Active solar radio regions at metric frequencies and the interplanetary sector structures
Metric frequency solar radio noise active regions relationship to interplanetary magnetic field polarity distribution
Sakurai, K.↗
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Shear free, twisting Einstein-Maxwell metrics in the Newman-Penrose formalism
The problem of finding algebraically special solutions to the vacuum Einstein-Maxwell equations was investigated using a spin coefficient formalism. The general case in which the degenerate null vectors are not hypersurface orthogonal is reduced to a problem of solving five coupled differential equations that are no longer dependent on the affine parameter along the degenerate null directions. It is shown that the most general regular, shear-free, nonradiating solution to these equations is the Kerr-Newman metric.
Lind, R. W.↗
Recurrent active regions related to metric radio continuum emissions and the interplanetary magnetic sector structure
Active heliographic longitudes at the sun are investigated by using the observational data for long-lived metric continuum noise sources. It is shown that, for the period from 1963 to 1969, the number of such longitudes was four in general and these longitudes were very stable for this radio activity since 1963. A discussion is given on the relationship between those longitudes and the sector structure of the interplanetary magnetic field.
Sakurai, K.↗
Automatic problem formulation using the metric properties of space.
The use of metric tensors as inputs to computer programs designed to formulate engineering and scientific problems is considered as an alternative to the use of coordinate transformation equations.
Howard, J. C.↗
Theoretical frameworks for testing relativistic gravity. IV - A compendium of metric theories of gravity and their post-Newtonian limits.
Metric theories of gravity are compiled and classified according to the types of gravitational fields they contain, and the modes of interaction among those fields. The gravitation theories considered are classified as (1) general relativity, (2) scalar-tensor theories, (3) conformally flat theories, and (4) stratified theories with conformally flat space slices. The post-Newtonian limit of each theory is constructed and its Parametrized Post-Newtonian (PPN) values are obtained by comparing it with Will's version of the formalism. Results obtained here, when combined with experimental data and with recent work by Nordtvedt and Will and by Ni, show that, of all theories thus far examined by our group, the only currently viable ones are general relativity, the Bergmann-Wagoner scalar-tensor theory and its special cases (Nordtvedt; Brans-Dicke-Jordan), and a recent, new vector-tensor theory by Nordtvedt, Hellings, and Will.
Ni, W.-T.↗
Photogeology. Part A: Relative ages of some near-side and far-side terra plains based on Apollo 16 metric photography
Relative age measurements were made for 14 light plains areas, using 30X enlargements of Apollo 16 metric camera photography. Results indicate that: (1) Crater morphology and frequency studies consistently indicate that the Fra Mauro Formation has received 2.5 to 3 times as much impact flux as the Cayley Formation. (2) Crater counts and relative age dating indicate that the Cayley Formation is only slightly older than the oldest mare units. (3) Assuming the rubidium-strontium ages of Apollo 14 basalt breccias give minimum age for Fra Mauro Formation, the Cayley Formation must have been generated throughout a period of less than 100 million years, approximately 3.8 to 3.9 billion years ago. (4) The Cayley Formation ages obtained on the near side and far side are the same, indicating a synchrony throughout the moon in these units. (5) The linear relationship as predicted by the small impact erosion model between net accumulated flux and the maximum diameter of a crater that could be eroded below recognition is confirmed.
Soderblom, L. A.↗
Motion of metric type 4 radio sources and its relation to shock waves responsible for type 2 radio bursts
The relation of the motion of type 4mA sources with shock waves responsible for type 2 bursts were considered using the observed data for these two radio sources. The difference of the emission mechanism between type 2 and type 4mA bursts suggest that the moving speed of the shock waves mentioned above is not necessarily equal to the metric type 4 sources. By analyzing the observed data on the speeds for both type 2 and type 4 sources., it was found that type 4 bursts decelerate and often cease to move in the solar envelop and that type 2 sources move at higher speeds than type 4 sources.
Sakurai, K.↗
Relative ages of some near-side Mare units based on Apollo 17 metric photographs
Relative flux ages were determined for 110 areas on parts of Serenitatis, Vaporum, and Imbrium, using Apollo 17 metric photographs. The crater-morphology technique for determining relative ages is described. It is concluded that these maria formed over an interval of 1.5 billion years, extending from 3.7 to 2.2 billion years ago.
Boyce, J. M.↗
The chromospheric association of the metric type 3 bursts - implications concerning the acceleration of solar electrons and the active streamers
In two recent papers it was shown that the metric type 3 emission is closely related to a transient perturbation seen in absorption in the H alpha line. In addition, this perturbation sometimes triggers a flare, sometimes not. This can explain why the type 3 have a poor H alpha flare correlation rate and still are a typical flash phase emission when flare-associated. The characteristics are summarized of the new association proposed. It is assumed that 10 to 100 keV electrons are accelerated in connection with a particular kind of transient H alpha absorbing feature. For as yet undetermined reasons, this process would often, but not always, result in a more efficient acceleration coincident with the early phase of the optical flare. The possibilities that this process could lead occasionally to long lasting subrelativistic particle emissive region are explored.
