Search NASA⌕ Search

SEARCH · Search NASA

Results for “ELECTROMAGNETISM”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8

SelenITA: A Dual-Spacecraft Lunar CubeSat Mission to Characterize the Near-Surface Electromagnetic Plasma Environment

SelenITA is an international interdisciplinary mission consisting of two CubeSats that will provide the first multi-point measurement in a sustained low lunar orbit. This mission will advance the understanding of spatiotemporal differentiation of the electromagnetic space environment at the Moon in support of Artemis crew and the geosciences. The mission science objectives are to: (1) further constrain the origins of crustal magnetic fields and their applications; (2) determine the nature of plasma interactions with crustal magnetic fields; (3) characterize plasma waves and turbulence at the Moon; (4) characterize the lunar surface potential in all plasma environments; (5) constrain the composition, thermal state, and structure of the lunar upper mantle and crust; (6) characterize the ionizing radiation in lunar orbit; (7) determine the density of the dust exosphere as a function of latitude, longitude, and altitude, including the lunar polar space environment. The measurement requirements include: 3-component vector magnetic field, plasma distribution (flux, energy, density, temperature), energetic particles (protons, electrons, gamma rays), and dust. SelenITA builds on a rich history of electromagnetic plasma observations of the near lunar surface and space environment, and it answers high level science questions with state of the art instruments in a small package. PLAIN LANGUAGE ABSTRACT – SelenITA comes from the greek word for Moon, selene, with the addition of “ITA” as a reference to the Brazilian teammate, Instituto Tecnológico de Aeronáutica. In addition, in Portuguese "ita" is a prefix similar to "ite" in English, used in naming minerals, so Selenita could be seen as a lunar gemstone. In Spanish, “ita” is a diminutive suffix for “little” which is appropriate for this CubeSat mission which consists of twin 12U CubeSats in low lunar orbit. The primary science goal of the mission is to distinguish time varying features within the electromagnetic plasma environment near the surface of the Moon. The science objectives include investigating the origins of crustal magnetic fields, plasma interactions with these fields, plasma waves, surface potential, and interior properties. This mission is also interested in the radiation environment at the Moon and the amount of dust at the lunar poles. This is important because it helps us understand how future astronauts will live and work on the lunar surface and identify hazards.

space weather↗

Three-Dimensional Deformable Grid Electromagnetic Particle-in-cell for Parallel Computers

We describe a new parallel, non-orthogonal grid, three-dimensional electromagnetic particle-in-cell (EMPIC) code based on a finite-volume formulation. This code uses a logically Cartesian grid of deformable hexahedral cells, a discrete surface integral (DSI) algorithm to calculate the electromagnetic field, and a hybrid logical-physical space algorithm to push particles.

Cartesian grid Grid Electromagnetic electromagneti↗

Electromagnetic form factor of the neutrino.

Electromagnetic form factors of electron and muon neutrinos evaluated, using intermediate vector- boson theory, noting renormalization induced by electromagnetic interactions

PARTICLE THEORY↗

Electromagnetic Basis of Metabolism and Heredity

Living organisms control their cellular biological clocks to maintain functional oscillation of the redox cycle, also called the "metabolic cycle" or "respiratory cycle". Organization of cellular processes requires parallel processing on a synchronized time-base. These clocks coordinate the timing of all biochemical processes in the cell, including energy production, DNA replication, and RNA transcription. When this universal time keeping function is perturbed by exogenous induction of reactive oxygen species (ROS), the rate of metabolism changes. This causes oxidative stress, aging and mutations. Therefore, good temporal coordination of the redox cycle not only actively prevents chemical conflict between the reductive and oxidative partial reactions; it also maintains genome integrity and lifespan. Moreover, this universal biochemical rhythm can be disrupted by ROS induction in vivo. This in turn can be achieved by blocking the electron transport chain either endogenously or exogenously by various metabolites, e.g. hydrogen sulfide (H2S), highly diffusible drugs, and carbon monoxide (CO). Alternatively, the electron transport in vivo can be attenuated via a coherent or interfering transfer of energy from exogenous ultralow frequency (ULF) and extremely low frequency (ELF) electromagnetic (EM) fields, suggesting that-on Earth-such ambient fields are an omnipresent (and probably crucially important) factor for the time-setting basis of universal biochemical reactions in living cells. Our work demonstrated previously un-described evidence for quantum effects in biology by electromagnetic coupling below thermal noise at the universal electron transport chain (ETC) in vivo.

Electromagnetic↗

Application of Energy-efficient Electromagnetic Melt-Processing for the Upcycling of Recycled Polyphenylene Sulfide into Multifunctional Segregated Nanocomposites

Polyphenylene sulfide (PPS) is widely used in structural and functional composites because of its thermal stability, chemical resistance, and mechanical strength. As circular manufacturing becomes increasingly important, extending the service life of recycled PPS (rPPS) is essential. However, conventional high-temperature reprocessing accelerates thermo-oxidative degradation, reducing recycled composite performance. This study proposes a rapid and potentially energy-saving upcycling strategy for rPPS using electromagnetic (EM) melt-processing to form segregated carbon nanotube (CNT) networks and produce EM-responsive nanocomposites. The aim was to determine whether CNT-assisted EM heating could reduce polymer degradation while improving multifunctional properties at ultralow filler loadings. rPPS micropellets were coated with CNTs by ball milling to create conductive shells, then compacted into green bodies (GBs) and selectively melted by rapid EM irradiation. Structural, electrical, mechanical, rheological, and electromagnetic interference (EMI) shielding properties were evaluated. Electrical percolation occurred at an ultralow CNT loading of 0.08 wt%, with conductivity reaching (1.24 ± 0.74) × 10 -5 S⋅m -1 at 0.1 wt%. At this concentration, tensile strength and modulus increased by 72% and 99%, respectively. At ~ 0.7 mm thickness, X-band EMI shielding effectiveness reached 6 dB for GBs and 3 dB after EM processing. This shows that EM melt-processing upcycles rPPS into high-performance multifunctional nanocomposites with minimum thermal degradation.

recycled↗

An overview of electromagnetic interference problems in spacecraft

Electromagnetic Interference Workshop held at JPL /Feb., 1968/ permitted an exchange of information on electromagnetic interference problems encountered in aerospace programs. The experiences related at this workshop dealt primarily with Surveyor, Lunar Orbiter, OGO, ATS, and Mariner unmanned programs.

