IMF control of the Earth's magnetosphere

We review recent progress in the understanding of the IMF control on the Earth's magnetosphere through the reconnection process. Major points include, (1) the identification of the magnetopause structure under the southward IMF polarity to be the rotational discontinuity and the resulting inference that the reconnection line is formed in the equatorial region, and (2) the confirmation from several observational aspects that under the northward IMF the reconnection takes place in the polar cusp. The point (1) is consistent with the observed correlations of geomagnetic indices with IMF but raises an important theoretical issue, and the point (2) is accompanied by an interesting issue of explaining why the polar cap electron precipitation is more energetic under such IMF conditions. Critical studies have reaffirmed the view that the energy supplied by reconnection is partly transported directly to the ionosphere to drive the DP-2 type current system but at the same time it is partly stored in the magnetic field of the tail to be unloaded 0.5 1 hr later to produce the expansion phase of substorm.Presented at the Fifth International Symposium on Solar-Terrestrial Physics, held at Ottawa, Canada, May 1982.     

Stable mid-latitude red arcs: Observations and theory

Summary The observational features of the arc are fairly well established. At present, the thermal conduction model appears to explain the red arc features most consistently, but it must be noted that a soft electron flux would give very similar results. Ion temperature measurements in the vicinity of an arc, which should be forthcoming in the very near future, can establish conclusively whether transverse electric fields play any important role in the formation of the arcs. Accepting the assumption that the arcs are the result of energy flowing down from the plasmasphere, the major remaining question is: where does the energy come from and how does it get into the plasmasphere? The various proposed mechanisms discussed in the previous chapter appear feasible, but much work needs to be done before this problem is completely resolved.On leave from the Department of Electrical Engineering, The University of Michigan, Ann Arbor.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

High-Speed Homopolar Inductor Alternators of Minimum Leakage Reactance

The leakage reactance of the machine is expressed as an equation involving slot leakage, end-connection leakage, differential leakage, stator-halves leakage, and tooth-top leakage reactance. This leakage reactance equation, or objective function, is then minimized under suitable constraints. Geometric programming is used to carry through the optimization procedure. A computer program is developed and applied to find the optimum leakage reactance for a 95 kVA, 208 V, wye-connected, 40 800 r/min aerospace alternator, using 8-, 10-, and 12-pole machines.     

One-kVA, Three-Phase dc-ac Inverter with Digital Control

This paper describes a method of applying digital techniques to the control of a 1-kVA three-phase dc-ac inverter to generate a sinusoidal 400-Hz output, using high-frequency bridge-chopper techniques. The model which was constructed used predominantly off-theshelf digital microcircuits and resulted in a device with an overall efficiency of 85 percent, in a 0.52 cubic-foot package which weighed 19.5 lbs. Sinusoidal output with less than 2 percent harmonic distortion at 115 volts line to neutral was obtained with 28 volts dc input.     

Aerodynamic Design Method of Integrated Aircraft with Submerged Intake Devices and Power Plant Included into Airframe Carrying System

This paper presents a theoretically and practically grounded architecture of design methods combination. A possibility and completeness of developing integral design solutions and intensifying the design process are provided by redistribution of emphases of numerical and natural experiments.     

Recursive temporal-spatial information fusion with applications totarget identification

Centralized/distributed recursive algorithms for temporal-spatial information integration using the Dempster-Shafer technique are developed. Compared with the Bayesian approach, the Dempster-Shafer technique has the strong capability of handling information uncertainties, which are particularly desirable in many applications. In the centralized integration algorithm, all information is pooled into the central processor and integrated. In contrast, the distributed integration algorithm shares the computational burden among the local processors, which increases the computational efficiency. The developed algorithms are effectively applied to a target identification problem with three sensors: identification of friend-foe-neutral (IFFN), electronic support measurement (ESM), and infrared search and track (IRST)     

Chaotic zero dynamics in kinematically redundant robots

The authors attempt to integrate two areas in robotics that are maturing rapidly: the control of kinematically redundant rigid robots and feedback linearization. Kinematically redundant robots have several advantages over nonredundant robot arms. The extra degrees of freedom are used to reach around or between obstacles. Unlike nonredundant rigid link robots that do not exhibit zero dynamics, the self motions of kinematically redundant robots can be used for torque optimization or avoiding obstacles. It is shown that induced self motions can be chaotic. The main contribution is to demonstrate chaos in cases of feedback linearization when the decoupling matrix is nonsquare and there are less outputs than inputs     

The astrophysical interest of EUV observations of extra-solar objects

The feasibility of observation of EUV sources is assessed. Many stars have been detected in the EUV range ( 100–1000); line fluxes from others can be predicted. Selected astrophysical problems are reviewed that can benefit from EUV spectroscopy. Included among them are the physics and dynamics of stellar coronae, confirmation of nuclear surface burning on cataclysmic variables, evolutionary properties of white dwarfs, the helium abundance in the interstellar medium, and spectroscopic signatures of neutrino oscillations.Proceedings of the Conference Solar Physics from Space, held at the Swiss Federal Institute of Technology Zurich (ETHZ), 11–14 November 1980.     

Optical observations of the X-ray source 2S0921-630

We report photometric observations of the optical counterpart of the X-ray source 2S0921-630. The data, obtained at the South African Astronomical Observatory during 3 weeks in 1980 and 1981, are consistent with a 17.9 day periodic modulation of the flux in the B band. Correlated variability of the (B-V) and (U-B) colour indices with the B mag. is demonstrated and quantified. The observed B mag. and colours at maximum and minimum light are used to compute some of the system parameters. A model of 2S0921-630 is proposed in terms of a binary system in which the variable inclination of a luminous accretion disc produces the long-term modulation of the optical flux.     

Maximum Likelihood Elevation Angle Estimates of Radar Targets Using Subapertures

The maximum likelihood estimates of the elevation angles of two closely spaced targets within the beamwidth is considered. For an array divided into three subapertures, a simple, closed form solution is found whose accuracy compares favorably to the maximum likelihood estimate which uses all the individual elements. Simulation results are presented for the case of a radar target located over a smooth reflecting surface.