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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Simultaneous observation of the plasma sheet in the near earth and distant magnetotail - ISEE-1 and ISEE-3

Particle data have been acquired by the 1981-025 and 1982-019 spacecraft at geosynchronous orbit, as well as ISEE-1 in the near earth geomagnetic tail, and ISEE-3 in the distant geomagnetic tail. These observations are supplemented by ground-based magnetograms from near local midnight stations. Attention is given to a substorm recovery phase, and to observations of ion beams at the plasma sheet boundary in the near earth and distant tail, respectively, which are found to flow in opposite directions.

Scholer, M.↗
NASA NTRS1985

LIMS HNO3 data above 5 mbar - Corrections based on simultaneous observations of other species

The Limb Infrared Monitor of the Stratosphere (LIMS) instrument monitored four trace gases (O3, H2O, HNO3, and NO2) and the temperature in the stratosphere and mesosphere. Recently, the seven months LIMS data, including the time from Oct. 25, 1978 to May 29, 1979, have become available to the scientific community. It is pointed out that the measurements are of great use in studying the dynamics and chemistry of the stratosphere. The LIMS HNO3 data appear to show a realistic behavior below 5 mbar, but above 5 mbar, the data appear to be too high. In the present paper, the LIMS HNO3 behavior is discussed, taking into account the reason for the unrealistic appearance of the data. Other LIMS data are used to derive HNO3 above 5 mbar through the intermediate species OH.

Jackman, C. H.↗
NASA NTRS1986

Active extragalactic sources - Nearly simultaneous observations from 20 centimeters to 1400 A

IRAS, IUE, and ground-based optical, NIR, mm and submm, and radio observations obtained mainly on Apr. 9-23, 1983, are reported for 19 active extragalactic sources and eight control sources. The overall spectra of the compact active sources are shown to be well represented by continuous-curvature functions such as parabolas. The spectra are found to be consistent with models involving continuous particle injection (with synchrotron losses) or first-order Fermi acceleration (with escape and synchrotron losses), but not with models using relativistic Maxwellian electron distributions.

Landau, R.↗
NASA NTRS1987

Simultaneous observations of the near-earth and distant geomagnetic tail during a substorm by ISEE-1, ISEE-3 and geostationary spacecraft

The structure of the geomagnetic tail during a substorm is investigated by combining plasma, magnetic field, and energetic particle data from the ISEE-3 spacecraft in the deep tail with similar near-earth observations from ISEE-1 and geostationary spacecraft. The observations can be interpreted in terms of the neutral-line model of substorms and indicate the formation of a closed-loop field region (plasmoid) following substorm onset, which is ejected down the tail. The plasmoid is observed to have a double-loop field strucure. This may be the result of a second substorm onset occurring about 25 min after the first, producing a further near-earth neutral line and closed field loop. During the substorm recovery phase, the substorm neutral line moves tailward to beyond 130 earth radii from earth by some 3 h after substorm onset.

Richardson, I. G.↗
NASA NTRS1987

Upstream waves simultaneously observed by ISEE and UKS

Measurements obtained in the solar wind by ISEE-2 and the United Kingdom Subsatellite (UKS) have been examined for observations of upstream waves. These data reveal that the waves in the foreshock region are enhanced at all frequencies from at least 0.003 Hz to 0.5 Hz. The wave spectra generally have a spectral peak, but this peak is usually broad and the peak frequency depends on the position of the spacecraft. Generally, the spectra seen at the two spacecraft are most similar at high frequencies and least similar at low frequencies. The geometry of the interaction is displayed in the plane containing the magnetic field, the solar wind velocity, and the spacecraft location. However, this coordinate system does not order all the observed wave properties. It does not clearly explain or order the handedness of the waves, or their direction of propagation. It is clear that the upstream region is inherently three-dimensional. The position-dependent nature of the upstream waves indicates that comparisons between ground-based measurements and in-situ observations must be undertaken with some caution.

