Search NASA⌕ Search

SEARCH · Search NASA

Results for “Spin injection”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Combustion Stability of the Gas Generator Assembly from J-2X Engine E10001 and Powerpack Tests

Testing of a powerpack configuration (turbomachinery and gas generator assembly) and the first complete engine system of the liquid oxygen/liquid hydrogen propellant J-2X rocket engine have been completed at the NASA Stennis Space Center. The combustion stability characteristics of the gas generator assemblies on these two systems are of interest for reporting since considerable effort was expended to eliminate combustion instability during early development of the gas generator assembly with workhorse hardware. Comparing the final workhorse gas generator assembly development test data to the powerpack and engine system test data provides an opportunity to investigate how the nearly identical configurations of gas generator assemblies operate with two very different propellant supply systems one the autonomous pressure-fed test configuration on the workhorse development test stand, the other the pump-fed configurations on the powerpack and engine systems. The development of the gas generator assembly and the elimination of the combustion instability on the pressure-fed workhorse test stand have been reported extensively in the two previous Liquid Propulsion Subcommittee meetings 1-7. The powerpack and engine system testing have been conducted from mid-2011 through 2012. All tests of the powerpack and engine system gas generator systems to date have been stable. However, measureable dynamic behavior, similar to that observed on the pressure-fed test stand and reported in Ref. [6] and attributed to an injection-coupled response, has appeared in both powerpack and engine system tests. As discussed in Ref. [6], these injection-coupled responses are influenced by the interaction of the combustion chamber with a branch pipe in the hot gas duct that supplies gaseous helium to pre-spin the turbine during the start transient. This paper presents the powerpack and engine system gas generator test data, compares these data to the development test data, and provides additional combustion stability analyses of the configurations.

Hulka, J. R.↗
NASA NTRS1994

Preferential heating of light ions during an ionospheric AR(+) injection experiment

The ARCS 4 sounding rocket was launched northward into high altitude from Poker Flat Research Range on February 23, 1990. The vehicle crossed geomagnetic field lines containing discrete auroral activity. An instrumented subpayload released 100 ev and 200 ev Ar(+) ion beams sequentially, in a direction largely perpendicular to both the local geomagnetic field and the subpayload spin axis. The instrumented main payload was separated along field lines from the beam emitting subpayload by a distance which increased at a steady rate of approx. 2.4 m/s. Three-dimensional mass spectrometric ion observations of ambient H(+) and O(+) ions, obtained onboard the main payload, are presented. Main payload electric field observations in the frequency range 0-16 kHz, are also presented. These observations are presented to demonstrate the operation of transverse ion acceleration, that was differential with respect to ion mass, primarily during 100-ev beam operations. The preferential transverse acceleration of ambient H(+) ions, as compared with ambient O(+) ions during the second, third, fourth, and fifth 100-ev beam operations, is attributed to a resonance at the injected the beam drift velocity among the thermal H(+) ions and plasma waves generated by the injected beam and propagating at the beam drift speed. This work provides experimental support of processes predicted by previously published theory and simulations.

Pollock, C. J.↗
NASA NTRS2013

Parameter Estimation for Compact Binary Coalescence Signals with the First Generation Gravitational-Wave Detector Network

Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational-wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance, that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a blind injection where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron-star and black-hole binary parameter space over the component mass range 1M25M and the full range of spin parameters. The cases reported in this study provide a snapshot of the status of parameter estimation in preparation for the operation of advanced detectors.

Aasi, J.↗
NASA NTRS1983

Gyrotron transmitting tube

An RF transmitting tube for the 20 GHz to 500 GHz range comprises a gyrotron and a multistage depressed collector. A winding provides a magnetic field which acts on spent, spinning or orbiting electrons changing their motion to substantially forward linear motion in a downstream direction. The spent electrons then pass through a focusser into the collector. Nearly all of the electrons injected into the collector will remain within an imaginary envelope as they travel forward toward the end collector plate. The apertures in the collector plates are at least as large in diameter as the envelope at any particular axial position.

