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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

The 2022 Plasma Roadmap: low temperature plasma science and technology

Abstract The 2022 Roadmap is the next update in the series of Plasma Roadmaps published by Journal of Physics D with the intent to identify important outstanding challenges in the field of low-temperature plasma (LTP) physics and technology. The format of the Roadmap is the same as the previous Roadmaps representing the visions of 41 leading experts representing 21 countries and five continents in the various sub-fields of LTP science and technology. In recognition of the evolution in the field, several new topics have been introduced or given more prominence. These new topics and emphasis highlight increased interests in plasma-enabled additive manufacturing, soft materials, electrification of chemical conversions, plasma propulsion, extreme plasma regimes, plasmas in hypersonics, data-driven plasma science and technology and the contribution of LTP to combat COVID-19. In the last few decades, LTP science and technology has made a tremendously positive impact on our society. It is our hope that this roadmap will help continue this excellent track record over the next 5–10 years.

plasma diagnostics↗
DOE OSTI2022

Plasma Science: Enabling Technology, Sustainability, Security, and Exploration

The Plasma2020 decadal report took a forward-looking, interagency perspective on how the different elements that constitute plasma science provide a broad interdisciplinary driver for capitalizing on future opportunities in the scientific community. Goals of the study were to (1) provide a retrospective survey of the field of plasma science; (2) illustrate the vibrant connections that unify the field of plasma science; (3) offer a vision for future developments in plasma science, such as those related to organizational structure, program balance, and funding; (4) provide an assessment of the demographic characteristics and human resource development of the field, such as those related to workforce, educational, and other societal needs; and (5) make recommendations to balance the objectives of the field in a sustainable and healthy manner over the long term. The resulting report was composed in a style accessible to the non-scientist reader. With this approach, a broad audience can understand the importance of plasma science and what researchers in the field want to learn in the coming decades.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Guest Editorial Special Issue on Plenary, Invited, and Tutorial Papers From ICOPS 2022

The IEEE International Conference on Plasma Science (ICOPS) is an annual meeting of plasma physics researchers with an emphasis on various applications of plasma science and technology. This meeting is organized by the Plasma Science and Application Committee (PSAC) of the IEEE Nuclear and Plasma Sciences Society (NPSS).

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1992

The Solar Array Module Plasma Interactions Experiment (SAMPIE): Science and technology objectives

The Solar Array Module Plasma Interactions Experiment (SAMPIE) is an approved NASA Space Shuttle space flight experiment to be launched in Jul. 1993. The SAMPIE experiment is designed to investigate the interaction of high voltage space power systems with ionospheric plasma. To study the behavior of solar cells, a number of cell coupons, representing technologies of current interest, will be biased to high voltages to characterize both negative potential arcing and positive potential current collection. Additionally, various theories of arc suppression will be tested by including several specially modified cell coupons. Finally, SAMPIE will include experiments to study the basic nature of these interactions. The rationale for a space flight experiment, the measurements to be made, the significance of the expected results, and the current design status of the flight hardware are described.

Hillard, G. Barry↗
NASA NTRS1993

Solar array module plasma interactions experiment (SAMPIE) - Science and technology objectives

The solar array module plasma interactions experiment (SAMPIE) is an approved NASA flight experiment manifested for Shuttle deployment in early 1994. The SAMPIE experiment is designed to investigate the interaction of high voltage space power systems with ionospheric plasma. To study the behavior of solar cells, a number of solar cell coupons (representing design technologies of current interest) will be biased to high voltages to measure both arcing and current collection. Various theories of arc suppression will be tested by including several specially modified cell coupons. Finally, SAMPIE will include experiments to study the basic nature of arcing and current collection. This paper describes the rationale for a space flight experiment, the measurements to be made, and the significance of the expected results. A future paper will present a detailed discussion of the engineering design.