Russell, C. T.↗
NASA NTRS1987

The lower thermosphere wind regime from simultaneous observations over Euroasia (Collm, Dushanbe, Frunze)

The circulation in the lower thermosphere as determined from the results of measurements in 1984 is considered. Ionospheric drift measurements were taken using the method of spaced reception in the long wave range. Other measurements were taken using the D2 method. Average daily values of wind velocity were used. Discontinuity of measurements ranged from a day to a week. Preliminary data were reduced to the common average height of 93 km with the help of vertical profiles of wind velocity components. The results of measurements of zonal and meridional wind velocity components are presented. Zonal circulation changes from westerly to easterly winds were observed in winter, in periods of spring time reversal and during stratomesospheric rises in temperature.

Schminder, R.↗
NASA NTRS1989

Simultaneous observations of electrostatic oxygen cyclotron waves and ion conics

A sounding rocket launched to 927 km apogee during an auroral substorm encountered regions of large quasi-static electric fields (not greater than 400 mV/m), ion conics (up to 700 eV maximum observed energy), and fluctuating electric fields near the oxygen cyclotron frequency. Since the fluctuating electric fields frequently exhibited spectral peaks just above the local oxygen cyclotron frequency, and since the fluctuating electric fields were linearly polarized, they are positively identified as electrostatic oxygen cyclotron waves (EOCW). The maximum amplitude of the EOCW was about 5 mV/m rms. The EOCW closely correlated with the presence of ion conics. Because of the relatively low amplitude of the EOCW and their relatively low coherence, it cannot be concluded that they are solely responsible for the production of the ion conics.

Kintner, P. M.↗
NASA NTRS1989

Characteristics of type III bursts in the solar wind from simultaneous observations on board ISEE-3 and Voyager

The properties of solar type III bursts observed aboard ISEE-3 and Voyager that originate behind the sun are analyzed and compared to those originating on the near side. The measurement of the burst parameters and the correction for proximity effects are described. The diminution of flux densities, the increase of source sizes, the difference of source azimuths and elevations, the change of spectral properties, and the anomalous delays in burst arrival time at one spacecraft relative to another are determined. Many of the observations imply that the beaming of type III radiation is much more widespread at all frequencies than has been derived from statistical studies. The effective beam appears to consist of at least two components: a Gaussian core of half width about 60 deg, and a very broad halo that extends to 180 deg with an amplitude of a few percent.

Lecacheux, A.↗
NASA NTRS1992

Lidar Probing of the Mesosphere: Simultaneous Observations of Sporadic Sodium and Iron Formations, Calcium Ion Layers, Neutral Temperature and Winds

Meteoritic ablation in the upper atmosphere is the commonly accepted source of the mesospheric metals between 80 and 105 km. The vertical and temporal behavior of some of these metals can be probed with high accuracy and resolution using resonance fluorescence lidar techniques. Of considerable interest in recent years has been the sporadic and rapid formation of thin, dense enhancements in these metallic layers. Since late Mar. 1991, the UIUC CEDAR lidar system, located at the Urbana Atmospheric Observatory, has been routinely operating at the Fe resonance line of 372 nm in order to probe the mesospheric Fe layer. In Nov. 1991, the capability to investigate mesospheric Ca(+) at the resonance line of 393.4 nm was added. The lidar's eximer-pumped dye laser uses Exciton QUI laser dye dissolved in p-dioxane, which can lase at both the Fe and Ca(+) frequencies. Various aspects of this investigation are discussed.

Kane, Timothy J.↗
NASA NTRS1992

Simultaneous observations of coronal bright points in X-ray and radio wavelengths

We present a first explicit comparison of coronal bright points in soft X-ray and radio wavelengths, using the Soft X-ray Telescope aboard the Yohkoh spacecraft and the Very Large Array. About half of the 33 compact sources identified in a 20-cm full-disk map appear as X-ray bright points in the X-ray data. The other half apparently corresponds to unipolar regions with enhanced magnetic fields. Thus, the identification of radio bright points alone cannot reliably serve as a proxy for X-ray bright points. A preliminary analysis reveals that bright points commonly observed at 20 cm and in X-rays have temperatures of (1.4-2.9) x 10 exp 6 K and emission measures of (0.4-2.5) x 10 exp 45/cu cm. The observed brightness temperatures at 20 cm (1-2.5) x 10 exp 5 K can be explained in terms of optically thin free-free emission from a plasma with these parameters.