Kosmahl, H. G.↗
NASA NTRS1995

Preferential heating of light ions during an ionospheric Ar(+) injection experiment

The Argon Release for Controlled Studies (ARCS) 4 sounding rocket was launched northward into high altitude from Poker Flat Research Range on February 23, 1990. The vehicle crossed geomagnetic field lines containing discrete auroral activity. An instrumented subpayload released 100-eV and 200-eV Ar(+) ion beams sequentially, in a direction largely perpendicular to both the local geomagnetic field and the subpayload spin axis. The instrumented main payload was separated along field lines from the beam emitting subpayload by a distance which increased at a steady rate of approximately 2.4 m/s. Three dimensional mass spectrometric ion observations of ambient H(+) and O(+) ions, obtained on board the main payload, are presented. Main payload electric field observations in the frequency range 0-16 kHz, are also presented. These observations are presented to demonstrate the operation of transverse ion acceleration, which was differential with respect to ion mass, primarily during 100-eV beam operations. The preferential transverse acceleration of ambient H(+) ions, as compared with ambient O(+) ions, during the second, third, fourth, and fifth 100-eV beam operations, is attributed to a resonance among the injected Ar(+) ions, beam-generated lower hybrid waves, and H(+) ions in the tail of the ambient thermal distribution. This work provides experimental support of processes predicted by previously published theory and simulations.

Pollock, C. J.↗
NASA NTRS2023

The Gamma-Ray Pulsar Phenomenology in View of 3D Kinetic Global Magnetosphere Models

We develop kinetic plasma models of pulsar magnetospheres with magnetic-field-line-dependent plasma injection that reveal the importance of various magnetosphere regions in regulating the gamma-ray emission. We set different particle injection rates for the so-called open, closed, and separatrix zones. Moderate particle injection rates in open and closed zones ensure a global field structure close to the force-free one, while the dissipation occurs mainly in and around the equatorial current sheet. The particles injected in the separatrix zone affect the particle populations that enter the equatorial current sheet region and, therefore, the corresponding accelerating electric fields, particle energies, the spectral cutoff energy, and gamma-ray efficiency. The separatrix zone models reproduce the recently discovered fundamental plane of gamma-ray pulsars consistent with curvature radiation emission, the gamma-ray light-curve shapes, and the radio-lag vs. peak-separation correlation reported in the Fermi second pulsar catalog. The model beaming factors indicate that the pulsar total gamma-ray luminosities listed in the Fermi catalogs are overestimations of the actual ones. We find that the radiation reaction limited regime starts ceasing to govern the high-energy emission for spin-down powers less than 1034 erg/s. Our results also indicate that toward high magnetic inclination angles, the "Y point" around the rotational equator migrates well inside the light cylinder sparking additional peaks in the gamma-ray pulse profiles. We find that an equivalent enhanced particle injection beyond the Y point strengthens these features making the model gamma-ray light curves inconsistent with those observed.

Neutron stars↗
NASA NTRS1974

Planetary accretions in jet streams

The problem of planetary accretion in a jet stream is studied using the model developed by Alfven and Arrhenius. We find that there are basically three types of planetary accretion, corresponding to cases where the characteristic time of the occurrence of catastrophic accretion is less than, equal to, or greater than the time-scale of mass injection to the planetary system (300 m.y.). These different time scales of accretion are found to be closely related to the primordial thermal profiles and equatorial inclinations of the planets. Finally, Venus' retrograde rotational spin is shown to be a possible result of accretion process in a jet stream.

