The dynamical state of the interstellar gas and field.
Dynamical requirements for existence of interstellar magnetic field in solar neighborhood
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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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The electrical conductivity and internal temperature of the moon.
Lunar dynamic response to discontinuities in interplanetary magnetic field to determine electrical conductivity and internal temperature
Ness, N. F.↗
The magnetic field structure in the active solar corona.
The structure of the magnetic field of the active solar corona is discussed with reference to optical and radio observations of the solar atmosphere. Eclipse observations provide evidence of fine scale structures in the solar atmosphere that appear to relate to the coronal magnetic field. The coronal magnetic field used for comparison is calculated from potential theory; the influence of solar activity upon the potential theory field is discussed with reference to observations of the Faraday rotation of a microwave signal from Pioneer 6 as it was occulted by the solar atmosphere. Evidence has been found suggesting the existence of expanding magnetic bottles located at 10 solar radii above flaring active regions. The dynamics of these events is discussed. It is further suggested that these magnetic bottles are an important component in the solar corona.
Schatten, K. H.↗
Dynamic properties of high-mobility garnet films in the presence of in-plane magnetic fields
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Shaw, R. W.↗
Fluxgate magnetometers for outer planets exploration
The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.
Acuna, M. H.↗
Transient and steady-state velocity of domain walls for a complete range of drive fields
Approximate analytic solutions for transient and steady-state 180 deg domain wall motion in bulk magnetic material are obtained from the dynamic torque equations with a Gilbert damping term. The results for the Walker region in which the transient solution approaches the familiar Walker steady-state solution are presented in a slightly new form for completeness. An analytic solution corresponding to larger drive fields predicts an oscillatory motion with an average value which decreases with drive field for reasonable values of the damping parameter. These results agree with those obtained by a computer solution of the torque equation and those obtained with the assumption of a very large anisotropy field.
Bourne, H. C., Jr.↗
Multi-mode optical sensor (B) evaluation test report
An evaluation test series was performed on the unit to develop realistic specifications for a similar device for use on the orbiter vehicle. Tests included sensitivity, target dynamic range, tracking angular rate, external magnetic field effects, and photocathode uniformity. Several demonstrations of operation under automatic control were also prepared, using a desk calculator for numerical control and for subsequent reduction of data derived from the test.
Smith, R. A.↗
Transient and steady-state velocity of domain walls for a complete range of drive fields
Approximate analytic solutions for transient and steady-state 180 deg domain-wall motion in bulk magnetic material are obtained from the dynamic torque equations with a Gilbert damping term. The results for the Walker region in which the transient solution approaches the familiar Walker steady-state solution are presented in a slightly new form for completeness. An analytic solution corresponding to larger drive fields predicts an oscillatory motion with an average value of the velocity which decreases with drive field for reasonable values of the damping parameter. These results agree with those obtained by others from a computer solution of the torque equation and those obtained by others with the assumption of a very large anisotropy field.
Bourne, H. C., Jr.↗
A Mars airplane
An airplane specifically designed for Mars flight is described, emphasizing its conceivable role as an aerial surveyor for visual imaging, gamma-ray and IR reflectance spectroscopy, studies of atmospheric composition and dynamics, and gravity-field, magnetic-field, and electromagnetic sounding. Possible imaging systems and surveying tasks are considered, along with a plausible mission scenario for a fleet of 12 airplanes, which would be taken to Mars in squadrons of four by three Shuttle/IUS Twin Stage/spacecraft carriers. A basic configuration closely resembling that of a competition glider is examined, and four types of airplane are discussed: hydrazine-powered cruisers and landers and electrically powered cruisers and landers. Attention is given to navigation, guidance, and control avionics, vehicle weight, the use of composite materials for the wing, and flight testing on earth.
Clarke, V. C.↗
On the physics of a long decay X-ray event
The paper discusses the long decay X-ray event which appeared as an expanding loop system on the solar limb on 13-14 Aug. 1973 which was also observed temporally and spectrally. A one-dimensional hydrodynamic study was undertaken to investigate increasing and decreasing phases of the event; it was shown that the inferred temperature gradients along the loops during the heating phase are consistent with unrestricted dynamic and conductive flows along the magnetic field lines. It was concluded that it cannot be definitely stated that enhanced emission at the tops of the loops is due to pressure gradients along the field lines; also, the large emission measure variations in the 10 to the 5th to 10 to the 6th K plasma during the event's decline may be due to the temperature dependence of radiative decay within a multiloop configuration.
Krall, K. R.↗
Coronal and chromospheric physics
Achievements and completed results are discussed for investigations covering solar activity during the solar maximum mission and the solar maximum year; other studies of solar activity and variability; infrared and submillimeter photometry; solar-related atomic physics; coronal and transition region studies; prominence research; chromospheric research in quiet and active regions; solar dynamics; eclipse studies; and polarimetry and magnetic field measurements. Contributions were also made in defining the photometric filterograph instrument for the solar optical telescope, designing the combined filter spectrograph, and in expressing the scientific aims and implementation of the solar corona diagnostic mission.