Hillard, G. B.↗
DOE OSTI2022

Tracking blobs in the turbulent edge plasma of a tokamak fusion device

Abstract The analysis of turbulence in plasmas is fundamental in fusion research. Despite extensive progress in theoretical modeling in the past 15 years, we still lack a complete and consistent understanding of turbulence in magnetic confinement devices, such as tokamaks. Experimental studies are challenging due to the diverse processes that drive the high-speed dynamics of turbulent phenomena. This work presents a novel application of motion tracking to identify and track turbulent filaments in fusion plasmas, called blobs, in a high-frequency video obtained from Gas Puff Imaging diagnostics. We compare four baseline methods (RAFT, Mask R-CNN, GMA, and Flow Walk) trained on synthetic data and then test on synthetic and real-world data obtained from plasmas in the Tokamak à Configuration Variable (TCV). The blob regime identified from an analysis of blob trajectories agrees with state-of-the-art conditional averaging methods for each of the baseline methods employed, giving confidence in the accuracy of these techniques. By making a dataset and benchmark publicly available, we aim to lower the entry barrier to tokamak plasma research, thereby greatly broadening the community of scientists and engineers who might apply their talents to this endeavor.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Perspectives on the FESAC transformative enabling capabilities: Priorities, plans, and Status

In early 2017, the Fusion Energy Sciences Advisory Committee (FESAC), an advisory committee to the United States Department of Energy, was charged with identifying transformative enabling capabilities (TECs) “that could promote efficient advance toward fusion energy, building on burning plasma science and technology.” A subcommittee with broad expertise was formed and sought feedback from scientific experts, including experts from outside the fusion community. Three workshops were conducted, and a report was approved by FESAC in 2018 that identified four of the “most promising” TECs: advanced algorithms, high-critical-temperature superconductors, advanced materials and manufacturing, and novel technologies for tritium fuel cycle control. In addition, one “promising” TEC was identified: fast flowing liquid metal plasma-facing components. This paper will give details on the promising TECs and an overview on considerations of these TECs in the United States since the publication of the report.

Lumsdaine, Arnold↗
DOE OSTI2023

Investigation of the silicon coated film characteristics on tungsten surface in EAST fusion device

Siliconization using 10 % SiD 4 + 90 % He assisted by ion cyclotron range of frequency discharge (ICRF) or glow discharge (GD) was performed in EAST with full tungsten (W) diverters. It was found that the coated Si film on W sample at a higher baking temperature (160 °C) was smoother than that at a lower baking temperature (60 °C). This was mainly because physically adsorbed gaseous impurities were released at a higher baker temperature. This process improved the adhesion between the film and the surface of W. An increase in the ICRF working power from 20 kW to 40 kW further increased the Si content and the film thickness by 1.5 times. The cleaning efficiency of ICRF on the surface of the W sample before siliconization was higher at 40 kW than that at 20 kW, which facilitated the removal of oxides and other compounds from the surface of W. The ratio of silicon/oxygen (Si/O) and the thickness improved considerably due to greater ionization and deposition of SiD 4 . Additionally, siliconization via GD was more uniform and 1.5 nm thicker than that via ICRF, which was because of the greater working gas pressure, coating duration, and homogeneity in GD. These results might be used as a reference for evaluating the effect of siliconization on plasma performance and its application in fusion devices.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

ITER Toroidal Interferometer and Polarimeter (TIP) beam refraction in 3D density profiles

Calculations of the expected refraction of the five ITER Toroidal Interferometer and Polarimeter (TIP) chords are presented for a range of conditions including high-density axisymmetric, ELMing H-mode cases and shattered pellet disruption mitigation cases. The calculations are carried out with a newly developed ray tracing code capable of following TIP’s 10.59 μm laser beams through arbitrary 3D electron density profiles. Using JOREK simulations of ELM density perturbations in a 15MA ITER baseline plasma, it is shown that refraction from ELMs is expected to be negligible. It is found, however, that TIP interferometers will be able to clearly resolve the line-integrated density perturbation from ELMs and contribute to the ITER measurement requirement “14. H-mode, ELMs and L-H mode transition indicator”. Calculations of the expected refraction in a NIMROD simulated shattered pellet disruption mitigation scenario with peak local electron densities of n e = 3.7 x 10 21 m -3 (max line-averaged densities of n avg = 1.3 x 10 21 m -3 ) also show tolerable refraction and it is likely that most, if not all chords, would avoid signal loss. In conclusion, for both axisymmetric and structured plasmas with line-averaged densities in the mid to upper 10 21 m -3 range, values likely present only during disruption mitigation, refraction becomes significant and could limit the ability of TIP to make reliable density measurements.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1991