Nitta, Nariaki↗
NASA NTRS1993

Simultaneous observations of subauroral electron temperature enhancements and electromagnetic ion cyclotron waves

Observational results from an investigation of LF (0.5-4.0 Hz) electromagnetic ion cyclotron waves and subauroral electron temperature enhancements recorded from the DE-2 satellite are presented. Four different wave events were analyzed, all recorded at magnetic latitudes from 57-60 deg, magnetic local times from 8-14 hr, and altitudes from 600-900 km. The peak wave amplitudes during the events ranged from 8-70 nT and 5-30 mV/m in the magnetic and electric field, respectively. Te enhancements at the time of the waves were observed in three of four events. A linear relationship between the wave magnetic field spectral density and Te enhancements was found for these events. The Te enhancements were also correlated with an enhanced flux of low energy electrons. During one event (82104) an enhanced flux of electrons were observed at energies up to 50 eV and at nearly all pitch angles, although the flux was largest in the precipitating and upflowing directions. It is suggested that the waves are responsible for heating the low energy electrons which precipitate to the ionosphere and produce the observed Te enhancements. The upflowing electron population appears to be heated at ionospheric altitudes, below the DE-2 satellite.

Erlandson, R. E.↗
NASA NTRS1997

Gamma-Ray Burst Arrival Time Localizations: Simultaneous Observations by Mars Observer, Compton Gamma Ray Observatory and Ulysses

Between 1992 October 4 and 1993 August 1, concurrent coverage by the Compton Gamma Ray Observatory (CGRO), Mars Observer (MO), and Ulysses spacecraft was obtained for 78 gamma-ray bursts (GRBs). Although most of these were below the MO and Ulysses thresholds, nine were positively detected by all three spacecraft, with data quality adequate for quantitative localization analysis. All were localized independently to approximately 2 deg accuracy by the CGRO Burst and Transient Source Experiment (BATSE). We computed arrival-time error boxes with larger dimensions ranging from a few arcminutes to the diameters of the BATSE-only boxes and with smaller dimensions in the arcminute range. Three events are of particular interest: GB 930704 (BATSE 2428) has been described as a possible repeater. The arrival-time information is consistent with that hypothesis, but only just so. The GB 930706 (2431) box, at approximately 1 min x 4 min, is the only one this small obtained since Pioneer Venus Orbiter (PVO) entered the Venusian atmosphere in 1992 October. Sensitive radio and optical observations of this location were made within 8 and 9 days of the burst, but no counterpart candidates were identified. GB 930801 (2477) is the first GRB that had its localization improved by taking into account BATSE Earth occultation.

Laros, J. G.↗
NASA NTRS1997

Ulysses and WIND simultaneous observations of the radio emission associated with the 6-7 January 1997 coronal mass ejection

The three dimensional source location of interplanetary type 2 radio bursts is intended to be determined from two spacecraft observations, performed by the radio receivers onboard the WIND and Ulysses spacecraft and associated with the interplanetary coronal mass ejection detected by the large advanced spectrometer coronagraph (LASCO) from the SOHO spacecraft. The intensity time profiles recorded by WIND and Ulysses were compared and their directivity is found to vary from one component of radio emission to another. The three dimensional location was obtained by radio triangulation and was deduced from the direction measured at WIND and the difference of the arrival times measured at both spacecraft. The sensitivity of both determination methods to wave scattering and refraction was discussed.

Hoang, S.↗
NASA NTRS2006

Simultaneous observation of the radiation environment inside and outside the ISS

The low-Earth orbit (LEO) radiation environment has been directly observed by the IV and EV charged particle directional spectrometers (CPDS) aboard the International Space Station (ISS). The EV instrument is mounted on the S0 truss of the ISS and consists of three separate silicon detector telescopes which are oriented in different directions. The IV instrument is a single silicon detector telescope located inside the US Laboratory module of the ISS. We report on the current state of the data analysis for these instruments, which includes the proton and He stopping particle spectra, relative CNO abundances, LET spectra, and measured dose rate as a function of time.

Lee, K. T.↗