Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Coil”

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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Feasibility study of a swept frequency electromagnetic probe (SWEEP) using inductive coupling for the determination of subsurface conductivity of the earth and water prospecting in arid regions

Techniques developed for electromagnetic probing of the lunar interior, and techniques developed for the generation of high power audio frequencies were combined to make practical a magnetic inductive coupling system for the rapid measurement of ground conductivity profiles which are helpful when prospecting for the presence and quality of subsurface water. A system which involves the measurement of the direction, intensity, and time phase of the magnetic field observed near the surface of the earth at a distance from a horizontal coil energized so as to create a field that penetrates the earth was designed and studied to deduce the conductivity and stratification of the subsurface. Theoretical studies and a rudimentary experiment in an arid region showed that the approach is conceptually valid and that this geophysical prospecting technique can be developed for the economical exploration of subterranean water resources.

Latorraca, G. A.↗
NASA NTRS1974

Study of the relation between Pc 3 micropulsations and magnetosheath fluctuations and for the multisatellite multimeasurement investigation of earths bow shock

Hourly averages of HEOS A interplanetary field and plasma parameters are compared with micropulsation spectrograms taken by auroral zone stations. Visual evaluation of tungsten induction coil records and a statistical summary indicate a class of pulsations sometimes in the Pc 3, sometimes in the Pc 4 range, whose appearance correlates with solar wind field flow alignment. It is concluded that there is a pulsation phenomenon of variable period strongly associated with certain interplanetary field directions.

Greenstadt, E. W.↗
NASA NTRS1973

Initial results from the NASA Lewis Bumpy Torus experiment

Initial results are given for low power operation of the NASA Lewis Bumpy Torus experiment in which a steady-state ion heating method based on a modified Penning discharge is applied to a bumpy torus confinement geometry. The magnet facility consists of 12 superconducting coils capable of 3.0 T each and equally spaced in a toroidal array 1.52 m in major diameter. A 18 cm i.d. anode ring is located at each of the 12 midplanes and is maintained at high positive potentials by a dc power supply. Initial observations indicate electron temperatures from 10 to 150 eV, and ion kinetic temperatures from 200 eV to 1200 eV. Two modes of operation with different radial density profiles can be achieved, depending on the background pressure applied.

Roth, J. R.↗
NASA NTRS1974

On the local time dependence of the bow shock wave structure

In the first 6 months after its launch, Ogo 3 crossed the earth's bow shock over 500 times. From this group, a set of 494 shock crossings were chosen for analysis. These crossings, as they were recorded by the UCLA/JPL search coil magnetometer, were scanned and classified according to the nature of the plasma waves detected near the shock. More than 85% of the shocks detected fell into a single category showing the predominance of two independent wave trains near the shock, the higher frequency appearing upstream and the lower downstream. The other 15%, which constitute an upper limit, appear to be composed of shocks dominated by a single wave pattern and of chaotic shocks showing no orderly progression of wave frequencies as the shock was penetrated. This division of wave pattern was found to occur at all local times, that is, in all regions where the satellite penetrated the shock.

Olson, J. V.↗
NASA NTRS1974

A correlated study of ELF waves and electron precipitation on Ogo 6

The Ogo 6 ELF chorus records from the search coil magnetometer have been compared with simultaneous electron precipitation records. The chorus signals observed in the vicinity of field lines passing through the outer magnetosphere were characteristically accompanied by electron precipitation in the same region. Both the chorus and the precipitation records consisted of a series of sharp peaks. Although in some cases chorus and precipitation peaks appeared to be associated, the observed peaks did not in general coincide. Comparison of the chorus measurements on Ogo 6 and Ogo 5 suggests a model in which the chorus is ducted along field lines to within less than 1 earth radius above the Ogo 6 orbit after which it diverges from the field lines and is deflected toward the local vertical. The result is equatorward skewing of the average wave pattern with respect to the precipitation pattern.

Holzer, R. E.↗
NASA NTRS1974

The origin and propagation of chorus in the outer magnetosphere

Wave normals of chorus in the outer magnetosphere have been determined for the first time from data obtained with the Ogo 5 search coil magnetometer. These measurements combined with simultaneous information concerning geomagnetic field, plasma density, and the electron energy and pitch angle distributions provide a consistent picture of the generation, propagation, and subsequent damping of chorus in agreement with theory. Specifically, the data are consistent with chorus generation within 25 deg of the equatorial plane on the dayside and within 2 deg on the nightside. Chorus is generated by a Doppler-shifted cyclotron resonance with electrons between 5 and 150 keV but only when the pitch angle distribution is peaked at 90 deg to the local magnetic field and the anisotropy exceeds a critical value.

Burton, R. K.↗
NASA NTRS1974

Plasmaspheric hiss intensity variations during magnetic storms

The storm time intensity variations of ELF electromagnetic emissions have been studied by using the Ogo 6 search coil magnetometer. Low-latitude signals exhibit a sharp low-frequency cutoff and are identified as plasmaspheric hiss. Such waves show pronounced intensification during the recovery phase of magnetic storms but remain close to background levels during the storm main phase. This behavior is consistent with cyclotron resonant generation within the plasmasphere as the latter expands into the intensified belt of outer zone electrons during the storm recovery.

