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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

The structure of the inner heliosphere from Pioneer Venus and IMP observations

The IMP 8 and Pioneer Venus Orbiter (PVO) spacecraft explore the region of heliographic latitudes between 8 deg N and 8 deg S. Solar wind observations from these spacecraft are used to construct synoptic maps of solar wind parameters in this region. These maps provide an explicit picture of the structure of high speed streams near 1 AU and how that structure varies with time. From 1982 until early 1985, solar wind parameters varied little with latitude. During the last solar minimum, the solar wind developed strong latitudinal structure; high speed streams were excluded from the vicinity of the solar equator. Synoptic maps of solar wind speed are compared with maps of the coronal source surface magnetic field. This comparison reveals the expected correlation between solar wind speed near 1 AU, the strength of the coronal magnetic field, and distance from the coronal neutral line.

Gazis, P. R.↗
NASA NTRS1993

Pioneer Venus and IMP 8 observations of the latitude dependence of the solar wind

Solar wind speeds and magnetic field data from the Pioneer Venus Orbiter (0.7 AU) and IMP 8 (1 AU) have been compared to infer the latitudinal structure of the solar wind in the inner heliosphere between 1984 and 1987. The solar wind in the inner heliosphere was found to exhibit an unusual structure during the last solar minimum (1986-1987). High-speed streams were excluded from the vicinity of the solar equator, and the solar wind at low heliographic latitudes (less than 3 deg) was characterized by low-speed solar wind with irregular fluctuations in velocity. At higher latitudes the solar wind had a conventional stream structure with two high-speed streams per solar rotation. While the velocities of these high-speed streams did not appear to vary significantly with latitude, the latitudinal gradients at the equatorward boundaries of high-speed streams were high.

Gazis, P. R.↗
NASA NTRS1994

Surface science capabilities from IMP spectral imaging

The Imager for Mars Pathfinder (IMP) had a single 12-position filter wheel for one of its two 'eyes'. Originally eight, and then nine, of these filters were optimized for surface science, and three narrow-band filters for atmospheric science. Because of some design revisions we will now have filter wheels on both sides. The wheels for right and left eyes are identical, 12 filter positions each, and rigidly linked to the same rotation shaft. There are now 13 surface filters, in addition to 5 for atmospheric observations. Details of all the filter positions are tabulated and approximate gaussian bandpasses for the 13 surface filters are shown.

Singer, Robert B.↗
NASA NTRS1996

Studies using IMP, Voyager and Pioneer cosmic ray data to determine the size of the heliosphere

The purpose of this project was to use the cosmic ray data from the IMP, Voyager and Pioneer spacecraft in the heliosphere out to approximately 65 AU to estimate the size of the heliosphere. We used several techniques to develop a consistent picture of the size of the heliosphere. The first method used a response function approach which determined the intensity as a function of time by scaling the modulation effect as they move outward and eventually reach the boundary of the heliosphere. In this model the effects of transient cosmic ray disturbances is included. A second approach using the perturbation method in which drifts are considered as a perturbation to the standard diffusion-convection modulation models was not fully developed. In a third approach the location of the modulation boundary beyond the termination shock was estimated using observations of the intensity and radial gradients between Voyager 2 and Pioneer 10 along with new estimates of the interstellar intensity of more than 70 MeV galactic cosmic rays. Using this method we found that for 7 years, from 1983 to 1990, the modulation boundary remained constant at 83 +/- 5 AU. We infer from these studies that a modulation boundary can be estimated only by extrapolating the observed radial gradients when the solar magnetic field polarity is such that cosmic-ray particles are drifting in the heliosphere inward toward the Earth along the neutral sheet. The boundary distance is larger than the estimates of the location of the termination shock at 67 +/- 5 AU using the same method. Two other studies partially supported by this grant are attached. The first deals with the recovery period of the greater than 70 MeV cosmic rays in the outer heliosphere from 1992-1995. In the second paper we compare the rigidity dependence of the 11-year cosmic ray variation at the Earth in two cycles of opposite solar magnetic field polarity.

Lockwood, John A.↗
NASA NTRS2002

Support of Data Access for the IMP-8 UMD Experiment

This grant report provides information on data from the Interplanetary Monitoring Platform-8 (IMP-8). Topics covered include: (1) the science involved in the project; (2) the collection of data; (3) the processing of data; (4) the submission of data to other facilities; (5) the availability of data on the world wide web (WWW). Graphs are also included of data on the interstellar medium.