Ip, W.-H.↗
NASA NTRS2012

EPE The Extreme Physics Explorer

The Extreme Physics Explorer (EPE) is a mission concept that will address fundamental and timely questions in astrophysics which are primary science objectives of IXO. The reach of EPE to the areas outlined in NASA RFI NNH11ZDA018L is shown as a table. The dark green indicates areas in which EPE can do the basic IXO science, and the light green areas where EPE can contribute but will not reach the full IXO capability. To address these science questions, EPE will trace orbits close to the event horizon of black holes, measure black hole spin in active galactic nuclei (AGN), use spectroscopy to characterize outflows and the environment of AGN, map bulk motions and turbulence in galaxy clusters, and observe the process of cosmic feedback where black holes inject energy on galactic and intergalactic scales. EPE gives up the high resolution imaging of IXO in return for lightweight, high TRL foil mirrors which will provide >20 times the effective area of ASTRO-H and similar spatial resolution, with a beam sufficient to study point sources and nearby galaxies and clusters. Advances in micro-calorimeters allow improved performance at high rates with twice the energy resolution of ASTRO-H. A lower TRL option would provide 200 times the area of ASTRO-H using a micro-channel plate optic (MCPO) and a deployable optical bench. Both options are in the middle range of RFI missions at between $600M and $1000M. The EPE foil optic has direct heritage to ASTRO-H, allowing robust cost estimates. The spacecraft is entirely off the shelf and introduces no difficult requirements. The mission could be started and launched in this decade to an L2 orbit, with a three-year lifetime and consumables for 5 years. While ASTRO-H will give us the first taste of high-resolution, non-dispersive X-ray spectroscopy, it will be limited to small numbers of objects in many categories. EPE will give us the first statistically significant samples in each of these categories.

Garcia, Michael↗
NASA NTRS1995

High pressure synthesis and magnetic studies of quasi one dimensional systems Sr(n-1)Cu(n+1)O(2n) (n=3,5)

SrCu2O3 and Sr2Cu3O5 containing two-leg and three-leg S = 1/2 ladders made of antiferromagnetic Cu-O-Cu linear bonds, respectively, were synthesized at high pressure, and their crystallographic and magnetic properties were investigated. Both susceptibility and T(1) data of NMR (nuclear magnetic resonance) revealed the existence of a large spin gap only for SrCu2O3. Superconductivity, which had been predicted theoretically for carrier-doped SrCu2O3 could not be realized although partial substitution of La(3+) for Sr(2+) seemed to be carried out successfully. Electron carriers injected seems to remain localized.

Azuma, M.↗
NASA NTRS1980

Observations of ULF electric field fluctuations in the dayside auroral oval

Electric field oscillations at frequencies centered below 10 Hz were measured by a payload equipped with double-probe electric field detectors which was launched into the dayside auroral oval during the Greenland rocket campaign on January 11, 1975. These oscillations exceeded an amplitude of 3 mV/m broadband and occurred over a period of about 90 s. These oscillations occurred during a proton injection event when the quasi-static electric field was less than 20 mV/m on the average. However, during a brief 2-s interval the electric field exceeded 50 mV/m. Analysis of the amplitude as a function of the spin frequency showed that the electric field was confined to a plane perpendicular to the magnetic field. The power spectrum was of the form f to the -6.5 + or - 1.5 power, where f is the frequency over the range from 8 to 18 Hz. The existence of a large electric field fluctuation in a spatially or temporally confined region of low-amplitude turbulence suggests that this may be an observation of the low-altitude projection of a turbulent region associated with electrostatic shocks which have recently been observed at higher altitudes.

Temerin, M.↗
NASA NTRS1978

An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

De, B. R.↗
NASA NTRS2006

Damage-Tolerant Fan Casings for Jet Engines

All turbofan engines work on the same principle. A large fan at the front of the engine draws air in. A portion of the air enters the compressor, but a greater portion passes on the outside of the engine this is called bypass air. The air that enters the compressor then passes through several stages of rotating fan blades that compress the air more, and then it passes into the combustor. In the combustor, fuel is injected into the airstream, and the fuel-air mixture is ignited. The hot gasses produced expand rapidly to the rear, and the engine reacts by moving forward. If there is a flaw in the system, such as an unexpected obstruction, the fan blade can break, spin off, and harm other engine components. Fan casings, therefore, need to be strong enough to contain errant blades and damage-tolerant to withstand the punishment of a loose blade-turned-projectile. NASA has spearheaded research into improving jet engine fan casings, ultimately discovering a cost-effective approach to manufacturing damage-tolerant fan cases that also boast significant weight reduction. In an aircraft, weight reduction translates directly into fuel burn savings, increased payload, and greater aircraft range. This technology increases safety and structural integrity; is an attractive, viable option for engine manufacturers, because of the low-cost manufacturing; and it is a practical alternative for customers, as it has the added cost saving benefits of the weight reduction.