Smith, E. J.↗
NASA NTRS1974

Magnetogasdynamic compression of a coaxial plasma accelerator flow for micrometeoroid simulation

A new configuration of a coaxial plasma accelerator with self-energized magnetic compressor coil attached is described. It is shown that the circuit may be treated theoretically by analyzing an equivalent circuit mesh. The results obtained from the theoretical analysis compare favorably with the results measured experimentally. Using this accelerator configuration, glass beads of 125 micron diameter were accelerated to velocities as high as 11 kilometers per second, while 700 micron diameter glass beads were accelerated to velocities as high as 5 kilometers per second. The velocities are within the hypervelocity regime of meteoroids.

Igenbergs, E. B.↗
NASA NTRS1974

Features of polar cusp electron precipitation associated with a large magnetic storm

Measurements of precipitating electrons made by the OGO-4 satellite reveal several interesting phenomena in the polar cusp. Extremely high fluxes of 0.7 keV electrons were observed in the polar cusp ninety minutes following the sudden commencement of a very large magnetic storm. Structured, fairly high fluxes of 7.3 keV electrons were also observed in the cusp region, accompanied by very strong search coil magnetometer fluctuations, indicative of strong field-aligned currents. The observations confirm previously reported latitudinal shifts in the location of the polar cusp in response to southward interplanetary magnetic fields.

Berko, F. W.↗
NASA NTRS1975

Modification, fabrication, testing and delivery of ITT model F4012 RP tube/coil assembly

Results of the improvement program for the ITT model F4012 RP image dissector tube and coil are presented. This program undertaken to improve the characteristics of this assembly to make it more accurate for the Large Space Telescope trackers' applications. Comparisons are given of the performance of the new components and the original design goals. Recommendations for further tests and/or design changes to further improve the F4012 tube/coil assembly performance are given.

Source record↗
NASA NTRS1975

Liquid neon heat transfer as applied to a 30 tesla cryomagnet

A 30-tesla magnet design is studied which calls for forced convection liquid neon heat transfer in small coolant channels. The design also requires suppressing boiling by subjecting the fluid to high pressures through use of magnet coils enclosed in a pressure vessel which is maintained at the critical pressure of liquid neon. This high pressure reduces the possibility of the system flow instabilities which may occur at low pressures. The forced convection heat transfer data presented were obtained by using a blowdown technique to force the fluid to flow vertically through a resistance heated, instrumented tube.

Papell, S. S.↗
NASA NTRS1975

Investigation of system integration methods for bubble domain flight recorders

System integration methods for bubble domain flight records are investigated. Bubble memory module packaging and assembly, the control electronics design and construction, field coils, and permanent magnet bias structure design are studied. A small 60-k bit engineering model was built and tested to demonstrate the feasibility of the bubble recorder. Based on the various studies performed, a projection is made on a 50,000,000-bit prototype recorder. It is estimated that the recorder will occupy 190 cubic in., weigh 12 lb, and consume 12 w power when all of its four tracks are operated in parallel at 150 kHz data rate.

Chen, T. T.↗
NASA NTRS1975

Study on processing immiscible materials in zero gravity

An experimental investigation was conducted to evaluate mixing immiscible metal combinations under several process conditions. Under one-gravity, these included thermal processing, thermal plus electromagnetic mixing, and thermal plus acoustic mixing. The same process methods were applied during free fall on the MSFC drop tower facility. The design is included of drop tower apparatus to provide the electromagnetic and acoustic mixing equipment, and a thermal model was prepared to design the specimen and cooling procedure. Materials systems studied were Ca-La, Cd-Ga and Al-Bi; evaluation of the processed samples included the morphology and electronic property measurements. The morphology was developed using optical and scanning electron microscopy and microprobe analyses. Electronic property characterization of the superconducting transition temperatures were made using an impedance change-tuned coil method.

Reger, J. L.↗
NASA NTRS1975

Multifilamentary niobium tin superconductor tape

In the method proposed for fabricating multifilamentary Nb3Sn tape, filamentary superconducting paths are produced in standard commercial superconductor tape by chemical milling of separator slots through the Nb3Sn layer. The multifilament configuration features a matrix of ten 1.2 mm wide parallel helical superconducting paths along the length of the tape. The paths are spaced 0.4 mm apart. Tapes tested as small pancake coils demonstrated the integrity and continuity of the matrix, and showed that critical current was sustained in direct proportion to retained superconductor.

Brisbin, P. H.↗
NASA NTRS1975

The Pioneer XI high field fluxgate magnetometer

The high field fluxgate magnetometer experiment flown aboard the Pioneer XI spacecraft is described. This extremely simple instrument was used to extend the spacecraft's upper-limit measurement capability by approximately an order of magnitude (from 0.14 mT to 1.00 mT) with minimum power and volume requirements. This magnetometer was designed to complement the low-field measurements provided by a helium vector magnetometer and utilizes magnetic ring core sensors with biaxial orthogonal sense coils. The instrument is a single-range, triaxial-fluxgate magnetometer capable of measuring fields of up to 1 mT along each orthogonal axis, with a maximum resolution of 1 microT.

Acuna, M. A.↗
NASA NTRS1976

Improved interferometer beam splitter

Cat's-eye retroreflector attached to motor driven lead screw allows low-frequency changes in optical path. Moving-coil actuator attached to other retroreflector allows mid-frequency movements. High-frequency movements are achieved by employing piezoelectric transducer attached to secondary mirror of same retroreflector.

Schindler, R. A.↗
NASA NTRS1977

Simplified cut-core inductor

Technical memorandum describes design of linear reactor fabricated from grain-oriented steel. It includes design charts and nomographs and illustrates design of grain-oriented inductor via seven-step example. Typical values of core inductance, operating frequency, and coil current (dc and ac) are given.

Mclyman, W. T.↗