Axisa, F.↗
Vector potential and metric perturbations of a rotating black hole
The assumption of factorized Green's functions together with the inhomogeneous Teukolsky equations are used to derive analytic expressions for homogeneous metric (and vector potential) perturbations of a Kerr black hole. These homogeneous solutions are used to construct solutions to the perturbation equations when sources are present. What one finds are particularly simple formulas for the energy and angular momentum flux in the asymptotic regions at plus or minus infinity.-
Chrzanowski, P. L.↗
An improved radiation metric
An improved radiation metric is obtained in which light rays make a small nonzero angle with the radius, thus representing a source of finite size. Kaufmann's previous solution is criticized. The stabilization of a scatterer near a source of gravitational field and radiation is slightly enhanced for sources of finite size.
Noerdlinger, P. D.↗
Gravitational radiation from binary systems in alternative metric theories of gravity - Dipole radiation and the binary pulsar
The generation of gravitational radiation in several currently viable metric theories of gravitation (Brans-Dicke, Rosen, Ni, and Lightman-Lee) is analyzed, and it is shown that these theories predict the emission of dipole gravitational radiation from systems containing gravitationally bound objects. In the binary system PSR 1913 + 16, this radiation results in a secular change in the orbital period of the system with a nominal magnitude of 3 parts in 100,000 per year. The size of the effect is proportional to the reduced mass of the system, to the square of the difference in (self-gravitational energy)/(mass) between the two components of the system, and to a parameter, xi, whose value varies from theory to theory. In general relativity xi equals 0, in Rosen's (1973) theory xi equals -20/3, and in Ni's (1973) theory xi equals -400/3. The current upper limit on such a secular period change is one part in 1 million per year. It is shown that further observations of the binary system that tighten this limit and that establish the masses of the components and the identity of the companion may provide a crucial test of otherwise viable alternatives to general relativity.
Will, C. M.↗
Development of a metric half-span model for interference free testing
A metric half-span model has been developed which allows measurement of aerodynamic forces and moments without support interference or model distortion. This is accomplished by combining the best features of the conventional sting/balance and half-span splitter plate supports, For example, forces and moments are measured on one-half of a symmetrical model which is mechanically supported by a sting on the nonmetric half. Tests were performed in the Langley Unitary Plan wind tunnel over a Mach range of 1.60 to 2.70 and an angle-of-attack range of 04 deg to 20 deg. Preliminary results on concept evaluation, and effect of fuselage modification to house a conventional balance and sting are presented.
Corlett, W. A.↗
Grid and metric generation on the assembly of locally bi-quadratic coordinate transformations
The generation of metric coefficients of the coordinate transformation from a generally curved-sided domain boundary to the unit square (cube) is required for efficient solution algorithms in computational fluid mechanics. An algebraic procedure is presented for establishment of these data on the union of arbitrarily selected sub-domains of the global solution domain. A uniformly smooth progression of grid refinement is readily generated, including multiple specification of refined grids for a given macro-element domain discretization. The procedure is illustrated as generally applicable to non-simply connected domains in two and three dimensions.
Baker, A. J.↗
A comparison of Type III metric radio bursts and global solar potential field models
Evidence of coronal magnetic fields from polarized metric type III radio bursts is compared with (1) global potential field models, (2) direct averages of the observed photospheric magnetic field, and (3) H-alpha synoptic charts. The comparison clearly indicates both that the principal aspects of type III burst radiation are understood and that global potential field models are a significantly more accurate representation of coronal magnetic field structure than either the large-scale photospheric field or H-alpha synoptic charts.
Jackson, B. V.↗
Metric camera experiment
A test of the mapping capabilities of high resolution space photography taken at the resolution limit of image motion on large film format is planned. The metric camera system and its planned operation are described.
Reynolds, M.↗
Current status of metric reduction of (passive) scanner data
The extraction of metric information from scanner (particularly multispectral) data is presented. Data from both aircraft and spacecraft; singly scanned areas and areas with multiple coverage; various mathematical models used up to the present time; and published numerical results are considered. Future trends are also discussed.
Mikhail, E. M.↗
Tests of general relativity using Starprobe radio metric tracking data
The potential of a proposed spacecraft mission, called Starprobe, for testing general relativity and providing information on the interior structure and dynamics of the sun is investigated. Parametric, gravitational perturbation terms are derived which represent relativistic effects and effects due to spatial and temporal variations in the solar potential at a given radial distance. A covariance analysis based on Kalman filtering theory predicts the accuracies with which the free parameters in the perturbation terms can be estimated with radio metric tracking data through the process of trajectory reconstruction. It is concluded that Starprobe can contribute significant information on both the nature of gravitation and the structure and dynamics of the solar interior.
Mease, K. D.↗