Source record↗
NASA NTRS1992

Prediction of propellant behavior in spinning flow of a space motor

A model for 2-phase flow dynamics in a spinning spherical rocket motor, developed for the Ofeq satellite program, is based on the sectional approach to solution of the flow equations. An experimental model was built, to enable the motion of the aluminum/aluminum-oxide particles resulting from combustion within a solid-fuel motor to be simulated by injected paraffin droplets. The injected droplets included under-5 micrometer droplets which move with the gas stream and larger droplets, averaging 20 micrometer diameter, which simulate the motion of aluminum particles. The test chamber comprised a pair of cylindrical pyrex tubes with a sharp contraction in diameter, rotated at various speeds by a frequency-controllable motor. An optical system, based on a 5 W argon ion laser with a beam splitter and frequency shifter, mounted on a movable table, facilitated sectional measurements of the three velocity components and determination of size-velocity relationships. Preliminary results indicate that the effect of rotation on axial velocity is negligible, while its effect on tangential velocity approximates to solid-body rotation.

Gany, A.↗
NASA NTRS1985

Tone excited jets. IV - Acoustic measurements

Attention is given to acoustic results from an experiment designed to deepen insight into the noise generated by a tone-excited jet, with emphasis on the mechanism of broadband jet noise amplification. Results are presented for both heated and unheated jets, with and without the effect of forward flight simulation over a range of excitation frequencies and levels, and for zero-order and first-order spinning modes. Broadband jet noise amplifications of up to 5 dB have been observed in this study. Relative velocity effects are the same for both excited and unexcited jets. It is concluded that small scale turbulence generates the additional broadband noise upon excitation of the jet by an upstream-injected discrete tone acoustic wave.

Ahuja, K. K.↗
NASA NTRS2012

The Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO)

Following recommendations from the 2010 "New Worlds, New Horizons" (NWNH) report, the Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO) concept streamlines the International X-ray Observatory (IXO) mission to concentrate on the science objectives that are enabled by high-resolution spectroscopic capabilities. AXSIO will trace orbits close to the event horizon of black holes, measure black hole spin for tens of supermassive black holes (SMBH), use spectroscopy to characterize outflows and the environment of AGN during their peak activity, observe 5MBH out to redshift z=6, map bulk motions and turbulence in galaxy clusters, find the missing baryons in the cosmic web using background quasars, and observe the process of cosmic feedback where black holes and supernovae inject energy on galactic and intergalactic scales. These measurements are enabled by a 0.9 sq m collecting area at 1.25 keV, a micro calorimeter array providing high-resolution spectroscopic imaging and a deployable high efficiency grating spectrometer. AXSIO delivers a 30-fold increase in effective area for high resolution spectroscopy. The key simplifications are guided by recommendations in the NWNH panel report include a reduction in focal length from 20m to 10m, eliminating the extendable optical bench, and a reduction in the instrument complement from six to two, avoiding a movable instrument platform. A focus on spectroscopic science allows the spatial resolution requirement to be relaxed to 10 arc sec (with a 5 arc sec goal). These simplifications decrease the total mission cost to under the $2B cost to NASA recommended by NWNH. AXSIO will be available to the entire astronomical community with observing allocations based on peer-review.