Ipavich, F. M.↗
NASA NTRS2002

Investigation of Solar Wind Correlations and Solar Wind Modifications Near Earth by Multi-Spacecraft Observations: IMP 8, WIND and INTERBALL-1

The foundation of this Project is use of the opportunity available during the ISTP (International Solar-Terrestrial Physics) era to compare solar wind measurements obtained simultaneously by three spacecraft - IMP 8, WIND and INTERBALL-1 at wide-separated points. Using these data allows us to study three important topics: (1) the size and dynamics of near-Earth mid-scale (with dimension about 1-10 million km) and small-scale (with dimension about 10-100 thousand km) solar wind structures; (2) the reliability of the common assumption that solar wind conditions at the upstream Lagrangian (L1) point accurately predict the conditions affecting Earth's magnetosphere; (3) modification of the solar wind plasma and magnetic field in the regions near the Earth magnetosphere, the foreshock and the magnetosheath. Our Project was dedicated to these problems. Our research has made substantial contributions to the field and has lead others to undertake similar work.

Paularena, Karolen I.↗
NASA NTRS2003

Reduction and Analysis of Data from the IMP 8 Spacecraft

The IMP 8 spacecraft was launched in 1973 and the MIT solar wind Faraday Cup experiment continues to produce excellent data except for a slightly increased noise level. Those data have been important for determining the solar wind interaction with Earth's magnetic field; studies of interplanetary shocks; studies of the correlation lengths of solar wind features through comparisons with other spacecraft; and more recently, especially important for determination of the regions in which the Wind spacecraft was taking data as it passed through Earth's magnetotail and for understanding the propagation of solar wind features from near 1 AU to the two Voyager spacecraft.

Source record↗
NASA NTRS2007

IMP 8 GME Particle Observations Over Three Solar Cycles

The Goddard Medium Energy experiment on the IMP 8 spacecraft has made nearly continuous observations of the near-Earth energetic particle environment from its launch in October, 1973 until near present. We summarize several aspects of these observations, including solar energetic particle events, CIR-associated events, and cosmic ray modulations. In particular, we note that, as expected fiom the pattern of smaller recurrent (27 day) cosmic ray modulations seen in the mid 1980's A less than 0 solar minimum compared to the previous and following (A greater than 0) minima, recurrent modulations are again reduced in the current solar minimum.

Richardson, Ian↗
NASA NTRS1964

Imp d&e feasibility study

Launching of Interplanetary Monitoring Platform spacecraft into lunar orbit

INTERPLANETARY SPACECRAFT↗
DOE OSTI2020

In cellulo crystallization of Trypanosoma brucei IMP dehydrogenase enables the identification of genuine co-factors

Sleeping sickness is a fatal disease caused by the protozoan parasite Trypanosoma brucei (Tb). Inosine-5’-monophosphate dehydrogenase (IMPDH) has been proposed as a potential drug target, since it maintains the balance between guanylate deoxynucleotide and ribonucleotide levels that is pivotal for the parasite. Here we report the structure of TbIMPDH at room temperature utilizing free-electron laser radiation on crystals grown in living insect cells. The 2.80 Å resolution structure reveals the presence of ATP and GMP at the canonical sites of the Bateman domains, the latter in a so far unknown coordination mode. Consistent with previously reported IMPDH complexes harboring guanosine nucleotides at the second canonical site, TbIMPDH forms a compact oligomer structure, supporting a nucleotide-controlled conformational switch that allosterically modulates the catalytic activity. The oligomeric TbIMPDH structure we present here reveals the potential of in cellulo crystallization to identify genuine allosteric co-factors from a natural reservoir of specific compounds.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP)

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R and D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe{sup 27+}, 236 eμA Xe{sup 30+}, and 64 eμA Xe{sup 35+}. Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi{sup 30+} and 202 eμA U{sup 33+} have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Cooling for SC devices of test cryomodule for ADS Injector II at IMP

The superconducting half-wave resonance cavities connected in series with superconducting solenoids will be applied to the Injector II of the Accelerator Driven Sub-critical System (ADS) to be built at the Modern Physics Institute, China. A test system has been developed for the purpose of performance test of the HWR cavities as well as validating the relevant technique for cooling the cavity and the solenoids together. It mainly comprises a cryogenic valve box (TVB), a test cryomodule (TCM1) and transfer lines. The TCM1 includes one HWR cavity, two superconducting solenoids, one cold BPM and their cooling system. The design of the TCM1 cryostat was carried out by the Shanghai Institute of Applied Physics (SINAP), CAS. Both the cavity and the solenoids will work at 4.4 K by bath cooling. The fast cooling down for the cavity from around 100 K to 120 K is required to avoid degrading of the cavity performance. After cool down and before energization, the solenoids should be warmed up to above 10 K and re-cooled down for the purpose of degaussing. The TCM1 can not only be cooled by using the dewar-filling system, but also operated by the refrigerator system. For the purpose of reducing the heat loads to the cold mass at 4 K from room temperature, thermal radiation shields cooled by liquid nitrogen flowing in tubing were employed. This paper presents the design details of cooling circuits and thermal shields of the TCM1 as well as related calculations and analyses.

43 PARTICLE ACCELERATORS↗