Jefferies, J. T.↗
Low-energy plasma ion observations in Saturn's magnetosphere
Attention is given to observational data gathered by Voyager plasma experiments in Saturn's magnetosphere which indicate that the number density and temperature of the plasma in the outer magnetosphere are very variable. The H(+) and either O(+) or N(+) ionic components resolved do not have the same thermal speeds or temperatures. There is some evidence for inward and outward radial flow, in addition to the azimuthal motion, in approximately one-third of the Voyager 1 cold ion spectra. The sources of the plasma are still undetermined. The plasma sheet becomes well established within 16 Saturn radii from the planet in the Voyager 1 data, and within 10 radii in the Voyager 2 data. In general, the plasma and magnetic field appear to be in dynamical equilibrium. In comparing the Saturn magnetosphere to that of Jupiter, much less acceleration of low energy plasma to high energies is found in Saturn.
Lazarus, A. J.↗
A unified theory of electrodynamic coupling in coronal magnetic loops - The coronal heating problem
The coronal heating problem is studied, and it is demonstrated that Ionson's (1982) LRC approach results in a unified theory of coronal heating which unveils a variety of new heating mechanisms and which links together previously proposed mechanisms. Ionson's LRC equation is rederived, focusing on various aspects that were not clarified in the original article and incorporating new processes that were neglected. A parameterized heating rate is obtained. It is shown that Alfvenic surface wave heating, stochastic magnetic pumping, resonant electrodynamic heating, and dynamical dissipation emerge as special cases of a much more general formalism. This generalized theory is applied to solar coronal loops and it is found that active region and large scale loops are underdamped systems. Young active region loops and (possibly) bright points are found to be overdamped systems.
Ionson, J. A.↗
Natural environment design criteria for the Advanced X-ray Astrophysics Facility (AXAF) definition and preliminary design
This document provides the natural environment design criteria requirements for use in the Advanced X-Ray Astrophysics Facility (AXAF) definition and preliminary design studies. The atmospheric dynamic and thermodynamic environments, meteoroids, radiation, magnetic fields, and physical constants are all addressed. This information will enable all groups involved in the definition and preliminary design studies to proceed with a common and consistent set of natural environment criteria requirements.
Greene, W. M.↗
Natural environment design criteria for the Space Station definition and preliminary design
The natural environment design criteria for the Space Station Program (SSP) definition and preliminary design are presented. Information on the atmospheric, dynamic and thermodynamic environments, meteoroids, radiation, magnetic fields, physical constants, etc. is provided with the intension of enabling all groups involved in the definition and preliminary design studies to proceed with a common and consistent set of natural environment criteria requirements. The space station program elements (SSPE) shall be designed with no operational sensitivity to natural environment conditions during assembly, checkout, stowage, launch, and orbital operations to the maximum degree practical.
Vaughan, W. W.↗
Ionospheric convection signatures observed by DE 2 during northward interplanetary magnetic field
Observations of the ionospheric convection signature at high latitudes are examined during periods of prolonged northward interplanetary magnetic field (IMF). The data from Dynamics Explorer 2 show that a four-cell convection pattern can frequently be observed in a region that is displaced to the sunward side of the dawn-dusk meridian regardless of season. In the eclipsed ionosphere, extremely structured or turbulent flow exists with no identifiable connection to a more coherent pattern that may simultaneously exist in the dayside region. The two highest-latitude convection cells that form part of the coherent dayside pattern show a dependence on the y component of the IMF. This dependence is such that a clockwise circulating cell displaced toward dawn dominates the high-latitude region when B(Y) is positive. Anti-clockwise circulation displaced toward dusk dominates the highest latitudes when B(Y) is negative. Examination of the simultaneously observed energetic particle environment suggests that both open and closed field lines may be associated with the high-latitude convection cells. On occasions these entire cells can exist on open field lines. The existence of closed field lines in regions of sunward flow is also apparent in the data.
Heelis, R. A.↗
Mars Observer: Phase 0 safety review data package
The Mars Observer Program has as its primary objectives a study of the geochemistry, atmospheric dynamics, atmosphere/surface interactions, seasonal variations, and magnetic field characteristics of Mars. The Mars Observer Spacecraft, safety critical spacecraft subsystems, ground support equipment, ground operations scenario, requirements matrix, and equipment specifications are described.
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Observed form and action of the magnetic energy release in flares
The observable spatio-temporal characteristics of the energy release in flares and their association with the magnetic environment and tracers of field dynamics are reviewed. The observations indicate that impulsive phase manifestations, like particle acceleration, may be related to the formation of neutral sheets at the interface between interacting bipoles, but that the site for the bulk of the energy release is within closed loops rather than at the interaction site.
Machado, Marcos E.↗