White, Nicholas E.↗
NASA NTRS2013

NanoTHOR: Low-Cost Launch of Nanosatellites to Deep Space

The rapid development of high-performance nanosatellite platforms is enabling NASA and commercial ventures to consider performing missions to the asteroids, the Moon, and Mars at lower cost and on shorter timelines than traditional large spacecraft platforms. Currently, however, opportunities to launch secondary payloads to Earth escape are rare, and using chemical rockets to propel secondary payloads from LEO rideshares to escape is problematic due to the risks posed to primary payloads. The NanoTHOR effort has explored the technical feasibility and value proposition for using a simple momentum-exchange tether system to scavenge orbital energy from an upper stage in geostationary transfer orbit in order to boost nanosatellites to Earth escape. A NanoTHOR module will accomplish rapid transfer of a nanosatellite to an escape trajectory by deploying the nanosat at the end of a long, slender, high-strength tether and then using winching in the Earth's gravity!gradient to convert orbital angular momentum into rotational angular momentum. In the Phase I effort, we developed and simulated methods for controlling tether deployment and retraction to spin up a tether system, and these simulations demonstrated the feasibility of providing delta-Vs on the order of 800 m/s with a simple, low-mass tether system. Moreover, the NanoTHOR tether can act as a reusable in-space upper stage, boosting multiple nanosatellites on a single launch and doing so with a mass requirement lower than that of conventional rocket technologies. Serving as an escape-injection stage, NanoTHOR can enable a 6U CubeSat to deliver small payloads to Mars orbit, lunar orbit, and rendezvous with at least 110 of the known near-Earth asteroids. Evaluation of the technology readiness of the component technologies required for NanoTHOR indicate that the hardware required is all mid-TRL, and the lower-TRL controls and integration components can be advanced to mid-TRL with modest investment. By scavenging orbital energy from upper stages without any stored energy or propellant requirements, NanoTHOR permits deep-space nanosat missions to launch on rideshare opportunities, enabling NASA and commercial ventures to conduct affordable and frequent missions to explore deep space destinations.

Hoyt, Robert↗
NASA NTRS1983

Simulations of beam excited minor species gyroharmonics in the Porcupine experiment

An active experiment for the study of wave particle interaction in the presence of a perpendicular beam type distribution is considered. The experiment involves the injection of a beam perpendicular to the magnetic field. Beam parameters can then be varied while local plasma parameters and associated wave phenomena are measured. Such an experiment was conducted as part of the Porcupine project. The present investigation has the objective to explain theoretically and by means of plasma particle simulations, some of the wave observations obtained. In the experiment, a main rocket payload and four subpayloads were employed. The subpayloads were ejected radially in different directions at an altitude of 240 km. One of the spinning subpayloads contained a plasma gun which emitted a beam of 200 eV xenon ions toward the main payload. The data recorded on the main payload revealed the existence of electrostatic waves with peaks at hydrogen gyroharmonics. A series of computer simulations approximating the xenon experiment was performed. The interpretation of the data is discussed.

Roth, I.↗
NASA NTRS2019

New Test Rig to Measure Alternating Current Losses of Both Low and High Critical Temperature Superconductors

This paper presents the design, development, operation, and test capabilities of a proposed superconducting coil testbed to measure alternating current (AC) losses at the NASA Glenn Research Center. Superconducting AC losses are important in the design of electric stators and rotors, power transmission lines, transformers, fault current limiters, magnets, and superconducting energy storage (not batteries). The new liquid-hydrogen-based rig will allow superconducting testing across a wide range of test parameters, including injected current up to 400 A, frequency (0 to 400 Hz), magnetic field (0 to 0.6 T), phase angle between induced voltage and injected current (–180° to 180°), coil coolant temperature (18 to 28 K), and AC power loss (5 to 30 W). While the target application of interest is 20 K superconducting MgB2 (the only superconductor that can presently be made with low losses) stator coils for future electric machines, the rig can accommodate test articles (TAs) with straight wire, tape, cables, coils of any shape, any allowable combination of superconducting wire and fluid (e.g., yttrium barium copper oxide (YBCO) coils and liquid nitrogen), and AC or direct current (DC) testing. The new spin rig builds upon the existing Air Force spin rig through a more flexible mode of fluid control, a wider gap space (up to 10.2 cm) for TAs, and the ability to accommodate TAs over a wider range of operating temperatures (18 to 95 K) using liquid hydrogen, gaseous helium, or liquid nitrogen as the working fluid, thus supporting direct cooled machines below 77 K.

liquid hydrogen↗