Los Alamos NEP research in advanced plasma thrusters

Research was initiated in advanced plasma thrusters that capitalizes on lab capabilities in plasma science and technology. The goal of the program was to examine the scaling issues of magnetoplasmadynamic (MPD) thruster performance in support of NASA's MPD thruster development program. The objective was to address multi-megawatt, large scale, quasi-steady state MPD thruster performance. Results to date include a new quasi-steady state operating regime which was obtained at space exploration initiative relevant power levels, that enables direct coaxial gun-MPD comparisons of thruster physics and performance. The radiative losses are neglible. Operation with an applied axial magnetic field shows the same operational stability and exhaust plume uniformity benefits seen in MPD thrusters. Observed gun impedance is in close agreement with the magnetic Bernoulli model predictions. Spatial and temporal measurements of magnetic field, electric field, plasma density, electron temperature, and ion/neutral energy distribution are underway. Model applications to advanced mission logistics are also underway.

Schoenberg, Kurt↗
DOE OSTI2020

Plasma and X-ray radiation-induced damage mechanisms in a tungsten heavy alloy

Tungsten-based materials are among the main candidate plasma-facing materials for future fusion reactors where extreme conditions of thermomechanical stresses, radiation, and energetic particles must be withstood. Here a hybrid X-pinch platform combined with a pulsed power machine was used to study damage mechanisms in 90W–4Cu–6Ni tungsten heavy alloy as a result of exposure to high energy density plasma, X-ray radiation, and the resulting thermal shock. It was found that the plasma-facing surface of the material undergoes severe melting and ablation with the extent of ablation being higher in the Cu–Ni phase than the W particles. Rapid melting and solidification transform the W particles into fine dendrite morphologies embedded in the Cu–Ni solid solution. Cracking was also observed in the subsurface layers at the interfaces between the W particles and the Cu-rich phase of the Cu–Ni matrix. X-ray radiation, on the other hand, cause slight melting on the surface without significant ablation and no cracking.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Commissioning of the Power Supplies and Coils of the SMART Tokamak

The small aspect ratio tokamak (SMART) is a spherical tokamak (ST) that offers unique capabilities for studying the potential of negative triangularity. It has been designed, constructed, and is currently being operated by the Plasma Science Fusion Technology (PSFT) Laboratory at the University of Seville. SMART has a total of 21 coils, organized into seven independent circuits and driven by five modular power supplies (PS). The PS operation relies on switching converter technology based on IGBT and supercapacitors (SCs). The PS delivers predefined current waveforms to the copper coil system consisting of the central solenoid (CS), 12 toroidal field (TF) coils, three series pairs of poloidal field (PF) coils, and two independent PF coils. This study details the commissioning and validation of the PS toroidal and solenoid coils, as well as the assembly of coils in SMART. The maximum rated current and slope were measured, along with the series impedance of the coils, the output current ripple, and the noise levels. The internal parameters of the SCs were measured, and optimized current profiles were proposed to enhance overall performance. A comparison has been made between the theoretical values and the experimental results, providing insight into the performance of the PS and areas for improvement.

Power electronics↗
DOE OSTI2021

Application of machine learning for the estimation of electron energy distribution from optical emission spectra

Abstract This paper discusses the use of probabilistic deep neural networks for the prediction of the electron energy probability function in low-temperature non-thermal plasmas. The neural networks are trained using optical emission spectroscopy and Langmuir probe measurements, with the goal of providing a reliable estimate of the electron energy probability function solely from optical emission data. The performance of both non-Bayesian and Bayesian networks is evaluated. It is found that Bayesian models are preferable as they assign a higher level of uncertainty to their prediction especially when the dataset used to train them is small. This work describes one of the many potential applications of machine learning in plasma science and technology.

Physics↗
NASA NTRS1988

Lessons learned in ground processing scientific and applications payloads at Kennedy Space Center

The payload ground processing of experiments which flew on the Shuttle is examined, including studies of atmosphere and earth observation, life science, advance technology, materials science, plasma physics, astrophysics and solar physics, astronomy, navigation and communication, and fluid mechanics. The process of designing and development payloads, the integration of instruments, carrier interface verification, and late servicing at the launch pad are discussed. The problems of cost, red tape, contamination, safety, and propriety protection are considered.

Elfrey, Priscilla↗