Bastow, J. G.↗

Measurement of the nuclear electromagnetic cascade development in glass at energies above 200 GeV

The longitudinal development of nuclear-electromagnetic cascades with energies greater than 200 GeV was measured in a low-Z (glass) absorber. This was done in the course of operating an ionization spectrometer at mountain altitude in an experiment to study the properties of gamma rays emitted from individual interactions at energies around 10,000 GeV. The ionization produced by a cascade is sampled by 20 sheets of plastic scintillator spaced uniformly in depth every 2.2 radiation lengths. Adjacent pairs of scintillators are viewed by photomultipliers which measure the mean ionization produced by an individual cascade in 10 layers each 1.1 interaction length (4.4 radiation lengths) thick. The longitudinal development of the cascades was measured for about 250 cascades having energies ranging from 200 GeV to 2500 GeV. The observations are compared with the predictions of calculations made for this specific spectrometer using a three-dimensional Monte Carlo model of the nuclear-electromagnetic cascade.

Gillespie, C. R.↗

Assessment and control of spacecraft electromagnetic interference

Design criteria are presented to provide guidance in assessing electromagnetic interference from onboard sources and establishing requisite control in spacecraft design, development, and testing. A comprehensive state-of-the-art review is given which covers flight experience, sources and transmission of electromagnetic interference, susceptible equipment, design procedure, control techniques, and test methods.

Source record↗

Current driven electrostatic and electromagnetic ion cyclotron instabilities

Growth rates and parameter dependences are calculated for the current driven instabilities of electrostatic (with finite-beta corrections) and electromagnetic ion cyclotron waves. For 0.25 (T sub e)/(T sub i) 2.5, ion cyclotron waves have large growth rates, while ion acoustic waves are still stable. In fusion devices, where electrostatic waves may be stable, electromagnetic ion cyclotron waves are unstable for beta sub i 0.001.

Forslund, D. W.↗

Ordinary-mode electromagnetic instability in colliding plasma streams.

The instability of the electromagnetic linearly polarized mode propagating perpendicularly to the magnetic field is studied for a system composed of two colliding plasma streams, in each of which the electrons and ions are streaming at the same velocity. Using linearized Vlasov-Maxwell equations and allowing for anisotropic temperatures, it is found that in the presence of streaming ions the instability can occur in very low-beta plasmas. The plasma is increasingly susceptible to the electromagnetic instability with increasing values of beta, streaming velocity, temperature ratio of parallel to perpendicular electrons, and temperature ratio of perpendicular electrons to perpendicular ions.

Lee, K. F.↗

Physical picture for the anomalous progagation of ordinary electromagnetic waves in a plasma

It is shown that the physical mechanism for the anomalous propagation of electromagnetic waves at frequencies below the plasma frequency is due to the deflection of particle thermal motions by the wave magnetic field, leading to a density perturbation which can be large when enhanced by some resonance. In presence of an external magnetic field, cyclotron resonance provides the enhancement for ordinary waves. A waveparticle resonance gives rise to anomalous propagation if the velocity distribution is anisotropic with respect to the wave vector, which allows slow electromagnetic waves, with phase velocity less than the velocity of light.

Fried, B. D.↗

Electromagnetic radiation screening of semiconductor devices for long life applications

A review is presented of the mechanism of interaction of electromagnetic radiation in various spectral ranges, with various semiconductor device defects. Previous work conducted in this area was analyzed as to its pertinence to the current problem. The task was studied of implementing electromagnetic screening methods in the wavelength region determined to be most effective. Both scanning and flooding type stimulation techniques are discussed. While the scanning technique offers a considerably higher yield of useful information, a preliminary investigation utilizing the flooding approach is first recommended because of the ease of implementation, lower cost and ability to provide go-no-go information in semiconductor screening.

Hall, T. C.↗

Electromagnetic position sensor for a magnetically supported model in a wind tunnel

An investigation was undertaken to determine the feasibility of using superconducting force-producing coils for positioning a model in a wind tunnel. The cryostat containing the forcing coils surrounded the test section of the tunnel, thus favoring an electromagnetic position sensor. Another reason favoring this choice was the fact that the performance of an electromagnetic sensor is essentially unaffected by the shape of the model.

Towler, W. R.↗

Electromagnetic interference of power conditioners for solar electric propulsion

Electrical, multikilowatt power conditioning (PC) equipment needed on board a spacecraft utilizing solar electric propulsion creates an electromagnetic environment that is potentially deterimental to the science, navigation, and radio communication hardware. Within the scope of the solar electric propulsion system technology program, three lightweight, 2.5-kW PCs were evaluated in terms of their electromagnetic characteristics. It was found that the levels of radiated and conducted interference exceeded the levels anticipated for a solar electric propulsion mission. These noise emissions, however, were the result of deficient interference design in these models, rather than a basic inability to control interference in this type of PC.

Whittlesey, A. C.↗