Recent international developments in controlled thermonuclear fusion.
Controlled thermonuclear fusion technology including production, heating and containment of extreme temperature plasmas
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Controlled thermonuclear fusion technology including production, heating and containment of extreme temperature plasmas
Optical heterodyne system used to measure electron density of plasma
Time and space development equations for longitudinal and transverse modes in Vlasov plasma
Plasma rotation in MPD arc measured for electric and magnetic field distribution and current and electron density distribution
Anode heat transfer in MPD arc, discussing configurations and thrustors
Distributions of current, potential, electron density and pressure and ion velocity vector orientation in MPD arc, verifying electromagnetic effects presence
Spacecraft-space plasma electric equilibrium, discussing active spacecraft configurations for control
Density, electric field and volt-ampere characteristics for spherical electrostatic Langmuir probe in collision plasma with weak ionization and recombination, using asymptotic method
Steady flow ammonia MPD arc jet thrustor propulsion performance, discussing test chamber pressure variation, thrust data and cooling systems
The seventh Orbiting Solar Observatory (OSO-7) in the continuing series designed to gather solar and celestial data that cannot be obtained from the earth's surface is described. OSO-7 was launched September 29, 1971. It has been highly successful in returning scientific data giving new and important information about solar flare development, coronal temperature variations, streamer dynamics of plasma flow, and solar nuclear processes. OSO-7 is expected to have sufficient lifetime to permit data comparisons with the Skylab A mission during 1973. The OSO-7 is a second generation observatory. It is about twice as large and heavy as its predecessors, giving it considerably greater capability for scientific measurements. This report reviews mission objectives, flight history, and scientific experiments; describes the observatory; briefly compares OSO-7 with the first six OSO's; and summarizes the performance of OSO-7.
Three silicide coated columbium alloys and two cobalt alloys were subjected to identical simulated reentry profiling exposures in both static (controlled vacuum leak) and dynamic (hypersonic plasma shear) environments. Primary emphasis in the columbium alloy evaluation was on the Cb752 and C129Y alloys with a lesser amount on FS85. Commercial silicide coatings of the R512E and VH109 formulations were used. The coated specimens were intentionally defected to provide the types of coating flaws that are expected in service. Temperatures were profiled up to peak temperatures of either 2350 F or 2500 F for 15 minutes in each cycle.
Isis 2 observations of a variety of topside ionospheric 'signatures' of the plasmapause are compared with simultaneously acquired equatorial electron-density profiles obtained by the whistler technique. The satellite data were acquired at about 1400-km altitude at dusk and dawn in the sunlit Northern Hemisphere summer ionosphere within about 15 deg longitude of the VLF receiver. Results suggest that the dynamics of plasma coupling between the ionosphere and plasmasphere dominate the topside data and obscure the location of the equatorial plasmapause field line. The total density and light-ion troughs begin 2 to 10 deg equatorward of the field line through the equatorial plasmapause and are not clear plasmapause signatures. The invariant latitude of the region of steep spatial gradient in thermal plasma density, the plasmapause, appears to increase with altitude. Thus measurements of its position at different altitudes may give different results. Plasma-sheet electrons, however, are observed on field lines just outside the equatorial plasmapause at both dawn and dusk. Their low-latitude extent at 1400-km altitude can be used as a signature of the equatorial plasmapause position.
Scientific and technical progress made in the utilization of electron beams injected from large sounding rockets for the investigation of magnetospheric structure and dynamics and plasma physics is reviewed. Consideration is given to the problem of vehicle neutralization during the generation of electron beams in the ionosphere and the stability and electromagnetic wave emissions of electron beams propagating in space. Optical effects observed during the two Hess artificial aurora experiments, the Minnesota Echo IV and V experiments, the Zarnitsa-1 artificial aurora experiment and the Precede-Excede experiments are discussed, together with atmospheric scattering effects observed during Echo I, II and III, and results of the three experimental programs which have detected and analyzed beams after passage through the distant magnetosphere (the second Hess experiment, ARAKS and the Electron Echo experiments) are presented. Finally, plans for future research are outlined, and a chronology and complete bibliography of the programs conducted to date are included.
Initial measurements of thermal ions (0 to 50 eV) at mid-latitudes by the Retarding Ion Mass Spectrometer (RIMS) on DE-1 are presented. These measurements show the plasmapause signature in H(+), He(+), and m/q = 2 ions, an enhancement or torus of O(+) and O(++) in the outer plasmasphere and the suggestion of a disconnection between the ionosphere and the bulge region of the plasmasphere.
Recent work on the observation and theory of solar and stellar magnetic field activity and its relation to stellar activity is reviewed, emphasizing those aspects relevant to the problem of activity of red dwarf stars. New observational facts relevant to understanding the root cause of stellar surface activity are summarized and theoretical questions concerning the underlying physical basis for the observed correlations between stellar activity, rotation, and magnetic fields are addressed. These include dyanamo theory and the rotation-activity connection as well as flux tube dynamics and plasma heating.
A plan to develop a space technology experiments platform (STEP) was examined. NASA Langley Research Center held a STEP Experiment Requirements Workshop on June 29 and 30 and July 1, 1983, at which experiment proposers were invited to present more detailed information on their experiment concept and requirements. A feasibility and preliminary definition study was conducted and the preliminary definition of STEP capabilities and experiment concepts and expected requirements for support services are presented. The preliminary definition of STEP capabilities based on detailed review of potential experiment requirements is investigated. Topics discussed include: Shuttle on-orbit dynamics; effects of the space environment on damping materials; erectable beam experiment; technology for development of very large solar array deployers; thermal energy management process experiment; photovoltaic concentrater pointing dynamics and plasma interactions; vibration isolation technology; flight tests of a synthetic aperture radar antenna with use of STEP.
Initial observations from the energetic ion composition spectrometer on the DE-1 spacecraft have found mass or charge dependent processes to be operating in the vicinity of an inverted-V event in the auroral acceleration region, above the polar cap ionosphere, and in the mid-altitude dayside cusp. Separate color spectrograms for the different ion species provide a synoptic picture of these processes that can contribute significantly to our understanding of both the solar wind and the ionosphere as sources of energetic magnetospheric ions.
An analytical model is defined to demonstrate that parallel acceleration of an O(+) ion beam in the ionosphere can occur naturally due to the presence of a quasi-static parallel electric field. Momentum equations are defined for friction between hydrogen ions and electrons, which produces a quasi-static electric field. The field can accelerate ions, e.g., the O(+) ions, which do not participate in the frictional momentum exchange. The conditions are shown to be applicable to the auroral field line plasma if a current is present along the magnetic field. A simulation performed with the equations shows that the field line plasma exhibits dynamic behavior after a field-aligned current appears. The resulting momentum gain by O(+) ions can be sufficient for causing a potential drop of several kilovolts along the field line.