility tests confirmed that the circuit’s output is invariable under small power supply instabilities and equipment shutdown. Instruments and applications designed to quantify the magnetic field by integrating voltage signals may use the pulse generator proposed in this paper for verification purposes.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Impact of the chiral asymmetry and a magnetic field on the passage of an energetic test parton in a QCD medium

We study the dependence of soft contribution to the energy loss of a test parton moving with a high velocity on the chiral imbalance and magnetic field in the QCD medium. A semiclassical approach is adopted to estimate the parton energy loss that takes into account the back-reaction on the parton due to the polarization effects of the QCD medium while traversing through the medium. We find that the motion of the parton is sensitive to the chiral asymmetry in the medium. Further, we investigate the effect of magnetic field-induced anisotropy on the energy transfer between the moving parton and the medium. Our results show that the energy loss of the parton is strongly influenced by the strength of the magnetic field as well as the relative orientation of the motion of the parton and the direction of the magnetic field in the medium.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Fast cycling HTS based superconducting accelerator magnets: Feasibility study and readiness demonstration program driven by neutrino physics and muon collider needs

Development of energy-efficient fast cycling accelerator magnets is critical for the next generation of proton rapid cycling synchrotrons (RCS) for neutrino research and booster accelerators of future muon colliders. We see a unique opportunity for having such magnets to be built on base of High Temperature Superconductors (HTS). Besides being superconducting at relatively high temperatures, rare-earth HTS tapes have shown very small AC losses compared to low-temperature NbTi superconductor cables. Recent tests of the HTS-based 0.5 m long two-bore superconducting accelerator magnet have shown record high dB/dt ramping rates of about 300 T/s at 10 Hz repetition rate and 0.5 T B-field span. No temperature rise in 6 K cooling He was observed within the 0.003 K error setting the upper limit on the cryogenic power loss in the magnet conductor coil to be less than 0.2 W/m. Based on this result we outline a possible upgrade of this test magnet design to 2 T B-field in the 10 mm beam gap with the dB/dt ramping rates up to 1000 T/s. The power test results of this short sample magnet will be used to project both cryogenic and electrical power losses as a function of the magnet B-field and the dB/dt ramping rates. Then these projections will be scaled to the range of expected accelerator magnet beam gaps and B-fields for the proton and muon RCS accelerators. We invite collaborators to join these studies and call for support of the R&D program aimed at comprehensive demonstration of this approach that includes design, construction, and power tests of a long prototype of the HTS-based fast-cycling accelerator magnet by 2028.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Reassembly and Test of High-Field Nb3Sn Dipole Demonstrator MDPCT1

In the framework of the U.S. Magnet Development Program (MDP), Fermilab has developed and tested a high-field Nb$_3$Sn dipole demonstrator MDPCT1 for a post-LHC Hadron Collider. The magnet was first assembled with a lower coil pre-load to minimize the risk of coil damage during assembly and test. In the first test the magnet reached its test goal producing a world record field of 14.1 T at 4.5 K. Next the magnet was reassembled with nominal pre-load to achieve its design field limit of 15 T. This paper describes the details of MDPCT1 inspection, design modifications and reassembly. The magnet quench performance, including training, ramp rate and temperature dependences in the temperature range of 1.9-4.5 K, is presented and discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

MASK4 Test Campaign for Sandia WaveBot Device

This data and report details the findings from a wave tank test focused on production of useful work of a wave energy converter (WEC) device. The experimental system and test were specifically designed to validate models for power transmission throughout the WEC system. Additionally, the validity of co-design informed changes to the power take-off (PTO) were assessed and shown to provide the expected improvements in system performance. These data describe the "MASK4" wave tank test of the Sandia WaveBot device. The WaveBot device has been tested a number of times in different permutations at the US Navy's Maneuvering and Sea Keeping (MASK) basin. Each test in this series is referred to as MASK1, MASK2, etc. The WaveBot device was first tested in one degree of freedom (heave) in 2016. This MASK1 test focused primarily on system identification and modeling. After MASK1, major modifications were performed to improve the overall real-time control and measurement system, improve the heave drive train, and add surge and pitch degrees of freedom. The second set of testing, which was broken up in to two stages: MASK2A and MASK2B, focused on bench testing and closed-loop control performance as well as nonlinear modeling. MASK3 then focused on multi-input, multi-output modeling and control for maximization of electrical power. The attached report presents the results from MASK4, which focuses on detailed modeling of the power conversion chain and validation co-design principles by way of the introduction of a magnetic spring. The test log, report, and data from the MASK4 test of the WaveBot augmented with a tunable magnetic spring. Processing codes can be found at the Github link below.

16 TIDAL AND WAVE POWER↗
DOE OSTI2025

Testing of Novel Semiconductor Opening Switches Using Magnetic Switching

The performance of semiconductor opening switch (SOS) diodes with different doping profiles is assessed with the primary aim of enhancing or substituting hard-to-find devices. SOS devices are capable of providing long lifetime, gigawatt level pulses in generators with risetimes on the nanosecond scale with pulse widths on the order of 20 ns. An experimental testbed is described which allows for rapid testing of diodes with control of the forward pumping time which is a crucial parameter of SOS diodes. A saturable pulse transformer provides both the initial voltage multiplication and reverse current pulse required to drive SOS diodes. Voltage multiplication ratios of 16:1 were achieved with a modest charging voltage of 800 V and simple circuitry. With current densities of up to 1.4 kA ⋅ cm -2 , the testbed produces 10 kV output pulses into a 56 Ω load with a pulsewidth of 16 ns and delivered power of up to 1.9 MW. These novel devices are compared to legacy SOS diodes originating from Russia, with one of the profiles yielding increased performance. Finally, these profiles are studied in hopes of creating manufacturing demand to augment the availability of these useful devices.

drift step recovery diodes↗
DOE OSTI2026

US HL-LHC cryo-assemblies at FNAL - testing and lessons learned

The U.S. High-Luminosity LHC Accelerator Upgrade Project (AUP) is fabricating ten cryogenic assemblies for the HL-LHC Q1/Q3 quadrupole optics at CERN, each integrating two Nb_{3}Sn-based magnets. Fermilab has tested three assemblies (LQXFA/B01–03) at its upgraded horizontal test stand under 1.9 K conditions. Overview of the test stand and the cryo-assembly tests is given along with main results. Challenges met and lessons learned are discussed. Successful testing validates the design and integration of U.S.-produced cryo-assemblies, keeping the project on track for timely delivery to CERN.

Stoynev, Stoyan [Fermilab] (ORCID:0000000345637702↗